Pub Date : 2024-11-19DOI: 10.1016/j.envexpbot.2024.106046
Haizhen Zhang , Shuhan Ye , Nan Wang, Ziping Xu, Shufang Gong
As one of the largest families of transcription factors in plants, the basic helix-loop-helix (bHLH) transcription factor family regulates a wide range of functions in plants. However, little is known about the functions of bHLH family members in Populus trichocarpa during plant growth and in the response to drought stress. In our study, 190 PtbHLH genes were identified in the P. trichocarpa genome and classified into 21 groups. Analyses of microarray datasets showed that most PtbHLH members not only have multiple functions in poplar growth, but also respond rapidly to drought stress in the leaves or roots. We selected four genes, PtbHLH35, PtbHLH121, PtbHLH137, and PtbHLH152, which were highly expressed in leaves or roots under drought stress, for functional validation analyses. These genes encoded nucleus-localized bHLH transcription factors. Transient expression of PtbHLH35, PtbHLH121, and PtbHLH152 in P. trichocarpa improved drought tolerance by activating the antioxidant system to eliminate reactive oxygen species and reduce the degree of cell damage in the leaves under drought stress. Overexpression of PtbHLH137 improved drought tolerance by activating antioxidant enzymes in the roots to eliminate reactive oxygen species, and by increasing the abscisic acid content in the roots in response to drought stress. Together, our findings provide insights into the functions of PtbHLH family members in growth and in the response to drought.
{"title":"Analyses of the bHLH gene family in Populus trichocarpa reveal roles of four PtbHLHs in regulating the drought stress response","authors":"Haizhen Zhang , Shuhan Ye , Nan Wang, Ziping Xu, Shufang Gong","doi":"10.1016/j.envexpbot.2024.106046","DOIUrl":"10.1016/j.envexpbot.2024.106046","url":null,"abstract":"<div><div>As one of the largest families of transcription factors in plants, the basic helix-loop-helix (bHLH) transcription factor family regulates a wide range of functions in plants. However, little is known about the functions of bHLH family members in <em>Populus trichocarpa</em> during plant growth and in the response to drought stress. In our study, 190 <em>PtbHLH</em> genes were identified in the <em>P. trichocarpa</em> genome and classified into 21 groups. Analyses of microarray datasets showed that most <em>PtbHLH</em> members not only have multiple functions in poplar growth, but also respond rapidly to drought stress in the leaves or roots. We selected four genes, <em>PtbHLH35</em>, <em>PtbHLH121</em>, <em>PtbHLH137,</em> and <em>PtbHLH152,</em> which were highly expressed in leaves or roots under drought stress, for functional validation analyses. These genes encoded nucleus-localized bHLH transcription factors. Transient expression of <em>PtbHLH35</em>, <em>PtbHLH121,</em> and <em>PtbHLH152</em> in <em>P. trichocarpa</em> improved drought tolerance by activating the antioxidant system to eliminate reactive oxygen species and reduce the degree of cell damage in the leaves under drought stress. Overexpression of <em>PtbHLH137</em> improved drought tolerance by activating antioxidant enzymes in the roots to eliminate reactive oxygen species, and by increasing the abscisic acid content in the roots in response to drought stress. Together, our findings provide insights into the functions of <em>PtbHLH</em> family members in growth and in the response to drought.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"228 ","pages":"Article 106046"},"PeriodicalIF":4.5,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-17DOI: 10.1016/j.envexpbot.2024.106033
Varisha Khan , Noushina Iqbal , Shahid Umar , Sayeed Ahmad
Salt stress is a major constraint on agricultural productivity, particularly affecting crop growth and yield. This study aims to evaluate salt resilience in mustard (Brassica juncea) by investigating variations in growth, yield, and physiological tolerance indicators among selected cultivars. Advanced analytical techniques, including Near-Infrared Spectroscopy (NIRS) and Gas Chromatography-Mass Spectrometry (GC-MS) profiling, were employed to decipher the mechanisms underlying salt tolerance. NIRS was utilized for its rapid, non-destructive analysis of biochemical variations among the cultivars, while GC-MS profiling provided a detailed understanding of the metabolomic changes induced by salt stress. This integrated approach enabled the identification of crucial metabolites and biomarkers associated with salt tolerance and yield enhancement. The results indicated significant cultivar-specific differences in metabolic profiles which correlated with growth and yield (pod number, pod length,pod biomass, seed number and seed weight) under salt stress. The most resilient cultivar demonstrated increased accumulation of osmoprotectants, antioxidants, and other stress-related metabolites. These findings underscore the importance of specific traits and metabolites in conferring salt tolerance.
This comprehensive study offers valuable insights for breeding programs aimed at developing salt-tolerant mustard cultivars, thereby contributing to sustainable agriculture in saline environments.
{"title":"Assessing salt resilience in mustard: Growth, yield, tolerance indicators, and metabolite profiling to decipher the mechanism of salt tolerance in selected cultivars","authors":"Varisha Khan , Noushina Iqbal , Shahid Umar , Sayeed Ahmad","doi":"10.1016/j.envexpbot.2024.106033","DOIUrl":"10.1016/j.envexpbot.2024.106033","url":null,"abstract":"<div><div>Salt stress is a major constraint on agricultural productivity, particularly affecting crop growth and yield. This study aims to evaluate salt resilience in mustard (<em>Brassica juncea</em>) by investigating variations in growth, yield, and physiological tolerance indicators among selected cultivars. Advanced analytical techniques, including Near-Infrared Spectroscopy (NIRS) and Gas Chromatography-Mass Spectrometry (GC-MS) profiling, were employed to decipher the mechanisms underlying salt tolerance. NIRS was utilized for its rapid, non-destructive analysis of biochemical variations among the cultivars, while GC-MS profiling provided a detailed understanding of the metabolomic changes induced by salt stress. This integrated approach enabled the identification of crucial metabolites and biomarkers associated with salt tolerance and yield enhancement. The results indicated significant cultivar-specific differences in metabolic profiles which correlated with growth and yield (pod number, pod length,pod biomass, seed number and seed weight) under salt stress. The most resilient cultivar demonstrated increased accumulation of osmoprotectants, antioxidants, and other stress-related metabolites. These findings underscore the importance of specific traits and metabolites in conferring salt tolerance.</div><div>This comprehensive study offers valuable insights for breeding programs aimed at developing salt-tolerant mustard cultivars, thereby contributing to sustainable agriculture in saline environments.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"228 ","pages":"Article 106033"},"PeriodicalIF":4.5,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-17DOI: 10.1016/j.envexpbot.2024.106038
Ádám Horváth , Zita Berki , Krisztina Balla , Judit Bányai , Marianna Mayer , András Cseh , Tibor Kiss , Ildikó Karsai
The complexity of heat stress hinders both the exploration of the genetic basis of stress response and breeding of genotypes with increased stress tolerance. Our main goal was to analyze and compare the possibilities of evaluating heat stress responses of barley cultivars in field sowing and controlled environmental experiments. For this purpose, a four-year field-sown experiment was carried out at one location in a panel of 190 winter and facultative barleys. In parallel, a subset of 28 cultivars were included into controlled environmental tests, where their reactions were determined to single heat stress treatment applied at heading and to combined heat stresses applied at first node appearance and then at heading. Based on the grain-yield related parameters, seven distinct clusters of the cultivars could be established with specific reaction patterns across the years. There was one year with close to optimal weather conditions and one year, when heat stress occurred during flowering and grain setting, making it possible to evaluate the heat stress responses of the 190 barley genotypes. In the heat stress prone 2022 year, the general trends were a strong reduction in the reproductive tiller number and a slight reduction in the fertility. In several groups, these negative effects were compensated with significant increases in grain number per ears and with strong increases in the average grain weight. Under controlled conditions, heat stress significantly reduced most of the grain-yield related traits. Among the more tolerant genotypes, two basic response types could be distinguished. One group was able to better preserve the grain number and weight in the main ear under heat stress, while the other was more able to allocate resources into the side tillers during the recovery period. In the combined heat stress, the average trait values were similar to those in the single stress or even lower, and there was no general priming effect clearly detectable. In the case of the 28 genotypes, there were significant correlations between the stress-induced changes in grain-yield related traits measured under field and under controlled conditions, underlining the possibility of combining the information originating from the two different environments.
{"title":"Field versus controlled environmental experiments to evaluate the heat stress response of barley (Hordeum vulgare L.)","authors":"Ádám Horváth , Zita Berki , Krisztina Balla , Judit Bányai , Marianna Mayer , András Cseh , Tibor Kiss , Ildikó Karsai","doi":"10.1016/j.envexpbot.2024.106038","DOIUrl":"10.1016/j.envexpbot.2024.106038","url":null,"abstract":"<div><div>The complexity of heat stress hinders both the exploration of the genetic basis of stress response and breeding of genotypes with increased stress tolerance. Our main goal was to analyze and compare the possibilities of evaluating heat stress responses of barley cultivars in field sowing and controlled environmental experiments. For this purpose, a four-year field-sown experiment was carried out at one location in a panel of 190 winter and facultative barleys. In parallel, a subset of 28 cultivars were included into controlled environmental tests, where their reactions were determined to single heat stress treatment applied at heading and to combined heat stresses applied at first node appearance and then at heading. Based on the grain-yield related parameters, seven distinct clusters of the cultivars could be established with specific reaction patterns across the years. There was one year with close to optimal weather conditions and one year, when heat stress occurred during flowering and grain setting, making it possible to evaluate the heat stress responses of the 190 barley genotypes. In the heat stress prone 2022 year, the general trends were a strong reduction in the reproductive tiller number and a slight reduction in the fertility. In several groups, these negative effects were compensated with significant increases in grain number per ears and with strong increases in the average grain weight. Under controlled conditions, heat stress significantly reduced most of the grain-yield related traits. Among the more tolerant genotypes, two basic response types could be distinguished. One group was able to better preserve the grain number and weight in the main ear under heat stress, while the other was more able to allocate resources into the side tillers during the recovery period. In the combined heat stress, the average trait values were similar to those in the single stress or even lower, and there was no general priming effect clearly detectable. In the case of the 28 genotypes, there were significant correlations between the stress-induced changes in grain-yield related traits measured under field and under controlled conditions, underlining the possibility of combining the information originating from the two different environments.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"228 ","pages":"Article 106038"},"PeriodicalIF":4.5,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-17DOI: 10.1016/j.envexpbot.2024.106043
Jianshun Liang , Xiashun Liu , Lei Xu , Rongbo Mu , Nengshuang Shen , ShanShan Li , Cong Cheng , Yanping Ren , Li Ma , Bo Wang , Zhengpei Yao , Hua Zhang
Maintaining the growth of reproductive branches during the summer is crucial for the seed setting of the perennial xerophytic plant H. ammodendron (Haloxylon ammodendron). In this study, we screened and cloned the NAC transcription factor HaNAC12 from the transcriptomes of different tissue of the desert plant H. ammodendron and from the transcriptome of seedlings under drought stress. Real-time quantitative fluorescence analysis showed that the expression level of HaNAC12 in reproductive branches was higher than that in vegetative branches. It was able to respond to treatments of drought, high salinity and low-temperature stress, as well as to the external induction of plant hormones such as IAA, ABA, SA and MeJA. The GFP- HaNAC12 fusion protein localized to the nucleus of tobacco epidermal cells. Heterologous expression of HaNAC12 revealed that the transgenic Arabidopsis exhibited enhanced drought resistance and showed early flowering after natural drought stress, promoting reproductive growth. Transcriptomic analysis indicated that fatty acid metabolic pathways were upregulated in transgenic Arabidopsis thaliana. DNA affinity purification analysis showed that HANAC12 binds to elements in the downstream target genes primarily associated with the linoleic acid metabolic pathway. The total fatty acid content in the reproductive branches of transgenic Arabidopsis and H. ammodendron is greater than that in the wild-type Arabidopsis and the vegetative branches of H. ammodendron. Under drought stress, plants can adapt to arid conditions by increasing the proportion of unsaturated fatty acids, thereby enhancing membrane fluidity, reducing membrane damage, and maintaining the requirements for cell division and growth. Therefore, HaNAC12 may improve the drought resistance of Arabidopsis and promote reproductive growth under drought stress by regulating fatty acid metabolism.
{"title":"A novel NAC transcription factor from Haloxylon ammodendron promotes reproductive growth in Arabidopsis thaliana under drought stress","authors":"Jianshun Liang , Xiashun Liu , Lei Xu , Rongbo Mu , Nengshuang Shen , ShanShan Li , Cong Cheng , Yanping Ren , Li Ma , Bo Wang , Zhengpei Yao , Hua Zhang","doi":"10.1016/j.envexpbot.2024.106043","DOIUrl":"10.1016/j.envexpbot.2024.106043","url":null,"abstract":"<div><div>Maintaining the growth of reproductive branches during the summer is crucial for the seed setting of the perennial xerophytic plant <em>H. ammodendron</em> (<em>Haloxylon ammodendron</em>). In this study, we screened and cloned the NAC transcription factor <em>HaNAC12</em> from the transcriptomes of different tissue of the desert plant <em>H. ammodendron</em> and from the transcriptome of seedlings under drought stress. Real-time quantitative fluorescence analysis showed that the expression level of <em>HaNAC12</em> in reproductive branches was higher than that in vegetative branches. It was able to respond to treatments of drought, high salinity and low-temperature stress, as well as to the external induction of plant hormones such as IAA, ABA, SA and MeJA. The GFP- <em>HaNAC12</em> fusion protein localized to the nucleus of tobacco epidermal cells. Heterologous expression of <em>HaNAC12</em> revealed that the transgenic <em>Arabidopsis</em> exhibited enhanced drought resistance and showed early flowering after natural drought stress, promoting reproductive growth. Transcriptomic analysis indicated that fatty acid metabolic pathways were upregulated in transgenic <em>Arabidopsis thaliana</em>. DNA affinity purification analysis showed that HANAC12 binds to elements in the downstream target genes primarily associated with the linoleic acid metabolic pathway. The total fatty acid content in the reproductive branches of transgenic <em>Arabidopsis</em> and <em>H. ammodendron</em> is greater than that in the wild-type <em>Arabidopsis</em> and the vegetative branches of <em>H. ammodendron</em>. Under drought stress, plants can adapt to arid conditions by increasing the proportion of unsaturated fatty acids, thereby enhancing membrane fluidity, reducing membrane damage, and maintaining the requirements for cell division and growth. Therefore, <em>HaNAC12</em> may improve the drought resistance of <em>Arabidopsis</em> and promote reproductive growth under drought stress by regulating fatty acid metabolism.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"228 ","pages":"Article 106043"},"PeriodicalIF":4.5,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-14DOI: 10.1016/j.envexpbot.2024.106042
Jianming Wei , Yunzhou Li , Ping Tan , Dalong Zhang , Yan Liang
Tomato (Solanum lycopersicum) cultivation in the off-season is significantly hindered by cold stress; hence, utilising stress-resistant rootstocks in grafting is a critical solution. This study used 30 semi-wild tomato GZ-05 plants as rootstocks and Ailsa Craig (AC) tomatoes as scions. After cold stress, the scion tolerance index, leaf ion permeability, and other physiological and biological indicators were used to determine the most tolerant plants. To understand the molecular basis of GZ-05 rootstock cold stress resistance, RNA sequencing and reverse transcription polymerase chain reaction techniques were used to compare the varying genes expressed in the grafted AC/GZ-05 and self-grafted AC/AC plant scion leaves. The results indicated that genes associated with melatonin (MT) and jasmonic acid (JA) production and their signalling pathways were considerably altered. The initial MT and JA levels in the GZ-05-grafted plant scions were high, and when they were exposed to cold stress, the amount of active MT and JA in AC/GZ-05 heterologous grafts were great. Using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9, we knocked out the MT synthesis gene (SlCOMT14) and JA synthesis gene (SlLoxD) and found that GZ-05 plant cold stress tolerance decreased. External tests were conducted to evaluate the GZ-05 SlCOMT14 and SlLoxD knockout lines. Source spraying with MT and methyl jasmonate showed that knockout strain cold stress tolerance could be recovered. SlICE1, a tomato cold stress tolerance transcription factor, was silenced, resulting in decreased tolerance to MT- and JA-induced cold stress. The MT/JA-inducer of C-repeat binding factor (CBF) expression 1-CBF pathway may be the mechanism by which the semi-wild tomato GZ-05 rootstock confers cold tolerance to plants. This study has uncovered the molecular mechanism by which grafting semi-wild tomato GZ-05 rootstocks increases plant cold tolerance, thereby laying the groundwork for the utilisation of Guizhou's native semi-wild tomato germplasm resources.
{"title":"Grafting semi-wild tomato GZ-05 rootstocks improved cold tolerance via the signalling of melatonin and jasmonic acid","authors":"Jianming Wei , Yunzhou Li , Ping Tan , Dalong Zhang , Yan Liang","doi":"10.1016/j.envexpbot.2024.106042","DOIUrl":"10.1016/j.envexpbot.2024.106042","url":null,"abstract":"<div><div>Tomato (<em>Solanum lycopersicum</em>) cultivation in the off-season is significantly hindered by cold stress; hence, utilising stress-resistant rootstocks in grafting is a critical solution. This study used 30 semi-wild tomato GZ-05 plants as rootstocks and Ailsa Craig (AC) tomatoes as scions. After cold stress, the scion tolerance index, leaf ion permeability, and other physiological and biological indicators were used to determine the most tolerant plants. To understand the molecular basis of GZ-05 rootstock cold stress resistance, RNA sequencing and reverse transcription polymerase chain reaction techniques were used to compare the varying genes expressed in the grafted AC/GZ-05 and self-grafted AC/AC plant scion leaves. The results indicated that genes associated with melatonin (MT) and jasmonic acid (JA) production and their signalling pathways were considerably altered. The initial MT and JA levels in the GZ-05-grafted plant scions were high, and when they were exposed to cold stress, the amount of active MT and JA in AC/GZ-05 heterologous grafts were great. Using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9, we knocked out the MT synthesis gene (<em>SlCOMT14</em>) and JA synthesis gene (<em>SlLoxD</em>) and found that GZ-05 plant cold stress tolerance decreased. External tests were conducted to evaluate the GZ-05 <em>SlCOMT14</em> and <em>SlLoxD</em> knockout lines. Source spraying with MT and methyl jasmonate showed that knockout strain cold stress tolerance could be recovered. SlICE1, a tomato cold stress tolerance transcription factor, was silenced, resulting in decreased tolerance to MT- and JA-induced cold stress. The MT/JA-inducer of C-repeat binding factor (CBF) expression 1-CBF pathway may be the mechanism by which the semi-wild tomato GZ-05 rootstock confers cold tolerance to plants. This study has uncovered the molecular mechanism by which grafting semi-wild tomato GZ-05 rootstocks increases plant cold tolerance, thereby laying the groundwork for the utilisation of Guizhou's native semi-wild tomato germplasm resources.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"228 ","pages":"Article 106042"},"PeriodicalIF":4.5,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-13DOI: 10.1016/j.envexpbot.2024.106041
Mao Hattori, Clarissa Frances Frederica , Louis John Irving
Holoparasites are non-photosynthetic plants which derive all their growth requirements from their host plant and are thought to act as a very strong sink for host resources. Here, we grew red clover plants in split-root boxes to explore the effect of nutrient supply to Orobanche minor parasitized or unparasitized host roots. Where nutrients were supplied to parasitized roots, parasite growth was strongly promoted at the expense of the host. Conversely, host growth did not differ significantly from unparasitized controls where nutrients were supplied to unparasitized roots. While 15N labelling suggested both strong parasitic ammonium abstraction and reduced nitrate uptake in parasitized roots, the total N content of systems where nutrients were fed to parasitized roots was approximately 26 % higher than control plants, suggesting that changes in host and parasite growth rates were due to changes in sink strength, rather than nutrient uptake. Parasitism and nutrient supply had strong effects on leaf carbohydrate metabolism but did not affect photosynthetic rates or leaf N concentration. In the second experiment, we investigated the importance of light level on the host – parasite relationship, concluding that parasitism had a diminished effect on host growth under low light conditions. Total system mass was unaffected by the apparent sink strength of the parasite. Our results suggest a dynamic relationship between host shoot and parasite sink strengths, mediated by changes in nutrient status.
{"title":"Nutrient mediation of sink strength in the Orobanche minor – Red clover association","authors":"Mao Hattori, Clarissa Frances Frederica , Louis John Irving","doi":"10.1016/j.envexpbot.2024.106041","DOIUrl":"10.1016/j.envexpbot.2024.106041","url":null,"abstract":"<div><div>Holoparasites are non-photosynthetic plants which derive all their growth requirements from their host plant and are thought to act as a very strong sink for host resources. Here, we grew red clover plants in split-root boxes to explore the effect of nutrient supply to <em>Orobanche minor</em> parasitized or unparasitized host roots. Where nutrients were supplied to parasitized roots, parasite growth was strongly promoted at the expense of the host. Conversely, host growth did not differ significantly from unparasitized controls where nutrients were supplied to unparasitized roots. While <sup>15</sup>N labelling suggested both strong parasitic ammonium abstraction and reduced nitrate uptake in parasitized roots, the total N content of systems where nutrients were fed to parasitized roots was approximately 26 % higher than control plants, suggesting that changes in host and parasite growth rates were due to changes in sink strength, rather than nutrient uptake. Parasitism and nutrient supply had strong effects on leaf carbohydrate metabolism but did not affect photosynthetic rates or leaf N concentration. In the second experiment, we investigated the importance of light level on the host – parasite relationship, concluding that parasitism had a diminished effect on host growth under low light conditions. Total system mass was unaffected by the apparent sink strength of the parasite. Our results suggest a dynamic relationship between host shoot and parasite sink strengths, mediated by changes in nutrient status.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"228 ","pages":"Article 106041"},"PeriodicalIF":4.5,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-12DOI: 10.1016/j.envexpbot.2024.106040
Jingjing Li , Haiou Liu , Yanjing Guo , Yuan Chang , Jing Zhang , He Wang , Qing Liu , Yu Ji , Zheng Zhang , Yujing Liu , Bernal E. Valverde , Shiguo Chen
Plant resistant induction is considered as a promising strategy for protecting crops against extreme high temperature (HT). However, a high-throughput method to accurately estimate the capacity of plant resistance inducers (PRIs) for HT resistance has not been developed. Here, we present a simple approach using fast chlorophyll fluorescence kinetics in Arabidopsis leaf discs to assess PRI efficacy in inducing HT resistance. Both 2-amino-3-methylhexanoic acid (AMHA) and salicylic acid (SA) significantly alleviated the temperature-dependent increase in the K-peak of the OJIP curve and variations in amplitude of heat-responsive JIP-test parameters within the elevated-temperature range of 25–42℃. The PIABS (performance index on absorption basis) and WK (relative variable fluorescence at the K-step to the amplitude FJ - FO) as two classical heat-responsive characteristic parameters were used to produce a novel hypersensitive parameter HT sensitivity indicator, PIABS/WK (named Hs). Based on the correlation of logHs with elevated temperatures, a model for quantifying the capacity of HT-resistance induction (called Ci) by AMHA or SA was established. A three-grade classification according to the Ci value was proposed as low (0< Ci ≤ 1℃), moderate (1℃ < Ci ≤ 2℃), and high resistance (Ci > 2℃). AMHA at 1 µM and SA at 100 µM had Ci values of 2.49℃ and 4.09℃ in Arabidopsis plants, respectively, associated with their high level of HT resistance induction. Additionally, the EC50 derived from the relative stimulation ratio (Kc) was also introduced as a quantitative index for measuring the ability of AMHA and SA to induce HT resistance. The EC50 value of AMHA is about 0.1 µM in Arabidopsis and 0.35 µM in tomato, being much lower than that of SA (approximately 63 µM in Arabidopsis). Thus, AMHA is a more potent plant inducer than SA. The model was validated through additional experimental evidence, demonstrating its reliability and applicability. This study provides an expeditious high-throughput method for screening promising PRI candidates.
{"title":"Fast chlorophyll fluorescence rise kinetics as a high-throughput diagnostic tool for evaluating the capacity of 2-amino-3-methylhexanoic acid at inducing plant resistance against high temperature","authors":"Jingjing Li , Haiou Liu , Yanjing Guo , Yuan Chang , Jing Zhang , He Wang , Qing Liu , Yu Ji , Zheng Zhang , Yujing Liu , Bernal E. Valverde , Shiguo Chen","doi":"10.1016/j.envexpbot.2024.106040","DOIUrl":"10.1016/j.envexpbot.2024.106040","url":null,"abstract":"<div><div>Plant resistant induction is considered as a promising strategy for protecting crops against extreme high temperature (HT). However, a high-throughput method to accurately estimate the capacity of plant resistance inducers (PRIs) for HT resistance has not been developed. Here, we present a simple approach using fast chlorophyll fluorescence kinetics in <em>Arabidopsis</em> leaf discs to assess PRI efficacy in inducing HT resistance. Both 2-amino-3-methylhexanoic acid (AMHA) and salicylic acid (SA) significantly alleviated the temperature-dependent increase in the K-peak of the OJIP curve and variations in amplitude of heat-responsive JIP-test parameters within the elevated-temperature range of 25–42℃. The PI<sub>ABS</sub> (performance index on absorption basis) and W<sub>K</sub> (relative variable fluorescence at the K-step to the amplitude F<sub>J</sub> - F<sub>O</sub>) as two classical heat-responsive characteristic parameters were used to produce a novel hypersensitive parameter HT sensitivity indicator, PI<sub>ABS</sub>/W<sub>K</sub> (named <em>H</em><sub>s</sub>). Based on the correlation of log<em>H</em><sub>s</sub> with elevated temperatures, a model for quantifying the capacity of HT-resistance induction (called <em>C</em><sub><em>i</em></sub>) by AMHA or SA was established. A three-grade classification according to the <em>C</em><sub><em>i</em></sub> value was proposed as low (0< <em>C</em><sub><em>i</em></sub> ≤ 1℃), moderate (1℃ < <em>C</em><sub><em>i</em></sub> ≤ 2℃), and high res<sub><em>i</em></sub>stance (<em>C</em><sub><em>i</em></sub> > 2℃). AMHA at 1 µM and SA at 100 µM had <em>C</em><sub><em>i</em></sub> values of 2.49℃ and 4.09℃ in <em>Arabidopsis</em> plants, respectively, associated with their high level of HT resistance induction. Additionally, the EC<sub>50</sub> derived from the relative stimulation ratio (<em>K</em><sub>c</sub>) was also introduced as a quantitative index for measuring the ability of AMHA and SA to induce HT resistance. The EC<sub>50</sub> value of AMHA is about 0.1 µM in <em>Arabidopsis</em> and 0.35 µM in tomato, being much lower than that of SA (approximately 63 µM in <em>Arabidopsis</em>). Thus, AMHA is a more potent plant inducer than SA. The model was validated through additional experimental evidence, demonstrating its reliability and applicability. This study provides an expeditious high-throughput method for screening promising PRI candidates.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"229 ","pages":"Article 106040"},"PeriodicalIF":4.5,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rice is known for its tolerance to high aluminum (Al) concentrations in soil. However, the precise genetic and physiological mechanisms are yet to be fully understood. Recent research has identified several candidate genes (CGs) and quantitative trait loci (QTLs) associated with Al toxicity tolerance in rice. Nevertheless, many more QTLs/genes are yet to be precisely mapped. We employed meta-QTL (M-QTL) analysis, integrating 12 independent mapping studies and 5 Genome-Wide Association Studies (GWAS). The meta-analysis identified 53 M-QTLs from 157 projected QTLs, which were further narrowed down to 28 M-QTLs based on the number of overlapping QTLs on a consensus map. Gene identification through batch retrieval from the RAP database yielded 2765 non-redundant genes within the 28 M-QTL regions. Comparison of M-QTL CGs with six expression datasets associated with Al toxicity tolerance in rice resulted in the identification of 219 CGs with significant differential expression. Notably, 34 CGs were identified to be common across at least 2 studies. Further downstream analyses of CGs revealed the presence of cis-regulatory elements, transcription factors, and transporter proteins related to the Al toxicity tolerance response. Additionally, we analyzed the expression patterns of the four CGs, namely NRT2.3, ALMT4, MT1, and MTP11, which showed significant upregulation in the Al toxicity-tolerant rice genotype, Anjali. Conversely, in the sensitive genotype Swarna, only NRT2.3 exhibited upregulation, while ALMT4, MT1, and MTP11 were downregulated. Our study highlights significant meta-regions that hold the potential for improving rice genotypes for enhanced tolerance to Al toxicity in acidic soils.
{"title":"Deciphering genetic mechanisms of Al toxicity tolerance through meta-QTL analysis in rice (Oryza sativa L.)","authors":"Sandeep Jaiswal , Anita Kumari , Kuldeep Kumar , Vijaya Laxmi , Simardeep Kaur , Amit Kumar , Harendra Verma , Philanim Shimray , Letngam Touthang , Manjeet Talukdar , Vinay Kumar Mishra , Binay K. Singh","doi":"10.1016/j.envexpbot.2024.106030","DOIUrl":"10.1016/j.envexpbot.2024.106030","url":null,"abstract":"<div><div>Rice is known for its tolerance to high aluminum (Al) concentrations in soil. However, the precise genetic and physiological mechanisms are yet to be fully understood. Recent research has identified several candidate genes (CGs) and quantitative trait loci (QTLs) associated with Al toxicity tolerance in rice. Nevertheless, many more QTLs/genes are yet to be precisely mapped. We employed meta-QTL (M-QTL) analysis, integrating 12 independent mapping studies and 5 Genome-Wide Association Studies (GWAS). The meta-analysis identified 53 M-QTLs from 157 projected QTLs, which were further narrowed down to 28 M-QTLs based on the number of overlapping QTLs on a consensus map. Gene identification through batch retrieval from the RAP database yielded 2765 non-redundant genes within the 28 M-QTL regions. Comparison of M-QTL CGs with six expression datasets associated with Al toxicity tolerance in rice resulted in the identification of 219 CGs with significant differential expression. Notably, 34 CGs were identified to be common across at least 2 studies. Further downstream analyses of CGs revealed the presence of <em>cis</em>-regulatory elements, transcription factors, and transporter proteins related to the Al toxicity tolerance response. Additionally, we analyzed the expression patterns of the four CGs, namely <em>NRT2.3</em>, <em>ALMT4</em>, <em>MT1</em>, and <em>MTP11</em>, which showed significant upregulation in the Al toxicity-tolerant rice genotype, Anjali. Conversely, in the sensitive genotype Swarna, only <em>NRT2.3</em> exhibited upregulation, while <em>ALMT4</em>, <em>MT1</em>, and <em>MTP11</em> were downregulated. Our study highlights significant meta-regions that hold the potential for improving rice genotypes for enhanced tolerance to Al toxicity in acidic soils.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"228 ","pages":"Article 106030"},"PeriodicalIF":4.5,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-10DOI: 10.1016/j.envexpbot.2024.106035
Xueqi Liu , Hongzhuang Niu , Jiazhe Li, Decheng Jiang, Ruihong Chen, Rui Zhang, Qian Li
Saline-alkaline stress not only leads to reduced crop yields but also diminishes the ornamental value of flowers. While petunia exhibits tolerance to saline-alkaline stress, research on the mechanisms underlying this tolerance remains unreported. We investigated the physiological and molecular mechanisms underlying saline-alkaline stress tolerance using two petunia genotypes (Haishishenlou and Mitchell Diploid) with differing tolerance levels. Haishishenlou exhibited less inhibition of growth under saline-alkaline stress compared to Mitchell Diploid, as indicated by higher biomass. Higher endogenous concentration of abscisic acid (ABA) and greater expression levels of ABA biosynthetic genes and lower expression levels of ABA catabolic genes in Haishishenlou than in Mitchell Diploid were observed when challenged by saline-alkaline stress, suggesting that a higher concentration of ABA may underpin the greater tolerance of Haishishenlou to saline-alkaline stress than that of Mitchell Diploid. Under saline-alkaline conditions, Haishishenlou displayed higher chlorophyll content, photosynthetic rates, Pro and soluble sugars content, as well as higher activities of catalase (CAT), superoxide dismutase (SOD) and peroxidase (POD), and a lower Na+/K+ ratio. Exogenous application of ABA alleviated the growth inhibition induced by saline-alkaline stress, promoted the accumulation of proline and soluble sugar, reduced reactive oxygen species (ROS) content and Na+/K+ ratio, and improved antioxidative capacity. These results indicated that a higher endogenous concentration of ABA may underpin the greater tolerance of petunia seedlings to saline-alkaline stress, and exogenous ABA improves the saline-alkaline tolerance of petunia seedlings.
盐碱胁迫不仅会导致作物减产，还会降低花卉的观赏价值。虽然牵牛花对盐碱胁迫具有耐受性，但有关其耐受机制的研究仍未见报道。我们利用两种耐盐碱程度不同的牵牛花基因型（海神楼和米切尔二倍体）研究了耐盐碱胁迫的生理和分子机制。与米切尔二倍体相比，海神楼在盐碱胁迫下的生长抑制较小，表现为生物量较高。与米切尔二倍体相比，在盐碱胁迫下，海神楼的脱落酸（ABA）内源浓度更高，ABA生物合成基因的表达水平更高，而ABA分解基因的表达水平更低，这表明较高浓度的ABA可能是海神楼比米切尔二倍体更能承受盐碱胁迫的原因。在盐碱条件下，海神楼表现出更高的叶绿素含量、光合速率、Pro和可溶性糖含量，以及更高的过氧化氢酶（CAT）、超氧化物歧化酶（SOD）和过氧化物酶（POD）活性和更低的Na+/K+比率。外源施用 ABA 可减轻盐碱胁迫引起的生长抑制，促进脯氨酸和可溶性糖的积累，降低活性氧（ROS）含量和 Na+/K+ 比率，提高抗氧化能力。这些结果表明，较高的内源 ABA 浓度可能是矮牵牛幼苗更耐盐碱胁迫的基础，而外源 ABA 能提高矮牵牛幼苗的耐盐碱能力。
{"title":"Higher endogenous abscisic acid confers greater tolerance to saline-alkaline stress in Petunia hybrida","authors":"Xueqi Liu , Hongzhuang Niu , Jiazhe Li, Decheng Jiang, Ruihong Chen, Rui Zhang, Qian Li","doi":"10.1016/j.envexpbot.2024.106035","DOIUrl":"10.1016/j.envexpbot.2024.106035","url":null,"abstract":"<div><div>Saline-alkaline stress not only leads to reduced crop yields but also diminishes the ornamental value of flowers. While petunia exhibits tolerance to saline-alkaline stress, research on the mechanisms underlying this tolerance remains unreported. We investigated the physiological and molecular mechanisms underlying saline-alkaline stress tolerance using two petunia genotypes (Haishishenlou and Mitchell Diploid) with differing tolerance levels. Haishishenlou exhibited less inhibition of growth under saline-alkaline stress compared to Mitchell Diploid, as indicated by higher biomass. Higher endogenous concentration of abscisic acid (ABA) and greater expression levels of ABA biosynthetic genes and lower expression levels of ABA catabolic genes in Haishishenlou than in Mitchell Diploid were observed when challenged by saline-alkaline stress, suggesting that a higher concentration of ABA may underpin the greater tolerance of Haishishenlou to saline-alkaline stress than that of Mitchell Diploid. Under saline-alkaline conditions, Haishishenlou displayed higher chlorophyll content, photosynthetic rates, Pro and soluble sugars content, as well as higher activities of catalase (CAT), superoxide dismutase (SOD) and peroxidase (POD), and a lower Na<sup>+</sup>/K<sup>+</sup> ratio. Exogenous application of ABA alleviated the growth inhibition induced by saline-alkaline stress, promoted the accumulation of proline and soluble sugar, reduced reactive oxygen species (ROS) content and Na<sup>+</sup>/K<sup>+</sup> ratio, and improved antioxidative capacity. These results indicated that a higher endogenous concentration of ABA may underpin the greater tolerance of petunia seedlings to saline-alkaline stress, and exogenous ABA improves the saline-alkaline tolerance of petunia seedlings.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"228 ","pages":"Article 106035"},"PeriodicalIF":4.5,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-10DOI: 10.1016/j.envexpbot.2024.106039
Kun Li , Mengxin Shen , Ran Wang , Wenqi Yang , Lingmin Zou , Kun-Peng Jia , Haipeng Li , Rui Xu , Qianyun Jia , Cheng Zhang , Yujie Wang , Zhikun Duan , Xuwu Sun , Jose R. Botella , Yuchen Miao , Jinggong Guo
Carotenoids are essential isoprenoids with vital roles in photoprotection and antioxidative processes in photosynthetic organisms. Lycopene Beta-cyclase (β-LCY) is a key enzyme in carotenoid biosynthesis; however, the role of β-LCY in photoprotection is still unclear. In this study, we characterized two β-LCY genes in an allotetraploid tobacco cultivar K326, that are primarily expressed in leaves. Reduction of β-LCY expression by RNA interfercnce (RNAi) resulted in decreased carotenoid content, leaf variegation, impaired photosynthetic efficiency, and abnormal chloroplast morphology. β-LCY RNAi plants exhibited hypersensitivity to high light and lower non-photochemical quenching (NPQ) values under both normal and high light conditions. The stability of D1, a core subunit of photosystem II reaction center, was dramatically impaired β-LCY RNAi plants upon exposure to high light, suggesting severe photodamage of photosystem. Furthermore, reactive oxygen species (ROS) content was increased in β-LCY RNAi plants compared to WT plants under both normal and high light conditions. These results indicate that β-LCY is crucial for NPQ, D1 stability and ROS homeostasis, thus protecting photosystem from photooxidative damage. These findings contribute to our understanding on the function of plant β-LCY and its potential implications for plant growth, development, and photoprotection.
{"title":"Characterization of two lycopene beta-cyclases reveal their essential roles in photoprotection in Nicotiana tabacum","authors":"Kun Li , Mengxin Shen , Ran Wang , Wenqi Yang , Lingmin Zou , Kun-Peng Jia , Haipeng Li , Rui Xu , Qianyun Jia , Cheng Zhang , Yujie Wang , Zhikun Duan , Xuwu Sun , Jose R. Botella , Yuchen Miao , Jinggong Guo","doi":"10.1016/j.envexpbot.2024.106039","DOIUrl":"10.1016/j.envexpbot.2024.106039","url":null,"abstract":"<div><div>Carotenoids are essential isoprenoids with vital roles in photoprotection and antioxidative processes in photosynthetic organisms. Lycopene Beta-cyclase (<em>β</em>-LCY) is a key enzyme in carotenoid biosynthesis; however, the role of <em>β</em>-LCY in photoprotection is still unclear. In this study, we characterized two <em>β</em>-<em>LCY</em> genes in an allotetraploid tobacco cultivar K326, that are primarily expressed in leaves. Reduction of <em>β-LCY</em> expression by RNA interfercnce (RNAi) resulted in decreased carotenoid content, leaf variegation, impaired photosynthetic efficiency, and abnormal chloroplast morphology. <em>β-LCY</em> RNAi plants exhibited hypersensitivity to high light and lower non-photochemical quenching (NPQ) values under both normal and high light conditions. The stability of D1, a core subunit of photosystem II reaction center, was dramatically impaired <em>β-LCY</em> RNAi plants upon exposure to high light, suggesting severe photodamage of photosystem. Furthermore, reactive oxygen species (ROS) content was increased in <em>β-LCY</em> RNAi plants compared to WT plants under both normal and high light conditions. These results indicate that <em>β</em>-LCY is crucial for NPQ, D1 stability and ROS homeostasis, thus protecting photosystem from photooxidative damage. These findings contribute to our understanding on the function of plant <em>β</em>-LCY and its potential implications for plant growth, development, and photoprotection.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"228 ","pages":"Article 106039"},"PeriodicalIF":4.5,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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