Environmental and Experimental Botany最新文献

{"title":"Knockout of OsBURP12 enhances salt tolerance in rice seedlings","authors":"Zengtong Luo ,&nbsp;Sijia Yu ,&nbsp;Jialing Chen ,&nbsp;Qianyi Liu ,&nbsp;Mangu Hu ,&nbsp;Xiao Yang ,&nbsp;Yongxiang Huang ,&nbsp;Wuming Xiao","doi":"10.1016/j.envexpbot.2025.106097","DOIUrl":"10.1016/j.envexpbot.2025.106097","url":null,"abstract":"<div><div>The BURP gene family encodes the BURP domain protein, a type of plant-specific protein that plays an important role in plant development, metabolism and stress resistance. Salt stress is one of the major stresses faced by rice. However, there is a lack of systematic understanding of the BURP family involved in the regulation of salt stress in rice, especially for the gene <em>OsBURP12</em>. Our study used <em>japonica</em> rice variety Zhonghua 11 (ZH11), as the wild type (WT), and its <em>OsBURP12</em> knockout lines to fill the gap of the understanding. NaCl solution was used for salt stress treatment. Related physiological and biochemical analyses were carried out to investigate the regulatory mechanism of <em>OsBURP12</em> on salt tolerance in rice seedlings. The results showed that the survival rate, seedling height, root length and fresh weight of the knockout lines were significantly higher than those of the WT under salt stress, indicating that the salt tolerance of the knockout lines was significantly better than that of the WT. Under salt stress, the knockout lines had significantly higher antioxidant enzyme activity, lower accumulation of ROS (reactive oxygen species) and higher expression of genes related to ROS-scavenging than the WT. In addition, the knockout lines showed significantly lower PG activity and Na⁺ content, but significantly higher pectin content, K⁺ and Ca²⁺ content than the WT. Furthermore, the knockout lines had significantly higher ABA and ACC levels than the WT. Quantitative PCR analysis showed that the expression levels of genes related to ABA and ethylene synthesis and signaling were significantly higher in the knockout lines than in the WT. The results suggested that the knockout of <em>OsBURP12</em> can improve ROS-scavenging ability, affect PG activity, regulate Na⁺ uptake, and mediate the synthesis and metabolism of ABA and ACC in response to salt stress for a tolerance in rice. Our study laid the foundation for further analysis of the function of BURP family genes in plants, and provided a valuable genetic resource for studying the mechanism of salt tolerance in rice.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"231 ","pages":"Article 106097"},"PeriodicalIF":4.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143103437","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}

{"title":"Elevated nitrogen supply enhances the recovery capability of alfalfa following rewatering by regulating carbon allocation","authors":"Luanzi Sun ,&nbsp;Kun Zhou ,&nbsp;Jiacun Guo ,&nbsp;Junrui Zang ,&nbsp;Shipeng Liu","doi":"10.1016/j.envexpbot.2025.106095","DOIUrl":"10.1016/j.envexpbot.2025.106095","url":null,"abstract":"<div><div>Drought events are increasingly frequent, posing a significant threat to plant growth and survival. Nitrogen (N) has been shown to improve drought tolerance in plants, but its role in facilitating recovery growth following rewatering after drought stress remains poorly understood. The alfalfa cultivated under hydroponic conditions with varying levels of N (Low N: 1 mM; Medium N: 4 mM; High: 7 mM) was subjected to drought-rewatering which was simulated by the addition and subsequent removal of PEG from the nutrient solution. The allocation of biomass (R/S) and non-structural carbohydrates (NSC) between shoots and roots, and the percentage of assimilation allocated to NSC were investigated at the end of the drought, early stage (7 days post-rewatering), and late stage of rewatering (35 days post-rewatering). The results revealed that after 35 days of rewatering, the alfalfa grown under medium N level had fully recovered its growth to that of their well-watered control groups, with no significant difference in total dry weights; nevertheless, those grown under low and high N levels had total dry weights that were 18.3 % and 18.8 % lower than those of their corresponding control groups, respectively. Following rewatering, similar to the drought period, plants exposed to higher N levels tended to allocate more biomass and NSC toward roots rather than shoots. At 35 days after rewatering, the R/S of plants under the low N supply level decreased by 9.6 %; that of plants under the medium N supply did not change significantly; whereas that of plants under the high N supply increased by 46.6 % in comparison with their corresponding control group. Furthermore, a higher N supply level facilitated carbon allocation for tissue growth rather than reserving NSC, similar to the effect of N supply during the drought period. Therefore, a higher N supply may enhance the recovery capability of the plant after rewatering but may delay the recovery rate. During various stages of the drought-rewatering process, increasing the N supply level influenced the allocation of biomass and NSC between shoots and roots through different key enzymes and sucrose transporters. Our study provides valuable insights into the carbon regulatory mechanisms utilized by plants in response to rewatering after drought under varying N supply conditions. This contributes to a deeper understanding of plant adaptation strategies in the face of drought events.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"231 ","pages":"Article 106095"},"PeriodicalIF":4.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143103438","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}

{"title":"Transcriptomic insights into the stress signaling and drought tolerance mechanisms in sea-island cotton (Gossypium barbadense)","authors":"Tahir Mahmood ,&nbsp;Shoupu He ,&nbsp;De Zhu ,&nbsp;Hongge Li ,&nbsp;Xiaoli Geng ,&nbsp;Baojun Chen ,&nbsp;Xianpeng Xiong ,&nbsp;Xuai Dai ,&nbsp;Xiongfeng Ma ,&nbsp;Xiongming Du ,&nbsp;Guanjing Hu","doi":"10.1016/j.envexpbot.2024.106048","DOIUrl":"10.1016/j.envexpbot.2024.106048","url":null,"abstract":"<div><div>Drought stress significantly impacts plant growth and agricultural productivity. Elucidating the molecular mechanisms underlying drought stress response and plant tolerance is crucial for developing resilient crops. In <em>Gossypium barbadense</em> (<em>G. barbadense</em>), the specific genetic responses to drought stress remain underexplored. To provide insights into the transcriptomic dynamics and tolerance mechanisms in <em>G. barbadense</em>, we screened a diverse panel of <em>G. barbadense</em> accessions to identify drought-tolerant genotypes and investigate drought-stress responses across root and shoot tissues at two distinct time points. Differentially expressed genes (DEGs) analysis revealed diverse drought-responsive genes across tissue types and treatment time points. Functional enrichment and predictive protein-protein interaction (PPI) network analyses elucidated intricate patterns of drought-stress signaling pathways and transcriptional regulatory mechanisms. These upregulated DEGs were enriched in functional categories such as hormone signal transduction, phosphatidylinositol signaling system, ubiquitin-mediated proteolysis, phenylpropanoid biosynthesis, glutathione metabolism, and carbon metabolism pathways. The PPI network analysis underscores the activation of key signaling genes such as plant U-box E3 ubiquitin ligases (PUBs), protein phosphatase 2 C (PP2Cs), and F-Box genes, as well as transcriptional factors (CBF/NFYA) and various effector genes. These networks revealed the activation of effector genes involved in phenylpropanoid biosynthesis (<em>Thioredoxin like 2–1, 1-Cys</em>), glutathione metabolism (<em>Thioredoxin, GPX6</em>), and carbohydrate/sugar metabolism (<em>GBSSI, AMY1.1</em>). Gene silencing experiments validated the regulatory roles predicted for PUBs and PP2Cs in stress signaling and <em>NFYA</em> transcriptional factor in modifying the plant morphology and physiology to enhance drought tolerance. This research provides critical insights into the genetic signatures of stress signaling and regulatory pathways associated with drought tolerance in <em>G. barbadense</em>. The identified candidate genes are valuable for targeted breeding efforts to enhance drought tolerance and crop yield.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"228 ","pages":"Article 106048"},"PeriodicalIF":4.5,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745045","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}

{"title":"Exogenous γ-aminobutyric acid (GABA) provides a carbon skeleton to promote the accumulation of sugar and unsaturated fatty acids in vegetable soybean seeds","authors":"Fengqiong Chen ,&nbsp;Yating Wang ,&nbsp;Yiyang Liu ,&nbsp;Qiusen Chen ,&nbsp;Hanlin Liu ,&nbsp;Jin Tian ,&nbsp;Mengxue Wang ,&nbsp;Chunyuan Ren ,&nbsp;Qiang Zhao ,&nbsp;Fengjun Yang ,&nbsp;Jinpeng Wei ,&nbsp;Gaobo Yu ,&nbsp;Yuxian Zhang","doi":"10.1016/j.envexpbot.2024.106052","DOIUrl":"10.1016/j.envexpbot.2024.106052","url":null,"abstract":"<div><div>γ-aminobutyric acid (GABA) influences various physiological processes in plants, particularly in carbon and nitrogen metabolism. However, the mechanism underlying carbon (sucrose and unsaturated fatty acid) metabolism in vegetable soybeans was still unknown. In this study, a foliar spray of GABA (10 mM) elevated the level of Ca²⁺ by up-regulating the expression of calmodulin (<em>GmCaM</em>), which increased glutamate decarboxylase (GAD) activity and boosted endogenous GABA content. This, in turn, enhanced the expression of coding genes of GABA transferase (<em>GmGABA-T</em>) and succinic semialdehyde dehydrogenase (<em>GmSSADH</em>), as well as the activity of GABA transferase (GABA-T), activated the GABA shunt to supply carbon to the tricarboxylic acid (TCA) cycle, thus improved carbon metabolism. The gene expression and activity of sucrose metabolism-related enzymes were also enhanced, leading to the increased accumulation of total soluble sugars, sucrose, glucose, etc. Additionally, exogenous GABA treatment elevated the level of unsaturated fatty acids, including omega-3 arachidonic acid, linoleic acid, alpha-linolenic acid, etc. However, these effects were attenuated by 3-mercaplopropionic acid (3-MP), an inhibitor of GABA synthesis. In summary, exogenous GABA provides a carbon skeleton that promotes the accumulation of sugar and unsaturated fatty acids in vegetable soybean seeds. This research provides a valuable theory for further improving the yield and quality of vegetable soybeans.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"229 ","pages":"Article 106052"},"PeriodicalIF":4.5,"publicationDate":"2024-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745070","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}

{"title":"RhbHLH92 positively regulates the dehydration tolerance by interacting with RhMYB123 in rose petals (Rosa hybrida)","authors":"Ping Luo ,&nbsp;Huanyu Zhang ,&nbsp;Yeni Chen ,&nbsp;Yongyi Cui ,&nbsp;Wen Chen","doi":"10.1016/j.envexpbot.2024.106049","DOIUrl":"10.1016/j.envexpbot.2024.106049","url":null,"abstract":"<div><div>Drought increasingly constitutes a significant constraint that detrimentally affects plant growth and the productivity of agricultural crops. The bHLHs is pivotal in enabling plants to withstand various abiotic stresses. However, the specific roles of bHLHs in stress remain limited. Here, we explore the role of <em>RhbHLH92</em> from the <em>Rosa hybrida</em> according to the previous RNA-seq data. The expression of <em>RhbHLH92</em> was enhanced under several abiotic stress conditions, especially dehydration. RhbHLH92 is located in the nucleus. Enhanced dehydration and drought tolerance were observed in tobacco and rose petals overexpressing <em>RhbHLH92.</em> These genetically modified plants maintained better water balance, showed decreased levels of reactive oxygen species, and exhibited elevated activity of antioxidant enzymes along with increased expression of drought resistance genes compared to WT. Conversely, suppression of <em>RhbHLH92</em> in rose petals using virus-induced gene silencing (VIGS) heightened their vulnerability to dehydration and reduced the expression of genes associated with stress tolerance. Yeast two-hybrid and BiFC confirmed that RhbHLH92 physically interacts with RhMYB123, a R2R3-type TF. <em>RhMYB123</em> overexpression in rose petals similarly boosted dehydration tolerance. RhbHLH92 and RhMYB123 could directly bind to the <em>Δ-1-pyrroline-5-carboxylate synthetase</em> (<em>RhP5CS</em>) promoter, the RhbHLH92-RhMYB123 complex led to higher transcript levels of <em>RhP5CS</em>. These findings elucidate a new pathway through which <em>RhbHLH92</em> enhances drought tolerance in roses, offering potential strategies for the development of drought-resistant crop varieties.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"228 ","pages":"Article 106049"},"PeriodicalIF":4.5,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142720402","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}

{"title":"PagbZIP75 decreases the ROS accumulation to enhance salt tolerance of poplar via the ABA signaling","authors":"Jia Hu ,&nbsp;Siyuan Nan ,&nbsp;Lieding Zhou ,&nbsp;Changhong Yu ,&nbsp;Yajing Li ,&nbsp;Kai Zhao ,&nbsp;Shuhui Du ,&nbsp;Youzhi Han ,&nbsp;Shengji Wang","doi":"10.1016/j.envexpbot.2024.106051","DOIUrl":"10.1016/j.envexpbot.2024.106051","url":null,"abstract":"<div><div>Poplar (<em>Populus</em> L.) is a fast-growing economic timber plant that is susceptible to salt stress. Here, <em>PagbZIP75</em> (<em>Potri.014G120800</em>), which was isolated from 84 K poplar and upregulated in response to salt treatment, was investigated by generating overexpression (OE) and repression (RNAi) transgenic lines to elucidate its role in poplar salt stress tolerance through molecular and physiological approaches. PagbZIP75 localized in the nucleus and cell membrane but lacked transcriptional activation activity in yeast cells. Expression pattern analysis revealed that <em>PagbZIP75</em> was induced by salt stress, peaking at 12 hours in roots and stems and 24 hours in leaves. Under salt stress, OE exhibited enhanced growth and a more robust root system compared to non-transgenic 84 K poplar (WT) and RNAi. DAB and NBT staining results demonstrated lower levels of reactive oxygen species (ROS) in OE leaves, alongwith reduced electrolyte leakage rate and superoxide anion (O₂^-) content, while the proline content and superoxide dismutase (SOD) activity were significantly elevated under salt stress. Based on the RNA-seq data, multilayered hierarchical gene regulatory network (ML-hGRN) around <em>bZIP75</em> was illustrated and indicated that <em>PagbZIP75</em> was induced by ABA hormone along with 10 salt-related co-expressed genes. Yeast one-hybrid (Y1H) experiments indicated the binding of PagAREB1 protein to the 0–208 bp upstream fragments of <em>PagbZIP75</em>, and dual luciferase assays (LUC) confirmed a negative interaction between AREB1 and bZIP75. Overall, this study provides a theoretical foundation for the enhancement of poplar salt tolerance by <em>PagbZIP75</em> through the reduction of ROS accumulation via ABA signaling.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"228 ","pages":"Article 106051"},"PeriodicalIF":4.5,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142720401","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}

{"title":"Light-nutrient interaction orchestrates leaf dynamics, nitrogen assimilation, and cellular energetics in Agastache rugosa (Fisch. & C.A.Mey.) Kuntze","authors":"Khairul Azree Rosli ,&nbsp;Azizah Misran ,&nbsp;Latifah Saiful Yazan ,&nbsp;Puteri Edaroyati Megat Wahab","doi":"10.1016/j.envexpbot.2024.106044","DOIUrl":"10.1016/j.envexpbot.2024.106044","url":null,"abstract":"<div><div>Light and nutrients are vital environmental factors shaping plant growth and metabolism, yet their interactive effects on leaf dynamics, nitrogen assimilation, and cellular energetics remain largely unexplored. We aimed to investigate these processes in <em>Agastache rugosa</em> (Fisch. &amp; C.A.Mey.) Kuntze under two light levels; high-light (HL, 0 % shade) and low-light (LL, 50 % shade) combined with four nutrient levels; low (NPK1, 40 mg kg⁻¹), moderate (NPK2, 80 mg kg⁻¹), high (NPK3, 120 mg kg⁻¹) and very high (NPK4, 160 mg kg⁻¹). High-light conditions and high-nutrient levels (HL-NPK3) synergistically enhanced leaf mass area by 44 % with net photosynthesis rates and nitrate reductase activity increasing by up to 17.62 ± 0.89 µmol CO₂ m⁻² s⁻¹ and 0.34 ± 0.02 μmol NO₂ cm⁻² h⁻¹ each. Low-light and moderate-nutrient levels (LL-NPK2) triggered a 42 % increase in specific leaf area and threefold higher photosynthetic nitrogen use efficiency. Unexpectedly, high-light and moderate-nutrient levels (HL-NPK2) elicited peak vacuolar H⁺-ATPase and H⁺-pyrophosphatase activities at 15.6 % and 53.1 % each. This study also found significant positive correlations between chlorophyll content, nitrate reductase (r = 0.62, P &lt; 0.01), and vacuolar H⁺-ATPase activity (r = 0.58, P &lt; 0.01), suggesting a mechanism for maintaining high photosynthetic capacity and efficient nitrogen assimilation. The clustering of leaf area index, specific leaf area, and photosynthetic nitrogen use efficiency (similarity of &gt; 70 %) suggests optimized leaf structure and nitrogen use in light-limited but nutrient-rich environments. Our findings show how <em>A</em>. <em>rugosa</em> adjusts its physiology in response to environmental conditions, with implications for understanding plant adaptation and improving cultivation practices.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"229 ","pages":"Article 106044"},"PeriodicalIF":4.5,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745156","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}

{"title":"Rocky soils alter the diurnal photosynthetic behavior of xerophytic species by regulating hydraulic properties","authors":"Xiulong Zhang ,&nbsp;Fanglan Li ,&nbsp;Lulu Xie ,&nbsp;Weikai Bao","doi":"10.1016/j.envexpbot.2024.106045","DOIUrl":"10.1016/j.envexpbot.2024.106045","url":null,"abstract":"<div><div>Functional relationships between photosynthetic behavior and hydraulic properties are essential to characterize plant drought adaptation strategies. However, little is known about such relationships in response to varying rock fragment content (RFC), which could induce severe soil water deficit. We evaluated the leaf hydraulic properties and the timing of diurnal depression of photosynthesis in three xerophytic shrub species grown under different RFC levels (0, 25, 50, 75 % v v⁻¹). We found that studied species grown in 25 % RFC soil conditions had higher leaf hydraulic conductance (<em>K</em>_leaf) and reached maximum photosynthetic rate (<em>A</em>_max) in the morning, while those grown in 75 % RFC soil conditions had lower <em>K</em>_leaf, but reached their <em>A</em>_max in the afternoon. In addition, species in 75 % RFC soil conditions also exhibited low leaf hydraulic vulnerability and narrow leaf hydraulic safety margins. Our results indicate that RFC modifies the diurnal gas exchange dynamics of xerophytic species by decreasing leaf hydraulic vulnerability and hydraulic safety margins. Specifically, species surviving in 75 % RFC soils are less vulnerable to drought induced water loss, and carbon assimilation depression were later than in 25 % or 0 % RFC soil conditions. However, when faced with severe drought, these species with latter CO₂ uptake depression are at higher risk of hydraulic failure, because their safety margins are relatively narrow. Our results contribute to the knowledge of drought adaptation strategies in xerophytic species native to dry-hot rocky mountains.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"228 ","pages":"Article 106045"},"PeriodicalIF":4.5,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700706","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}

{"title":"Physiological and biochemical changes induced by drought stress during the stem elongation and anthesis stages in the Triticum genus","authors":"Sumitra Pantha ,&nbsp;Benjamin Kilian ,&nbsp;Hakan Özkan ,&nbsp;Frederike Zeibig ,&nbsp;Michael Frei","doi":"10.1016/j.envexpbot.2024.106047","DOIUrl":"10.1016/j.envexpbot.2024.106047","url":null,"abstract":"<div><div>Drought stress negatively influences the growth, development, and grain yield of wheat by disrupting its morphological, physiological, and biochemical processes. This study examined the effects of drought stress during the stem elongation and anthesis developmental stages of species within the <em>Triticum</em> genus along with their drought adaptation mechanisms under fully watered and drought conditions. We tested the following two hypotheses: (1) drought tolerance mechanisms for osmotic and stomatal regulation that lead to oxidative stress are correlated between the stem elongation and anthesis stages and affect grain yield loss, and (2) compared with modern cultivars, wild wheat cultivars exhibit greater drought tolerance. To test these hypotheses, a greenhouse pot experiment was conducted using 17 genotypes of wild wheat relatives and landraces, with modern cultivars included for comparison. Drought stress was induced during the stem elongation and anthesis stages until the average soil moisture was approximately 15 % and 18 %, respectively, of the pot’s water holding capacity. The soil moisture was maintained at 80–90 % for the fully watered treatment. An examination of physiological and biochemical traits revealed that drought significantly reduced stomatal conductance (gsw) and relative water content (RWC) during both developmental stages. However, significant increases occurred in the malondialdehyde (MDA) content during both stages and in the proline content during the anthesis stage. Drought stress significantly decreased the number of days to heading and anthesis, indicating that drought escape occurs under severe drought stress. Furthermore, drought significantly decreased morphological and yield-related traits, with the greatest reduction (51 %) occurring in grain yield. Weakly significant positive associations of biochemical and some physiological traits between the stem elongation and anthesis stages partially confirmed our first hypothesis, whereas our results relating to the second hypothesis were inconclusive. We observed genotype-dependent responses to drought stress during both stages for various measured traits. No associations of RWC, proline, or MDA with grain yield were found. However, stomatal conductance was negatively correlated with grain yield under drought stress at the anthesis stage. Certain wild wheat genotypes and landraces exhibited drought avoidance, escape, and tolerance mechanisms, which positively contributed to grain yield. We identified <em>T. monococcum</em> subsp. <em>sinskajae</em>, <em>T. boeoticum</em> and <em>T. dicoccoides</em> as the most drought-tolerant genotypes. The findings of this study provide important insight for understanding the drought adaptation traits and their use in wheat breeding programs.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"228 ","pages":"Article 106047"},"PeriodicalIF":4.5,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142703034","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}

{"title":"Analyses of the bHLH gene family in Populus trichocarpa reveal roles of four PtbHLHs in regulating the drought stress response","authors":"Haizhen Zhang ,&nbsp;Shuhan Ye ,&nbsp;Nan Wang,&nbsp;Ziping Xu,&nbsp;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}