The distribution of spikelets significantly affects wheat (Triticum aestivum L.) spike architecture. However, traditional methods lack the precision to study spikelet distribution effectively. We developed RachisSeg, a deep learning-based phenotyping pipeline that automatically measures traits from scanned rachis images. In addition to traditional spikelet number per spike (SNS), rachis length (RL), and spikelet density (SD, SNS/RL), we introduced spikelet distribution traits based on rachis internode lengths, providing quantitative insights into spike architecture. RachisSeg showed high consistency with manual measurements for SNS and RL, with the R2 values of 0.975 and 0.998, respectively. Using RachisSeg, we analyzed spikelet distribution patterns across wheat germplasm and found that traits such as spikelet distribution index (SDI) and apical-to-basal spikelet number ratio (AVB_SNS) were moderately correlated with grain yield per spike (GYPS) (r = 0.57 and 0.53, respectively), while internode width (IW) showed a strong positive correlation with GYPS (r = 0.75). Specifically, a denser spikelet arrangement in the upper spike negatively impacted grain number and weight in that section. Furthermore, comparative analysis revealed distinct spikelet distribution patterns among landraces, American cultivars, and Chinese cultivars. In a recombinant inbred line population, we identified 46 quantitative trait loci (QTLs) associated with rachis traits. A major QTL controlling SDI was detected on chromosome 6B, explaining up to 24.8% of the phenotypic variance. Candidate gene analysis suggested TraesCS6B02G417000 as a potential gene, whose mutant exhibited significant changes in RL and SDI. RachisSeg is a powerful tool for quantifying spikelet distribution, facilitating wheat genetic analysis, gene discovery, and breeding.
{"title":"Image-based rachis phenotyping facilitates genetic dissection of spikelet distribution in wheat","authors":"Renxiang Lu, Shusong Zheng, Lingjie Yang, Zongyang Li, Yaoqi Si, Minru Yan, Xigang Liu, Hong-Qing Ling, Ni Jiang","doi":"10.1093/plphys/kiaf666","DOIUrl":"https://doi.org/10.1093/plphys/kiaf666","url":null,"abstract":"The distribution of spikelets significantly affects wheat (Triticum aestivum L.) spike architecture. However, traditional methods lack the precision to study spikelet distribution effectively. We developed RachisSeg, a deep learning-based phenotyping pipeline that automatically measures traits from scanned rachis images. In addition to traditional spikelet number per spike (SNS), rachis length (RL), and spikelet density (SD, SNS/RL), we introduced spikelet distribution traits based on rachis internode lengths, providing quantitative insights into spike architecture. RachisSeg showed high consistency with manual measurements for SNS and RL, with the R2 values of 0.975 and 0.998, respectively. Using RachisSeg, we analyzed spikelet distribution patterns across wheat germplasm and found that traits such as spikelet distribution index (SDI) and apical-to-basal spikelet number ratio (AVB_SNS) were moderately correlated with grain yield per spike (GYPS) (r = 0.57 and 0.53, respectively), while internode width (IW) showed a strong positive correlation with GYPS (r = 0.75). Specifically, a denser spikelet arrangement in the upper spike negatively impacted grain number and weight in that section. Furthermore, comparative analysis revealed distinct spikelet distribution patterns among landraces, American cultivars, and Chinese cultivars. In a recombinant inbred line population, we identified 46 quantitative trait loci (QTLs) associated with rachis traits. A major QTL controlling SDI was detected on chromosome 6B, explaining up to 24.8% of the phenotypic variance. Candidate gene analysis suggested TraesCS6B02G417000 as a potential gene, whose mutant exhibited significant changes in RL and SDI. RachisSeg is a powerful tool for quantifying spikelet distribution, facilitating wheat genetic analysis, gene discovery, and breeding.","PeriodicalId":20101,"journal":{"name":"Plant Physiology","volume":"31 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145784777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anthocyanins critically determine fruit color, nutrition, and stress resilience in cultivated strawberry (Fragaria × ananassa), directly influencing consumer preference. Despite complex genetic and environmental regulation of their biosynthesis, the basis for tissue-specific pigmentation, notably the widespread occurrence of red skin and pale flesh, remains poorly understood. We integrated genomic, transcriptomic, and functional analyses across 200 cultivars to dissect receptacle pigmentation regulation. Approaches included FaMYB10-2 allele mining, promoter structural variant (SV) identification, expression profiling, regulatory interaction assays, and characterization of upstream light-responsive factors. FaMYB10-2 was identified as the key R2R3-MYB regulator of fruit anthocyanin biosynthesis. Alleles FaMYB10-2.2 and FaMYB10-2.3 encode truncated proteins retaining bHLH-binding capacity but lacking activation domains, functioning as dominant-negative repressors. A promoter SV 986 bp upstream of FaMYB10-2 was associated with reduced pale fruit due to cis-regulatory divergence. The SV (Alt) allele is prevalent in Asian cultivars, while the Ref allele is enriched in Western germplasm. Crucially, a light-responsive FaHYH-FaWRKY71 cascade activates FaMYB10-2 and structural genes haplotype-dependently, compensating for weak MYB activity in the skin. Our findings reveal a multilayered regulatory system integrating allelic variation, cis-regulatory divergence, and environmental signals, advancing anthocyanin understanding and providing engineering targets for polyploid crop color improvement.
{"title":"Allelic variation and light-responsive regulation of FaMYB10-2 underlie tissue-specific anthocyanin accumulation in strawberry","authors":"Huazhao Yuan, Chao Wang, Feiyue Quan, Linlin Xu, Jiahui Liang, Fuhua Pang, Zhiliang Pan, Bingbing Li, Yushan Qiao, Mizhen Zhao","doi":"10.1093/plphys/kiaf665","DOIUrl":"https://doi.org/10.1093/plphys/kiaf665","url":null,"abstract":"Anthocyanins critically determine fruit color, nutrition, and stress resilience in cultivated strawberry (Fragaria × ananassa), directly influencing consumer preference. Despite complex genetic and environmental regulation of their biosynthesis, the basis for tissue-specific pigmentation, notably the widespread occurrence of red skin and pale flesh, remains poorly understood. We integrated genomic, transcriptomic, and functional analyses across 200 cultivars to dissect receptacle pigmentation regulation. Approaches included FaMYB10-2 allele mining, promoter structural variant (SV) identification, expression profiling, regulatory interaction assays, and characterization of upstream light-responsive factors. FaMYB10-2 was identified as the key R2R3-MYB regulator of fruit anthocyanin biosynthesis. Alleles FaMYB10-2.2 and FaMYB10-2.3 encode truncated proteins retaining bHLH-binding capacity but lacking activation domains, functioning as dominant-negative repressors. A promoter SV 986 bp upstream of FaMYB10-2 was associated with reduced pale fruit due to cis-regulatory divergence. The SV (Alt) allele is prevalent in Asian cultivars, while the Ref allele is enriched in Western germplasm. Crucially, a light-responsive FaHYH-FaWRKY71 cascade activates FaMYB10-2 and structural genes haplotype-dependently, compensating for weak MYB activity in the skin. Our findings reveal a multilayered regulatory system integrating allelic variation, cis-regulatory divergence, and environmental signals, advancing anthocyanin understanding and providing engineering targets for polyploid crop color improvement.","PeriodicalId":20101,"journal":{"name":"Plant Physiology","volume":"17 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145786041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Iron (Fe) deficiency is a major limitation to apple (Malus domestica) growth in calcareous soils. Understanding the molecular mechanisms underlying Fe deficiency responses is crucial for improving Fe use efficiency in fruit trees. In this study, we identified the ETHYLENE RESPONSE FACTOR 4 (MxERF4) as a negative regulator of the Fe deficiency response in apple. Transgenic analysis revealed that overexpression of MxERF4 exacerbated leaf chlorosis and reduced root Fe content under Fe-deficient conditions, whereas RNA interference (RNAi) lines exhibited enhanced tolerance. We further identified the MITOGEN-ACTIVATED PROTEIN KINASE (MxMPK6-2) as an interactor of MxERF4. MxMPK6-2 phosphorylates MxERF4, reducing its protein stability and promoting its degradation. MxERF4 interacted with the key Fe uptake regulator FER-LIKE FE DEFICIENCY-INDUCED TRANSCRIPTION FACTOR (MxFIT) and co-localized with it in root tissues. Phosphorylation weakened the MxERF4-MxFIT interaction, thereby relieving the inhibition of MxFIT-basic Helix-Loop-Helix 38/39 (MxbHLH38/39) complex formation. This in turn restored the activation of Fe uptake genes IRON TRANSPORTER1 (MxIRT1) and FERRIC REDUCTASE OXIDASE 2 (MxFRO2), enhanced ferric chelate reductase (FCR) activity, and promoted active Fe accumulation. Together, these findings reveal a previously uncharacterized MPK6-2-ERF4 signaling module that regulates Fe deficiency responses in apple by modulating ERF4 stability and its interaction with FIT, providing insights into the molecular basis of Fe efficiency and offering potential strategies for breeding Fe-efficient rootstocks.
缺铁是制约苹果在钙质土壤中生长的主要因素。了解缺铁反应的分子机制对提高果树铁利用效率具有重要意义。在本研究中，我们确定了乙烯反应因子4 （MxERF4）是苹果铁缺乏反应的负调控因子。转基因分析显示，在缺铁条件下，过表达MxERF4加剧了叶片黄化，降低了根系铁含量，而RNA干扰（RNAi）系表现出增强的耐受性。我们进一步鉴定了丝裂原活化蛋白激酶（MxMPK6-2）是MxERF4的相互作用物。MxMPK6-2磷酸化MxERF4，降低其蛋白稳定性，促进其降解。MxERF4与关键的铁摄取调节因子Fe - like Fe deficient induced TRANSCRIPTION FACTOR （MxFIT）相互作用，并在根组织中共定位。磷酸化削弱了MxERF4-MxFIT相互作用，从而减轻了对MxFIT-basic Helix-Loop-Helix 38/39 （MxbHLH38/39）复合物形成的抑制。这反过来恢复了铁摄取基因铁转运蛋白1 （MxIRT1）和铁还原酶氧化酶2 （MxFRO2）的激活，增强了铁螯合还原酶（FCR）的活性，促进了铁的活性积累。总之，这些发现揭示了一个以前未被发现的MPK6-2-ERF4信号模块，该信号模块通过调节ERF4的稳定性及其与FIT的相互作用来调节苹果铁缺乏反应，为铁效率的分子基础提供了见解，并为培育铁高效砧木提供了潜在的策略。
{"title":"MPK6-2-mediated phosphorylation of ERF4 releases the Fe uptake regulator FIT and enhances Fe uptake in apple.","authors":"Yue Wu,Qiran Sun,Danrui Zhao,Xu Zhang,Longmei Zhai,Jiahong Lv,Ting Wu,Xinzhong Zhang,Zhenhai Han,Yi Wang","doi":"10.1093/plphys/kiaf657","DOIUrl":"https://doi.org/10.1093/plphys/kiaf657","url":null,"abstract":"Iron (Fe) deficiency is a major limitation to apple (Malus domestica) growth in calcareous soils. Understanding the molecular mechanisms underlying Fe deficiency responses is crucial for improving Fe use efficiency in fruit trees. In this study, we identified the ETHYLENE RESPONSE FACTOR 4 (MxERF4) as a negative regulator of the Fe deficiency response in apple. Transgenic analysis revealed that overexpression of MxERF4 exacerbated leaf chlorosis and reduced root Fe content under Fe-deficient conditions, whereas RNA interference (RNAi) lines exhibited enhanced tolerance. We further identified the MITOGEN-ACTIVATED PROTEIN KINASE (MxMPK6-2) as an interactor of MxERF4. MxMPK6-2 phosphorylates MxERF4, reducing its protein stability and promoting its degradation. MxERF4 interacted with the key Fe uptake regulator FER-LIKE FE DEFICIENCY-INDUCED TRANSCRIPTION FACTOR (MxFIT) and co-localized with it in root tissues. Phosphorylation weakened the MxERF4-MxFIT interaction, thereby relieving the inhibition of MxFIT-basic Helix-Loop-Helix 38/39 (MxbHLH38/39) complex formation. This in turn restored the activation of Fe uptake genes IRON TRANSPORTER1 (MxIRT1) and FERRIC REDUCTASE OXIDASE 2 (MxFRO2), enhanced ferric chelate reductase (FCR) activity, and promoted active Fe accumulation. Together, these findings reveal a previously uncharacterized MPK6-2-ERF4 signaling module that regulates Fe deficiency responses in apple by modulating ERF4 stability and its interaction with FIT, providing insights into the molecular basis of Fe efficiency and offering potential strategies for breeding Fe-efficient rootstocks.","PeriodicalId":20101,"journal":{"name":"Plant Physiology","volume":"34 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145777270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ultraviolet-B (UV-B) radiation negatively affects photosynthesis; however, some studies have also demonstrated positive effects of UV-B radiation on photosynthesis. In cyanobacteria, histidine kinase Hik33 plays an important role in mediating responses to multiple environmental stresses, but whether Hik33 is involved in the positive regulation of photosynthesis by UV-B remains unclear. Here, we successfully established CRISPR-Cpf1-based genetic transformation in the UV-B-tolerant cyanobacterium Nostoc sphaeroides CCNUC1, paving the way for unveiling the regulatory mechanism of UV-B-induced photoacclimation. We constructed a nshik33 knockout mutant that lacked the UV-B-induced positive effects on growth, photosynthetic activity, and cyclic electron flow around photosystem I seen in non-acclimated control cells. We determined that nsHik33 attenuates the phosphorylation of nsRpaB under low UV-B light, thereby upregulating the transcription of photosynthesis-associated genes (such as psbA and psaA, encoding core subunits of photosystems II and I, respectively) in Nostoc sphaeroides CCNUC1. To investigate the conservation of nsHik33 function, we heterologously expressed nshik33 of N. sphaeroides CCNUC1 in the Δhik33 mutant of Synechocystis sp. PCC 6803 and discovered that nsHik33 complements the defective photosynthesis phenotype of Δhik33 mutant cells acclimated to low UV-B. These data indicate that Hik33 plays a crucial role in UV-B-induced photosynthetic acclimation in cyanobacteria.
{"title":"Histidine kinase Hik33 plays a crucial role in UV-B-induced photosynthetic acclimation in cyanobacteria.","authors":"Zhen Chen,Zhen He,Wei-Xin Luo,Zhe Liu,Hai-Feng Xu,Hua-Hua Yue,Fei-Fei Li,Wei-Zhi Li,Chun Chen,Shan Zhang,Kui Xu,Bao-Sheng Qiu,Xiong-Wen Chen","doi":"10.1093/plphys/kiaf661","DOIUrl":"https://doi.org/10.1093/plphys/kiaf661","url":null,"abstract":"Ultraviolet-B (UV-B) radiation negatively affects photosynthesis; however, some studies have also demonstrated positive effects of UV-B radiation on photosynthesis. In cyanobacteria, histidine kinase Hik33 plays an important role in mediating responses to multiple environmental stresses, but whether Hik33 is involved in the positive regulation of photosynthesis by UV-B remains unclear. Here, we successfully established CRISPR-Cpf1-based genetic transformation in the UV-B-tolerant cyanobacterium Nostoc sphaeroides CCNUC1, paving the way for unveiling the regulatory mechanism of UV-B-induced photoacclimation. We constructed a nshik33 knockout mutant that lacked the UV-B-induced positive effects on growth, photosynthetic activity, and cyclic electron flow around photosystem I seen in non-acclimated control cells. We determined that nsHik33 attenuates the phosphorylation of nsRpaB under low UV-B light, thereby upregulating the transcription of photosynthesis-associated genes (such as psbA and psaA, encoding core subunits of photosystems II and I, respectively) in Nostoc sphaeroides CCNUC1. To investigate the conservation of nsHik33 function, we heterologously expressed nshik33 of N. sphaeroides CCNUC1 in the Δhik33 mutant of Synechocystis sp. PCC 6803 and discovered that nsHik33 complements the defective photosynthesis phenotype of Δhik33 mutant cells acclimated to low UV-B. These data indicate that Hik33 plays a crucial role in UV-B-induced photosynthetic acclimation in cyanobacteria.","PeriodicalId":20101,"journal":{"name":"Plant Physiology","volume":"21 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145777264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chongzhao Li, Qiqi Zhao, Qian Luo, Xinyi Zhou, Xi Zhang, Yong Wang
Cuticular wax protects the aerial organs of land plants from environmental stresses, especially drought. Glaucousness is an important wax phenotype that is closely related to drought tolerance in wheat (Triticum aestivum). However, how wheat glaucousness is regulated remains largely unknown. In this study, three homeologous R2R3-type MYB transcription factors, TaMYB96-2A, TaMYB96-2B and TaMYB96-2D, were identified from wheat sub-genomes 2A, 2B and 2D, respectively. Compared with wild-type, TaMYB96-2D-overexpressing lines exhibited a more severe glaucous phenotype with significantly enhanced total wax loads and amounts of individual cuticular wax components in flag leaves, flag leaf sheaths, peduncles, and glumes. In addition, overexpression of TaMYB96-2D led to lower water loss rates, less chlorophyll leaching, and increased drought tolerance. By contrast, the three TaMYB96-2A/2B/2D genes knockout lines displayed a green phenotype with reduced total wax loads and amounts of individual cuticular wax components, particularly diketones (β-diketone and hydroxy-β-diketone). The knockout lines also showed higher water loss rates, more chlorophyll leaching, and reduced drought tolerance. TaMYB96-2D directly bound to the consensus CAACCA motif present in the promoter regions of three diketone biosynthetic genes, TaDMH, TaDMP, and TaDMC, and positively regulated their expression. Taken together, these results demonstrate that TaMYB96-2D enhances the glaucous phenotype and drought tolerance by promoting cuticular wax accumulation on the aerial organs of wheat. TaMYB96-2D can serve as a valuable tool to improve wax production and enhance drought tolerance in wheat breeding programs.
{"title":"Wheat TaMYB96-2D positively regulates glaucousness and drought tolerance by promoting cuticular wax accumulation","authors":"Chongzhao Li, Qiqi Zhao, Qian Luo, Xinyi Zhou, Xi Zhang, Yong Wang","doi":"10.1093/plphys/kiaf668","DOIUrl":"https://doi.org/10.1093/plphys/kiaf668","url":null,"abstract":"Cuticular wax protects the aerial organs of land plants from environmental stresses, especially drought. Glaucousness is an important wax phenotype that is closely related to drought tolerance in wheat (Triticum aestivum). However, how wheat glaucousness is regulated remains largely unknown. In this study, three homeologous R2R3-type MYB transcription factors, TaMYB96-2A, TaMYB96-2B and TaMYB96-2D, were identified from wheat sub-genomes 2A, 2B and 2D, respectively. Compared with wild-type, TaMYB96-2D-overexpressing lines exhibited a more severe glaucous phenotype with significantly enhanced total wax loads and amounts of individual cuticular wax components in flag leaves, flag leaf sheaths, peduncles, and glumes. In addition, overexpression of TaMYB96-2D led to lower water loss rates, less chlorophyll leaching, and increased drought tolerance. By contrast, the three TaMYB96-2A/2B/2D genes knockout lines displayed a green phenotype with reduced total wax loads and amounts of individual cuticular wax components, particularly diketones (β-diketone and hydroxy-β-diketone). The knockout lines also showed higher water loss rates, more chlorophyll leaching, and reduced drought tolerance. TaMYB96-2D directly bound to the consensus CAACCA motif present in the promoter regions of three diketone biosynthetic genes, TaDMH, TaDMP, and TaDMC, and positively regulated their expression. Taken together, these results demonstrate that TaMYB96-2D enhances the glaucous phenotype and drought tolerance by promoting cuticular wax accumulation on the aerial organs of wheat. TaMYB96-2D can serve as a valuable tool to improve wax production and enhance drought tolerance in wheat breeding programs.","PeriodicalId":20101,"journal":{"name":"Plant Physiology","volume":"93 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145784403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Photoperiod is a critical environmental cue that determines the timing of flowering in plants. During the domestication of rice (Oryza sativa), natural allelic variation in photoperiodic flowering regulators played an important role in adaptation to a wide range of latitudes. Here, we demonstrate the involvement of the R2R3-type MYB protein OsMYB44 in photoperiodic flowering in rice. Overexpression of OsMYB44 accelerated flowering under short-day (SD) conditions and delayed flowering under long-day conditions. Meanwhile, osmyb44 knockout mutants showed delayed flowering under SD conditions. We determined that the C-terminal region of OsMYB44 interacts with Heading date 1 (Hd1), a primary photoperiodic flowering regulator in rice. OsMYB44 also interacts with Days to heading 8 (DTH8) and OsNF-YC2, forming an NF-Y transcriptional complex with Hd1. This suggests that OsMYB44 participates in transcriptional regulation along with NF-Y components. We also showed that OsMYB44 binds to MYB-core type I motifs in the promoter region of Early heading date 1 (Ehd1) and activates its expression. Analysis of natural variation in OsMYB44 identified four haplotypes, OsMYB44a–d, and revealed that a single amino acid substitution in OsMYB44b may contribute to delayed flowering by reducing the binding affinity of OsMYB44b to Hd1. Further examination of the geographical distribution of the four OsMYB44 haplotypes suggested that natural variation in the OsMYB44 haplotypes contributed to regional adaptation during rice domestication. Together, these findings underscore the pivotal role of OsMYB44 in the transcriptional regulation of photoperiodic flowering in rice.
{"title":"Rice OsMYB44 regulates Early heading date 1 expression for photoperiodic flowering","authors":"Hyeryung Yoon, Sang-Ji Lee, Jinku Kang, Sae Hyun Lee, Tae-Jin Yang, Gynheung An, Kiyoon Kang, Sung-Hwan Cho, Nam-Chon Paek","doi":"10.1093/plphys/kiaf639","DOIUrl":"https://doi.org/10.1093/plphys/kiaf639","url":null,"abstract":"Photoperiod is a critical environmental cue that determines the timing of flowering in plants. During the domestication of rice (Oryza sativa), natural allelic variation in photoperiodic flowering regulators played an important role in adaptation to a wide range of latitudes. Here, we demonstrate the involvement of the R2R3-type MYB protein OsMYB44 in photoperiodic flowering in rice. Overexpression of OsMYB44 accelerated flowering under short-day (SD) conditions and delayed flowering under long-day conditions. Meanwhile, osmyb44 knockout mutants showed delayed flowering under SD conditions. We determined that the C-terminal region of OsMYB44 interacts with Heading date 1 (Hd1), a primary photoperiodic flowering regulator in rice. OsMYB44 also interacts with Days to heading 8 (DTH8) and OsNF-YC2, forming an NF-Y transcriptional complex with Hd1. This suggests that OsMYB44 participates in transcriptional regulation along with NF-Y components. We also showed that OsMYB44 binds to MYB-core type I motifs in the promoter region of Early heading date 1 (Ehd1) and activates its expression. Analysis of natural variation in OsMYB44 identified four haplotypes, OsMYB44a–d, and revealed that a single amino acid substitution in OsMYB44b may contribute to delayed flowering by reducing the binding affinity of OsMYB44b to Hd1. Further examination of the geographical distribution of the four OsMYB44 haplotypes suggested that natural variation in the OsMYB44 haplotypes contributed to regional adaptation during rice domestication. Together, these findings underscore the pivotal role of OsMYB44 in the transcriptional regulation of photoperiodic flowering in rice.","PeriodicalId":20101,"journal":{"name":"Plant Physiology","volume":"20 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145770638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"PII controls ACCase assembly to co-regulate oil and protein metabolism in plants.","authors":"Asif Ali,Maneesh Lingwan","doi":"10.1093/plphys/kiaf649","DOIUrl":"https://doi.org/10.1093/plphys/kiaf649","url":null,"abstract":"","PeriodicalId":20101,"journal":{"name":"Plant Physiology","volume":"153 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145765282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pavol Melicher, Petr Dvořák, Maryna Tsinyk, Jan Řehák, Olga Šamajová, Kateřina Hlaváčková, Miroslav Ovečka, Jozef Šamaj, Tomáš Takáč
The generation of reactive oxygen species (ROS) and their regulation by antioxidant enzymes such as IRON SUPEROXIDE DISMUTASE 1 (FSD1) are critical for managing plant responses to salt stress. However, the protein networks modulating ROS levels during salt stress remain incompletely understood. Our co-immunoprecipitation analysis identified FSD1 as an interaction partner of the scaffolding protein RECEPTOR FOR ACTIVATED C KINASE 1A (RACK1A). Bimolecular fluorescence complementation analyses revealed that RACK1A interacts with FSD1 predominantly in the cytoplasm. Despite elevated FSD1 activity in rack1a mutants, the abundance of FSD1 protein remained unchanged. Advanced fluorescence microscopy and genetic studies further confirmed localization patterns of RACK1A and FSD1 during salt stress responses. Additionally, we found that the RACK1A-FSD1 module was involved in root hair tip growth, highlighting the developmental significance of this interaction. While rack1a mutants exhibited salt resilience, the fsd1-1 rack1a-1 double mutant displayed reduced salt stress resistance, which was substantiated by reduced ROS levels. Upon salt stress, a distinct pool of RACK1A and FSD1 proteins accumulated in cycloheximide-sensitive structural condensates in the cytoplasm that colocalized with the stress granule (SG) marker protein RNA-BINDING PROTEIN 47. FSD1 activity was lower in SGs compared to the soluble extract. RACK1A also interacted with TUDOR STAPHYLOCOCCAL NUCLEASE 2, which participates in SG formation. However, RACK1A knock-out completely abolished salt-stress-dependent accumulation of FSD1 in structural condensates, suggesting that RACK1A likely mediates the recruitment of FSD1 to SGs. Thus, this study uncovers a mechanism for the regulation of RACK1/FSD1-dependent antioxidant defense in response to salt stress in Arabidopsis thaliana.
活性氧（ROS）的产生及其由抗氧化酶如铁超氧化物歧化酶1 （FSD1）调控是管理植物对盐胁迫反应的关键。然而，在盐胁迫下调节ROS水平的蛋白质网络仍然不完全清楚。我们的共免疫沉淀分析发现FSD1是支架蛋白受体活化C激酶1A （RACK1A）的相互作用伙伴。双分子荧光互补分析显示RACK1A主要在细胞质中与FSD1相互作用。尽管rack1a突变体中FSD1活性升高，但FSD1蛋白的丰度保持不变。先进的荧光显微镜和遗传学研究进一步证实了RACK1A和FSD1在盐胁迫响应中的定位模式。此外，我们发现RACK1A-FSD1模块参与了根毛尖端的生长，突出了这种相互作用的发育意义。rack1a突变体表现出耐盐性，而fsd1-1 rack1a-1双突变体表现出较低的盐胁迫抗性，这可以通过降低ROS水平得到证实。在盐胁迫下，细胞质中的环己亚胺敏感结构凝聚体中积累了大量RACK1A和FSD1蛋白，这些结构凝聚体与应激颗粒（SG）标记蛋白RNA-BINDING protein 47共定位。与可溶性提取物相比，SGs中FSD1活性较低。RACK1A还与TUDOR葡萄球菌核酸酶2相互作用，后者参与SG的形成。然而，RACK1A敲除完全消除了FSD1在结构凝析油中盐胁迫依赖性的积累，这表明RACK1A可能介导了FSD1向SGs的募集。因此，本研究揭示了拟南芥RACK1/ fsd1依赖性抗氧化防御在盐胁迫下的调控机制。
{"title":"RACK1A interacts and co-localizes with FSD1 in stress granules to regulate salt stress response in Arabidopsis","authors":"Pavol Melicher, Petr Dvořák, Maryna Tsinyk, Jan Řehák, Olga Šamajová, Kateřina Hlaváčková, Miroslav Ovečka, Jozef Šamaj, Tomáš Takáč","doi":"10.1093/plphys/kiaf659","DOIUrl":"https://doi.org/10.1093/plphys/kiaf659","url":null,"abstract":"The generation of reactive oxygen species (ROS) and their regulation by antioxidant enzymes such as IRON SUPEROXIDE DISMUTASE 1 (FSD1) are critical for managing plant responses to salt stress. However, the protein networks modulating ROS levels during salt stress remain incompletely understood. Our co-immunoprecipitation analysis identified FSD1 as an interaction partner of the scaffolding protein RECEPTOR FOR ACTIVATED C KINASE 1A (RACK1A). Bimolecular fluorescence complementation analyses revealed that RACK1A interacts with FSD1 predominantly in the cytoplasm. Despite elevated FSD1 activity in rack1a mutants, the abundance of FSD1 protein remained unchanged. Advanced fluorescence microscopy and genetic studies further confirmed localization patterns of RACK1A and FSD1 during salt stress responses. Additionally, we found that the RACK1A-FSD1 module was involved in root hair tip growth, highlighting the developmental significance of this interaction. While rack1a mutants exhibited salt resilience, the fsd1-1 rack1a-1 double mutant displayed reduced salt stress resistance, which was substantiated by reduced ROS levels. Upon salt stress, a distinct pool of RACK1A and FSD1 proteins accumulated in cycloheximide-sensitive structural condensates in the cytoplasm that colocalized with the stress granule (SG) marker protein RNA-BINDING PROTEIN 47. FSD1 activity was lower in SGs compared to the soluble extract. RACK1A also interacted with TUDOR STAPHYLOCOCCAL NUCLEASE 2, which participates in SG formation. However, RACK1A knock-out completely abolished salt-stress-dependent accumulation of FSD1 in structural condensates, suggesting that RACK1A likely mediates the recruitment of FSD1 to SGs. Thus, this study uncovers a mechanism for the regulation of RACK1/FSD1-dependent antioxidant defense in response to salt stress in Arabidopsis thaliana.","PeriodicalId":20101,"journal":{"name":"Plant Physiology","volume":"156 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145770639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shenchang Li, Ling Yuan, Haibo Yu, Yang Li, Lingchao Kong, Wei Duan, Zhenchang Liang, Lijun Wang
Grapevines (Vitis vinifera) are economically important crops increasingly threatened by climate change–induced heat stress. Wild species such as V. davidii display markedly higher thermotolerance than the widely cultivated V. vinifera. Our previous research indicated that heat shock transcription factor A2 (VdHSFA2) from V. davidii confers higher thermotolerance than VvHSFA2 from V. vinifera, with HSFB2a as a potential downstream target of HSFA2. However, the precise mechanism by which HSFA2 modulates thermotolerance is not fully understood. Here, we demonstrated that HSFA2 directly activates HSFB2a, which in turn represses the transcription factor WRKY10. DAP-seq, yeast one-hybrid, and electrophoretic mobility shift assays confirmed HSFB2a binds to the WRKY10 promoter, and functional assays indicated that WRKY10 diminishes thermotolerance by repressing L-ascorbate peroxidase 3(APX3) and 18.1 kDa class I heat shock protein (HSP18.1). However, HSFA2 does not bind to the WRKY10 promoter, and HSFA2, HSFB2a and WRKY10 do not physically interact with one another. Transient expression in grapevine plants and stable transformation of suspension cells demonstrated that HSFB2a enhances, whereas WRKY10 reduces, thermotolerance-associated physiological performance. Notably, the V. davidii HSFB2a promoter is more active than that of V. vinifera HSFB2a, potentially contributing to species-level differences in thermotolerance. Our findings reveal the HSFA2-HSFB2a-WRKY10 transcriptional cascade modulating heat stress responses in grapevine, providing molecular targets for breeding heat-resilient cultivars.
{"title":"The HSFA2–HSFB2a–WRKY10 transcriptional cascade mediates thermotolerance across grape germplasms","authors":"Shenchang Li, Ling Yuan, Haibo Yu, Yang Li, Lingchao Kong, Wei Duan, Zhenchang Liang, Lijun Wang","doi":"10.1093/plphys/kiaf651","DOIUrl":"https://doi.org/10.1093/plphys/kiaf651","url":null,"abstract":"Grapevines (Vitis vinifera) are economically important crops increasingly threatened by climate change–induced heat stress. Wild species such as V. davidii display markedly higher thermotolerance than the widely cultivated V. vinifera. Our previous research indicated that heat shock transcription factor A2 (VdHSFA2) from V. davidii confers higher thermotolerance than VvHSFA2 from V. vinifera, with HSFB2a as a potential downstream target of HSFA2. However, the precise mechanism by which HSFA2 modulates thermotolerance is not fully understood. Here, we demonstrated that HSFA2 directly activates HSFB2a, which in turn represses the transcription factor WRKY10. DAP-seq, yeast one-hybrid, and electrophoretic mobility shift assays confirmed HSFB2a binds to the WRKY10 promoter, and functional assays indicated that WRKY10 diminishes thermotolerance by repressing L-ascorbate peroxidase 3(APX3) and 18.1 kDa class I heat shock protein (HSP18.1). However, HSFA2 does not bind to the WRKY10 promoter, and HSFA2, HSFB2a and WRKY10 do not physically interact with one another. Transient expression in grapevine plants and stable transformation of suspension cells demonstrated that HSFB2a enhances, whereas WRKY10 reduces, thermotolerance-associated physiological performance. Notably, the V. davidii HSFB2a promoter is more active than that of V. vinifera HSFB2a, potentially contributing to species-level differences in thermotolerance. Our findings reveal the HSFA2-HSFB2a-WRKY10 transcriptional cascade modulating heat stress responses in grapevine, providing molecular targets for breeding heat-resilient cultivars.","PeriodicalId":20101,"journal":{"name":"Plant Physiology","volume":"15 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145765024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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