Fusarium wilt has a substantial impact on global banana production, posing a threat to food security worldwide. However, breeding new Fusarium-resistant cultivars is difficult and time-consuming. Alternatively, endophytic biostimulants that could combat such pervasive plant diseases provide possible novel solutions. Our prior research demonstrated that a pyrroloquinoline quinone (PQQ)-producing endophytic bacterium, Burkholderia seminalis 869T2, can enhance the growth of various plant species and protect bananas from Fusarium wilt in the field. PQQ is a peptide-derived redox cofactor known to stimulate mitochondrial biogenesis and metabolism in animals, but its molecular roles, especially in plants, remain to be elucidated. In this study, multi-omics approaches were employed to explore the potential mechanisms through which PQQ influences banana plants. The result of in situ imaging mass spectrometry revealed that the endophytic metabolite PQQ does not function through direct antagonism against Fusarium. The follow-up transcriptomic profiling shows it could regulate plant respiration, TCA cycle, oxidative phosphorylation, NAD/NADP-dependent dehydrogenases, MAPK signalling, and various phytohormone signalling pathways. Furthermore, PQQ appeared to trigger plant systemic immunity, thereby enhancing plant health and resistance to biotic stress. Beyond that, the complete genome of 869T2 was determined for follow-up comparative genomics analyses, revealing its genetic contexts, potential evolutionary events of PQQ operons among the Burkholderia species, and the absence of human virulence-facilitating genes within those PQQ-producing agricultural isolates. In summary, this study facilitates our understanding of PQQ in plant-microbe mutualisms and provides scientific evidence for its future application in agriculture.
{"title":"Endophytic pyrroloquinoline quinone enhances banana growth and immunity against Fusarium wilt for plant-microbe mutualisms","authors":"Shih-Hsun Walter Hung, Man-Yun Yu, Chia-Ho Liu, Tsai-Ching Huang, Jian-Hau Peng, Nai-Yun Jang, Chih-Horng Kuo, Yu-Liang Yang, Ying-Ning Ho, En-Pei Isabel Chiang, Hau-Hsuan Hwang, Chieh-Chen Huang","doi":"10.1101/2024.08.20.608638","DOIUrl":"https://doi.org/10.1101/2024.08.20.608638","url":null,"abstract":"Fusarium wilt has a substantial impact on global banana production, posing a threat to food security worldwide. However, breeding new Fusarium-resistant cultivars is difficult and time-consuming. Alternatively, endophytic biostimulants that could combat such pervasive plant diseases provide possible novel solutions. Our prior research demonstrated that a pyrroloquinoline quinone (PQQ)-producing endophytic bacterium, Burkholderia seminalis 869T2, can enhance the growth of various plant species and protect bananas from Fusarium wilt in the field. PQQ is a peptide-derived redox cofactor known to stimulate mitochondrial biogenesis and metabolism in animals, but its molecular roles, especially in plants, remain to be elucidated. In this study, multi-omics approaches were employed to explore the potential mechanisms through which PQQ influences banana plants. The result of in situ imaging mass spectrometry revealed that the endophytic metabolite PQQ does not function through direct antagonism against Fusarium. The follow-up transcriptomic profiling shows it could regulate plant respiration, TCA cycle, oxidative phosphorylation, NAD/NADP-dependent dehydrogenases, MAPK signalling, and various phytohormone signalling pathways. Furthermore, PQQ appeared to trigger plant systemic immunity, thereby enhancing plant health and resistance to biotic stress. Beyond that, the complete genome of 869T2 was determined for follow-up comparative genomics analyses, revealing its genetic contexts, potential evolutionary events of PQQ operons among the Burkholderia species, and the absence of human virulence-facilitating genes within those PQQ-producing agricultural isolates. In summary, this study facilitates our understanding of PQQ in plant-microbe mutualisms and provides scientific evidence for its future application in agriculture.","PeriodicalId":501341,"journal":{"name":"bioRxiv - Plant Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The microRNA miR319 regulates leaf shape and size in diverse plant species by reducing the level of the target transcripts that encode JAW-TCP proteins, the transcription factors (TF) which commit the proliferating pavement cells to differentiation. Expression of MIR319C, one of the three miR319-producing genes in Arabidopsis, is expressed throughout the incipient leaf primordia, and the expression domain gets restricted to the base at later stages, partly due to the direct action of JAW-TCPs. However, the factors that activate and maintain MIR319C expression in leaf primordia are yet unknown. Here, we report the CUP-SHAPED COTYLEDON2 (CUC2) transcription factor as a direct activator of MIR319C transcription. In a yeast one-hybrid (Y1H) screen, we identified several NAC domain TFs as potential regulators of MIR319C. Subsequent ex vivo binding and transactivation assays suggested that CUC2 may bind to distal promoter region of MIR319C. Mutants with compromised CUC2 and MIR319C activities exhibited smaller leaf areas and reduced pavement cell numbers due to early cell proliferation-to-differentiation transition. Morphometric analysis of higher order CUC2 and MIR319 loss-of-function mutants highlighted the crucial role of the CUC2-MIR319 module in promoting leaf cell proliferation and indicated functional redundancy among the three MIR319 genes in regulating JAW-TCP levels during leaf growth. Additionally, the phenotypes of mutants with altered CUC2 and MIR319/JAW-TCP activities demonstrated that CUC2 enhances leaf size through the MIR319C-JAW-TCP pathway. Overall, our findings uncovered a novel role for CUC2 in promoting cell proliferation by activating MIR319C transcription in the leaf primordia.
{"title":"CUP-SHAPED COTYLEDON2 activates MIR319C transcription and promotes cell proliferation in Arabidopsis leaf primordia","authors":"Naveen Shankar Alanga, Abhishek Gupta, Somsree Roy, Vishwadeep Mane, Olivier Hamant, Utpal Nath","doi":"10.1101/2024.09.07.611804","DOIUrl":"https://doi.org/10.1101/2024.09.07.611804","url":null,"abstract":"The microRNA miR319 regulates leaf shape and size in diverse plant species by reducing the level of the target transcripts that encode JAW-TCP proteins, the transcription factors (TF) which commit the proliferating pavement cells to differentiation. Expression of MIR319C, one of the three miR319-producing genes in Arabidopsis, is expressed throughout the incipient leaf primordia, and the expression domain gets restricted to the base at later stages, partly due to the direct action of JAW-TCPs. However, the factors that activate and maintain MIR319C expression in leaf primordia are yet unknown. Here, we report the CUP-SHAPED COTYLEDON2 (CUC2) transcription factor as a direct activator of MIR319C transcription. In a yeast one-hybrid (Y1H) screen, we identified several NAC domain TFs as potential regulators of MIR319C. Subsequent ex vivo binding and transactivation assays suggested that CUC2 may bind to distal promoter region of MIR319C. Mutants with compromised CUC2 and MIR319C activities exhibited smaller leaf areas and reduced pavement cell numbers due to early cell proliferation-to-differentiation transition. Morphometric analysis of higher order CUC2 and MIR319 loss-of-function mutants highlighted the crucial role of the CUC2-MIR319 module in promoting leaf cell proliferation and indicated functional redundancy among the three MIR319 genes in regulating JAW-TCP levels during leaf growth. Additionally, the phenotypes of mutants with altered CUC2 and MIR319/JAW-TCP activities demonstrated that CUC2 enhances leaf size through the MIR319C-JAW-TCP pathway. Overall, our findings uncovered a novel role for CUC2 in promoting cell proliferation by activating MIR319C transcription in the leaf primordia.","PeriodicalId":501341,"journal":{"name":"bioRxiv - Plant Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142182983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Japanese morning glory (Ipomoea nil), a short day plant, has been used for studying flowering times. Here, quantitative trait loci (QTL) analysis for days from sowing to flowering (DTF) of F2 between I. nil var. Tokyo Kokei Standard (TKS) and I. hederacea line var. Q65, an early flowering variety, revealed four QTLs: QTL Ipomoea Flowering 1-4 (qIF1-4). The position of qIF3, which had the most significant effect among the four QTLs, corresponds with that of I. nil (or I. hederacea) CONSTANS (InCO/IhCO) in the linkage map. There is a single-base In/Del in the coding sequence of InCO/IhCO. The single-base deletion (SBD) causes a frame-shift mutation and loss of function in TKS allele (inco-1). I. nil accessions bearing inco-1 tend to flower early, similarly to rice varieties bearing the loss of function allele of CO ortholog, hd1. Consequently, inco-1 was inferred to reduce DTF. This inferred effect of inco-1 corresponds with the effect of the TKS allele of qIF3. Because inco-1 is found exclusively in Asian accessions, the SBD in inco-1 might have played an important role in the expansion of Japanese morning glories, originally native to the tropical regions of the Americas, into temperate Asia.
日本牵牛花（Ipomoea nil）是一种短日照植物，一直被用于研究开花时间。在此，对I.nil变种Tokyo Kokei Standard（TKS）和I.hederacea品系变种Q65（一个早花品种）之间的F2从播种到开花的天数（DTF）进行了数量性状位点（QTL）分析，发现了四个QTL：QTL Ipomoea Flowering 1-4（qIF1-4）。在四个 QTL 中，qIF3 的位置与 I. nil（或 I. hederacea）CONSTANS（InCO/IhCO）在连接图中的位置相对应，其影响最为显著。InCO/IhCO 的编码序列中有一个单碱基 In/Del。单碱基缺失（SBD）导致了 TKS 等位基因（inco-1）的移帧突变和功能缺失。携带 inco-1 的 I. nil 品种倾向于早开花，这与携带 CO 同源物 hd1 功能缺失等位基因的水稻品种类似。因此，推断 inco-1 会降低 DTF。inco-1 的这一推断效应与 qIF3 的 TKS 等位基因的效应一致。由于 inco-1 只存在于亚洲品种中，因此在原产于美洲热带地区的日本牵牛花向温带亚洲扩展的过程中，inco-1 中的 SBD 可能发挥了重要作用。
{"title":"Frame-shift mutation of InCO might cause early flowering of Japanese morning glory and might have contributed to northward expansion","authors":"Hiroaki Katsuyama, Takuro Ito, Kyousuke Ezura, Emdadul Haque, Atsushi Hoshino, Eiji Nitasaka, Michiyuki Ono, Shusei Sato, Sachiko Isobe, Hiroyuki Fukuoka, Nobuyoshi Watanabe, Tsutomu Kuboyama","doi":"10.1101/2024.09.05.611556","DOIUrl":"https://doi.org/10.1101/2024.09.05.611556","url":null,"abstract":"Japanese morning glory (Ipomoea nil), a short day plant, has been used for studying flowering times. Here, quantitative trait loci (QTL) analysis for days from sowing to flowering (DTF) of F2 between I. nil var. Tokyo Kokei Standard (TKS) and I. hederacea line var. Q65, an early flowering variety, revealed four QTLs: QTL Ipomoea Flowering 1-4 (qIF1-4). The position of qIF3, which had the most significant effect among the four QTLs, corresponds with that of I. nil (or I. hederacea) CONSTANS (InCO/IhCO) in the linkage map. There is a single-base In/Del in the coding sequence of InCO/IhCO. The single-base deletion (SBD) causes a frame-shift mutation and loss of function in TKS allele (inco-1). I. nil accessions bearing inco-1 tend to flower early, similarly to rice varieties bearing the loss of function allele of CO ortholog, hd1. Consequently, inco-1 was inferred to reduce DTF. This inferred effect of inco-1 corresponds with the effect of the TKS allele of qIF3. Because inco-1 is found exclusively in Asian accessions, the SBD in inco-1 might have played an important role in the expansion of Japanese morning glories, originally native to the tropical regions of the Americas, into temperate Asia.","PeriodicalId":501341,"journal":{"name":"bioRxiv - Plant Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142182984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-08DOI: 10.1101/2024.09.06.611683
Mastoureh Sedaghatmehr, Frieda Roessler, Alexander P Hertle
Essential proteins involved in thylakoid formation, including chloroplast-localized Sec14-like protein (CPSFL1) and the vesicle-inducing protein in plastids (VIPP1), bind PPIs in vitro with high affinity. PPIs are a class of phospholipids characterized by a phosphorylated inositol head group. Although PPIs constitute a relatively small proportion of the total phospholipids, they play essential roles in various regulatory processes. The exact subcellular localization of most PPI species in plants is incomplete due to their rapid turnover and low abundance. Currently there is no documented evidence for the presence and function of phosphoinositides (PPIs) in chloroplasts. In our study, we developed genetically encoded biosensors targeted into plastids, enabling the detection of various PPI isoforms (PI3P, PI4P, PI5P, PI(4,5)P2 and PI(3,5)P2) within the chloroplasts. We effectively demonstrated the specificity of our PPI biosensors in detection of PPIs, as evidenced by the alterations in PPI biosensor distribution patterns upon co-expression of PPI modifying enzymes (cTP-SAC7, cTP-PTEN, and cTP-dOCRL). Additionally, our research confirmed the capability of the generated PPI biosensors to detect PPIs within the chloroplasts of both tobacco and Arabidopsis in a concentration-dependent manner. Furthermore, we unveiled the association and potential interaction of PI3P with VIPP1. We could show that the increased PPI flux within the cell during heat stress affects PPI levels in the chloroplasts, resulting in different distribution patterns of the PPI biosensors. Finally, plants expressing PPI modifiers cTP-SAC7, cTP-PTEN, and cTP-dOCRL, in the chloroplast, showed increased sensitivity to drought stress, likely due to impaired PPI signaling.
参与形成类叶绿体的重要蛋白质，包括叶绿体定位的 Sec14 样蛋白（CPSFL1）和质体中的囊泡诱导蛋白（VIPP1），在体外与 PPIs 具有高亲和力。PPIs 是一类磷脂，以磷酸化肌醇头基为特征。虽然 PPIs 在磷脂总量中所占比例较小，但它们在各种调控过程中发挥着至关重要的作用。由于 PPI 更替快、丰度低，植物中大多数 PPI 物种的亚细胞定位尚不完整。目前还没有关于叶绿体中磷酸肌醇（PPIs）的存在和功能的文献证据。在我们的研究中，我们开发了针对质体的基因编码生物传感器，能够检测叶绿体中的各种 PPI 异构体（PI3P、PI4P、PI5P、PI(4,5)P2 和 PI(3,5)P2）。我们有效地证明了我们的 PPI 生物传感器在检测 PPI 方面的特异性，PPI 生物传感器在共同表达 PPI 修饰酶（cTP-SAC7、cTP-PTEN 和 cTP-dOCRL）时分布模式的改变就是证明。此外，我们的研究还证实了所生成的 PPI 生物传感器能够以浓度依赖的方式检测烟草和拟南芥叶绿体中的 PPI。此外，我们还揭示了 PI3P 与 VIPP1 的关联和潜在相互作用。我们可以证明，热胁迫期间细胞内增加的 PPI 通量会影响叶绿体中的 PPI 水平，从而导致 PPI 生物传感器的不同分布模式。最后，在叶绿体中表达 PPI 改性剂 cTP-SAC7、cTP-PTEN 和 cTP-dOCRL 的植物对干旱胁迫的敏感性增加，这可能是由于 PPI 信号转导受损所致。
{"title":"New evidence for the presence and function of phosphoinositides (PPIs) in the chloroplast","authors":"Mastoureh Sedaghatmehr, Frieda Roessler, Alexander P Hertle","doi":"10.1101/2024.09.06.611683","DOIUrl":"https://doi.org/10.1101/2024.09.06.611683","url":null,"abstract":"Essential proteins involved in thylakoid formation, including chloroplast-localized Sec14-like protein (CPSFL1) and the vesicle-inducing protein in plastids (VIPP1), bind PPIs in vitro with high affinity. PPIs are a class of phospholipids characterized by a phosphorylated inositol head group. Although PPIs constitute a relatively small proportion of the total phospholipids, they play essential roles in various regulatory processes. The exact subcellular localization of most PPI species in plants is incomplete due to their rapid turnover and low abundance. Currently there is no documented evidence for the presence and function of phosphoinositides (PPIs) in chloroplasts. In our study, we developed genetically encoded biosensors targeted into plastids, enabling the detection of various PPI isoforms (PI3P, PI4P, PI5P, PI(4,5)P2 and PI(3,5)P2) within the chloroplasts. We effectively demonstrated the specificity of our PPI biosensors in detection of PPIs, as evidenced by the alterations in PPI biosensor distribution patterns upon co-expression of PPI modifying enzymes (cTP-SAC7, cTP-PTEN, and cTP-dOCRL). Additionally, our research confirmed the capability of the generated PPI biosensors to detect PPIs within the chloroplasts of both tobacco and Arabidopsis in a concentration-dependent manner. Furthermore, we unveiled the association and potential interaction of PI3P with VIPP1. We could show that the increased PPI flux within the cell during heat stress affects PPI levels in the chloroplasts, resulting in different distribution patterns of the PPI biosensors. Finally, plants expressing PPI modifiers cTP-SAC7, cTP-PTEN, and cTP-dOCRL, in the chloroplast, showed increased sensitivity to drought stress, likely due to impaired PPI signaling.","PeriodicalId":501341,"journal":{"name":"bioRxiv - Plant Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142182985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-07DOI: 10.1101/2024.09.04.611222
Crispus Mbaluto, Sharon E Zytynska
Interactions between plant and soil microbes are widespread and modulate plant-insect herbivore interactions. Still, it remains unclear how these shapes the overall plant defence responses and the mechanisms involved. Here, we performed bioassays with barley (Hordeum vulgare) plants to study the underlying molecular pathways induced by two rhizobacteria, Acidovorax radicis or Bacillus subtilis, against the phloem feeding aphid Sitobion avenae over three timepoints. Root colonization by A. radicis or B. subtilis suppressed aphid populations on barley. Analysis of differentially expressed genes and co-expressed gene modules revealed a combination of rhizobacteria and aphid induced plant responses. Aphid feeding triggered distinct plant responses in rhizobacteria-inoculated barley compared to controls, in phytohormone, glutathione, and phenylpropanoid pathways within 24 hours. By day 7, stronger responses were observed in phenylpropanoid and nutrient pathways. By day 21, changes occurred in flavonoid pathways and genes related to tissue damage and repair. Our study suggests that rhizobacteria inoculation of barley against aphids is dynamic and acts through several molecular pathways to induce plant resistance (defences) and tolerance (nutrition and growth) to aphids. Future research holds promise for exploiting these interactions for sustainable crop protection and pest management in agriculture.
{"title":"Rhizobacteria prime the activation of defence and nutritional responses to suppress aphid populations on barley","authors":"Crispus Mbaluto, Sharon E Zytynska","doi":"10.1101/2024.09.04.611222","DOIUrl":"https://doi.org/10.1101/2024.09.04.611222","url":null,"abstract":"Interactions between plant and soil microbes are widespread and modulate plant-insect herbivore interactions. Still, it remains unclear how these shapes the overall plant defence responses and the mechanisms involved. Here, we performed bioassays with barley (Hordeum vulgare) plants to study the underlying molecular pathways induced by two rhizobacteria, Acidovorax radicis or Bacillus subtilis, against the phloem feeding aphid Sitobion avenae over three timepoints. Root colonization by A. radicis or B. subtilis suppressed aphid populations on barley. Analysis of differentially expressed genes and co-expressed gene modules revealed a combination of rhizobacteria and aphid induced plant responses. Aphid feeding triggered distinct plant responses in rhizobacteria-inoculated barley compared to controls, in phytohormone, glutathione, and phenylpropanoid pathways within 24 hours. By day 7, stronger responses were observed in phenylpropanoid and nutrient pathways. By day 21, changes occurred in flavonoid pathways and genes related to tissue damage and repair. Our study suggests that rhizobacteria inoculation of barley against aphids is dynamic and acts through several molecular pathways to induce plant resistance (defences) and tolerance (nutrition and growth) to aphids. Future research holds promise for exploiting these interactions for sustainable crop protection and pest management in agriculture.","PeriodicalId":501341,"journal":{"name":"bioRxiv - Plant Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-07DOI: 10.1101/2024.09.03.611075
Zhongze Li, Minjae Kim, Jose Robert da Silva Nascimento, Bertrand Legeret, Gabriel Lemes Jorge, Marie Bertrand, Frederic Beisson, Jay J. Thelen, Yonghua Li-Beisson
The first step in chloroplast de novo fatty acid synthesis is catalyzed by acetyl-CoA carboxylase (ACCase). As the rate-limiting step for this pathway, ACCase is subject to both positive and negative regulation. In this study, we identify a Chlamydomonas homolog of the plant carboxyltransferase interactor 1 (CrCTI1) and show that this protein, interacts with the Chlamydomonas alpha-carboxyltransferase (Cra-CT) subunit of the ACCase by yeast two-hybrid protein-protein interaction assay. Three independent CRISPR-Cas9 mediated knock-out mutants for CrCTI1 each produced an enhanced-oil phenotype, accumulating 25% more total fatty acids and storing up to five-fold more triacylglycerols (TAGs) in lipid droplets. The TAG phenotype of the crcti1 mutants was not influenced by light but was affected by trophic growth conditions. By growing cells under heterotrophic conditions, we observed a crucial function of CrCTI1 in balancing lipid accumulation and cell growth. Mutating a previously mapped in vivo phosphorylation site (CrCTI1 Ser108 to either Ala or to Asp), did not affect the interaction with Cra-CT. However, mutating all six predicted phosphorylation sites within Cra-CT to create a phosphomimetic mutant reduced significantly this pairwise interaction. Comparative proteomic analyses of the crcti1 mutants and WT suggested a role for CrCTI1 in regulating carbon flux by coordinating carbon metabolism, antioxidant and fatty acid beta-oxidation pathways, to enable cells adapt to carbon availability. Taken together, this study identifies CrCTI1 as a negative regulator of fatty acid synthesis in algae and provides a new molecular brick for genetic engineering of microalgae for biotechnology purposes.
{"title":"Knocking out the carboxyltransferase interactor 1 (CTI1) in Chlamydomonas boosted oil content by fivefold without affecting cell growth","authors":"Zhongze Li, Minjae Kim, Jose Robert da Silva Nascimento, Bertrand Legeret, Gabriel Lemes Jorge, Marie Bertrand, Frederic Beisson, Jay J. Thelen, Yonghua Li-Beisson","doi":"10.1101/2024.09.03.611075","DOIUrl":"https://doi.org/10.1101/2024.09.03.611075","url":null,"abstract":"The first step in chloroplast de novo fatty acid synthesis is catalyzed by acetyl-CoA carboxylase (ACCase). As the rate-limiting step for this pathway, ACCase is subject to both positive and negative regulation. In this study, we identify a Chlamydomonas homolog of the plant carboxyltransferase interactor 1 (CrCTI1) and show that this protein, interacts with the Chlamydomonas alpha-carboxyltransferase (Cra-CT) subunit of the ACCase by yeast two-hybrid protein-protein interaction assay. Three independent CRISPR-Cas9 mediated knock-out mutants for CrCTI1 each produced an enhanced-oil phenotype, accumulating 25% more total fatty acids and storing up to five-fold more triacylglycerols (TAGs) in lipid droplets. The TAG phenotype of the crcti1 mutants was not influenced by light but was affected by trophic growth conditions. By growing cells under heterotrophic conditions, we observed a crucial function of CrCTI1 in balancing lipid accumulation and cell growth. Mutating a previously mapped in vivo phosphorylation site (CrCTI1 Ser108 to either Ala or to Asp), did not affect the interaction with Cra-CT. However, mutating all six predicted phosphorylation sites within Cra-CT to create a phosphomimetic mutant reduced significantly this pairwise interaction. Comparative proteomic analyses of the crcti1 mutants and WT suggested a role for CrCTI1 in regulating carbon flux by coordinating carbon metabolism, antioxidant and fatty acid beta-oxidation pathways, to enable cells adapt to carbon availability. Taken together, this study identifies CrCTI1 as a negative regulator of fatty acid synthesis in algae and provides a new molecular brick for genetic engineering of microalgae for biotechnology purposes.","PeriodicalId":501341,"journal":{"name":"bioRxiv - Plant Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-06DOI: 10.1101/2024.09.04.611195
Ines Moura, Joao Neves, Ana Seneca, Jose Pissarra, Susana Pereira, Claudia Pereira
Due to plants' inability to escape adverse conditions, they must adapt and adjust their endomembrane system through protein sorting and distribution. Cardosins A and B are key models for studying intracellular trafficking. They are aspartic proteinases in thistle flowers that mediate different vacuolar pathways despite sharing high sequence similarity, and both are responsive to stress conditions. The Plant Specific Insert (PSI) is a 100 amino acid domain found in these proteins. It is known that stress can impact protein sorting, shifting it from the conventional pathway (ER-Golgi) to a Golgi-independent route. In this work we assessed changes in the expression and localization of PSI from Cardosin B (PSI B) in Arabidopsis plants overexpressing PSI B-mCherry submitted to different abiotic stress conditions (saline, hydric, oxidative, metals). Aside from potential PSI B localization changes, we focused on characterizing the homozygous line, alongside assessing several biometric parameters and biochemical endpoints. The results revealed that the PSI B line responded differently depending on the stress conditions. Biometric and biochemical analyses emphasized the roles of PSI B in enhancing plant fitness and supporting adaptation to abiotic stress. Besides, confocal microscopy allowed us to find PSI B accumulation in Endoplasmic Reticulum-derived vesicles (ER bodies), indicating a shift from the common PSI B-mediated route. These findings underscore the role of PSI B in enhancing plant fitness and adaptation to abiotic stress through altered protein trafficking.
由于植物无法逃避不利条件，它们必须通过蛋白质分拣和分布来适应和调整其内膜系统。Cardosins A 和 B 是研究细胞内运输的关键模型。它们是蓟花中的天冬氨酸蛋白酶，尽管序列高度相似，但却能介导不同的液泡途径，而且都能对胁迫条件做出反应。植物特异性插入（PSI）是这些蛋白中的一个 100 氨基酸结构域。众所周知，胁迫会影响蛋白质的分选，使其从传统途径（ER-高尔基）转向独立于高尔基的途径。在这项工作中，我们评估了在不同的非生物胁迫条件（盐碱、潮湿、氧化、金属）下，过量表达 PSI B-mCherry 的拟南芥植物中来自卡多辛 B 的 PSI（PSI B）的表达和定位的变化。除了潜在的 PSI B 定位变化外，我们还重点研究了同源品系的特征，同时评估了几个生物计量参数和生化终点。结果表明，PSI B品系在不同的胁迫条件下有不同的反应。生物计量和生化分析强调了 PSI B 在提高植物适应性和支持适应非生物胁迫方面的作用。此外，共聚焦显微镜让我们发现 PSI B 在内质网衍生囊泡（ER 体）中的积累，表明 PSI B 介导的常见途径发生了转变。这些发现强调了 PSI B 在通过改变蛋白质运输提高植物适应性和适应非生物胁迫方面的作用。
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Pub Date : 2024-09-06DOI: 10.1101/2024.09.03.611018
Virginia Cointry, Reyes Rodenas, Nelly Morellet, Valerie Cotelle, Julie Neveu, Gregory Vert
The plant IRT1 iron transporter is a plasma membrane protein that takes up iron in root upon iron-limited conditions. Besides its primary metal substrate iron, IRT1 also transports other divalent metals that overaccumulate in plants when soil iron is low and IRT1 is highly expressed. We previously reported that the intracellular regulatory loop between transmembrane helices TM4 and TM5, comprising IRT1 residues from 144 to 185, is involved in the post-translational regulation of IRT1 by its non-iron metal substrates. Upon excess of zinc, IRT1 (144-185) undergoes phosphorylation by the CIPK23 kinase followed by its ubiquitination by IDF1 to target IRT1 for vacuolar degradation. This zinc-dependent downregulation of IRT1 requires the presence of four histidine (H) residues in IRT1 loop, that directly bind zinc. However, how selective metal binding is achieved and how this allows downstream regulation to take place is largely unknown. Here, we characterized the metal binding properties and structure of IRT1 loop to better understand the molecular basis of non-iron metal sensing and signaling. Using a combination of circular dichroism and NMR, we demonstrate that zinc and manganese bind to IRT1 loop with nanomolar range affinity, and that metal binding does not trigger structuration of the loop. We prove that zinc and manganese binding is mediated by the four H residues and identify aspartic acid (D) residue D173 as helping in metal coordination and participating to metal sensing and metal-dependent degradation of IRT1 in plants. Altogether, our data provide further evidence of how the regulatory loop of IRT1 senses high cytosolic divalent metal concentrations to regulate metal uptake in plants.
{"title":"Metal sensing properties of the disordered loop from the Arabidopsis metal transceptor IRT1","authors":"Virginia Cointry, Reyes Rodenas, Nelly Morellet, Valerie Cotelle, Julie Neveu, Gregory Vert","doi":"10.1101/2024.09.03.611018","DOIUrl":"https://doi.org/10.1101/2024.09.03.611018","url":null,"abstract":"The plant IRT1 iron transporter is a plasma membrane protein that takes up iron in root upon iron-limited conditions. Besides its primary metal substrate iron, IRT1 also transports other divalent metals that overaccumulate in plants when soil iron is low and IRT1 is highly expressed. We previously reported that the intracellular regulatory loop between transmembrane helices TM4 and TM5, comprising IRT1 residues from 144 to 185, is involved in the post-translational regulation of IRT1 by its non-iron metal substrates. Upon excess of zinc, IRT1 (144-185) undergoes phosphorylation by the CIPK23 kinase followed by its ubiquitination by IDF1 to target IRT1 for vacuolar degradation. This zinc-dependent downregulation of IRT1 requires the presence of four histidine (H) residues in IRT1 loop, that directly bind zinc. However, how selective metal binding is achieved and how this allows downstream regulation to take place is largely unknown. Here, we characterized the metal binding properties and structure of IRT1 loop to better understand the molecular basis of non-iron metal sensing and signaling. Using a combination of circular dichroism and NMR, we demonstrate that zinc and manganese bind to IRT1 loop with nanomolar range affinity, and that metal binding does not trigger structuration of the loop. We prove that zinc and manganese binding is mediated by the four H residues and identify aspartic acid (D) residue D173 as helping in metal coordination and participating to metal sensing and metal-dependent degradation of IRT1 in plants. Altogether, our data provide further evidence of how the regulatory loop of IRT1 senses high cytosolic divalent metal concentrations to regulate metal uptake in plants.","PeriodicalId":501341,"journal":{"name":"bioRxiv - Plant Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-06DOI: 10.1101/2024.09.04.611169
Sujit Jung Karki, Paola Pilo, Colleen Lawless, Nikolaos Mastrodimos, Jimmy Burke, Anna Tiley, Angela Feechan, Angela Feechan
Zymoseptoria tritici is an ascomycete fungus and the causal agent of Septoria tritici leaf blotch (STB) in wheat. Z. tritici secretes an array of effector proteins that are likely to facilitate host infection, colonisation and pycnidia production. In this study we demonstrate a role for Zt-11 as a Z. tritici effector during disease progression. Zt-11 is upregulated during the transition of the pathogen from the biotrophic to necrotrophic phase of wheat infection. Deletion of Zt-11 delayed disease development in wheat, reducing the number and size of pycnidia, as well as the number of macropycnidiospores produced by Z. tritici. This delayed disease development by the deltaZt-11 mutants was accompanied by a lower induction of PR genes in wheat, when compared to infection with wildtype Z. tritici. Overall, these data suggest that Zt-11 plays a role in Z. tritici aggressiveness and STB disease progression possibly via a salicylic acid associated pathway.
三尖孢霉菌（Zymoseptoria tritici）是一种子囊真菌，是小麦三尖孢（Septoria tritici）叶斑病（STB）的病原菌。Z. tritici分泌一系列效应蛋白，这些蛋白可能有助于宿主感染、定殖和产生菌丝。在本研究中，我们证明了 Zt-11 在病害发展过程中作为 Z. tritici 效应蛋白的作用。在病原体从小麦感染的生物营养阶段向坏死营养阶段过渡的过程中，Zt-11 被上调。Zt-11的缺失会延缓小麦的病害发展，减少胞囊的数量和大小，并减少三尖杉球孢子虫产生的大孢子数量。与感染野生型 Z. tritici 相比，deltaZt-11 突变体的病害发展延迟伴随着较低的 PR 基因诱导。总之，这些数据表明，Zt-11 可能通过与水杨酸相关的途径在 Z. tritici 的侵染性和 STB 病害发展中发挥作用。
{"title":"The Zymoseptoria tritici effector Zt-11 contributes to aggressiveness in wheat","authors":"Sujit Jung Karki, Paola Pilo, Colleen Lawless, Nikolaos Mastrodimos, Jimmy Burke, Anna Tiley, Angela Feechan, Angela Feechan","doi":"10.1101/2024.09.04.611169","DOIUrl":"https://doi.org/10.1101/2024.09.04.611169","url":null,"abstract":"Zymoseptoria tritici is an ascomycete fungus and the causal agent of Septoria tritici leaf blotch (STB) in wheat. Z. tritici secretes an array of effector proteins that are likely to facilitate host infection, colonisation and pycnidia production. In this study we demonstrate a role for Zt-11 as a Z. tritici effector during disease progression. Zt-11 is upregulated during the transition of the pathogen\u0000from the biotrophic to necrotrophic phase of wheat infection. Deletion of Zt-11 delayed disease development in wheat, reducing the number and size of pycnidia, as well as the number of macropycnidiospores produced by Z. tritici. This delayed disease development by the deltaZt-11 mutants was accompanied by a lower induction of PR genes in wheat, when compared to infection with wildtype Z. tritici. Overall, these data suggest that Zt-11 plays a role in Z. tritici aggressiveness and STB disease progression possibly via a salicylic acid associated pathway.","PeriodicalId":501341,"journal":{"name":"bioRxiv - Plant Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-06DOI: 10.1101/2024.08.31.610611
Neila Ait Kaci, Alice Diot, Beatrice Quinquiry, Olivier Yobregat, Anne Pellegrino, Pierre Maury, Christian Chervin
Studies suggest that ethanol (EtOH), triggers plant adaptation to various stresses at low concentrations (10 microM to 10 mM). This study investigates whether EtOH induces drought acclimation in grapevine, as demonstrated previously in Arabidopsis, rice, and wheat. Preliminary results with bare root Gamay cuttings showed that those pre-treated with 10 microM EtOH aqueous solutions lost fewer leaves when deprived of water compared to controls. Subsequently, we ran a potted-cutting experiment with progressive soil water deficit. Plants pre-treated with EtOH solutions (0.4 and 250 mM) exhibited slower depletion of the fraction of transpirable soil water (FTSW), compared to controls. While 0.4 and 250 mM EtOH tended to decrease transpiration in early days, these EtOH pre-treated plants maintained higher leaf transpiration than controls after 10 days of soil water depletion. The transpiration response to FTSW was affected by EtOH application. EtOH pre-treatments limited plant leaf expansion without increasing leaf senescence, and increased root dry mass. The grapevine responses to EtOH priming followed typical hormesis curves. RNA-seq data revealed transcripts related to this EtOH priming effect. These results suggest that EtOH improves grapevine acclimation to drought, leading to potential water-savings in wine growing regions prone to high water shortages, linked to climate change.
{"title":"Ethanol reduces grapevine water consumption by limiting transpiration","authors":"Neila Ait Kaci, Alice Diot, Beatrice Quinquiry, Olivier Yobregat, Anne Pellegrino, Pierre Maury, Christian Chervin","doi":"10.1101/2024.08.31.610611","DOIUrl":"https://doi.org/10.1101/2024.08.31.610611","url":null,"abstract":"Studies suggest that ethanol (EtOH), triggers plant adaptation to various stresses at low concentrations (10 microM to 10 mM). This study investigates whether EtOH induces drought acclimation in grapevine, as demonstrated previously in Arabidopsis, rice, and wheat. Preliminary results with bare root Gamay cuttings showed that those pre-treated with 10 microM EtOH aqueous solutions lost fewer leaves when deprived of water compared to controls. Subsequently, we ran a potted-cutting experiment with progressive soil water deficit. Plants pre-treated with EtOH solutions (0.4 and 250 mM) exhibited slower depletion of the fraction of transpirable soil water (FTSW), compared to controls. While 0.4 and 250 mM EtOH tended to decrease transpiration in early days, these EtOH pre-treated plants maintained higher leaf transpiration than controls after 10 days of soil water depletion. The transpiration response to FTSW was affected by EtOH application. EtOH pre-treatments limited plant leaf expansion without increasing leaf senescence, and increased root dry mass. The grapevine responses to EtOH priming followed typical hormesis curves. RNA-seq data revealed transcripts related to this EtOH priming effect. These results suggest that EtOH improves grapevine acclimation to drought, leading to potential water-savings in wine growing regions prone to high water shortages, linked to climate change.","PeriodicalId":501341,"journal":{"name":"bioRxiv - Plant Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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