{"title":"The brassinosteroid signaling-related ILI-OsAIF-OsbHLH92 transcription factor module antagonistically controls leaf angle and grain size in rice.","authors":"Mingmin Lu, Mingqian Liu, Qin Luo, Yubing He, Yanan Tian, Huadong Zhan","doi":"10.1093/plphys/kiae668","DOIUrl":null,"url":null,"abstract":"<p><p>Atypical basic helix-loop-helix (bHLH) transcription factors, which lack the basic region for DNA binding, are important elements of brassinosteroid (BR) signaling. Recently, our systematic characterization of the rice (Oryza sativa) INCREASED LEAF INCLINATION (ILI) subfamily of atypical bHLHs revealed their indispensable roles in BR-mediated growth and development. Here, we reported the isolation of two additional rice ILI-interacting atypical bHLHs, ATBS1-INTERACTING FACTOR 1 (OsAIF1)/OsbHLH176 and OsAIF2/OsbHLH178. Genetic and cytological analyses of the OsAIFs knockout mutants and overexpression lines revealed that OsAIF1 and OsAIF2 negatively regulate rice leaf inclination and grain size in a synergistic and redundant manner. Compared to the wild type, osaif knockout mutants exhibited hypersensitivity to BR, while OsAIF1 and OsAIF2 overexpression lines showed greatly reduced sensitivity or complete insensitivity to BR, indicating that these two OsAIFs act as major negative regulators of rice BR signaling. As ILI-interacting negative atypical HLHs, OsAIF1 and OsAIF2 genetically counteracted the positive ILI subfamily of atypical HLHs. Moreover, OsAIF1 and OsAIF2 physically interacted with and antagonized OsbHLH92, a positive regulator of BR signaling, thereby modulating rice development and gene transcription. These findings suggested that the atypical HLHs (ILIs and OsAIF1/OsAIF2) and the bHLH (OsbHLH92) transcription factors form a triantagonistic cascade in rice, counteracting each other to fine-tune leaf angle and grain size through BR signaling. Our results provide insights into the mechanisms balancing BR signaling and growth in rice.</p>","PeriodicalId":20101,"journal":{"name":"Plant Physiology","volume":" ","pages":""},"PeriodicalIF":6.5000,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Plant Physiology","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1093/plphys/kiae668","RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"PLANT SCIENCES","Score":null,"Total":0}
引用次数: 0
Abstract
Atypical basic helix-loop-helix (bHLH) transcription factors, which lack the basic region for DNA binding, are important elements of brassinosteroid (BR) signaling. Recently, our systematic characterization of the rice (Oryza sativa) INCREASED LEAF INCLINATION (ILI) subfamily of atypical bHLHs revealed their indispensable roles in BR-mediated growth and development. Here, we reported the isolation of two additional rice ILI-interacting atypical bHLHs, ATBS1-INTERACTING FACTOR 1 (OsAIF1)/OsbHLH176 and OsAIF2/OsbHLH178. Genetic and cytological analyses of the OsAIFs knockout mutants and overexpression lines revealed that OsAIF1 and OsAIF2 negatively regulate rice leaf inclination and grain size in a synergistic and redundant manner. Compared to the wild type, osaif knockout mutants exhibited hypersensitivity to BR, while OsAIF1 and OsAIF2 overexpression lines showed greatly reduced sensitivity or complete insensitivity to BR, indicating that these two OsAIFs act as major negative regulators of rice BR signaling. As ILI-interacting negative atypical HLHs, OsAIF1 and OsAIF2 genetically counteracted the positive ILI subfamily of atypical HLHs. Moreover, OsAIF1 and OsAIF2 physically interacted with and antagonized OsbHLH92, a positive regulator of BR signaling, thereby modulating rice development and gene transcription. These findings suggested that the atypical HLHs (ILIs and OsAIF1/OsAIF2) and the bHLH (OsbHLH92) transcription factors form a triantagonistic cascade in rice, counteracting each other to fine-tune leaf angle and grain size through BR signaling. Our results provide insights into the mechanisms balancing BR signaling and growth in rice.
期刊介绍:
Plant Physiology® is a distinguished and highly respected journal with a rich history dating back to its establishment in 1926. It stands as a leading international publication in the field of plant biology, covering a comprehensive range of topics from the molecular and structural aspects of plant life to systems biology and ecophysiology. Recognized as the most highly cited journal in plant sciences, Plant Physiology® is a testament to its commitment to excellence and the dissemination of groundbreaking research.
As the official publication of the American Society of Plant Biologists, Plant Physiology® upholds rigorous peer-review standards, ensuring that the scientific community receives the highest quality research. The journal releases 12 issues annually, providing a steady stream of new findings and insights to its readership.