{"title":"Actin-bundling protein fimbrin serves as a new auxin biosynthesis orchestrator in Arabidopsis root tips.","authors":"Yan-Kun Liu, Jing-Jing Li, Qiao-Qiao Xue, Shu-Juan Zhang, Min Xie, Ting Cheng, Hong-Li Wang, Cui-Mei Liu, Jin-Fang Chu, Yu-Sha Pei, Bing-Qian Jia, Jia Li, Li-Jun Tian, Ai-Gen Fu, Ya-Qi Hao, Hui Su","doi":"10.1111/nph.19959","DOIUrl":null,"url":null,"abstract":"<p><p>Plants delicately regulate endogenous auxin levels through the coordination of transport, biosynthesis, and inactivation, which is crucial for growth and development. While it is well-established that the actin cytoskeleton can regulate auxin levels by affecting polar transport, its potential role in auxin biosynthesis has remained largely unexplored. Using LC-MS/MS-based methods combined with fluorescent auxin marker detection, we observed a significant increase in root auxin levels upon deletion of the actin bundling proteins AtFIM4 and AtFIM5. Fluorescent observation, immunoblotting analysis, and biochemical approaches revealed that AtFIM4 and AtFIM5 affect the protein abundance of the key auxin synthesis enzyme YUC8 in roots. AtFIM4 and AtFIM5 regulate the auxin synthesis enzyme YUC8 at the protein level, with its degradation mediated by the 26S proteasome. This regulation modulates auxin synthesis and endogenous auxin levels in roots, consequently impacting root development. Based on these findings, we propose a molecular pathway centered on the 'actin cytoskeleton-26S proteasome-YUC8-auxin' axis that controls auxin levels. Our findings shed light on a new pathway through which plants regulate auxin synthesis. Moreover, this study illuminates a newfound role of the actin cytoskeleton in regulating plant growth and development, particularly through its involvement in maintaining protein homeostasis via the 26S proteasome.</p>","PeriodicalId":48887,"journal":{"name":"New Phytologist","volume":null,"pages":null},"PeriodicalIF":9.4000,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"New Phytologist","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1111/nph.19959","RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"Agricultural and Biological Sciences","Score":null,"Total":0}
引用次数: 0
Abstract
Plants delicately regulate endogenous auxin levels through the coordination of transport, biosynthesis, and inactivation, which is crucial for growth and development. While it is well-established that the actin cytoskeleton can regulate auxin levels by affecting polar transport, its potential role in auxin biosynthesis has remained largely unexplored. Using LC-MS/MS-based methods combined with fluorescent auxin marker detection, we observed a significant increase in root auxin levels upon deletion of the actin bundling proteins AtFIM4 and AtFIM5. Fluorescent observation, immunoblotting analysis, and biochemical approaches revealed that AtFIM4 and AtFIM5 affect the protein abundance of the key auxin synthesis enzyme YUC8 in roots. AtFIM4 and AtFIM5 regulate the auxin synthesis enzyme YUC8 at the protein level, with its degradation mediated by the 26S proteasome. This regulation modulates auxin synthesis and endogenous auxin levels in roots, consequently impacting root development. Based on these findings, we propose a molecular pathway centered on the 'actin cytoskeleton-26S proteasome-YUC8-auxin' axis that controls auxin levels. Our findings shed light on a new pathway through which plants regulate auxin synthesis. Moreover, this study illuminates a newfound role of the actin cytoskeleton in regulating plant growth and development, particularly through its involvement in maintaining protein homeostasis via the 26S proteasome.
期刊介绍:
New Phytologist is a leading publication that showcases exceptional and groundbreaking research in plant science and its practical applications. With a focus on five distinct sections - Physiology & Development, Environment, Interaction, Evolution, and Transformative Plant Biotechnology - the journal covers a wide array of topics ranging from cellular processes to the impact of global environmental changes. We encourage the use of interdisciplinary approaches, and our content is structured to reflect this. Our journal acknowledges the diverse techniques employed in plant science, including molecular and cell biology, functional genomics, modeling, and system-based approaches, across various subfields.