Table_2_Soybean F-Box-Like Protein GmFBL144 Interacts With Small Heat Shock Protein and Negatively Regulates Plant Drought Stress Tolerance.xls

The F-box gene family is one of the largest gene families in plants. These genes regulate plant growth and development, as well as biotic and abiotic stress responses, and they have been extensively researched. Drought stress is one of the major factors limiting the yield and quality of soybean. In this study, bioinformatics analysis of the soybean F-box gene family was performed, and the role of soybean F-box-like gene GmFBL144 in drought stress adaptation was characterized. We identified 507 F-box genes in the soybean genome database, which were classified into 11 subfamilies. The expression profiles showed that GmFBL144 was highly expressed in plant roots. Overexpression of GmFBL144 increased the sensitivity of transgenic Arabidopsis to drought stress. Under drought stress, the hydrogen peroxide (H2O2) and malonaldehyde (MDA) contents of transgenic Arabidopsis were higher than those of the wild type (WT) and empty vector control, and the chlorophyll content was lower than that of the control. Y2H and bimolecular fluorescence complementation (BiFC) assays showed that GmFBL144 can interact with GmsHSP. Furthermore, our results showed that GmFBL144 can form SCFFBL144 (E3 ubiquitin ligase) with GmSkp1 and GmCullin1. Altogether, these results indicate that the soybean F-box-like protein GmFBL144 may negatively regulate plant drought stress tolerance by interacting with sHSP. These findings provide a basis for molecular genetics and breeding of soybean.

F-box基因家族是植物中最大的基因家族之一。此类基因可调控植物生长发育，同时参与生物与非生物胁迫应答，相关研究已得到广泛开展。干旱胁迫是限制大豆产量与品质的主要胁迫因素之一。本研究对大豆F-box基因家族开展了生物信息学分析，并对大豆F-box类基因GmFBL144在干旱胁迫适应过程中的功能进行了表征。本研究在大豆基因组数据库中共鉴定出507个F-box基因，可将其划分为11个亚家族。表达谱分析结果显示，GmFBL144在植物根系中呈高表达水平。将GmFBL144过表达后，转基因拟南芥对干旱胁迫的敏感性显著升高。在干旱胁迫条件下，转基因拟南芥的过氧化氢（H₂O₂）与丙二醛（MDA）含量均高于野生型（WT）及空载体对照，而其叶绿素含量则低于对照。酵母双杂交（Yeast Two-Hybrid, Y2H）与双分子荧光互补（Bimolecular Fluorescence Complementation, BiFC）实验结果表明，GmFBL144可与GmsHSP发生相互作用。此外，本研究证实GmFBL144可与GmSkp1及GmCullin1共同组成SCFFBL144（E3泛素连接酶）复合体。综上，大豆F-box类蛋白GmFBL144可能通过与小分子热激蛋白（small heat shock protein, sHSP）相互作用，负调控植物的干旱胁迫耐受性。本研究结果为大豆的分子遗传育种提供了重要的理论基础。