Wu Nan, Lan Hujiao, Huang Minjun, Wang Wenxu, Liu Jianzhong
College of Life Sciences, Zhejiang Normal University, Jinhua 321004, Zhejiang, China.
Zhejiang Provincial Key Laboratory of Biotechnology on Specialty Economic Plants, College of Life Sciences, Zhejiang Normal University, Jinhua 321004, Zhejiang, China.
Sheng Wu Gong Cheng Xue Bao. 2024 Apr 25;40(4):1050-1064. doi: 10.13345/j.cjb.230429.
Heterotrimeric GTP-binding protein (G-proteins) complex, which consists of Gα, Gβ and Gγ subunits, plays critical roles in defense signaling. genome contains only a single Gβ-encoding gene, . Loss function of in results in enhanced susceptibility to a wide range of pathogens. However, the function of soybean in immunity has not been previously interrogated. Bioinformatic analysis indicated that there are four homologous genes in soybean genome, sharing homology of 86%-97%. To overcome the functional redundancy of these homologs, virus-induced gene silencing (VIGS) mediated by the bean pod mottle virus (BPMV) was used to silence these four genes simultaneously. As expected, these four homologous genes were indeed silenced by a single BPMV-VIGS vector carrying a conserved fragments among these four genes. A dwarfed phenotype was observed in silenced soybean plants, suggesting that AGB1s play a crucial role in growth and development. Disease resistance analysis indicated that silencing significantly compromised the resistance of soybean plants against pv. (). This reduced resistance was correlated with the decreased accumulation of pathogen-induced reactive oxygen species (ROS) and the reduced activation of MPK3 in response to flg22, a conserved N-terminal peptide of flagellin protein. These results indicate that AGB1 functions as a positive regulator in disease resistance and AGB1 is indispensable for the ROS production and MPK3 activation induced by pathogen infection. Yeast two hybrid assay showed that AGB1 interacted with AGG1, suggesting that an evolutionary conserved heterotrimeric G protein complex similarly functions in soybean.
异源三聚体GTP结合蛋白（G蛋白）复合体由Gα、Gβ和Gγ亚基组成，在防御信号传导中起关键作用。基因组仅包含一个编码Gβ的基因。在[具体物种]中该基因的功能丧失导致对多种病原体的易感性增强。然而，大豆中[该基因名称]在免疫中的功能此前尚未被研究。生物信息学分析表明，大豆基因组中有四个[该基因名称]同源基因，同源性为86%-97%。为了克服这些同源物的功能冗余，利用菜豆斑驳病毒（BPMV）介导的病毒诱导基因沉默（VIGS）同时沉默这四个基因。正如预期的那样，这四个[该基因名称]同源基因确实被携带这四个基因保守片段的单个BPMV-VIGS载体沉默。在沉默的大豆植株中观察到矮化表型，表明AGB1在生长发育中起关键作用。抗病性分析表明，沉默[该基因名称]显著降低了大豆植株对[病原体名称]pv.[具体菌株名称]（[病原体名称]）的抗性。这种抗性降低与病原体诱导的活性氧（ROS）积累减少以及响应鞭毛蛋白保守N端肽flg22时MPK3的激活减少有关。这些结果表明，AGB1在抗病性中起正调控作用，并且AGB1对于病原体感染诱导的ROS产生和MPK3激活是不可或缺的。酵母双杂交试验表明，AGB1与AGG1相互作用，表明进化保守的异源三聚体G蛋白复合体在大豆中具有类似功能。
