State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, PR China.
Centre for Integrative Legume Research, School of Agriculture and Food Sciences, The University of Queensland, St. Lucia, QLD, Australia.
J Exp Bot. 2019 Jun 28;70(12):3165-3176. doi: 10.1093/jxb/erz144.
Auxin plays central roles in rhizobial infection and nodule development in legumes. However, the sources of auxin during nodulation are unknown. In this study, we analyzed the YUCCA (YUC) gene family of soybean and identified GmYUC2a as an important regulator of auxin biosynthesis that modulates nodulation. Following rhizobial infection, GmYUC2a exhibited increased expression in various nodule tissues. Overexpression of GmYUC2a (35S::GmYUC2a) increased auxin production in soybean, resulting in severe growth defects in root hairs and root development. Upon rhizobial infection, 35S::GmYUC2a hairy roots displayed altered patterns of root hair deformation and nodule formation. Root hair deformation occurred mainly on primary roots, and nodules formed exclusively on primary roots of 35S::GmYUC2a plants. Moreover, transgenic 35S::GmYUC2a composite plants showed delayed nodule development and a reduced number of nodules. Our results suggest that GmYUC2a plays an important role in regulating both root growth and nodulation by modulating auxin balance in soybean.
生长素在根瘤菌感染和豆科植物结瘤发育中起着核心作用。然而，结瘤过程中生长素的来源尚不清楚。在本研究中，我们分析了大豆的 YUCCA（YUC）基因家族，并鉴定出 GmYUC2a 是调节生长素生物合成的重要调节剂，可调节结瘤。在根瘤菌感染后，GmYUC2a 在各种根瘤组织中表达增加。过表达 GmYUC2a（35S::GmYUC2a）会增加大豆中的生长素产量，导致根毛和根系发育的严重生长缺陷。在根瘤菌感染后，35S::GmYUC2a 毛状根显示出根毛变形和结瘤形成模式的改变。根毛变形主要发生在主根上，而 35S::GmYUC2a 植株的主根上仅形成根瘤。此外，转基因 35S::GmYUC2a 复合植物表现出结瘤发育延迟和结瘤数量减少。我们的结果表明，GmYUC2a 通过调节大豆中生长素的平衡，在调节根系生长和结瘤方面发挥着重要作用。
