Ai Guo, Huang Rong, Zhang Dedi, Li Miao, Li Guobin, Li Wangfang, Ahiakpa John K, Wang Yikui, Hong Zonglie, Zhang Junhong
National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
Vegetable Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, Guangxi, 530007, China.
Plant Sci. 2023 May;330:111638. doi: 10.1016/j.plantsci.2023.111638. Epub 2023 Feb 15.
Multiple Gretchen Hagen 3 (GH3) genes have been implicated in a range of processes in plant growth and development through their roles in maintaining hormonal homeostasis. However, there has only been limited study on the functions of GH3 genes in tomato (Solanum lycopersicum). In this work, we investigated the important function of SlGH3.15, a member of the GH3 gene family in tomato. Overexpression of SlGH3.15 led to severe dwarfism in both the above- and below-ground sections of the plant, accompanied by a substantial decrease in free IAA content and reduction in the expression of SlGH3.9, a paralog of SlGH3.15. Exogenous supply of IAA negatively affected the elongation of the primary root and partially restored the gravitropism defects in SlGH3.15-overexpression lines. While no phenotypic change was observed in the SlGH3.15 RNAi lines, double knockout lines of SlGH3.15 and SlGH3.9 were less sensitive to treatments with the auxin polar transport inhibitor. Overall, these findings revealed important roles of SlGH3.15 in IAA homeostasis and as a negative regulator of free IAA accumulation and lateral root formation in tomato.
多个格雷琴·哈根3（GH3）基因通过其在维持激素稳态中的作用，参与了植物生长和发育的一系列过程。然而，关于GH3基因在番茄（Solanum lycopersicum）中的功能研究还很有限。在这项工作中，我们研究了番茄GH3基因家族成员SlGH3.15的重要功能。SlGH3.15的过表达导致植株地上和地下部分严重矮化，同时游离IAA含量大幅降低，且其旁系同源基因SlGH3.9的表达也减少。外源供应IAA对主根伸长有负面影响，并部分恢复了SlGH3.15过表达系中的向地性缺陷。虽然在SlGH3.15 RNAi系中未观察到表型变化，但SlGH3.15和SlGH3.9的双敲除系对生长素极性运输抑制剂处理的敏感性较低。总体而言，这些发现揭示了SlGH3.15在IAA稳态中的重要作用，以及作为番茄中游离IAA积累和侧根形成的负调控因子的作用。
