Liu Cheng-Chen, Liu Ying-Na, Cheng Jian-Fei, Guo Rui, Tian Li, Wang Bin
State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China.
Front Plant Sci. 2022 Apr 11;13:853435. doi: 10.3389/fpls.2022.853435. eCollection 2022.
Several angiosperm () genes, including tomato and rice are induced during arbuscular mycorrhizal (AM) symbiosis, but their functions remain largely unclear. Recently, tomato was suggested to negatively regulate arbuscule incidence decreasing auxin levels in colonized cells. In this study, by acquiring rice :β-glucuronidase () transgenic plants and generating mutants CRISPR/Cas9 technique, the roles of in modulating rice root morphology and affecting AM symbiosis were investigated through time course experiments. Unlike , showed asymbiotic expression in rice young lateral roots, and its mutation resulted in a "shallow" root architecture. Such root morphological change was also observed under symbiotic condition and it likely promoted AM fungal colonization, as the mutants exhibited higher colonization levels and arbuscule incidence than wild-type at early stages. Similar to , showed symbiotic expression in cortical cells that have formed mature arbuscules. At late stages of symbiosis, mutants showed elongated cortical cells and larger arbuscules than wild-type, indicating elevated auxin level in the colonized cells. Together, these results revealed both asymbiotic and symbiotic roles of in modulating rice root architecture and controlling auxin levels in arbusculated cells, which further affected colonization rate and arbuscule phenotype.
包括番茄和水稻在内的几种被子植物基因在丛枝菌根（AM）共生过程中被诱导，但它们的功能仍不清楚。最近，有人提出番茄通过降低定殖细胞中的生长素水平来负调控丛枝发生率。在本研究中，通过获得水稻：β-葡萄糖醛酸酶（GUS）转基因植物并利用CRISPR/Cas9技术产生突变体，通过时间进程实验研究了该基因在调节水稻根系形态和影响AM共生中的作用。与番茄不同，该基因在水稻幼侧根中表现出非共生表达，其突变导致根系结构“浅”。在共生条件下也观察到这种根系形态变化，并且它可能促进了AM真菌定殖，因为突变体在早期阶段表现出比野生型更高的定殖水平和丛枝发生率。与番茄类似，该基因在已形成成熟丛枝的皮层细胞中表现出共生表达。在共生后期，该基因的突变体皮层细胞比野生型更长，丛枝更大，表明定殖细胞中生长素水平升高。总之，这些结果揭示了该基因在调节水稻根系结构和控制丛枝细胞中生长素水平方面的非共生和共生作用，这进一步影响了定殖率和丛枝表型。
