Su, Bohong;Guo, Yong;Li, Zhongfeng;Gao, Huawei;Wei, Zhongyan;Qiu, Lijuan

Northeast Agr Univ;Henan Agr Univ;Ningbo Univ;Chinese Acad Agr Sci

Intragenic mutations;Microtubules;Plant architecture;Soybean;α-Tubulin

Plant architecture is a target of crop improvement. The soybean mutant ideal type 1 (it1) displays a pleio-tropic phenotype characterized by compact plant architecture, reduced plant height, shortened petioles, wrinkled leaves, and indented seeds. Genetic analysis revealed that the pleiotropic phenotype was con-trolled by an incomplete dominant gene. We characterized the cellular phenotypes of it1 and positionally cloned the it1 locus. Detailed morphogenetic analysis of the it1 mutant revealed an excess of xylem cells and expanded phloem, and polygonal pavement cells. Positional cloning showed that the phenotype was caused by a G-to-A mutation in the second exon of the a-tubulin gene (Glyma.05G157300). The mutation altered microtubule arrangement in pavement cells, changing their morphology. Overexpression of Gmit1 resulted in an it1-like phenotype and polygonal pavement cells and microtubules of overexpressors were parallel or slightly inclined. Five suppressor mutants able to suppress the phenotype of it1 were obtained by EMS mutagenesis in the it1 background. All these mutants carried an additional mutation in the it1 gene. These results suggest that the pleiotropic phenotype of it1 is caused by the mutation in the a- tubulin gene.& COPY; 2022 Crop Science Society of China and Institute of Crop Science, CAAS. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).