Ectopic expression of VRT-A2 underlies the origin of Triticum polonicum and Triticum petropavlovskyi with long outer glumes and grains  

作　　者：Jing Liu Zhaoyan Chen Zhihui Wang Zhaoheng Zhang Xiaoming Xie Zihao Wang Lingling Chai Long Song Xuejiao Cheng Man Feng Xiaobo Wang Yanhong Liu Zhaorong Hu Jiewen Xing Zhenqi Su Huiru Peng Mingming Xin Yingyin Yao Weilong Guo Qixin Sun Jie Liu Zhongfu Ni 

机构地区：[1]State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization(MOE)and Beijing Key Laboratory of Crop Genetic Improvement,China Agricultural University,Beijing 100193,P.R.China

出　　处：《Molecular Plant》2021年第9期1472-1488,共17页分子植物（英文版）

基　　金：This work was supported by grants from the National Natural Science Foundation of China(32072055,31991210,and 91935304).

摘　　要：Polish wheat (Triticum polonicum) is a unique tetraploid wheat species characterized by an elongated outer glume. The genetic control of the long-glume trait by a single semi-dominant locus, P1 (from Polish wheat), was established more than 100 years ago, but the underlying causal gene and molecular nature remain elusive. Here, we report the isolation of VRT-A2, encoding an SVP-clade MADS-box transcription factor, as the P1 candidate gene. Genetic evidence suggests that in T. polonicum, a naturally occurring sequence rearrangement in the intron-1 region of VRT-A2 leads to ectopic expression of VRT-A2 in floral organs where the long-glume phenotype appears. Interestingly, we found that the intron-1 region is a key ON/OFF molecular switch for VRT-A2 expression, not only because it recruits transcriptional repressors, but also because it confers intron-mediated transcriptional enhancement. Genotypic analyses using wheat accessions indicated that the P1 locus is likely derived from a single natural mutation in tetraploid wheat, which was subsequently inherited by hexaploid T. petropavlovskyi. Taken together, our findings highlight the promoter-proximal intron variation as a molecular basis for phenotypic differentiation, and thus species formation in Triticum plants.

关 键 词：long glume P1 species differentiation T.polonicum VRT-A2 

分 类 号：S512.1[农业科学—作物学]