Evolution of the leucine-rich repeat receptor-like protein kinase gene family： Ancestral copy number and functional divergence of BAM1 and/3AM2 in Brassicaceae  

作　　者：Hao Li Qian Shit, Zai-Bao Zhang, Li-Ping Zeng, Ji Qi, and Hong Ma. qian Sh Zai-Bao Zhang Li-Ping Zeng Ji Qi Hong Ma 

机构地区：[1]State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, Ministry of Education KeyLaboratory for Biodiversity Science and Ecological Engineering, institute of Plant Biology, institute of Biodiversity Sciences, Center forEvolutionary Biology, School of Life Sciences, Fudan University, Shanghai 200438, China [2]Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China

出　　处：《Journal of Systematics and Evolution》2016年第3期204-218,共15页植物分类学报（英文版）

基　　金：Acknowledgements We thank Yamao Chen for manuscript editing and Yaqiong Wang, Ren Ren, Haifeng Wang, and Lei Wang for technical assistance and discussion. This work was supported by grants from the National Natural Science Foundation of China （Grant No. 31130006） to H.M. and （Grant No. 31371330） to J.Q.

摘　　要：Gene duplication allows for functional divergence and innovation that provide selective advantages. However, in flowering plants genetic studies have revealed that single-gene mutations affecting one of two or more closely related paralogs often fail to cause detectable morphological defects, suggesting functional redundancy. Flowering plants have hundreds of genes encoding leucine-rich repeat receptor-like protein kinases （LRR-RLKs）, several of which play important roles in anther development, but little is known about their evolutionary history and possible functional divergence. We investigated the evolutionary relationship of the LRR-RLK gene family by phylogenetic analysis and found that these closely related paralogs resulted from multiple duplication events, such as the one resulting in BAM1 and BAM2. We further used quantitative real-time reverse transcription-polymerase chain reaction to verify gene expression changes in immature anthers from the bamllbam2 single and double mutants compared with wild type, providing strong evidence that the BAM1 and BAM2 genes have evolved different functions, with differential effects on anther gene expression. Moreover, careful examination of anther development in ham1 and bum2 single mutants revealed previously unrecognized extra cell division in tapetum cell layers. Thus our results from phylogenetic, molecular, and morphological analyses uncover sequence and functional differences between paralogs whose single mutants lack obvious fertility defects, effectively revealing functional divergence of duplicate genes.Gene duplication allows for functional divergence and innovation that provide selective advantages. However, in flowering plants genetic studies have revealed that single-gene mutations affecting one of two or more closely related paralogs often fail to cause detectable morphological defects, suggesting functional redundancy. Flowering plants have hundreds of genes encoding leucine-rich repeat receptor-like protein kinases （LRR-RLKs）, several of which play important roles in anther development, but little is known about their evolutionary history and possible functional divergence. We investigated the evolutionary relationship of the LRR-RLK gene family by phylogenetic analysis and found that these closely related paralogs resulted from multiple duplication events, such as the one resulting in BAM1 and BAM2. We further used quantitative real-time reverse transcription-polymerase chain reaction to verify gene expression changes in immature anthers from the bamllbam2 single and double mutants compared with wild type, providing strong evidence that the BAM1 and BAM2 genes have evolved different functions, with differential effects on anther gene expression. Moreover, careful examination of anther development in ham1 and bum2 single mutants revealed previously unrecognized extra cell division in tapetum cell layers. Thus our results from phylogenetic, molecular, and morphological analyses uncover sequence and functional differences between paralogs whose single mutants lack obvious fertility defects, effectively revealing functional divergence of duplicate genes.

关 键 词：anther development BAM1/BAM2 Brassicaceae leucine-rich repeat receptor-like kinases LRR-RLK subfunctionalization. 

分 类 号：Q949.748.3[生物学—植物学] S565.1[农业科学—作物学]