Zheng Kaifeng, Pang Lu, Xue Xiuhua, Gao Ping, Zhao Heping, Wang Yingdian, Han Shengcheng
Beijing Key Laboratory of Gene Resources and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China.
Academy of Plateau Science and Sustainability of the People's Government of Qinghai Province and Beijing Normal University, Qinghai Normal University, Xining, China.
Front Plant Sci. 2022 Jun 20;13:943184. doi: 10.3389/fpls.2022.943184. eCollection 2022.
Subtilisin-like proteases (SUBs), which are extensively distributed in three life domains, affect all aspects of the plant life cycle, from embryogenesis and organogenesis to senescence. To explore the role of SUBs in rice caryopsis development, we recharacterized the gene family in rice ( ssp. ). In addition, investigation of the was conducted across cultivated and wild rice in seven other diploid species (, , , , , , and ssp. ). Sixty-two were identified in the latest ssp. genome, which was higher than that observed in wild species. The gene family was classified into six evolutionary branches, and SUB1 and SUB3 possessed all tandem duplication (TD) genes. All paralogous in eight plants underwent significant purifying selection. The expansion of in cultivated rice was primarily associated with the occurrence of tandem duplication events and purifying selection and may be the result of rice domestication. Combining the expression patterns of in different rice tissues and qRT-PCR verification, four were expressed in rice caryopses. Moreover, expressed in rice caryopses possessed an earlier origin in , and the gene cluster formed by together with the surrounding gene blocks may be responsible for the specific expression of in caryopses. All the above insights were inseparable from the continuous evolution and domestication of . Together, our findings not only contribute to the understanding of the evolution of SUBs in cultivated and wild rice but also lay the molecular foundation of caryopsis development and engineering improvement of crop yield.
枯草杆菌蛋白酶样蛋白酶（SUBs）广泛分布于三个生命域，影响植物生命周期的各个方面，从胚胎发生、器官发生到衰老。为了探究SUBs在水稻颖果发育中的作用，我们重新鉴定了水稻（亚种）中的该基因家族。此外，还对其他七个二倍体物种（、、、、、和亚种）的栽培稻和野生稻进行了研究。在最新的亚种基因组中鉴定出62个，这一数量高于在野生种中观察到的数量。SUB基因家族被分为六个进化分支，SUB1和SUB3拥有所有串联重复（TD）基因。八种植物中的所有旁系同源基因都经历了显著的纯化选择。栽培稻中SUB基因的扩增主要与串联重复事件的发生和纯化选择有关，可能是水稻驯化的结果。结合SUBs在不同水稻组织中的表达模式和qRT-PCR验证，有四个SUBs在水稻颖果中表达。此外，在水稻颖果中表达的SUBs在中起源较早，由SUBs与周围基因块形成的基因簇可能负责SUBs在颖果中的特异性表达。上述所有见解都离不开水稻的持续进化和驯化。总之，我们的研究结果不仅有助于理解栽培稻和野生稻中SUBs的进化，也为颖果发育和作物产量的工程改良奠定了分子基础。
