Lin Dongbo, Xiang Ya, Xian Zhiqiang, Li Zhengguo
Genetic Engineering Research Center, College of Life Sciences, Chongqing University, Chongqing, 400030, China.
Botanic Garden, Chongqing University, Chongqing, 400030, China.
Physiol Plant. 2016 Aug;157(4):490-506. doi: 10.1111/ppl.12425. Epub 2016 May 3.
ARGONAUTE7 (AGO7), a key regulator of the trans-acting small interfering RNAs (ta-siRNA) pathway, plays a conserved role in controlling leaf pattern among species. However, little is known about the ta-siRNA pathway in regulating inflorescence architecture and fruit yield. In this study, we characterized the expression pattern, subcellular localization and developmental functions of SlAGO7 in tomato (Solanum lycopersicum). Overexpressing SlAGO7 in tomato exhibited pleiotropic phenotypes, including improved axillary bud formation, altered leaf morphology and inflorescence architecture, and increased fruit yield. Cross-sectioning of leaves showed that the number of vascular bundles was significantly increased in 35:SlAGO7 lines. Overexpression of SlAGO7 increased the production of ta-siRNA, and repressed the expression ta-siRNA-targeted genes (SlARF2a, SlARF2b, SlARF3 and SlARF4). Further analysis showed that overexpression of SlAGO7 alters the expression of key genes implicated in leaf morphology, inflorescence architecture, auxin transport and signaling. In addition, the altered auxin response of 35:SlAGO7 lines were also investigated. These results suggested that SlAGO7 plays a positive role in determining inflorescence architecture and fruit yield though the ta-siRNA pathway. Therefore, SlAGO7 represents a useful gene that can be incorporated in tomato breeding programs for developing cultivars with yield potential.
AGO7是反式作用小干扰RNA（ta-siRNA）途径的关键调节因子，在控制物种间叶型方面发挥着保守作用。然而，关于ta-siRNA途径在调节花序结构和果实产量方面的了解却很少。在本研究中，我们对番茄（Solanum lycopersicum）中SlAGO7的表达模式、亚细胞定位及发育功能进行了表征。在番茄中过表达SlAGO7表现出多效性表型，包括腋芽形成改善、叶片形态和花序结构改变以及果实产量增加。叶片横切显示，35:SlAGO7株系中维管束数量显著增加。SlAGO7的过表达增加了ta-siRNA的产生，并抑制了ta-siRNA靶向基因（SlARF2a、SlARF2b、SlARF3和SlARF4）的表达。进一步分析表明，SlAGO7的过表达改变了与叶片形态、花序结构、生长素运输和信号传导相关的关键基因的表达。此外，还研究了35:SlAGO7株系中生长素反应的改变。这些结果表明，SlAGO7通过ta-siRNA途径在决定花序结构和果实产量方面发挥积极作用。因此，SlAGO7是一个有用的基因，可用于番茄育种计划，以培育具有产量潜力的品种。
