REVOLUTA基因在豆科模式植物蒺藜苜蓿复叶发育中的功能研究

Leaves are derived from the shoot apical meristem (SAM) in higher plants, regulated by various transcription factors. REVOLUTA (REV), a class III homeodomain-leucine zipper (HD-ZIP III) transcription factor, is involved in leaf polarity and pattern development. REV has been well studied in simple leaf plants, but its role in compound leaf development is still unknown. Several important forages, including alfalfa (Medicago sativa), belong toLeguminosae. For these forages, leaf development is crucial to their quality, thus people use the ratio of leave/stem as one of the most important indicators. Therefore, to study compound leaf development has its significance both in scientific research and industrial application. To learn the mechanism underlying compound leaf development, we screened 13,000 Tnt1 retrotransposon-tagged mutants of the model legume species Medicago truncatula, and identified a knockout mutant of REV with altered leaf pattern. This is the firstrev mutant reported in compound-leafed species. In this project, we propose to study the roles of MtREV, anda putative MtREV regulator,MtmicroRNA166, in compound leaf development in M. truncatula, as well as its relationship with auxin distribution and transport. This functional study of MtREV will shed the light on compound leaf patterning in M.truncatula, and provide the potential for the quality improvement of the important forage alfalfa.

高等植物的叶由茎端分生组织分化而来，受到各种不同的调节因子控制，其中HD-ZIPIII转录因子家族成员REVOLUTA（REV）在叶的极性和形态建成中起重要作用。迄今为止，有关REV基因的研究都是以单叶植物为研究对象，而其在复叶发育中的功能还未知。豆科牧草的叶片/茎秆比例关系到牧草品质，对叶片发育进行研究具有重要科学和实践意义。为了研究豆科牧草的复叶发育机制，我们筛选了豆科模式植物蒺藜苜蓿（Medicago truncatula）的Tnt1逆转录转座子标记的突变体库，在13,000个突变株系中鉴定得到REV在蒺藜苜蓿同源基因（MtREV）的突变体，这是首次在复叶植物中获得该基因的突变体。该突变体的复叶数目多于野生型植株，暗示MtREV在复叶发育中起关键作用。在本项目中，我们拟对MtREV及MtmicroRNA166在蒺藜苜蓿复叶发育过程中的作用机制进行研究，同时对MtREV与植物激素生长素

HD-ZIPIII转录因子家族成员PPF1在叶的极性和形态建成中起重要作用。迄今为止，有关PPF1基因的研究都是以单叶植物为研究对象，而其在复叶发育中的功能还未知。豆科牧草的叶片/茎秆比例关系到牧草品质，对叶片发育进行研究具有重要科学和实践意义。为了研究豆科牧草的复叶发育机制，我们筛选了豆科模式植物蒺藜苜蓿（Medicago truncatula）的Tnt1逆转录转座子标记的突变体库，鉴定得到蒺藜苜蓿基因PPF1的突变体，这是首次在复叶植物中获得该基因的突变体。该突变体的复叶数目多于野生型，暗示PPF1在复叶发育中起关键作用。进化树分析结果表明，PPF1是REV在蒺藜苜蓿中的同源基因MtREV。在本项目中，我们发现PPF1在蒺藜苜蓿的叶片极性和复叶发育过程中具有重要作用，与植物激素生长素关系密切，在PPF1的突变体以及过表达植株中MtYABBY3的表达发生变化。这一项目为蒺藜苜蓿的叶片极性与复叶模式建成提供新的研究线索，为重要近缘牧草紫花苜蓿的品质改良提供新的研究思路。