Mori Akiko, Toyota Masatsugu, Shimada Masayoshi, Mekata Mika, Kurata Tetsuya, Tasaka Masao, Morita Miyo T
Graduate School of Bioagricultural Sciences, Nagoya University Nagoya, Japan.
Department of Botany, University of WisconsinMadison, MadisonWI, USA; Japan Science and Technology Agency, Precursory Research for Embryonic Science and TechnologySaitama, Japan.
Front Plant Sci. 2016 Sep 29;7:1443. doi: 10.3389/fpls.2016.01443. eCollection 2016.
Forward genetics is a powerful approach used to link genotypes and phenotypes, and mutant screening/analysis has provided deep insights into many aspects of plant physiology. Gravitropism is a tropistic response in plants, in which hypocotyls and stems sense the direction of gravity and grow upward. Previous studies of gravitropic mutants have suggested that shoot endodermal cells in stems and hypocotyls are capable of sensing gravity (i.e., statocytes). In the present study, we report a new screening system using hypergravity conditions to isolate enhancers of gravitropism mutants, and we also describe a rapid and efficient genome mapping method, using next-generation sequencing (NGS) and single nucleotide polymorphism (SNP)-based markers. Using the () mutant, which exhibits defective development of endodermal cells and gravitropism, we found that hypergravity (10 g) restored the reduced gravity responsiveness in hypocotyls and could, therefore, be used to obtain mutants with further reduction in gravitropism in the background. Using the new screening system, we successfully isolated six () mutants that exhibited little or no gravitropism under hypergravity conditions, and using NGS and map-based cloning with SNP markers, we narrowed down the potential causative genes, which revealed a new genetic network for shoot gravitropism in .
正向遗传学是一种用于将基因型和表型联系起来的强大方法，突变体筛选/分析为植物生理学的许多方面提供了深入见解。向重力性是植物中的一种向性反应，其中下胚轴和茎感知重力方向并向上生长。先前对向重力性突变体的研究表明，茎和下胚轴中的茎内皮层细胞能够感知重力（即平衡细胞）。在本研究中，我们报告了一种使用超重力条件来分离向重力性突变体增强子的新筛选系统，并且我们还描述了一种使用下一代测序（NGS）和基于单核苷酸多态性（SNP）的标记的快速高效的基因组定位方法。使用表现出内皮层细胞发育缺陷和向重力性缺陷的（）突变体，我们发现超重力（10g）恢复了下胚轴中降低的重力反应性，因此可用于在背景中获得向重力性进一步降低的突变体。使用新的筛选系统，我们成功分离出六个在超重力条件下几乎没有或没有向重力性的（）突变体，并且使用NGS和基于SNP标记的图位克隆，我们缩小了潜在的致病基因范围，这揭示了中茎向重力性的新遗传网络。
