The tin1 gene retains the function of promoting tillering in maize

First author: Xuan Zhang; Affiliations: China Agricultural University (中国农业大学): Beijing, China

Corresponding author: Zhongwei Lin

Sweet maize and popcorn retain tillering growth habit during maize diversification. However, the underlying molecular genetic mechanism remains unknown. Here, we show that the retention of maize tillering is controlled by a major quantitative trait locus (QTL), tin1, which encodes a C2H2-zinc-finger transcription factor that acts independently of tb1. In sweet maize, a splice-site variant from G/GT to C/GT leads to intron retention, which enhances tin1 transcript levels and consequently increases tiller number. Comparative genomics analysis and DNA diversity analysis reveal that tin1 is under parallel selection across different cereal species. tin1 is involved in multiple pathways, directly represses two tiller-related genes, gt1 and Laba1/An-2, and interacts with three TOPLESS proteins to regulate the outgrowth of tiller buds. Our results support that maize tin1, derived from a standing variation in wild progenitor teosinte (大刍草) population, determines tillering retention during maize diversification.

甜玉米和爆花玉米在玉米驯化过程中保留了分蘖生长的习性。然而，潜在的分子遗传调控机制仍然不是很清楚。本文中，作者的研究显示玉米的分蘖是由一个主效数量性状位点tin1所控制的，而该位点编码了一个C2H2-锌指转录因子，并且其功能独立于tb1。在甜玉米中，一个从G/GT到C/GT的剪切位点变异保留了内含子，从而增强了tin1的转录水平，最终增加了玉米植株的分蘖数量。比较基因组学分析和DNA多态性分析显示tin1基因在不同的谷类作物中存在平行选择。tin1参与了多个通路，会直接抑制两个分蘖相关的基因，gt1和Laba1/An-2，并且能够与三个TOPLESS蛋白互作，从而调控分蘖芽向外的生长。本文的结果揭示了玉米中的tin1基因源自于野生祖先种大刍草中的变异，其在玉米驯化过程中决定了分蘖习性的保留。

通讯：林中伟 (http://cab.cau.edu.cn/art/2017/6/12/art_27218_150.html)

个人简介：1996-2000年，中国农业大学，学士；2002-2007年，中国农业大学，博士；2007-2012年，美国堪萨斯州立大学，博士后。

研究方向：1. 玉米演化过程中关键遗传变异的分子基础；2. 玉米重要农艺性状的高通量解析；3. 比较功能基因组；4. 玉米改良过程中关键基因的利用。

doi: https://doi.org/10.1038/s41467-019-13425-6

Journal: Nature Communications

Published date: December 06, 2019