Gene identification and functional analysis of high tillering mutants in barley

谷类作物产量受分蘖（侧枝）数量和每穗种子数量的影响。这两种性状在大麦和小麦的驯化过程中都得到了改变。野生型的特点是高和异步分蘖，而栽培型显示低同步分蘖。驯化相关的变化，穗包括失败的穗disarticulate和（ii）改变小穗育性。分蘖数与穗粒数往往呈负相关，这给提高总产量带来困难。因此，对影响花序和茎结构的分子机制的基本理解对于提高产量是重要的。该项目的总体目标是鉴定和表征影响大麦分蘖和种子数量的基因，大麦是一种新兴的小粒谷物模型系统。我们将利用高分蘖突变体granum-a（gra-a）和intermedium-m（int-m）来研究茎和花序构型的遗传和分子相关性。本研究的主要目的有三：（1）鉴定gra-a和int-m的致病基因;（2）通过对茎尖分生组织（SAM）和腋生分生组织进行显微表型分析和全转录组分析，鉴定gra-a和int-m突变位点的功能（3）野生和栽培大麦基因型中gra-a和int-m候选基因的自然变异分析。总的来说，拟议的项目将揭示新的遗传和分子组成控制芽和穗架构，从而提供了新的见解种子和分蘖数量之间的权衡的分子基础。

Cereal crop yield is influenced by the number of tillers (side shoots) and the number of seeds per spike. Both traits have been modified during domestication of barley and wheat. The wild forms are characterized by high and asynchronous tillering while the cultivated forms show low synchronous tillering. Domestication related changes of the spike included the failure of the spike to disarticulate and (ii) altered spikelet fertility. Tiller number and seed number per spike are often negatively correlated which complicates the improvement of overall yield. Consequently, a fundamental understanding of the molecular mechanisms that affect both inflorescence and shoot architecture is important to improve yield. The overall objective of this project is to identify and characterize the genes that affect both tiller and seed number in barley, an emerging model system for small grain cereals. We will use the high tillering mutants granum-a (gra-a) and intermedium-m (int-m) to investigate the genetic and molecular correlations of shoot and inflorescence architecture. There are three main objectives; (1) identification of the causal genes underlying gra-a and int-m; (2) functional characterization of the gra-a and int-m mutant loci by microscopic phenotyping and whole transcriptome analysis of developing shoot apical meristems (SAM) and axillary meristems (AM, tillers); (3) analysis of natural variation of the candidate genes for gra-a and int-m in a diverse set of wild and cultivated barley genotypes. Overall, the proposed project will reveal novel genetic and molecular components controlling shoot and spike architecture and thus provides novel insights into the molecular basis underlying the trade-off between seed and tiller number.