Genetic and metabolic control of grain shape and weight in wheat

小麦粒形和粒重是与产量相关的重要参数。因此，关于小麦潜在决定因素和机制的知识具有很高的经济意义。在这里，我们利用两个独特的模型来展示通过潜在的不同机制增加的谷粒重量。在高产冬小麦品种PRINZ的遗传背景中，一个导入代表了合成小麦M6的基因组片段，该片段与籽粒大小，特别是籽粒长度的数量性状基因座有关。来自冬小麦品种Certo的转基因品系，过表达大麦的蔗糖转运蛋白基因，可以增加粒重，这主要与较高的粒宽有关。我们计划在这些模型中分析与特征、颗粒大小和形状规范相关的特征。组织学分析将被用来识别那些在细胞数量和/或细胞扩张方面存在差异的谷物组织。将对谷物发育进行全面的表型鉴定，包括母体和子代谷物器官的组织特异性转录本、代谢物和激素谱。主要目的是了解在谷物发育过程中负责细胞分裂和扩张调节的信号通路，以响应代谢信号。参与调控子房和果皮生长的基因网络将从转录组数据中推断出来，这些数据与平行的发育和生理研究有关。预期的结果将导致对颗粒大小和重量规范背后的生理、分子和代谢网络的更深入了解。在未来，这些知识将使育种者能够制定提高产量潜力的策略。

Grain shape and weight in wheat are important yield-related parameters. Knowledge about underlying determinants and mechanisms in wheat is therefore of high economic relevance. We here make use of two unique models displaying increased grain weight by potentially different mechanisms. An introgression, within the genetic background of the high-yield winter wheat variety Prinz, represents a genomic fragment of the synthetic wheat M6, which is related to a quantitative trait locus for grain size, especially grain length. A transgenic line, derived from the winter wheat variety Certo, overexpressing a sucrose transporter gene from barley confers increased grain weight, predominantly related to higher grain width. We plan to analyse characteristics associated with specification of the traits grain size and shape in these models. Histological analyses will be used to identify those grain tissues showing differences in cell number and/or cell expansion. Comprehensive phenotyping of grain development will be performed including tissue-specific transcript, metabolite and hormone profiling in maternal and filial grain organs. Main objective is to understand signalling pathways responsible for cell division and expansion modulations during grain development in response to metabolic signals. Gene networks involved in the regulation of ovary and pericarp growth will be inferred from transcriptome data linked to parallel developmental and physiological studies. The expected outcome will lead to deeper understanding of the physiological, molecular and metabolic network underlying the specification of grain size and weight. Such knowledge in the future will allow breeders to develop strategies to increase yield potential.