INTERMEDIUM-M encodes an HvAP2L-H5 ortholog and is required for inflorescence indeterminacy and spikelet determinacy in barley

第一作者：Jinshun Zhong

第一单位：德国海因里希海涅大学

通讯作者：Maria von Korff

 Abstract 

背景回顾：Inflorescence architecture dictates the number of flowers and, ultimately, seeds. The architectural discrepancies between two related cereals, barley and wheat, are controlled by differences in determinacy of inflorescence and spikelet meristems. 

主要研究：Here, we characterize two allelic series of mutations named intermedium-m (int-m) and double seed1 (dub1) that convert barley indeterminate inflorescences into wheat-like determinate inflorescences bearing a multifloreted terminal spikelet and spikelets with additional florets.

结果1-编码基因：INT-M/DUB1 encodes an APETALA2-like transcription factor (HvAP2L-H5) that suppresses ectopic and precocious spikelet initiation signals and maintains meristem activity. 

结果2-大麦中基因功能：HvAP2L-H5 inhibits the identity shift of an inflorescence meristem (IM) to a terminal spikelet meristem (TSM) in barley. Null mutations in AP2L-5 lead to fewer spikelets per inflorescence but extra florets per spikelet. 

结果3-小麦中基因功能：In wheat, prolonged and elevated AP2L-A5 activity in rAP2L-A5 mutants delays but does not suppress the IM−TSM transition. 

假设：We hypothesize that the regulation of AP2L-5 orthologs and downstream genes contributes to the different inflorescence determinacy in barley and wheat. 

演化保守性：We show that AP2L-5 proteins are evolutionarily conserved in grasses, promote IM activity, and restrict floret number per spikelet. 

结论：This study provides insights into the regulation of spikelet and floret number, and hence grain yield in barley and wheat.

 摘 要 

 通讯作者 

**Maria von Korff**

个人简介：

Journal: PNAS

Published date: Feb 23, 2021