INTERMEDIUM-M encodes an HvAP2L-H5 ortholog and is required for inflorescence indeterminacy and spikelet determinacy in barley
| Autor: | Rainer Franzen, Maria von Korff, Qing Sang, Xiaojing Bi, G. Wilma van Esse, Jinshun Zhong, Tianyu Lan, Agatha Walla |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Multidisciplinary
inflorescence determinacy Mutant fungi Barley and wheat food and beverages Plant Biology Meristem Biology Biological Sciences MADS1 Inflorescence determinacy Inflorescence Botany Grain yield Laboratorium voor Moleculaire Biologie MADS3/58 Laboratory of Molecular Biology barley and wheat Gene APETALA2/Q |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America Proceedings of the National Academy of Sciences of the United States of America 118 (2021) 8 Proceedings of the National Academy of Sciences of the United States of America, 118(8) |
| ISSN: | 0027-8424 |
| Popis: | Significance Meristem determinacy/indeterminacy influences flower number and seed production in crops. Two closely related cool-season cereals, barley and wheat, produce variable and defined numbers of spikelets in their inflorescences, respectively. In this study, we identify a series of allelic barley mutants named intermedium-m and double seed1 that develop wheat-like determinate inflorescences producing a terminal spikelet and a reduced number of spikelets. INT-M/DUB1 is an APETALA2-like transcription factor that promotes an active inflorescence meristem via suppression of spikelet initiation and the maintenance of meristem identity. Our work has identified key regulators that may prolong meristem activities and could be genetically engineered in barley, wheat, and other cereals to improve grain yield. 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. 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. INT-M/DUB1 encodes an APETALA2-like transcription factor (HvAP2L-H5) that suppresses ectopic and precocious spikelet initiation signals and maintains meristem activity. 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. In wheat, prolonged and elevated AP2L-A5 activity in rAP2L-A5 mutants delays but does not suppress the IM−TSM transition. We hypothesize that the regulation of AP2L-5 orthologs and downstream genes contributes to the different inflorescence determinacy in barley and wheat. We show that AP2L-5 proteins are evolutionarily conserved in grasses, promote IM activity, and restrict floret number per spikelet. This study provides insights into the regulation of spikelet and floret number, and hence grain yield in barley and wheat. |
| Databáze: | OpenAIRE |
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