RESUMO
Panicle architecture directly affects crop productivity and is a key target of high-yield rice breeding. Panicle length strongly affects panicle architecture, but the underlying regulatory mechanisms are largely unknown. Here, we show that two quantitative trait loci (QTLs), PANICLE RACHIS LENGTH5 (Prl5) and PRIMARY BRANCH LENGTH6 (Pbl6), independently regulate panicle length in rice. Prl5 encodes a gibberellin biosynthesis enzyme, OsGA20ox4. The expression of Prl5 was higher in young panicles resulting in panicle rachis elongation. Pbl6 is identical to ABERRANT PANICLE ORGANIZATION 1 (APO1), encoding an F-box-containing protein. We found a novel function that higher expression of Pbl6 is responsible for primary branch elongation. RNA-seq analysis revealed that these two genes independently regulate panicle length at the level of gene expression. QTL pyramiding of both genes increased panicle length and productivity. By combining these two genes in various combinations, we designed numerous panicle architecture without trade-off relationship.
Assuntos
Regulação da Expressão Gênica de Plantas , Oryza/anatomia & histologia , Proteínas de Plantas/genética , Caules de Planta/anatomia & histologia , Locos de Características Quantitativas , Alelos , Oryza/genética , Oryza/crescimento & desenvolvimento , Melhoramento Vegetal , Proteínas de Plantas/metabolismo , Caules de Planta/genética , Caules de Planta/crescimento & desenvolvimento , RNA-SeqRESUMO
Rice grain number directly affects crop yield. Identifying alleles that improve panicle architecture would greatly aid the development of high-yield varieties. Here, we show that the quantitative trait locus qSrn7 contains rice FRIZZY PANICLE (FZP), a previously reported gene encoding an ERF transcription factor that promotes floral transition. Reduced expression of FZP in the reproductive stage increases the extent of higher order branching of the panicle, resulting in increased grain number. Genotype analysis of this gene in cultivars from the publicly available National Institute of Agrobiological Sciences (NIAS) Core Collection demonstrated that the extent of higher order branching, especially in the upper panicle, was increased in those cultivars carrying the FZP allele associated with qSrn7. Furthermore, chromosome segment substitution lines resulting from a cross between Koshihikari and Kasalath, the latter of which carries qSrn7/FZP, also showed that upper panicle higher order branching and grain yield were increased by qSrn7/FZP. Our findings indicate that qSrn7/FZP influences panicle branching pattern and is thus useful in the breeding of high-yield rice varieties.
