Gene mapping and expression analysis of a novel mutantreproduce organs absent (roa) in rice

Abstract

Mutant plays an important role in function analysis in plant. A rice flower mutant reproduce organs absent (roa), showing a stable inheritance during several years of study, was identified in rice (Oryza sativa L. ssp. Indica) cultivar Jinhui10 treated with EMS and used in this study. This mutant showed following: elongated palea and pedicle; absence of inner three whorls of floral organs; multi-whorls glume like organs inside the lemma/palea; spikelet meristem like organ upon the pedicle. These phenotypes suggested that ROA is a key gene in rice spikelet development. Genetic analysis confirmed that the mutant traits were controlled by a single recessive nuclear gene. By gene mapping, ROA was restricted between two SSR markers RM221 and RM1342 on the chromosome 2. It concluded that ROA was a novel gene involving in flower development in rice. Besides, the mutation of ROA influenced the transcription level of floral homeotic genes; the expression of floral homeotic genes decreased in roa panicle compared with wild-type, and it suggested that ROA affected flower development by influencing the expression of floral homeotic genes.