Characterization and Gene Mapping of <i>non-open hull 1 (noh1)</i> Mutant in Rice (<i>Oryza sativa</i> L.)

Hull opening is a key physiological process during reproductive development, strongly affecting the subsequent fertilization and seed development in rice. In this study, we characterized a rice mutant, non-open hull 1 (noh1), which was derived from ethylmethane-sulfonate (EMS)-treated Xinong 1B (Oryza sativa L.). All the spikelets of noh1 developed elongated and thin lodicules, which caused the failure of hull opening and the cleistogamy. In some spikelets of the noh1, sterile lemmas transformed into hull-like organs. qPCR analysis indicated that the expression of A- and E-function genes was significantly upregulated, while the expression of some B-function genes was downregulated in the lodicules of noh1. In addition, the expression of A-function genes was significantly upregulated, while the expression of some sterile-lemma maker genes was downregulated in the sterile lemma of noh1. These data suggested that the lodicule and sterile lemma in noh1 mutant gained glume-like and lemma-like identity, respectively. Genetic analysis showed that the noh1 trait was controlled by a single recessive gene. The NOH1 gene was mapped between the molecular markers ZJ-9 and ZJ-25 on chromosome 1 with a physical region of 60 kb, which contained nine annotated genes. These results provide a foundation for the cloning and functional research of NOH1 gene