Cloning And Function Analysis Of A Narrow And Rolled Leaves Gene NRL3in Rice (Oryza Sativa L.)

The leaf blades are the basic components of plant photosynthesis organ, the leaf size and shape had an imorptant impact on the plant photosynthesis, rice leaf was directly related to the production. Narrow leaf blade mutation is an important trait, which had a strong impact on the study about the mechanism of leaves. In this text, we isolated and identified a narrow and rolled leaves mutant, which was termed as nrl3(narrow and rolled leaves3) from over15,000independent transgenic lines consisting of T-DNA insertion in our mutant library. Main studies of character identification, genetic analysis, cloning and preliminary functional analysis were conducted in our text. The main findings are as follows:1. nrl3mutant was characterized with narrow and rolled leaves, which is clearly distinguished from wild type during the whole growth period, and the growth period of nrl3was later than wild type. At mature stage, the nrl3mutant has a significant reduction in plant stature and panicle size, the angle between the blade and stem to which it is attached is larger in the nrl3mutant and the width of seed was reduced. Microscopic analysis indicated that nrl3has fewer and smaller adaxial bulliform cells compared with the wild type, and the number of vascular bundles was reduced in nrl3. The pigment contents of nrl3were also reduced.2. Gentic analysis showed that the nrl3phenotype was controlled by a single recessive gene. Both hygromycin resistance assay and PCR analysis indicated that the mutation was not caused by T-DNA insertion. So we used a map-based cloning strategy to isolate the nrl3gene. The results showed that chromodomain-heliase-DNA-binding gene was nrl3gene. Sequence analysis of the candidate region revealed a large deletion difference between wild type and nrl3mutant. This deletion is from the second to sixth exon of CHD3gene, which is results in the gene could not work at all. To verify this result, we construct two RNAi vectors, the transgentic plants showed narrow and rolled leaves.3. We were not detect any transcript production of OsCHD3in nrl3mutant. Quantitative real-time RT-PCR analysis revealed the expression of OsCHD3in various tissues with relatively high expression in leaves, sheaths and culms.