Phenotypic Analysis And Gene Mapping About A Rice Leaf Tip Withered Mutant Xynln

Leaf is one of main organs of plant, the main place for plant to complete photosynthesis and transpiration, it has close relationship with plant growth and development. The leaf was influenced easily by related gene and environment factors outside, these factors will lead the leaf senescence. To the crop, it will dramatically decrease the yield of rice. As rice is the main food crops for nearly half populations in the world, and its yields would affect the safety and stability of the world grain. Therefore, it’s important to get well understanding with the mechanism of rice premature senescence. With the completion of rice genome sequencing, the basic research in the field of development, However, with the completion of rice genome sequencing, the fundamental research for gene function become full of popularity. More and more people tried to learn how gene works to express the function through the construction of the mutant sources.In this study, we have selected the xynln mutant through the inducement of EMS chemical compounds. A The leaf tip became withered from tillering stage to late maturity in mutant. The mutant exhibited significantly lower height, thinner width both in the leaf and stem, smaller panicle, lower seed setting and 1,000-grain weight than R498. Genetic analysis shows that the mutant was controlled by a single recessive gene. Mutant was mapped into a 48-kb interval flanked by markers F99 and F98 on chromosome 3 by map-based cloning. Eight ORFs, including one mutant gene, were identified in this region. Sequencing reveals that the G base at site of 340 the coding region was changed to A. The results of photosynthesis rate measurement showed that mutant is significant lower than Wild type in the net photosynthesis rate and transpiration rate. An allele gene for xynln from other mutant called xynln-1 was also identified. Sequencing reveals that the C base at site of 80 the coding region was changed to T in the mutant xynln-1, and the most important is that,two mutant locus both in the same conservative protein domain.The XYNLN gene is Glycoside hydrolase family 10. The Glycoside hydrolase participate in many plants metabolic activity. Cloning of xynln will contribute to dissecting molecular mechanism that senescence in rice, which will be beneficial to molecular assisted selection of this important trait.