Genetic Mapping Of The Rice Plant Architecture Genes And Screening Proteins Interacting With Lax

Rice (Oryza sativa) plant architecture, including plant height, tiller number, tiller angle, and panicle morphology, is one of the key factors that affect plant survival and productivity. Panicle size, branch number and spikelet number in a panicle are directly associated with rice productivity. So, in this research, a cDNA library of the young panicles from the cultivar Zhonghua11was constructed for yeast two-hybrid to identify novel proteins, which would interact with LAX1or LAX2. In addition, we screened some rice plant architecture mutants from the Rice Mutant Database, RMD, and investigated their phenotype. To clone the genes, we used the map-based method and generated mapping populations by hybrids between the homozygous mutants and indica rice varity Zhenshan97. In this study, it’s expected that some proteins which would interact with LAX1or LAX2, can be screened and some new genes of plant architecture can be cloned. Thus, it will be helpful to establish the mechanism of rice plant architecture morphogenesis with these theoretical and material resources in this research. The main results of this study are as follows:1. Total RNA was extracted from the young panicles(<4.0mm), and the cDNA library was generated by recombination-mediated SMART technology in yeast strain Y187. The titers, transformation efficiency and recombinant rate of the cDNA library were suitable for the experimental requirements. Then constructed the bait vectors of LAX1and LAX2for screening the cDNA library. We obtained6putative interacting proteins with LAX1, including nucleoside diphosphate kinase, ubiquitin-activating enzyme and a protein with the F-box domain. We also obtained12putative interacting proteins with LAX2, including2proteins which belong to F-box family, and one of them also can interacted with LAX2. And more experiments are needed to prove these results.2. PS4was roughly mapped on chromosome4, and in the ps4mutant, there were41bp deletion in the first exon of HTD1. The results of co-segregation analysis showed that the mutant phenotype segregated with its genotype. PS4was a new allele of HTD1.3. ps30was a mutant with lax panicle. PS30was located between SSR markers RM3827and RM5957on chromosome6, within physical distance about2.2Mb, and MOC1also locates in this region. There was a large fragment which was inserted in the promotor of MOC1in the ps30mutant by compared amplification. A part of the fragment was got by TAIL-PCR, and this fragment was inserted at-1091in the promotor of MOC1. In addition, the ps30mutant phenotype segregated with its genotype.4. ps12was a plant architecture mutant, and was located between molecular markers03Indel-3and RM14817on chromosome3, within physical distance about0.3Mb. In this candidate region, there was no genes which had been cloned. So PS12may be a new gene controlling rice plant architecture.5. PS9was located between SSR markers RM6362and RM234on chromosome7, within physical distance about1.25Mb, and PS15was located between SSR markers RM267and RM169on chromosome5, within physical distance about4.58Mb. Based on the mutant phenotype and the candidate region in the genome, PS9may be a allele of FH5/RMD and PS15may be a allele of srs-3.