Genetic Analysis And Fine Mapping Of Rice Semi-dwarf Mutant Sd377 And Leafy Head Mutant Pla1-6

1.Genetic analysis and fine mapping of rice semi-dwarf mutant sd377 in ricePlant height is an important plant type factor of rice for grain crops,which is closely related to plant lodging resistance,photo synthetic efficiency and yield.It has become an entry for breeders to improve varieties.Moderate reduction of rice plant height not only can improve the photosynthetic efficiency of rice,but also can provide some conditions for the current routine breeding requirements.On the other hand,the study of the mechanism of dwarfing of rice is also helpful in providing a clear theoretical support for the regulation of crop height in the production of plant endogenous hormones.In this study,a dwarf mutant sd377 was obtained by treatment of Zhonghua 11 in rice cultivars with ethyl methanesulfonate(EMS),and its agronomic traits,genetic patterns and gene loci were studied.The main results are as follows:(1)The agronomic traits showed that the plant height of sd377 decreased by 37%,the tiller was reduced by about 30%,and the panicle length,seed setting rate and 1000-grain weight of the whole plant decreased somewhat with the wild type.(2)Genetic analysis showed that the sd377 mutant was controlled by a recessive nuclear genes.The mutant gene was mapped to the region between the two InDel markers W3 and W5,and the physical distance was 183kb,The genetic distance was 0.5cM and 1.0cM,respectively.(3)Genetic analysis of candidate gene regions showed that there was no reported rice dwarfing-related gene in the region,and the a-amylase identification test showed that the pathway of GA response was normal and GA-hypersensitive.therefore,we suggested that it may be a new semi-dwarf gene..2 Fine mapping and candidate genes analysis of leafy head mutant pla1-6 in riceThe yield of rice was determined by four important factors,namely,the effective panicle per plant,the number of grains per panicle,the grain weight per seed and the seed setting rate,Leaf and tiller as important organs of rice,its relationship with the yield of rice is very large,it is very important to improve the yield,so the development of rice leaf and tiller development related genes,cloning and its support for the tiller development and control network Is particularly important.In this study,a kind of leafy head mutant plal-6 was obtained by using ethyl methanesulfonate(EMS)to treat the restorer varieties Lehui 188,and its agronomic traits,genetic patterns and candidate genes were studied,The main results are as follows:(1)Under field conditions,Compared with the wild type,plal-6 plants showed significant high tillering phenomenon,the number of tillers and in the upper part of plal-6 was higher than that of the wild type.The plant height was significantly decreased and the number of the leaves increased.Because developmental abnormalities,plal-6 can not be divided into spikelets,so that fail to be seed setting.(2)Genetic analysis indicated that the pla1-6 mutant phenotype was controlled by a single recessive nuclear gene.Using the plal-6 hybrids/Nipponbare as F2 mapping population.The mutant gene was located within the 84kb region between the two InDel markers W6 and W8 of the long chromosom eof rice.The distances were 0.15cM and 0.15cM,respectively.(3)6 predicted genes had been annotated within this interval.Sequencing analysis revealed that LOC_Os10g26340 gene is abnormal which Encods Cytochrome P450 CYP78A11 in mutant plal-6,A single base was changed(T213A)in the coding region of the PLA1 gene lead to missense mutation(V213D).Comprehensive analysis of the mutation sites and the phenotypes of reported pla1-6 allelic mutants hinted that this site(V213D)may be a more key amino acid of PLA1.PLA1-6 may be allelic to PLA1 gene.