Agronomic Traits Evaluation And Gene Mapping The Wax-layer Deficient Mutant Sb1 Of Sorghum Bicolor

The mechanisms of wax synthesis,transport,secretion and transcriptional regulation are not clear,meanwhile,there are few studies on the related genes of sorghum wax.Therefore,cloning and identification wax-related genes of sorghum are very important for revealing the molecular mechanism of sorghum wax formation,the role of sorghum wax for drought resistance and in-depth development of sorghum wax.The seeds of sorghum BTx623 were mutagenized by 0.2% EMS solution for 20 h.The stem and leaf wax-layer deficient mutant sb1(sorghum bloomless 1)during the whole growth period was isolated by screening mutational population.In this study,the agronomic traits,the water loss rate of the detached leaves,genetic trait and gene mapping between BTx623 and sb1 have been researched.The results as follows:1.Statistical analysis of agronomic traits for two years,the plant height was obviously reduced of sb1 comparing with wild-type BTx623.However,the other agronomic traits of sb1 were not significantly affected because of wax-layer deficient.In heading and flowering period,the water loss rate of detached leaves for sb1 was faster than wild-type BTx623,which indicated that wax plays an important role in leaf water retention.2.The separation ratio of F2(sb1×BTx623;sb1×Rio)population phenotypes were analyzed,which demonstrated that sb1 was controlled by a single recessive nuclear gene.Using the method of Super-BSA,we developed 210,411 SLAF tags and 286,161 polymorphic SNP tags.By the method of SNP-index,sb1 was mapped in a range of about 0.81 Mb on chromosome 10(1502260-2308026),which including 148 genes.3.Verify the result of coarse mapping for sb1 using two SSR markers,containing sam51358(1.64Mb)and sam01243(2.16Mb).7 polymorphic SSR markers(SB5164,sam51358,10-5,SB5180,SB5182,sam01243 and sam27102a)and 1 InDel marker(10d4A3)were found and developed in the coarse mapping region and its both sides.Using the screened polymorphic markers,the sb1 mutant gene was fine mapped in 140 Kb region between these two SSR markers,10-5(1.66Mb)and SB5180(1.80Mb),which including 15 genes.