Genetic Analysis,Gene Mapping And Primary Functional Analysis Of A Salt Tolerance Gene SST(t) In Rice

Salt-tolerance seedling chlorosis is an important physiological character in rice.Research of the genetic basis of this character is significant in both theory and application.Previous studies of our laboratory have found that a salt tolerant mutant at seeding stage was received from an M2 population of radiation mutagenesis of an indica rice cultivar R401.For this mutant,We did a genetic analysis of mutants,gene mapping,identification of candidate genes by sequencingand candidate and further into the validated candidate genes by complementation,GUS expression analysis of gene expression experiments.The main results are as follows:1)At seedling stage,The mutant seedling could survive under the treatment of sodium chloride solution at the concentration of 150 mmol/L,while the wild-type control seedling wilting death.In this study,with a large F2 population derived from a cross between mutant sst(t)and a japonica cultivar Nipponbare(salt sensetive).At seedling stage,By surveying the performance of the F2 population under the treatment of sodium chloride solution at the concentration of 150 mmol/L,We discovered that the mutant phenotype was controlled by the recessive mutation of a single gene,temporarily designated SST(t).2)Gene mapping of the target gene was performed using 1559 salt-induced plants from two F2 popuulations of mutant sst(t)and a japonica cultivar Nipponbare.First,Bulked segregant analysis(BSA)based in the F2 mapping population revealed that SST(i)is located on chromosome 6.Then,new SSR and InDel marker were developed,SST(t)was further fine mapped to a 17-kb interval between InDel markers ID27101 and ID27118.3)Only one comment gene OsSPL10 at 17Kb positioning range,primers were designed to determine the candidate gene sequencing.Sequence analysis showed that the 232nd base of the coding sequence of OsSPL10 was deleted in the sst(t)allele,compared with the alleles from the wild type R401 and Nipponbare,The deletion resulted in a frame-shift mutation,forming early stop codons.This result suggests that the OsSPL10 gene is quite possibly the candidate of SST(t).4)Genetic complementation experiments:A complementary vector containing of the promoter,coding region and terminator of the candidate gene from Nipponbare was constructed and introduced into population of radiation mutagenesis of an indica rice cultivar R401,twenty positive transgenic plants were obtained and from resistant callus.5)Gene expression analysis:Build a candidate gene promoter-driven GUS expression vector by Agrobacterium-mediated transformation to Nipponbare,only one positive transgenic plant was obtained.