Fine Mapping Of A Photo-thromo-sensitive Genic Male Sterile Gene And Proteomic Analysis Of Silk Viability In Maize

Maize(Zea mays L.)is considered as an important crop,whether in China or in all world,whether from the area it planted,the range it distributed or from the yearly output,whether from the function and purpose or from the development prospect.As the first majority crop,maize usually concerns the national food security and has an important position which is irreplaceable.Heterosis utilization helps increasingly improve maize yield,while male sterility is the key of heterosis use.Thus,identification new male sterile material and exploration the genetic mechanism of heterosis are efficient for heterosis utilization.In this study,a new photo-thromo-sensitive genic male sterile gene was fine mapped and the heterotic genetic mechanism of silk viability was surveyed in maize.And the major results are as follows:1.The technology of seed production by using male sterile can provide cost savings,high efficiency of seed production and high purity of seed.The study of photo-thromo-sensitive genic male sterile is helpful to provide a new way,widened the genetic background and avoids the southern leaf spot in maize seed production,and has great prospect in maize production.In this study,CHUNZA was identified as a photo-thromo-sensitive genic male sterile line.Two back-crossed segregation populations were derived from CHUNZA crossing with B73 and 87-1,respectively.The genetic analysis showed that CHUNZA was controlled by a recessive gene.The gene was named p/tms1 in this study.Bulked Segregated Analysis method was used for molecular study with 772 SSR markers which are average located on the ten chromosomes of maize.p/tms1 gene was mapped on 6.03 bin between SSR marker umc1595 and umc1887 by BC1 of CHUNZA and 87-1;meanwhile it was mapped on 6.03 bin between umc1083 and umc1857 by BC1 of CHUNZA and B73.A large BC1 population of CHUNZA and 87-1 with 30000 individuals and 358 newly developed SSR markers in our lab were used for fine mapping of p/tms1 gene.p/tms1 gene was finally mapped between 6.03y6-59 and 6.03y5-19 by nine polymorphic SSR markers,the physical distance was 51 kb.After gene prediction,the candidate gene was identified as Rpc34 which was a special subunit of RNA polymerase III,and the genes of CHUNZA,87-1 and B73 were sequenced.The results of sequenced showed that there was a single nucleotide deletion between CHUNZA and B73 in 5'UTR,and the deletion didn't exist between CHUNZA and 87-1;there were 12 SNPs between CHUNZA and 87-1 include 2 synonymous mutations in protein-coding region,one synonymous mutations in terminator,3 SNPs in 5'UTR,6 SNPs in 3'UTR and one insertion mutation in 3'UTR.2.Silk viability is the direct indicator of seed setting rate,thus it has important significance for yield.To be emphasized,silk viability showed heterosis.In this study,the inbred lines xun928,lx9801,and zong3,and the hybrid xun928×zong3 and lx9801×zong3were used to explore heterosis of silk viabily by proteomic method.The results of fruiting rate showed that the seed setting rate of zong3 keep high level from 4 days to 12 days;the other inbred lines showed slow down as the increase of days;the seed setting rates of hybrids decreased more slowly than inbred lines,the hybrids showed typical mid-parent heterosis.After analysis of 66 differentially accumulated proteins in three inbred lines,gi?413944345,gi?414869037 and gi?195635739 were significant for the silk vigor.After analysis of metabolic pathways and function classify,the result showed that recycling of methionine,protein biosynthesis and supplying of ATP were positive regulation for silk vigor,the metabolism of fatty acids and biosynthesis of anthocyanin were significant factors for silk viability down,the metabolism of cutin and suberin slowed the decline of silk vigor by delaying cell senescence.In hybrids,233 differentially accumulated proteins were found by proteomics.In xun928 × zong3,gi ? 195643366,gi ? 413942605 and gi ? 413920184 showed correlation with heterosis of maize silk.In lx9801×zong3,gi?414878829 and gi?414881303 showed correlation with heterosis of maize silk,and in three periods of both hybrids gi?413944345 showed correlation with heterosis of maize silk.The statistical result showed that 215 proteins were more than twofold difference between hybrids and their parents,and 43%(93 proteins)showed non-additive effect,57%(122 proteins)showed additive effect.Analysis of protein functions show that the proteins related to heterosis mainly involved in biosynthisis of anthocyanin,metabolism of methionine and biosynthisis of suberin,and so on.