Genetic Mapping Of The Qd1 Gene Of Wheat Stem Quick Development And Transcriptome Analysis In Wheat

The stems provide base to the plant for high yield and good quality in wheat.However,the stem development-regulated genes used in wheat breeding are mainly dwarf genes and their genetic basis is increasingly narrow.Induced mutation techniques could broaden the genetic basis of wheat and explore new genes that regulate the development of wheat stems.In our lab,a quick development mutant?qd?was obtained from the winter wheat Lunxuan 987?LX987?by using ⁷Li ion beam mutagenesis.The stems development rate after jointing stage and the light induced coleopotile color of the mutant?qd?showed sigmificant phenotypic difference with wild type?WT?.In this study,BSR-Seq,transcriptome and 660K SNP microarrays were used to carry out the preliminary mapping of the gene controlling the quick development of the stem?qd1?and the anthocyanin-synthesized gene induced by strong light.The main results are as following:1.Mapping of the qd1 gene for the quick development of wheat stems.F₂ population drived from LX987×qd was used to obtain a region with a total length of 13.55 Mb?15.41 Mb-28.96 Mb?on chromosome 4B by using the BSR-Seq technique.Based on the SNP revealed by BSR-Seq,16 KASP?kompetitive allele specifc PCR?markers were identified in the target interval.These KASP markers were then used to verify the preliminary mapping interval in 153 recessive individuals of the F₂population.The results showed that there was a 2.16 Mb overlap region?26.80 Mb-28.96 Mb?with the BSR-Seq initial mapping region,which further mapped the qd1 initial region to a 5.08 Mb interval?26.80 Mb-31.88 Mb?.2.Transcriptome analysis of wild-type and mutant.KEGG?kyoto encyclopedia of genes and genomes?enrichment analysis showed that DEG?differential expression genes?was concentrated in benzoxazine biosynthetic pathways significantly.In addition,DEG enrichment was also found in the CPS?ent-copalyl diphosphate synthase?and GA20ox enzymes of the GA synthesis pathway.When FPKM?fragments per kilobase of transcript per million fragments mapped?value of all DEG corresponding to each enzyme were added,the GA20ox expression level was down-regulated in the mutants,implying that,at the booting stage,the decrease in the elongation rate of the mutant stem may result from the large decrease in the expression of the mutants GA20ox.3.Mapping of light-induced anthocyanin synthesis gene in mutants.The results from 660K SNP microarray ananlysis showed that there were three identical polymorphic SNP enrichment regions on chromosome 7A in the two F₂ populations generated from LX987×qd and HM247×qd.The proportion of polymorphic SNP enrichment in the 260 Mb-290 MB region was not less than 30%in both populations.The R2R3-MYB transcription factor located at 285 Mb was most likely to be a candidate gene.It was concluded that the BSR-Seq and 660K SNP chip technology could be used to quickly map key genes related the stems development and coleoptile anthocyanin synthesis in wheat.These results could be helpful to enhance the genetic resources of the stems development-regulated genes and further reveal the physiological functions of anthocyanins.