| Heading date is one of the most important agronomic traits of wheat.It plays a vital role in adapting to different environments.Proper heading date is the premise to keep the high and stable yield of crops.Therefore,excavating heading date genes can provide theoretical guidance for the cultivation of new varieties.TTD140 is a wild emmer line with high protein content and early maturity.In this study,the compositon of CASL3AL,one chromosome arm substitution line of wild emmer accession TTD140 in the genetic background of common wheat variety Chinese Spring?CS?,was determined by analyzing the CASL3AL transcriptome data.Light and temperature response characteristics of the QTL has been studied using the CASL3AL,CASL3AS and CS.And?CASL3AL×CS?F2 and F2:3 populations were used to mapping heading date QTL.The main results were as followed:1.The 3A chromosomes of CASL3AL and CASL3AS were identified by 242 SSR molecular markers.The polymorphic molecular markers were mainly concentrated between 110-750Mb of CASL3AL and 0-510Mb of CASL3AS,with 400Mb overlap area between the two materials.2.CASL3AL,CASL3AS and CS were treated with different vernalization time.The results showed that vernalization had a significant effect on heading date of CASL3AL compared with others.Under long day condition?16h light/8h dark?,the heading date of CASL3AL was 9.5 days earlier than CS without vernalization,35 days earlier than CS with 20 days of vernalization,and 8.5 days earlier with 30 days of vernalization,which showed that CASL3AL requires less vernalization than CS.With any treatment,the heading time of CASL3AS was between CASL3AL and CS,which indicated that the genes affecting the precocity of CASL3AL and CASL3AS were different.3.The young spike differentiation process of CASL3AL,CASL3AS and CS were observed under long-day condition.The young spike development of CASL3AL was faster than that of CASL3AS and CS.The double-ridge stage of young spike differentiation was the key turning point for the development of the three materials.After vernalization,CASL3AL passed through the double-ridge stage earlier,thus affecting the final heading date.4.The homozygous SNP between CASL3AL and CS was obtained by using three stage young spike and leaf of CASL3AL transcriptome data,which was used to identify the substitution region of TTD140in CASL3AL.The results showed that the number of homozygous SNPs in the young spike were more than those in leaves,but the homozygous SNPs of the four materials are mainly distributed on 108-750Mb segment of chromosome 3A.Sequencing the SNP enrichment region on chromosome 3A showed that base mutation type was consistent with TTD140.84 SSR polymorphic markers verified the distribution range of TTD140 fragment on 3A was basically consistent with the results of transcriptome data identification.So this method of combining homozygous SNP analysis with transcriptome data is an efficient way to verify chromosome constitution in CASL.5.The populations of two F2 and its F2:3 generations derived from the across between CASL3AL and CS were used to detect the quantitative trait loci?QTLs?for heading date?HD?.The genetic linkage map consists of 33 simple sequence repeat?SSR?markers covering chromosome 3A.Two QTLs were respectively mapped in 258 F2 populations and 243 F2:3 populations,and both QTLs were located between barc324-P1381 by QTL Icimapping.In greenhouse condition,another QTL was located between P1590-P1601 using a 96 F2 population,and three QTLs explained 5.47%to 15.17%of the phenotypic variation for HD.The result indicated that environment has a strong influence on QTL mapping,this QTL site still needs further verification.6.The transcriptional data of CASL3AL young spike were used to analyze the differential expression genes.Ten differential expressed genes were found in the QTL mapping interval in the field,and one candidate gene,TraesCS3A01G284400,was a MADS-box transcription factor,which may be involved in the control flowering time. |
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