Activities Of The Key Enzymes And Dynamic QTL Analysis Of Protein Components Content Of Grain Filling

Most of the traits (such as quality traits,yield traitsetc.) are controlled by quantitative trait locus (QTL).The protein is one of the major components of grain that is an important indicator of wheat quality. The protein synthesis is controlled by quantitative trait locus,and the activities of the key enzymes-Glutamine synthetase (GS) is controlled by quantitative trait locus.It is great significance to study the genetic improvement of the grain protein accumulation and QTL mapping for genetic improvement of the wheat quality.In this study, Use of103RIL population that is created by the common wheat strains R146and R97for the parents to determine the grain protein components and content, GS activities; use of SSR molecular marker to construct the genetic linkage map;use of composite interval mapping to analysis dynamic QTL mapping. It is wanted to be able to provide a theoretical basis for wheat quality breeding.The main results are as follows:1.The wheat grain GS and GPT activity is overall downward trend in grain filling stage.It is the highest on7d after anthesis, then decline gradually.The dynamic change of protein content in grain showed a "V"trend,and decline to minimum on21d after anthesis,then rise.It is the highest protein content of wheat grain maturity.The albumin content first decrease, then increase,it is in the "valley"in21d after anthesis to28d after anthesis.The dynamic change of the globulin protein content in grain showed a "V"trend. It is the highest the gliadin content in early grain filling stage,21d after anthesis decrease to minimum, then recover gradually. The gluten content is rising throughout the filling.2. The skewness and kurtosis of the protein components content and the key enzymes activity is less than1,which is normal distribution and can carry out QTL analysis.15linkage groups are located on chromosomes1A,1B,1D,2A,2B,4A,4D,5B,6B and the total length of the linkage map equals to881cm,with an average interval of14.4cm.3.The results of the QTL dynamic positioning show that the non-conditional QTLs and conditional QTL of the protein components and the key enzymes activities is not entirely consistent of the periods.There is6conditional QTL for GS activity detected, which QGS4D sites in7d after anthesisl4d after anthesis has been detected, that is great significance for GS activity. There are5non-conditional QTLs about protein content, which locate on chromosome1D,2B,6B. QGpc2B in7d after anthesis begin to express and it be able to explain the phenotypic variation of5.8%. In14d after anthesis QGpc6B can be detected,which the contribution rate is6.8%. QGpc1D continuous expression from21d to35d after anthesis, which contribution rates is8.61%,9.86%,3.31%.There are2conditional QTLs detected about protein content, which QGpc2B contribution rate is5.8%in7d after anthesis,and QGpc1D contribution rate is5.31%in28d after anthesis. There are4conditional QTL and7non-conditional QTLs for gliadin content, which Qgli4D sites in7d after anthesisl4d after anthesis has been detected.In7d after anthesis, contribution rate of non-conditional QTLs and conditional QTL is31.6%. The results of the QTL dynamic positioning for glutenin content show there are less QTL to express about glutenin content in7d after anthesis, which conditional and unconditional QTL can explain17.2%of phenotypic variation. As the grouting carried out, the initial expression QTL have not been detected in14d after anthesis,but there are new QTL detected on chromosomes1B and6B, conditional and unconditional QTL can explain21.52%of the phenotypic variation. In14d after anthesis Qgu11B and Qgu16B sustain to express and the contribution rate is27.07%.In28d and35d after anthesis, contribution rate isl5.83%and21.42%, which is significance for during this period glutenin accumulation.There are4conditional QTLs and8non-conditional QTLs about albumin content,which can explan37.8%phenotypic variation in7d after anthesis. So the QTL for the expression of albumin synthesis during this period have a major impact.4. Research to dynamic QTL for GS activities,GPT activities and the protein component content find that in7d after anthesis,the QTLs are detected on the xwmc473-xwmc311of chromosome4D associated with GS activity, gliadin content and gluten content. It is show that QGS4D is an important role in the synthesis of gliadin and glutenin. In14d after anthesis, the QTLs are detected on the xwmc222-xwmc232of chromosome1B associated with GS activity and gluten content. It is show that QGS1B is an important role about the accumulation of glutenin.It is find that QGS4D and Qgli4D are detected on xwmc473-xwmc311of chromosome4D,which indicate the QGS4D is significance to gliadin accumulation. In28d after anthesis, the QTLs arc detected on the xwmcl61a-xwmc468of chromosome4A associated with GS activity and gluten content. It is show that QGS4A is an important role about the accumulation of glutenin.