The Influence Of Different Wx Protein Deficiencies On Starch Biosynthesis In Wheat Grain

In this paper,the object of this experiment is to use the medium gluten wheat line 01-2,eight different types of Wx protein deficiency including three types of single deletion of Wx protein(A,B,D)types,double deletion of Wx protein(AB,BD,AD)and one type of total Wx protein deletion(ABD).To study the relationship between the accumulation of starch and its components and the activity of enzymes related to starch biosynthesis and the expression level of wx gene in Wheat during grain filling,and to analyze the influence of different Wx proteins deficiencies on Wheat starch biosynthesis in developing endosperm.Through this experiment,we get the following main results:1.Starch synthesis related genes were expressed during the whole flowering time,and the expression was different in grain filling periods.The relative expression of eight genes were higher in 0d-12 d and low in 12d-30 d.In the early and late grain filling stage,the expression of ADPGpyrophosphorylase(AGPase)gene was relatively higher,and had a maximum value at 12 d after anthesis,there were some differences in different periods.The soluble starch synthase(SS)enzyme owns different isoforms,and their expressions were different.The relative expression of SSI gene was the lowest,and the relative expression of SSIIa and SSIII gene was relatively higher.The expression of starch debranching enzyme(DEB)has the lowest expression and little difference.The starch branching enzyme encoding gene(SBE)has different isoforms,SBEI and SBEII have higher activity in 12d-18 d after flowering.2.The activity of related enzymes in starch synthesis decreased with the increase of days,and was significantly related to the gene encoding starch synthase.The expression of coding gene was higher and the enzyme activity was higher.After flowering,the activity of 0d-12 d was higher and the activity of 12d-30 d was lower,the activities of different enzymes were different in the experiment.The enzyme activities of AGPase,GBSS and SBE were relatively high,and the starch content was higher.These enzymes are also important enzymes in the formation of starch synthesis pathways,while DEB,SSIII and SBE enzymes are relatively low.3.Eight different genotypes of wheat in the experiment,the 3 subunits of Wx-A1,Wx-B1 and Wx-D1 had different effects on amylose content,among which Wx-B1>Wx-D1>Wx-A1.The accumulation of amylose,amylopectin and total starch content is rising,and the growth rate of accumulation changes slowly and steadily.The amylose content of single deficiency genotypes was higher than that of double deficiency genotypes Wheat.The total content of Wx protein was positively correlated with the amylose content in the endosperm,indicating that it plays an important role in the synthesis of amylose.Based on the above,we studied the content of wheat starch,enzyme activity and the expression of genes encoding enzymes,and found that the there are positive correlation.The higher the relative expression of the enzyme gene,the higher the amylase activity and the content of starch.In amylose,the content of the type of total deletion< double deletion type< single deletion< wid type.At the same time,amylopectin and total starch content showed a rising trend,the growth rate of accumulation is slow and steady.To understand the regulation mechanism of different Wx protein deficiency on the formation of starch synthesis in wheat grains,and to clarify the relationship between the accumulation of starch and its components and the activity of enzymes related to starch synthesis and the expression level of coding genes,exploring the effect of different Wx proteins and their interaction on starch synthesis and accumulation.In order to explore the formation mechanism of wheat starch and provide a reference about the breeding,development and utilization of partial waxy and whole waxy wheat.