Cloning,Functional Marker Development Of TaPod-A3 And Expression Analysis Of Wheat Peroxidase(POD) Activity Gene

Wheat is an important food crop in the world.The color of wheat flour has an important influence on the quality of its flour.Peroxidase(POD)in wheat grain has browning and bleaching effects on flour and its finished products at the same time.Studies have shown that the higher the POD activity,the whiter the wheat flour color.Therefore,the study on the characteristics of POD gene has become an important content to promote the improvement of wheat flour quality.In this study,we cloned the POD gene TaPod-A3 on the 7AL chromosome of Wheat by using homologous cloning method and Chinese Spring gDNA as template for PCR amplification,and three allelic variation types were found by using four pairs of materials with extremely high and low POD activity.We developed functional markers by analyzing the sequence of different allelic variations and the functional differences of the proteins they encode,and then selected genotypes and phenotypic values two varieties(lines)with high and low POD activity to study the expression of POD activity gene at different flowering stages of wheat and the expression differences among different allelic variations.The main results are as follows:1.TaPod-A3 gene is composed of 1163 base pairs.Three alleles,TaPod-A3a,TaPod-A3b and TaPod-A3c,respectively,contain an open reading frame(ORF)of 846 bp,867 bp and 708 bp,encoding 281,288 and 235 amino acids,respectively.The similarity between alleles is 88.09%.There are nine insertional deletions.The a mino acid residues encoded by TaPod-A3a,TaPod-A3b and TaPod-A3c genes were 77.31%similar.2.Three pairs of functional markers 7A1,7A2 and 7A3 were developed based on the variation of TaPod-A3 Alleles.TaPod-A3a(216 bp),TaPod-A3b(1012 bp)and TaPod-A3c(859 bp)were amplified by PCR.The functional markers TaPod-Al and TaPod-D1 were tested by using POD activity assay and molecular marker detection in Xinjiang wheat varieties,the POD activity of wheat varieties popularized in Xinjiang was higher than that popularized in the north of three main wheat-producing areas,the huang-huai wheat area,the Yangtze River valley and the southwest wheat area,the allelic variation types of TaPod-Ala and TaPod-Dla(low POD activity)were mainly used,and the functional markers of TaPod-Al and TaPod-D1 could distinguish the POD activity of wheat grains,it can effectively screen out the materials with high POD activity,increase the frequency of excellent allelic variation of Xinjiang wheat lines,and promote the genetic improvement of Xinjiang wheat quality.3.The expression of TaPod-Al and TaPod-D1 was analyzed in three main wheat producing regions(Yangtze River Valley and southwest wheat region,northern winter wheat region and Huanghuai Wheat Region)and wheat varieties(lines)popularized in Xinjiang.The results showed that except TaPod-D1b,TaPod-Ala,TaPod-Alb and TaPod-Dla tended to increase first and then decrease during wheat grain development Potential,in TaPod-A1 site,the expression of TaPod-Alb(36.29)was significantly higher(P<0.01)than that of TaPod-Ala(1.15),and TaPod-Alb was an excellent allelic variation;in TaPod-D1 site,the expression of TaPod-D1b(33.92)was higher than that of TaPod-D1a(22.47),TaPod-D1b was an excellent allelic variation,and the correlation analysis of the expression of TaPod-Al and TaPod-D1b allelic variations showed that,The expression of TaPod-Alb and TaPod-D1b were significantly correlated(P<0.01).TaPod-Alb and TaPod-D1b had stronger regulatory effect,which provided theoretical basis for further study on the function of TaPod-Al and TaPod-D1 in wheat.