Wx基因对小麦淀粉合成关键酶活性的影响

为研究Wx基因的缺失对小麦淀粉合成关键酶活性的影响,本试验以8个Wx小麦近等基因系为材料,在灌浆期的10、20、30和40 d取籽粒对ADP-葡萄糖焦磷酸化酶(AGPase)、可溶性淀粉合成酶(SSS)、颗粒结合型淀粉合成酶(GBSS)和淀粉分支酶(SBE)活性进行了测定。结果表明:野生型的AGPase、SSS、GBSS和SBE活性在花后所有时期均最高(GBSS花后40 d除外,处于中间水平),而WxABD型4种淀粉合成相关酶活性几乎在整个灌浆期均低于其余基因型,尤其是WxABD型的GBSS活性尽管也呈现先升高后降低、20 d左右达到高峰的趋势,但其升高或降低的幅度很小,其活性相对较为稳定。研究证明小麦Wx基因缺失对淀粉合成关键酶活性影响较大,依次为Wx-D1Wx-A1WxB1;淀粉合成关键酶活性在花后逐渐增加,以花后20 d最大,此后逐渐降低,到40 d达最低值;WxABD型缺失所有Wx基因,淀粉合成酶活性在花后各时期最低,其中GBSS活性远低于其余基因型且在花后各时期变化较小。

Effect of Wx Genes on Key Enzyme Activities of Starch Biosynthesis in Wheat

In order to investigate the effect of absence of Wx gene on key enzymes activity of starch biosynthesis in wheat, 8 near-isogenic Wx wheat lines were used. The activities of ADP-glucose pyrophosphorylase polypeptide (AGPase), soluble starch synthase (SSS), granule-bound starch synthase (GBSS) and starch branch-ingenzyme (SBE) were determined during the grain filling period of 10, 20, 30 and 40 days in this study. The results showed that the AGPase, SSS, GBSS and SBE activity of wild type were the highest at all times after anthesis (excepted for GBSS activity 40 days after anthesis which were at an intermediate level). However, the four key enzymes activity of starch synthesis in WxABD were lower than all other genotypes in the whole grain filling stage, especially the GBSS activity of which, although increased first and then decreased, and reached the peak trend about 20 days after anthesis, the increasing or decreasing of the amplitude was very small, and the activity of relatively was stable. This studies have shown that the greater impact of lack of Wx genes in wheat on the key enzyme activities of starch biosynthesis was observed, the effect of three Wx genes was Wx-D1>Wx-B1>Wx-B1; the activities of key enzyme of starch biosynthesis were gradually increased after flowering, which reached the maximum value 20 days after flowering, and then decreased gradually, which reached the minimum value 40 days after flowering; for lack of all Wx genes, the key enzyme activities of starch biosynthesis of WxABD were the lowest in the whole grain filling period, GBSS activity of which was much lower than the other Wx-genotypes and had little change after anthesis.