Starch accumulation, activities of key enzyme and gene expression in starch synthesis of wheat endosperm with different starch contents
Starch accumulation, activities of key enzyme and gene expression in starch synthesis of wheat endosperm with different starch contents
复制标题
不同淀粉含量小麦胚乳淀粉积累、淀粉合成关键酶活性及基因表达
DOI：
10.1007/s13197-011-0520-z
复制
发表时间：
2014-03-01
影响因子：
3.1
通讯作者：
Yin, Yongan
中科院分区：
文献类型：
--
作者：
Wang, Zibu;Li, Weihua;Yin, Yongan
为了研究小麦籽粒不同发育阶段淀粉积累、酶活性变化和基因表达水平及其相互关系。本研究选择安农9912和E28为供试材料。在淀粉积累速率和籽粒灌浆速率上，安农9912与E28存在明显的基因型差异。无论是低淀粉含量还是高淀粉含量，通过淀粉含量与DAP的关联，支链淀粉、直链淀粉和总淀粉的积累过程均符合Logistic方程。模拟参数表明，支链淀粉和直链淀粉含量较高是由于起始积累时间较早，积累速率较大所致。两种小麦的直链淀粉、支链淀粉和总淀粉积累速率与SBE、SSS和GBSS活性呈显著正相关，而E28的直链淀粉积累速率与SBE活性不相关。此外，两个小麦品种的SBE、SSS和GBSS活性之间也存在显著的相关性。我们推测，这些酶蛋白可能在淀粉体内的淀粉生物合成中具有协调作用，以功能性多蛋白复合体的形式运作。酶基因的表达水平呈单峰曲线，12-18DAP达到峰值后开始下降，在胚乳发育早期均有较高的表达水平，但E28的表达水平高于安农9912。在E28中，GBSS-I转录本的平均表达量是GBSS-II转录本的60多倍。SBE、SSS、DBE可能在转录水平调控淀粉合成，GBSS-IMA可能在转录后水平调控淀粉合成。DBE基因的平均表达水平低于SS-1和SBE-II基因，与Toss-III和SBE-IIb基因相似，但高于GBSS-I和GBSS-II基因。
In order to investigate starch accumulation, and the enzymes activity changes and the expression levels of genes and their relationships among them at different developmental stages of wheat grain. We choose Annong9912 and E28 were used in the study. During starch accumulating rate and grain filling rate, and there were obvious genotype difference between Annong9912 and E28. Whether low or high starch content of starch content, the accumulation courses of amylopectin, amylose and total starch were well fitted to the logistic equation by relating starch contents against DAP. The simulation parameters revealed that the higher contents of amylopectin and amylose resulted from earlier initiating accumulation time and greater accumulation rate. And amylose, amylopectin and total starch accumulation rate of two wheat cultures were significantly and positively correlated with activities of SBE, SSS and GBSS, but amylose accumulation rate of E28 had no correlation with the activities of SBE. In addition, there were significant correlations among activities of SBE, SSS and GBSS in two wheat cultivars. We speculated that these enzymes proteins may have a coordinating action in starch biosynthesis within the amyloplast, operating as functional multiprotein complexes. And expression levels of enzyme genes demonstrated a single-peak curve, and 12-18 DAP reached their peaks and then began to drop, and all had high expression level in earlier stage of endosperm development, but in E28 were higher than in Annong9912. TheGBSS-Itranscripts on average were expressed over 60 times more thanGBSS-IItranscript in E28.SBE, SSS, DBEmay control starch synthesis at the transcriptional level, andGBSS-Imay control starch synthesis at the post transcriptional level. The expression level ofDBEon average was lower thanSS-1andSBE-IIagenes, and similar toSS-IIIandSBE-IIbgenes, but higher thanGBSS-IandGBSS-IIgenes.