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蔗糖合成酶(Sucrose Synthase,EC 2.4.1.13,Sus)在植物不同组织及不同发育阶段起不同的作用,是参与植物糖类代谢调控的关键酶之一。本研究,我们利用目前已完全确定的亚洲棉(Gossypium arboretum L.)Sus基因7个成员(Ga Sus1-Ga Sus7,Gene Bank登录号JQ995522-JQ995528)进行同源克隆并通过q RT-PCR方法对不同纤维发育时期Sus表达模式进行了检测。得到的两个组配海岛棉(Gossypium barbadense L.)重组自交系(recombinant inbred line,RIL,F2:6)亲本材料5917(高比强度品种,平均比强度48.2 c N.tex-1)和Pima-7(低比强度品种,平均比强度37.6 c N.tex-1)的Sus g DNA序列。利用生物信息学方法对基因结构特征分析比较发现,5917、Pima-7与亚洲棉Sus编码区(CDS)中分别存在(Sus1与Ga Sus1:9,8;Sus2与Ga Sus2:25,8;Sus3与Ga Sus3:8,9;Sus4与Ga Sus4:40,41;Sus5与Ga Sus5:27,27;Sus6与Ga Sus6:16,16;Sus7与Ga Sus7:7,7)处单核苷酸多态性(SNP)位点。两个海岛棉品种间Sus1,Sus2,Sus3,Sus4 CDS中存在(1,21,4,1)处差异SNP位点,Sus5,Sus6,Sus7 CDS中无差异。海岛棉Sus CDS中核酸序列碱基置换虽改变了相应氨基酸组成,但氨基酸理化性质和蛋白质结构与功能均与亚洲棉相同未发生明显变化。海岛棉纤维发育过程中,Sus在纤维中的表达具有特异性。本研究在设立高、低比强度研究对象并比对8个纤维生育时期的基础上进一步发现Sus3在纤维次生壁加厚初期(20 DPA)开始大量表达到达峰值随后下降。高比强度海岛棉品种5917 Sus1除在纤维发育起始期(0 DPA~5 DPA)大量表达外,在纤维次生壁加厚后期和末期(30 DPA~35 DPA)表达量又重新升高,低比强度海岛棉品种Pima-7 Sus1无此回升现象且表达量远低于前者。研究表明,Sus3在纤维次生壁加厚初期起作用,Sus1作用于纤维次生壁加厚后期和末期,这两个Sus在纤维次生壁加厚期发挥重要的作用,可能与纤维比强度的形成和差异有关。
Sucrose Synthase (EC 2.4.1.13, Sus) plays a different role in different tissues and different developmental stages of plants and is one of the key enzymes involved in the regulation of plant carbohydrate metabolism. In this study, we used homologous cloning of seven members of the Susceptible Gossypium arboretum L. Sus gene (Ga Sus1-Ga Sus7, Gene Bank Accession No. JQ995522-JQ995528) Sus expression patterns at different stages of fiber development were examined. Two parental materials 5917 (high specific strength variety, average specific strength 48.2 c N. tex-1) and two recombinant inbred lines (RIL, F2: 6) The Sus g DNA sequence of Pima-7 (low specific-intensity, average specific intensity 37.6 c N. tetx-1). The results of bioinformatics analysis showed that there were (Sus1 and Ga Sus1: 9,8; Sus2 and Ga Sus2: 25,8; Sus3 respectively) in 5917, Pima-7 and Sus scrum With Ga Sus3: 8,9; Sus4 with Ga Sus4: 40,41; Sus5 with Ga Sus5: 27,27; Sus6 with Ga Sus6: 16,16; Sus7 with Ga Sus7: 7,7) Status (SNP) sites. There was no SNP loci (1, 21, 4, 1) in SusI, Sus2, Sus3 and Sus4 CDS between two IS cotton cultivars, but there was no difference between Sus5, Sus6 and Sus7 CDS. However, the physical and chemical properties of amino acids and the structure and function of amino acids were the same as that of Asian cotton. During island cotton fiber development, the expression of Sus in the fiber is specific. In this study, based on the establishment of high and low specific intensity subjects and comparison of eight fiber growth stages, it was further found that Sus3 reached its peak at the beginning of fiber secondary wall thickening (20 DPA) and then decreased. The expression of 5917 Sus1, a high specific-density island cotton variety, was up-regulated again in late and late stage (30 DPA ~ 35 DPA) except for the high expression of fiber at the initial stage of fiber development (0 DPA ~ 5 DPA) Pima-7 Sus1, a specific-intensity island cotton variety, showed no sign of recovery and its expression level was much lower than the former. Studies have shown that Sus3 plays an important role in the initial stage of fiber secondary wall thickening and Sus1 acts on the late and late stage of fiber secondary wall thickening. These two Sus plays an important role in secondary wall thickening, which may be related to fiber specific strength The formation and differences related.