灌浆期高温与干旱对小麦籽粒淀粉合成相关酶基因表达的影响

灌浆期高温与干旱是影响小麦籽粒淀粉合成与积累的重要因素。为探讨灌浆期高温、干旱及其复合胁迫对小麦籽粒淀粉合成及积累的影响机理,以郑麦366为试验材料,采用大田盆栽和人工气候室模拟高温相结合的方法,研究了灌浆期高温、干旱及其复合胁迫对小麦籽粒淀粉合成相关酶基因表达特性及淀粉含量的影响。结果表明,灌浆期高温导致小麦籽粒淀粉合成相关酶基因表达高峰期提前,并不同程度抑制淀粉合成相关酶基因的表达;干旱胁迫不同程度提高了 AGPL1、 AGP1-a、 AGP1-b、GBSSI、SSI、SSIIc、SSIIIb、BEI、BEIIb、 ISA2、PHOH基因的表达量,降低其余被测基因表达量;高温和干旱复合胁迫与单因素胁迫对被测指标的影响不尽相同,表明两者对某些指标存在互作效应。高温与干旱均导致成熟期籽粒直链、支链和总淀粉含量下降。淀粉合成相关酶基因表达特性与淀粉积累密切相关。综上所述,高温与干旱改变了淀粉合成相关酶基因的表达,使淀粉积累受抑,导致小麦籽粒淀粉含量和产量下降。

Temperature and Drought Stress during the Grain Filling Stage

High temperature and drought stress often occurred simultaneously and significantly affected starch biosynthesis and accumulation in wheat grains during the grain filling stage. In this paper,wheat cultivar Zhengmai 366 was used. Combined pot culture with climate-controlled greenhouse simulating high temperature,effects of high temperature(HT) and drought stress(DS) on genes expression involved in starch biosynthesis and starch accumulation in wheat grains were evaluated. The results showed that the genes expression under HT treatment peaked earlier compared with the control(CK),and high temperature reduced the genes relative expression involved in starch biosynthesis. While drought increased the genes expression of AGPL1, AGP1-a, AGP1-b,GBSSI,SSI,SSIIc,SSIIIb,BEI,BEIIb, ISA2,PHOH,and decreased the remaining genes expression. There is a synergistic interaction effect between high temperature and drought stress. High temperature and drought stress significantly reduced starch accumulation in wheat grains and led to a decrease of amylose,amylopectin and total starch contents. There was significant correlation between genes expression and amylopectin and total starch content. High temperature and drought stress influenced the genes synergistic expression characteristic involved in starch biosynthesis,and then led to the decline of amylopectin and total starch content,and thus the declined grain yield.