玉米茎秆抗倒伏相关生理生化指标及关键酶基因的表达分析

Physiological and biochemical indexes related to lodging resistance of maize stalk and expression analysis of key enzyme genes

为探究玉米(Zea mays)茎杆抗倒性的生理生化和分子机制,明确茎杆内部化学成分对茎杆抗倒伏的影响,以抗倒性较强的自交系辽3162和抗倒性较弱的自交系丹340为试验材料,测定3个时期(吐丝期、灌浆期和乳熟期)的茎秆抗推力、耐穿刺力、株高、穗位高和茎粗,比较分析了其茎秆激素含量及纤维含量的差异和相关酶基因的表达。结果表明,与丹340相比,辽3162的茎秆抗推力和耐穿刺力在3个时期均达到极显著差异,其它表型性状无显著差异。与丹340相比,辽3162中的木质素和纤维素含量只在吐丝期达到极显著差异,而半纤维素含量无显著差异。生长素(IAA)含量在灌浆期和乳熟期达到显著和极显著差异。实时荧光定量PCR表明,在吐丝期和灌浆期,与木质素合成相关的辅酶A连接酶基因(4CL)和咖啡酸-O-甲基转移酶基因(COMT)在辽3162中的相对表达量高于丹340,COMT基因在两个时期都表现为极显著差异,4CL基因仅在灌浆期表现为极显著差异,而在乳熟期两个基因在辽3162中的相对表达量均低于丹340,4CL基因差异极显著;与纤维素合成相关的基因纤维素合酶1(CESA1)和纤维素合酶9(CESA9)的变化趋势与木质素合成相关的基因基本一致;与生长素合成相关的生长素应答因子(ARF)在灌浆期在辽3162中相对表达量极显著高于丹340。本研究表明玉米茎杆内木质素、纤维素、生长素含量的增加以及相关酶基因表达能增强玉米的茎杆抗倒伏能力。

To explore the physiological,biochemical and molecular mechanisms in two maize (Zea mays L.) inbred lines with different lodging resistance and investigate the effect of stalk chemical components on lodging resistance,Liao 3162 with better lodging resistance and Dan 340 with weaker lodging resistance were used as materials.The stem thrust resistance,puncture resistance,plant height,ear height and stem diameter in two maize inbred lines were measured at three different stages (silking stage,filling stage and milking stage) and the differences of hormone content and fibre content in stem were compared,and then the expression of enzyme genes was analyzed.The results showed that the stem thrust resistance and puncture resistance of Liao 3162 were extremely significantly different at three different stages,but there was no significant difference in other phenotypic traits compared with Dan 340.For the fibre components,the lignin and cellulose contents in Liao 3162 were significantly different at silking stage,but there was no significant difference in hemicellulose content compared with Dan 340.For the hormone content,only indole-3-acetic acid (IAA) showed significant and extremely significant difference in Liao 3162 at filling and milky stages compared with Dan 340.The results of quantitative RT-PCR showed that the relative expression 4-coumarate: CoA ligase genes (4CL) and caffeic acid O-methyltransferases (COMT) related to lignin synthesis in Liao 3162 was higher than that of Dan 340 at silking stage and filling stage,COMT was significantly different at these two stages,4CL was only significantly different at filling stage,and the relative expression of these two genes in Dan 340 was higher than that in Liao 3162 at milky stage.The changes of the relative expression of cellulose synthase 1 gene (CESA1) and cellulose synthase 9 gene (CESA9) related to cellulose synthesis were consistent with the genes related to lignin synthesis.And the relative expression of gene auxin response factor (ARF) related to IAA in Liao 3162 was extremely significantly higher than that in Dan 340 at filling stage.This study showed that the higher contents of lignin,cellulose,IAA and related enzyme genes in maize stalk play an important role in improving the lodging resistance of maize stalk.