24-表油菜素内酯对干旱胁迫下辣椒幼苗叶片抗氧化酶系统及耐旱相关基因表达的影响

Effects of 24-Epibrassinolide on Antioxidant System and Expression of Drought-tolerance Relative Genes in Pepper Seedlings under Drought Stress

报道了干旱胁迫下外源24-表油菜素内酯(EBR)对辣椒幼苗叶片H2O2和MDA含量,抗氧化酶活性,以及耐旱相关基因表达的影响。结果表明,0.1μmol·L-1EBR处理诱导了辣椒幼苗叶片H2O2含量的增加,并提高了SOD、APX、CAT、DHAR、MDAR和GR活性;干旱胁迫下,EBR处理显著诱导了辣椒叶片抗氧化酶活性的增加,并抑制了H2O2和MDA含量的上升;EBR处理也促进了c APX和MDAR等抗氧化酶基因的表达,以及WRKY3、WRKY6和MYB等转录因子的表达。由此认为,适宜浓度的外源EBR可能是通过信号分子H2O2调控辣椒叶片中WRKY和MYB等转录因子的表达以调控相关耐旱基因表达,增强细胞的抗氧化酶活性,减轻干旱造成的膜质过氧化伤害,从而增强了辣椒幼苗的耐旱性。

We studied the effects of exogenous 24-epibrassinolide （EBR） on H2O2 and MDA content, antioxidant enzymes activities, and the expression of drought-tolerance relative genes in pepper （Capsicum annuum L. ） under drought stress. The results showed that 0. 1 μmol · L^-1 EBR induced H2O2 producing slightly, and significantly promoted the activities of SOD, APX, CAT, DHAR, MDAR and GR in leaves of pepper. While EBR significantly increased antioxidant enzymes activities, and alleviated H2O2 and MDA content in leaves of pepper under drought stress. EBR also induced the expression of antioxidant enzymes （cAPX and MDAR） and transcription factors （ WRKY3, WRKY6 and MYB） genes. It was considered that the suitable exogenous EBR（0.1μmol · L^-1） enhanced drought tolerance in pepper seedling maybe through induction of drought-tolerance relative genes expression and activations of antioxidative enzymes, and H2O2 signal was involved in EBR-indueed drought-tolerance relative genes expression.