印度梨形孢提高香蕉抗热性的生理生化机制

Physiological and biochemical mechanisms of Piriformospora indica-induced high-temperature resistance in banana

为研究印度梨形孢(Piriformospora Indica)对香蕉抗热性的影响及其生理生化机制,测定和比较了45℃高温处理0 h、3 h、6 h、12 h和24 h的有/无定殖的“天宝蕉”叶片中抗氧化活性物质活性或含量及激素含量变化情况.结果显示:高温处理后有/无P.indica定殖的香蕉叶片中H2O2含量呈先升后降的变化趋势,脯氨酸(Pro)和丙二醛(MDA)含量呈下降趋势,同时,P.indica定殖的香蕉叶片中H2O2、Pro和MDA含量均高于无定殖对照.高温处理下香蕉叶片超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)和苯丙氨酸酶(PAL)活性均逐步升高,且P.indica定殖的香蕉叶片中这些指标均低于无定殖组.P.indica定殖的香蕉多酚氧化酶(PPO)活性在高温处理各时间点变化不显著,而无定殖组PPO活性在高温处理3 h时显著升高.高温处理前后P.indica定殖香蕉叶片中吲哚乙酸(IAA)和赤霉素(GA)含量均低于无定殖组,脱落酸(ABA)含量显著高于无定殖组,茉莉酸(JA)和水杨酸(SA)含量差异不大.上述结果表明P.indica可以通过提高香蕉叶片中H2O2、Pro、MDA和ABA含量以及抑制IAA和GA含量提高香蕉抗热能力.

This study aimed to study the effects of Piriformospora indica colonization on the high temperature resistance of banana and to reveal the physiological and biochemical mechanisms underlying these effects.To achieve this,we detected and compared changes in the activities of antioxidant enzymes,contents of antioxidant molecules,and concentrations of phytohormones in leaves of“Tianbaojiao”banana seedlings,both colonized and non-colonized with P.indica,before and after high-temperature(HT)treatment at 45℃for 0 h,3 h,6 h,12 h,and 24 h.Results showed that H2O2 contents in the leaves of banana plants,both colonized and non-colonized with P.indica,first increased and then decreased after HT treatment.The contents of proline(Pro)and malondialdehyde(MDA)in banana leaves decreased after HT treatment.However,the contents of H2O2,Pro,and MDA in the leaves of banana seedlings colonized with P.indica were higher than those of the noncolonized banana seedlings.The activities of superoxide dismutase,catalase,peroxidase,and phenylalanine ammonia lyase(PAL)in banana leaves increased gradually under HT treatment,and these indices were all lower in the leaves of banana seedlings colonized with P.indica than in those of non-colonized banana seedlings.Polyphenol oxidase(PPO)activity in the leaves of P.indica-colonized banana seedlings showed no significant change after HT treatment,but the PPO activity in the non-colonized group increased significantly at 3 h after HT treatment.The indole-3-acetic acid(IAA)and gibberellin(GA)contents in the leaves of P.indicacolonized banana seedlings were lower than those of the non-colonized seedlings,both before and after HT treatment.By contrast,abscisic acid(ABA)contents were significantly higher in the colonized group than in the non-colonized group,and jasmonic acid and salicylic acid contents were not significantly different.The results obtained in this study indicate that P.indica could improve the heat resistance of banana by increasing the content of H2O2,Pro,MDA,and ABA and by inhibiting the concentration of IAA and GA in banana leaves.