摘要
以甜瓜感病品种‘0544’为试材,测定外源亚精胺(Spd)预处理和白粉病菌接种后甜瓜幼苗的光合参数、抗氧化酶活性、内源多胺含量及多胺合成与代谢相关基因表达等的变化,探讨外源Spd处理对甜瓜幼苗白粉病抗性的诱导作用机制。结果显示:(1)1.0mmol·L-1外源Spd处理可显著降低甜瓜幼苗的白粉病病情指数,缓解植株发病症状;(2)外源Spd处理可诱导甜瓜幼苗的多胺合成以及代谢相关基因(SAMDC、ADC、ODC、Spd、Spm、PAO)显著上调表达;(3)外源Spd处理可诱导甜瓜幼苗腐胺(Put)和Spd含量显著增加,而外源Spd并接种白粉病菌处理对甜瓜幼苗精胺(Spm)含量积累的诱导更加显著;(4)接种白粉病菌诱导了甜瓜幼苗的多酚氧化酶(PPO)、过氧化物酶(POD)和超氧化物歧化酶(SOD)的活性,外源Spd预处理后再接种白粉病的诱导作用更大,同时外源Spd处理还诱导了甜瓜幼苗过氧化氢(H_2O_2)含量的升高;(5)在观测期(120h)内,接种白粉病菌对甜瓜叶片的光合作用抑制较小,而外源Spd预处理并接种白粉病菌共同诱导了甜瓜幼苗的光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)的显著升高。研究认为,在外源Spd预处理甜瓜幼苗后再接种白粉病菌,甜瓜幼苗可以通过多胺的快速积累及代谢产生的H_2O_2来启动响应机制,进而通过增强防御酶活性等途径来提高对白粉病的抗性。
The effect of exogenous spermidine（Spd）on inducing resistance of Cucumis melo L.to powdery mildew was conducted with the susceptible cultivars‘0544＇,and the photosynthetic parameters,activities of antioxidant enzymes,contents of endogenous polyamines and the genes expression of polyamine synthesis and metabolism were tested in melon seedlings after pretreated with Spd then inoculated with powdery mildew.The results showed that：（1）1.0mmol·L-1 exogenous Spd could significantly reduce the disease index in melon seedlings resistance to powdery mildew and relieve the symptoms;（2）the genes related to polyamine syntheses and metabolism（SAMDC,ADC,ODC,Spd,Spm,PAO）were significantly induced by the exogenous Spd treatment during the seedling stage;（3）the contents of putrescine（Put）and spermine（Spd）were induced more significantly by the exogenous Spd while the spermine（Spm）content accumulated more by both the exogenous Spd treatment and powdery mildew inoculation;（4）the defense enzymes of melon seedlings such as polyphenol oxidase（PPO）,peroxidase（POD）and superoxide dismutase（SOD）ac-tivities were induced after powdery mildew inoculation,with both the exogenous Spd treatment and powdery mildew inoculation.Meanwhile,the H_2O_2 contents increased as well after the exogenous Spd treatment;（5）during the period of observation（120h）,the photosynthetic parameters were less affected after the powdery mildew inoculation.However,the photosynthetic rate（Pn）,stomatal conductance（Gs）and transpiration rate（Tr）increased significantly by both the exogenous Spd treatment and powdery mildew inoculation.This study suggested that pretreatment melon seedlings with the exogenous Spd before powdery mildew inoculation could obviously improve the resistance of melon to powdery mildew,which might via rapid accumulation of PAs and H_2O_2 contents metabolized form polymine,and then induced the activities of defense enzymes.
出处
《西北植物学报》
CAS
CSCD
北大核心
2016年第1期85-92,共8页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家自然科学基金(K305021310)
商洛学院博士启动项目(15SKY026)
关键词
亚精胺
病情指数
防御酶活性
光合参数
基因表达
spermidine
disease index
defense enzyme activities
photosynthetic characteristics
gene expression
