番木瓜感染畸形花叶病毒后的生理变化及扫描电镜观察

Physiological changes and scanning electron microscope observation of Carica papaya L. infected with PLDMV

【目的】阐明番木瓜畸形花叶病毒(Papaya leaf-distortion mosaic virus,PLDMV)的侵染机理及侵染后番木瓜自身防御体系对抗病毒的作用机制,为番木瓜病毒病防治提供参考。【方法】以台农二号番木瓜为材料,通过RTPCR检测接种PLDMV处理组(T)与健康空白对照组(CK)的病毒感染情况,采用分光光度法测定PLDMV侵染对番木瓜相关生理指标的影响,运用扫描电镜法观察两组番木瓜叶片的微观结构差异。【结果】通过RT-PCR检测,证明T番木瓜植株已感染PLDMV。T与CK番木瓜叶片在表征、微观解剖结构及生理指标等方面均存在明显差异,与CK番木瓜叶片相比,T番木瓜叶片纵切面栅海比及背部绒毛密度明显小于CK番木瓜,气孔密度大于CK番木瓜;T番木瓜的过氧化物酶(POD)、多酚氧化酶(PPO)、苯丙氨酸解氨酶(PAL)活性和脯氨酸(Pro)、丙二醛(MDA)、超氧阴离子(O)含量均显著高于CK番木瓜(P<0.05,下同),过氧化氢酶(CAT)活性和叶绿素(Chl)含量显著低于CK番木瓜,而超氧化物歧化酶(SOD)和几丁质酶活性两组间无显著差异(P>0.05)。【结论】番木瓜受PLDMV侵染后,其叶片结构被破坏,细胞毒害损伤严重,体内代谢紊乱,多种代谢调节平衡被打破,番木瓜的正常生长发育受阻。

【Objective】The infection mechanism of Papaya leaf-distortion mosaic virus(PLDMV)and the mechanism of Carica papaya L.defense system against virus after infection were elucidated to provide reference for papaya virus disease.【Method】C.papaya variety Tainong 2 was used as material.The infection situations of C.papaya in treatment group with PLDMV inoculation(T)and healthy blank control group(CK)were confirmed by RT-PCR detection.The influence of PLDMV infection on C.papaya related physiological indexes was determined by spectrophotometry.Scanning electron microscopy was used to observe the difference in microstructure between the two groups.【Result】RT-PCR test showed that T group was infected with PLDMV.There were obvious differences in the characterization,microstructure and physiological indexes between leaves in T and CK.Palisade tissue to cavernous tissue ratio of vertical section leaves and density of back tomentum in T were smaller than those in group CK,and the stomatal density in group T was larger than that in group CK.In physiological indexes,the activities of peroxidase(POD),polyphenol oxidase(PPO)and phenylalanine ammonia lyase(PAL),and contents of proline(Pro),malondialdehyde(MDA)and superoxide anion(O)in T group were significantly higher than those in CK group(P<0.05,the same below).Catalase(CAT)activity and chlorophyll(Chl)content in T group was significantly lower than those in CK group.Superoxide dismutase(SOD)and chitinase were not significantly different from each other(P>0.05).【Conclusion】After PLDMV infection,C.papaya leaf structure is damaged,the cells are seriously poisoned,metabolic disturbance occurs,multiple metabolic regulation are imbalanced,therefore,the development and growth of papaya is blocked.