Effect of defense enzyme activities, endogenous SA and MeSA in tea plants on the host adaptability of Toxoptera aurantii (Hemiptera: Aphididae)

Abstract

Toxoptera aurantii, a predominant pest species on tea plants, significantly hinders both the yield and quality of tea production. Elucidating the factors influencing host adaptability is a crucial approach for effectively managing T. aurantii proliferation. This study assessed the adaptability of T. aurantii to seven different tea cultivars using an age-stage, two-sex life table. Furthermore, the variations in the activities of PPO, POD, PAL, and SOD, along with the differences in the levels of SA, MeSA, and catechins, were compared between susceptible (HJY) and resistant (QC1 and QC10) cultivars. The study revealed significant disparities in the adaptability of T. aurantii to different tea cultivars. On HJY, aphids exhibited the shortest developmental duration, the longest total lifespan, and the maximum reproductive quantity; in contrast, these metrics were reduced on QC1 and QC10. Moreover, following the infestation by T. aurantii, the activities of PPO, POD, PAL, and SOD in tea plants exhibited a marked increase. The activities of POD and SOD in QC1 were significantly higher than those in HJY and QC10, while the increase in PAL activity in QC1 and QC10 far surpassed that in HJY. Notably, lower levels of SA, MeSA, and catechins were observed in HJY compared to those in QC1 and QC10. This study offers an initial elucidation of the factors affecting the host adaptability of T. aurantii, thereby providing a theoretical foundation for screening aphid-resistant tea germplasms.