木瓜秀粉蚧为害对不同木薯品种次生代谢物质含量的影响

次生代谢物质在植物防御植食性害虫时发挥重要作用,但目前尚无次生代谢物质与木薯品种抗虫相关性的报道。本研究系统开展了木瓜秀粉蚧为害前后不同木薯品种叶组织中总酚、丙二醛、单宁等次生代谢物质含量的差异分析。结果表明,与为害前相比,木瓜秀粉蚧为害1、4、8 d后,感虫木薯品种‘BRA900’‘面包’‘SC205’和‘瑞士T7’叶组织中总酚与丙二醛含量无显著差异,单宁含量则显著降低,而抗虫木薯品种‘缅甸’和‘C1115’叶组织中总酚和单宁含量显著增加,丙二醛含量显著降低。抗虫木薯品种的总酚含量在粉蚧为害前显著低于感虫木薯品种,而粉蚧为害1、4、8 d后显著高于感虫木薯品种;抗虫木薯品种丙二醛含量在为害前与感虫木薯品种无显著差异,粉蚧为害1、4、8 d后显著低于感虫木薯品种;抗虫木薯品种单宁含量在为害前后均显著高于感虫木薯品种。相关性分析发现,木薯对木瓜秀粉蚧的抗性与叶组织中总酚含量和单宁含量显著正相关,与丙二醛含量显著负相关。本研究初步阐明基于次生代谢物质总酚、丙二醛、单宁的木薯品种对木瓜秀粉蚧的抗性机理。

Paracoccus marginatus Infestation Influences the Content of Secondary Metabolites in Different Cassava Cultivars

Secondary metabolites play an important role in plant defense against phytophagous pests, however, to the best of our knowledge, there is lack of studies about the relationship between secondary metabolites and insect resistance of cassava. In this study, the contents of total phenol, malondialdehyde (MDA) and tannin in leaves of different cassava cultivars before and after being damaged by Paracoccus marginatus were analyzed. The results showed that there was no significant difference in the contents of total phenols and MDA in the leaves of the susceptible cassava cultivars such as ‘BRA900’ ‘bread’ cassava, ‘SC205’ and ‘Swiss T7’ after 1 d, 4 d and 8 d infestation, while the tannin content was significantly decreased over time. However, the content of total phenol and tannin in the leaves of the resistant cassava cultivars like ‘Myanmar’ and ‘C1115’ increased significantly, while the content of MDA decreased significantly. In addition, the content of total phenols in the insect-resistant cassava cultivars was significantly lower than those in susceptible ones before damaged by P. marginatus, while it was significantly higher than that of the susceptible cultivars as being damaged over time. There was no significant difference in MDA content between the insect-resistant and insect-susceptible cassava cultivars before damaged, while it was significantly lower than those in the susceptible ones after damaged for 1 d, 4 d and 8 d. Furthermore, the tannin content of the insect-resistant cassava cultivars was significantly higher than those of the susceptible ones before and after damaged by P. marginatus. The correlation analysis showed that the cassava resistance to P. marginatus was positively correlated with total phenol and tannin content, and negatively correlated with MDA content. This study preliminarily elucidated the mechanism of cassava resistance to P. marginatus based on secondary metabolites such as total phenols, MDA and tannin.