不同地理种群褐飞虱体内共生酵母菌的个体大小及数量差异

褐飞虱腹部脂肪体内普遍存在共生酵母菌,该类共生菌在褐飞虱的生理代谢和营养利用等方面起着重要作用。采用冷冻切片技术结合显微摄像系统观察法测定不同地理种群褐飞虱体内共生酵母菌的个体大小和数量。试验结果表明,不同地理种群褐飞虱雌(雄)成虫体内共生菌的个体大小和数量差异显著,依次为:对照种群>广西种群>浙江种群>福建种群。结合虫体内脂肪和糖元含量的分析得出,褐飞虱体内共生酵母菌的长、宽度和数量与脂肪和糖元含量显著正相关。文章从共生酵母菌的角度解释了不同地理种群褐飞虱致害性变异的内在原因,并推测,迁飞过程所导致的褐飞虱体内脂肪和糖元的消耗影响了该类共生菌的数量和质量,并最终导致褐飞虱对抗性品种水稻的致害性减弱。

Individual size and abundance of the yeast-like endosymbiote in different geographic populations of brown planthopper, Nilaparvata lugens

There are mass yeast-like endosymbiotes (YLES) in abdomen fat body of brown planthopper (BPH) Nilaparvata lugens (Stl). And the YLES plays vital physiological and nutritional role in their host, the BPH. In this study, morphological variance (i.e., individual size of length and width) and abundance of YLES in BPH from different geographic populations (i.e., Guangxi, Zhejiang, Fujian) was studied by the cryostat microtome method in combination with the photomicrography. The control population is, the BPH strain successively reared on the susceptible rice cultivar TN1 for 15 generations in laboratory. The results indicated that there was significant difference in individual size and abundance between different geographic populations of BPH, that is, CK > Guangxi > Zhejiang > Fujian. Compared with CK, significantly smaller YLES were observed in these three geographic populations; and significant decreases in quantity of YLES were also found in BPH of Zhejiang and Fujian populations. After the analyzing of the contents of fat and glycogen in BPH, significant positive correlation was observed between the two substances and YLES length, YLES width or YLES abundance. The internal factors resulting in the virulent shift of BPH to resistant rice varieties were elucidated from the variance in individual size and abundance of YLES in BPH, and it is presumed that the heavily loss of the carbohydrate (i.e. glycogen) and lipid deposited in abdomen fatty body of BPH during the migration process may cause YLES becoming smaller and decreased abundance, which in turn alleviating the virulent ability of BPH to BPH-resistant rice.