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Hangzhou, China

Xia J.,Institute of Insect science | Xia J.,Baylor College of Medicine | Zhang C.-R.,Institute of Insect science | Zhang S.,Institute of Insect science | And 4 more authors.
PLoS ONE | Year: 2013

Background:The fungal pathogen, Beauveria bassiana, is an efficient biocontrol agent against a variety of agricultural pests. A thorough understanding of the basic principles of insect-fungus interactions may enable the genetic modification of Beauveria bassiana to enhance its virulence. However, the molecular mechanism of insect response to Beauveria bassiana infection is poorly understood, let alone the identification of fungal virulent factors involved in pathogenesis.Methodology/Principal Findings:Here, next generation sequencing technology was applied to examine the expression of whitefly (Bemisia tabaci) genes in response to the infection of Beauveria bassiana. Results showed that, compared to control, 654 and 1,681genes were differentially expressed at 48 hours and 72 hours post-infected whiteflies, respectively. Functional and enrichment analyses indicated that the DNA damage stimulus response and drug metabolism were important anti-fungi strategies of the whitefly. Mitogen-activated protein kinase (MAPK) pathway was also likely involved in the whitefly defense responses. Furthermore, the notable suppression of general metabolism and ion transport genes observed in 72 hours post-infected B. tabaci might be manipulated by fungal secreted effectors. By mapping the sequencing tags to B. bassiana genome, we also identified a number of differentially expressed fungal genes between the early and late infection stages. These genes are generally associated with fungal cell wall synthesis and energy metabolism. The expression of fungal cell wall protein genes might play an important role in fungal pathogenesis and the dramatically up-regulated enzymes of carbon metabolism indicate the increasing usage of energy during the fungal infection.Conclusions/Significance:To our knowledge, this is the first report on the molecular mechanism of fungus-whitefly interactions. Our results provide a road map for future investigations on insect-pathogen interactions and genetically modifying the fungus to enhance its efficiency in whitefly control. © 2013 Xia et al.

Hao Z.-P.,Institute of Insect science | Zhao J.-R.,Institute of Insect science | Yuan Z.-Q.,Institute of Insect science | Zhao Y.-Q.,Institute of Insect science | And 2 more authors.
Journal of the Kansas Entomological Society | Year: 2012

Hydrogen peroxide is a toxic metabolite of oxidative metabolism, but may also serve as a broad spectrum signaling molecule controlling a variety of essential physiological processes. Photoperiod influences diapause beyond the maternal generation in Cotesia vestalis and we speculated that intracellular hydrogen peroxide was a possible signal mediating this generational effect. To investigate the signaling functions of hydrogen peroxide in diapause induction in C. vestalis, hydrogen peroxide and activities of the antioxidant enzymes superoxide dismutase, peroxidase, and catalase were measured at diapause, and in maternal non-diapausing prepupa, adult, and offspring egg stages form the cultures reared at 25°C under the photoperiods of 816, 1212, and 168 (LD) h. The hydrogen peroxide contents and activities of superoxide dismutase and peroxidase in maternal non-diapausing prepupae and adults declined as the light period was reduced, whereas catalase activity increased significantly. Compared to diapausing prepupae, maternal non-diapausing prepupae under 8 h short light had significantly higher superoxide dismutase, lower catalase, and similar peroxidase activities. Under the three photoperiods, the variation trends of protective enzyme activities in offspring eggs were similar to the trends in maternal prepupae and adults. The variation trends of hydrogen peroxide in eggs were opposite to the trends in maternal prepupae and adults. Peroxidase and catalase activities in eggs were significantly higher after oviposition than before oviposition. These findings indicate that hydrogen peroxide plays an important role in signal transduction between two generations. © 2012 Kansas Entomological Society.

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