Effects of tomato yellow leaf curl virus on the fitness of greenhouse whitefly
Author of the article:FU Xue1** ZHAO Kui-Jun2 ZHAO Na3 TAN Wei4 PEI Hai-Ying2 YAN Chun-Xiu2 YE Le-Fu2***
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Key Words： greenhouse whitefly, sweet potato whitefly, begomovirus, biomass, population
Abstract： [Objectives] The greenhouse whitefly is a major insect pest of multiple horticultural and vegetable crops in Northern China. The sweet potato whitefly species complex is another pest species that has recently spread into parts of Heilongjiang Province as a result of the flower trade and is rapidly replacing native species to become the new dominant species. The tomato yellow leaf curl virus (TYLCV) is a begomovirus transmitted by the sweet potato whitefly that can cause serious damage to plant crops. There has been little recent research on the effect of this virus on the greenhouse whitefly, or on competition between these two whitefly species. [Methods] We observed the population dynamics of both whitefly species on infected and un-infected tomato plants and related these to host plant’s morphological and physical indices. [Results] 1) Tomato plants infested by the sweet potato whitefly became short and thin with more root biomass; 2) Plants infested with the greenhouse whitefly became a little shorter but thicker; 3) Infected plants became shorter and thicker (or thinner), without significant root variance; 4) Compared with infested plants, plants that were both infected with the virus and infested with the greenhouse whitefly became shorter and thinner with a sharp decrease in root biomass, whereas those infested with the sweet potato whitefly showed much reduced symptoms; 5) Different enzymes responded differently to plant infection; higher AchE activity injured plants but higher GST was beneficial. [Conclusion] Infestation by the sweet potato whitefly injured tomato seedlings, but the greenhouse whitefly didn’t directly affect tomato plants; virus infection reduces the plant response to sweet potato whitefly infestation, but enhances the response to infestation by the greenhouse whitefly, that is to say, the growth and development of infected plants infested by the greenhouse whitefly was significantly suppressed. The sweet potato whitefly laid less eggs with a higher hatching rate on infected tomato plants whereas the greenhouse whitefly laid relatively more eggs with a lower hatching rate. These results have implications for the integrated management of whitefly pests in high latitude areas.