Submitted to: Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 22, 1998
Publication Date: N/A
Interpretive Summary: The silverleaf whitefly (Bemisia argentifolii) is a major agronomic pest that causes severe damage to a variety of crop species including cotton. Whiteflies are particularly destructive in warmer climates and they thrive even in such hot arid regions as the desert southwest of the United States. Whiteflies feed on plant sap to obtain nutrients including sugars and amino acids. In this study we examined the effect of elevated temperature on sugar metabolism in this insect. Our results demonstrate that whiteflies synthesize and accumulate sorbitol in response to both high temperature, and to high dietary sugar concentration. Sorbitol belongs to a group of compounds known to protect various animals against temperature extremes and from desiccation. These results indicate that the synthesis of sorbitol plays an important role in the whiteflies ability to withstand high temperature and maintain proper osmotic balance.
Technical Abstract: The silverleaf whitefly is a major agronomic pest in tropical and subtropical regions. The large surface area to volume of this small insect makes it particularly susceptible to desiccation and thermal stress. Measurements of polyol content showed that sorbitol levels in the whitefly were ten-fold higher at 42 than at 25 deg. C, and fluctuated diurnally. Both temperature and dietary sucrose concentration were key factors influencing sorbitol accumulation. Sorbitol synthesis in the whitefly was unconventional, involving conversion of fructose by an NADPH- dependent ketose reductase. We propose that accumulation of sorbitol serves as a mechanism for thermo/osmoprotection in this insect.