Provision of riboflavin to the host aphid, Acyrthosiphon pisum, by endosymbiotic bacteria, Buchnera

Differential cDNA display and quantitative RT-PCR suggested that the riboflavin synthase complex of the aphid endosymbiont, Buchnera, is active only when the symbiotic system is maintained and well organized in young hosts. Since this finding suggested the provision of riboflavin by Buchnera, we examined the effect of dietary riboflavin on the performance of symbiotic and aposymbiotic aphids using chemically-defined diets. Our results indicate: (1) dietary riboflavin is slightly detrimental to young, symbiotic aphids; (2) dietary riboflavin is essential to aposymbiotic aphids; (3) dietary riboflavin remarkably improves the performance of aposymbiotic aphids. These results strongly suggest that young, symbiotic aphids are provided with riboflavin by their endosymbionts, Buchnera. (C) 1998 Elsevier Science Ltd. All rights reserved.