Effects of facultative symbionts and heat stress on the metabolome of pea aphids

摘要

We examined metabolite pools of pea aphids with different facultative symbiont infections, andcharacterized their effects on aphid metabolism in baseline and heat stress conditions. The bacterialsymbiont Serratia symbiotica protects aphid hosts from the detrimental results of heat stress andshields the obligate symbiont Buchnera from effects of heat. We investigated whether broad effectson metabolism might correlate with this protection. Both facultative symbiont infection and heattreatment had large effects on the aphid metabolome. All three pea aphid facultative symbionts hadsimilar effects on aphid metabolism despite their evolutionary diversity. Paradoxically, heat triggerslysis of many S. symbiotica cells and a correlated rapid reduction in S. symbiotica titres within aphidhosts. We conclude that facultative symbionts can have substantial effects on host metabolic pools,and we hypothesize that the protective effects of S. symbiotica may reflect the delivery of protectivemetabolites to aphid or Buchnera cells, after heat exposure.