First evidence for thermal tolerance benefits of the bacterial symbiont Cardinium in an invasive whitefly, Bemisia tabaci

Abstract

BACKGROUD Cardinium symbiont is a maternally inherited bacterial endosymbiont and widely spreads in arthropods including Bemisia tabaci (Hemiptera: Aleyrodidae). However, the potential role of Cardinium played in the biology of their hosts is largely unknown. In two genetic lines (i.e. LS and SG lines) of B. tabaci MED, collected from different locations in China, we tested the effects of Cardinium on the performance of the host whitefly under a constant high temperature (31 °C) using the age‐stage two‐sex life table method, and explored the genes influenced by Cardinium‐infection by RNA‐sequencing. RESULTS We found that Cardinium did provide protection of B. tabaci against heat stress under 31 °C. However, there was a significant connection between Cardinium‐infection and whitefly genetic backgrounds. Performance revealed that Cardinium infection can increase the longevity of both female and male adults and oviposition periods in both lines, but it also conferred benefits of fecundity and pre‐adult period to LS line. Additionally, the population parameters such as intrinsic rate of increase (r), finite rate of increase (λ) and mean generation time (T) demonstrated that Cardinium infection conferred fitness benefits to LS line but not to SG line. Transcriptome analysis indicated that several genes related to homeostasis and metamorphosis such as ubiquitin‐related genes were highly expressed in Cardinium‐infected B. tabaci. CONCLUSION The research provided the first evidence that Cardinium can increase the thermal tolerance of whitefly, which may be associated with host genetic background.

The Costs and Benefits of Two Secondary Symbionts in a Whitefly Host Shape Their Differential Prevalence in the Field

“…There could be other fitness benefits/costs associated with the infection of Cardinium that were not examined in this study. For example, a recent study provides some preliminary indication indicates that Cardinium may increase the thermal tolerance of MED whitefly, which is likely associated with host genetic background ( Yang et al, 2021 ). Considering the high temperature in southern China, thermal tolerance could be an important factor responsible for the high prevalence of Cardinium in some southern provinces, i.e., Yunnan, Guangxi, Guangdong, and Hainan ( Figure 1B ).…”

Developing Wolbachia-based disease interventions for an extreme environment

“…Endosymbionts can modulate the desiccation [76,77] and thermal [78,79] tolerance of their hosts. Hence, we investigated the phenotypic effects of Wolbachia under a range of stressful environmental conditions.…”

A perspective on insect–microbe holobionts facing thermal fluctuations in a climate‐change context

“…Much less is known, however, about the ability of heat‐protective facultative symbionts to increase the resilience of these holobionts in such specific fluctuating thermal environments. Aphids and whiteflies could be valuable study models to tackle this question, because the facultative symbionts involved in heat protection and the underlying molecular mechanisms have been previously identified (Burke et al ., 2010; Brumin et al ., 2011; Yang et al ., 2021). It would thus be possible to test whether such heat responses could be triggered by recurrent exposure to stressful daytime or night‐time temperatures in a manner comparable to a single heat shock, as previously documented.…”