Effects of different temperature regimes on survival of Diaphorina citri and its endosymbiotic bacterial communities

Abstract

The Asian citrus psyllid, Diaphorina citri, is a major pest of citrus and vector of citrus greening (huanglongbing) in Asian. In our field-collected psyllid samples, we discovered that Fuzhou (China) and Faisalabad (Pakistan), populations harbored an obligate primary endosymbiont Candidatus Carsonella (gen. nov.) with a single species, Candidatus Carsonella ruddii (sp. nov.) and a secondary endosymbiont, Wolbachia surface proteins (WSP) which are intracellular endosymbionts residing in the bacteriomes. Responses of these symbionts to different temperatures were examined and their host survival assessed. Diagnostic PCR assays showed that the endosymbionts infection rates were not significantly reduced in both D. citri populations after 24 h exposure to cold or heat treatments. Although quantitative PCR assays showed significant reduction of WSP relative densities at 40°C for 24 h, a substantial decrease occurred as the exposure duration increased beyond 3 days. Under the same temperature regimes, Ca. C. ruddii density was initially less affected during the first exposure day, but rapidly reduced at 3-5 days compared to WSP. However, the mortality of the psyllids increased rapidly as exposure time to heat treatment increased. The responses of the two symbionts to unfavorable temperature regimes highlight the complex host-symbionts interactions between D. citri and its associated endosymbionts.

Increase in temperature enriches heat tolerant taxa in Aedes aegypti midguts

“…The impact of temperature change on the midgut microbiome diversity of insects has mainly been studied with constant temperature. The results of such studies show a significant reduction in the richness of the midgut microbiome to complete loss of midgut microbiome as well as reduction in the vertical transmission to the next generation [17][18][19][20] . Given that temperatures fluctuate in nature; using constant temperature to study the impact of temperature on the midgut microbiome may not provide an accurate depiction.…”

Biological, environmental and socioeconomic threats to citrus lime production

“…In a study on D. citri infected by an Isaria fumosorosea (i.e. an entomopathogenic fungus), Hussain et al (2017) found that the insect metabolism was inhibited whilst longevity declined (e.g. from 500 h at 25°C to 130 h at 41°C) with the increase in temperature; the same pattern was observed when insect were exposed to cooler temperatures.…”

Susceptibilities of Candidatus Liberibacter asiaticus‐infected and noninfected Diaphorina citri to entomopathogenic fungi and their detoxification enzyme activities under different temperatures

“…Temperature affects the rate of metabolism (Hussain, Akutse, et al, ; Hussain, Lin, et al, ), the binding of the enzyme with its substrate (Hochachka & Somero, ) and the rate of enzymatic activity (Hoffmann, ). Therefore, we assumed that the different levels of susceptibility of psyllids to entomopathogenic fungi due to temperature changes observed in this study might comprise altered levels of different enzyme activities.…”

“…In tropical and sub‐tropical areas where D. citri are present, the variation in toxicity of insecticides is caused by different temperature variations ranging between 5°C and 40°C (Boina, Onagbola, Salyani, & Stelinski, ). In some areas of the world, like Florida D. citri are occasionally exposed to cold stress below −6.5°C and −8°C; and it was reported that D. citri adults and nymphs tolerate these cold temperatures (Hall, Wenninger, & Hentz, ; Hussain, Lin, & Wang, ; Hussain, Akutse, et al, ). Thus, lethal concentration (LC 50 ) values of chemical insecticides for D. citri , based on the temperature regimes have been previously investigated (Boina et al., ).…”