Using RNA Interference to Reveal the Function of Chromatin Remodeling Factor ISWI in Temperature Tolerance in Bemisia tabaci Middle East–Asia Minor 1 Cryptic Species

Abstract

Invasive species often encounter rapid environmental changes during invasions and only the individuals that successfully overcome environmental stresses can colonize and spread. Chromatin remodeling may be essential in environmental adaptation. To assess the functions of imitation switch (ISWI) in invasive Bemisia tabaci Middle East–Asia Minor 1 (MEAM1) cryptic species, we cloned and characterized the MEAM1 BtISWI gene and determined its functions in response to thermal stress. The full-length cDNA of BtISWI was 3712 bp, with a 3068 bp open reading frame (ORF) encoding a 118.86 kDa protein. BtISWI mRNA expression was significantly up-regulated after exposure to heat shock or cold shock conditions, indicating that BtISWI expression can be induced by thermal stress. After feeding double-stranded RNA (dsRNA), specifically for BtISWI, resistance to both heat and cold decreased significantly, suggesting that BtISWI may function directly in the thermal tolerance of MEAM1. Moreover, the preferred temperature of MEAM1 adults fed dsRNA was 1.9–3.5 °C higher than the control groups. Taken together, our findings highlight the importance of epigenetic gene regulation in the thermal response or thermal adaptation of invasive Bemisia tabaci (B. tabaci), and provide a new potential target for establishing sustainable control strategies for B. tabaci.

Silencing the Myosin Regulatory Light Chain Gene sqh Reduces Cold Hardiness in Ophraella communa LeSage (Coleoptera: Chrysomelidae)

“…When MRLC-sqh was silenced using RNAi, the CCRT of the O. communa was significantly delayed ( Figure 6 B), indicating that the cold hardiness of O. communa had significantly decreased. CCRT is a widely used parameter to estimate the cold hardiness of insects [ 36 , 37 , 48 , 49 , 50 ]; it depends on the reestablishment of ion homeostasis and normal membrane potential [ 5 ]. Therefore, CCRT is a critical measure of cellular integrity and homeostasis.…”

“…Cold hardiness in these beetles was evaluated by measuring the recovery time following a chill coma induced by cold shock [ 35 , 36 , 37 ]. These assays also used three treatments, which were either injected with ds MRLC-sqh , injected with ds GFP , or uninjected.…”

NADPH‐cytochrome P450 reductase mediates the susceptibility of Asian citrus psyllid Diaphorina citri to imidacloprid and thiamethoxam

“…RNAi is useful for studying gene function in insects. Microinjection and artificial diets are the primary methods used to deliver dsRNA 39–44 . For D. citri and other small insects, feeding on an artificial diet with added dsRNA is the most effective strategy 30,45,46 .…”

Epigenetic Responses to Temperature and Climate

“…Moreover, heat shock exposure of Drosophila melanogaster Kc 'embryo' cells resulted in overall chromatin remodelling and activation of heat shock protein 70 (hsp70) and other temperature-responding factors, such as Poly(ADP) Ribose Polymerase -which potentially aids in thermotolerance in Drosophila (Petesch and Lis 2008). Similarly, chromatin remodelling and differential expression of dnmt1 and dnmt3 was found to be essential for heat shock survival and chill coma recovery in an invasive white fly (Bemisia tabaci) Mediterranean (MED) cryptic species (Dai et al 2017;Dai et al 2018;Ji et al 2020).…”