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.

Shun-Xia Ji,Xiao-Na Shen,Wan-Xue Liu,Xiao-Di Wang,Fang-Hao Wan,Lin Liang,Zhi-Chuang Lü

doi:10.3390/insects11020113

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.

Highlights

Epigenetics is attracting increasing research attention because it has rapid and long-lasting effects on gene expression in response to environmental changes without altering DNA sequences [1,2]
The complete complementary DNA (cDNA) of BtISWI consists of 3712 nucleotides and contains a 232 bp 50 -UTR
Conserved domains analysis of the deduced protein sequence showed that BtISWI contains the N-terminal ATPase domain (DEXDc positions 137–324 and HELICc positions 474–558), and the C-terminal HAND, SANT (SWI3, ADA2, N-CoR, TFIIIB domains)(positions 805–855), and SLIDE (SANT-like imitation switch (ISWI) domain) domains (Figure 2A)

Summary

Introduction

Epigenetics is attracting increasing research attention because it has rapid and long-lasting effects on gene expression in response to environmental changes without altering DNA sequences [1,2]. Epigenetic regulation mediates phenotypic changes caused by various stresses in numerous organisms [3]. Previous studies have suggested that epigenetic regulation may function directly in environmental adaptation, and may be important for the success of invasive species [8,9,10,11]. Adenosine triphosphate (ATP)-dependent chromatin remodeling factors are important components in epigenetic regulation. These factors are multisubunit protein complexes that utilize the Insects 2020, 11, 113; doi:10.3390/insects11020113 www.mdpi.com/journal/insects

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Conclusion