Molecular characterizations of DNA methyltransferase 3 and its roles in temperature tolerance in the whitefly, Bemisia tabaci Mediterranean

Abstract

The Bemisia tabaci Mediterranean (MED) cryptic species is an invasive pest, distributed worldwide, with high ecological adaptability and thermotolerance. DNA methylation (a reversible chromatin modification) is one possible change that may occur within an organism subjected to environmental stress. To assess the effects of temperature stress on DNA methyltransferase 3 (Dnmt3) in MED, we cloned and sequenced BtDnmt3 and identified its functions in response to high and low temperatures. The fulllength cDNA of BtDnmt3 was 3913 bp, with an open reading frame of 1962 bp, encoding a 73.89 kDa protein. In situ hybridization showed that BtDnmt3 was expressed mainly in the posterior region. BtDnmt3 messenger RNA expression levels were significantly down-regulated after exposure to heat shock and significantly up-regulated after exposure to cold shock. Furthermore, after feeding on double-stranded RNA specific for BtDnmt3, both heat resistance and cold resistance were significantly decreased, suggesting that BtDnmt3 is associated with thermal stress response and indicating a differential response to high-and low-temperature stress in MED. Together, these results highlight a potential role for DNA methylation in thermal resistance, which is a process important to successful invasion and colonization of an alien species in various environments.

Molecular characterization of DNA methyltransferase 1 and its role in temperature change of armyworm Mythimna separata Walker

“…A decreasing expression pattern was observed after short exposures to various temperatures. Additional research conducted in the whitefly Bemisia tabaci found that the expression of BtDnmt3 significantly decreased after exposure to higher temperatures (35°C and 40°C), while the chilling treatment increased expression (Dai et al, 2018). Besides insects, the zebrafish host different expression patterns in different development stages, and a similar result was observed at bud stages (Campos, Valente, & Fernandes, 2012).…”

“…Hence, we speculated that DNA methylation plays an important role in M. separata 's environmental adaptation and development. Relevant research conducted on the invasive insect whitefly Bemisia tabaci (Gennadius), found that both BtDnmt1 and BtDnmt3 play an essential role in the insect's temperature tolerance capacity (Dai et al, 2017; Dai, Lü, Wang, Liu, & Wan, 2018). Therefore, in this study, the full length of the MsDnmt1 gene complementary DNA (cDNA) sequence was cloned and analyzed.…”

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

“…Based on our previous studies [40,42], we selected 0, 12, 35, and 40 • C for short-term temperature stress treatments. Owing to research found that adult age was associated with different responses to thermal tolerance [47], we standardized adult age using only newly emerged whiteflies that were younger than 3 h. MEAM1 adults were placed together in a 1.5 mL centrifuge tube, then the tubes were placed in a constant-temperature environment (0, 12, 35, and 40 • C) for 1, 3, and 5 h. Adults maintained at 26 • C served as a control group.…”

“…Double-stranded RNA (dsRNA) used in this study was synthesized using the MEGAscript T7 High Yield Transcription Kit (Ambion, Austin, TX, USA) with gene-specific primers (Table 1). Then, the ISWI dsRNA was diluted to 0.4 µg/µL in a 10% sucrose solution for further feeding treatment (for detailed methods, refer to References [42,48]). Simultaneously, we set control groups including untreated whiteflies, those fed with eGFP-specific dsRNA (dseGFP), and those fed with 10% sucrose.…”

Recent Advances in Genetic and Epigenetic Modulation of Animal Exposure to High Temperature

“…Dynamic changes in DNA methylation present a specific pattern in tissues or cell types. Epigenetic mechanisms may play an important role in the formation of heat acclimation and the changes in mitochondrial respiratory chain (OXPHOS) (Dai et al, 2018). However, few studies have been conducted on the relationships between genetic and epigenetic regulations under heat stress.…”