Genome‐wide dissection of sex determination genes in the highly invasive whitefly species Bemisia tabaci Q/MED

Abstract

Sex determination genes are important regulators of reproduction as well as of the development of both behavioural and morphological sex characteristics. The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is an emerging insect pest worldwide. The recent release of the genome sequence of the highly invasive B. tabaciQ/MED allows us to investigate the mechanisms and genes involved in sex determination. The combined genome and transcriptome‐wide analyses identified 26 genes putatively associated with sex determination in B. tabaciQ/MED. The temporal profiles of these genes exhibited a consistent expression pattern at all B. tabaci developmental stages: the highest transcript levels were detected in eggs (21 genes, 80.8%) and the lowest in adults (24 genes, 92.3%). The expression pattern was further validated by quantitative real‐time reverse transcription PCR analysis. Alternative splicing analysis found that (1) da and mle have sex‐specific isoforms in B. tabaci adults, whereas Imp does not, and (2) exon skipping is a common splicing mechanism involved in B. tabaci sex determination. This research provides a comprehensive list of genes involved in B. tabaci sex determination and provides an opportunity to further understand the mechanisms underlying sex determination in a globally invasive insect pest that reproduces both sexually and asexually.

Splicing and Expression Regulation of fruitless Gene in Bemisia tabaci (Hemiptera: Aleyrodidae)

“…Unmated females only give birth to haploid males, and mated females can give birth to both males and females [19]. Previously, we identified 26 sex-determining genes in B. tabaci and confirmed by RNAi the interaction between Btdsx and Bttra2 and their important role in male genital formation, as well as the relationship between Btix and female fertility [20][21][22][23]. In addition, we identified a number of candidate genes for female mating response by transcriptomic analysis [24].…”

Characteristic and Functional Study of Intersex, a Gene Related to Female Fertility in Bemisia tabaci

“…The whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) is a worldwide agricultural pest with a haplodiploid reproductive system (Blackman and Cahill, 1998). Our laboratory previously identified 26 genes putatively associated with sex determination in B. tabaci and found that da, mle, and PSI undergo sexspecific splicing in B. tabaci, while Imp, dsx, and tra2 do not (Liu et al, 2016(Liu et al, , 2019Guo et al, 2018). Using RNAi experiments, we also found that Btdsx and Bttra2 affect each other and are important for male genitalia formation (Guo et al, 2018).…”

“…The annotated sequences obtained from our previous study (Liu et al, 2019) were used to design full-length primers to amplify the Btix gene ( Table 1). The PCRs were performed using Es-Taq Master Mix (CWBIO, Beijing, China) under the following conditions: initial denaturation at 95 • C for 5 min, followed by 35 cycles of 95 • C for 30 s, 55 • C for 30 s, and 72 • C for 1 min, and a final extension at 72 • C for 10 min.…”

“…Based on our previously annotated sequence from the Q/MED B. tabaci genome database (Xie et al, 2017;Liu et al, 2019), the full-length cDNA sequence of the Btix gene was obtained from PCR amplification, using adult cDNA as a template. The ORF encoded a protein of 181 amino acids with a predicted MW of ∼19.85 kDa and an isoelectric point (pI) of 5.65.…”

Transcriptome Profiling Reveals Genes Related to Sex Determination and Differentiation in Sugarcane Borer (Chilo sacchariphagus Bojer)

“…It has been used for the screening of genes associated with various traits in sugarcane, such as sucrose accumulation [ 39 , 40 ], smut resistance [ 41 , 42 ] and the response to low nitrogen [ 43 ]. Transcriptome analysis was also used for the identification of sex-determining genes in many insects, such as Plutella xylostella [ 44 ], Phlebotominae sand flies [ 45 ], whitefly [ 46 ], Sogatella furcifera [ 47 ] and Zeugodacus tau (Walker) [ 48 ].…”