Deep Sequencing of Small RNAs in the Whitefly Bemisia tabaci Reveals Novel MicroRNAs Potentially Associated with Begomovirus Acquisition and Transmission

Abstract

The whitefly Bemisia tabaci (Gennadius) is a notorious insect vector that transmits hundreds of plant viruses, affecting food and fiber crops worldwide, and results in the equivalent of billions of U.S. dollars in crop loss annually. To gain a better understanding of the mechanism in virus transmission, we conducted deep sequencing of small RNAs on the whitefly B. tabaci MEAM1 (Middle East-Asia Minor 1) that fed on tomato plants infected with tomato yellow leaf curl virus (TYLCV). Overall, 160 miRNAs were identified, 66 of which were conserved and 94 were B. tabaci-specific. Among the B. tabaci-specific miRNAs, 67 were newly described in the present study. Two miRNAs, with predicted targets encoding a nuclear receptor (Bta05482) and a very-long-chain (3R)-3-hydroxyacyl-CoA dehydratase 2 (Bta10702), respectively, were differentially expressed in whiteflies that fed on TYLCV-infected versus uninfected plants. To better understand the regulatory effects of identified miRNAs and their target genes, we correlated expression profiles of miRNAs and their target transcripts and found that, interestingly, miRNA expression was inversely correlated with the expression of ~50% of the predicted target genes. These analyses could serve as a model to study gene regulation in other systems involving arthropod transmission of viruses to plants and animals.

Selection and Evaluation of Reference Genes for miRNA Expression Analysis in Bemisia tabaci Under Insecticide Tolerance

“…Then, with the use of RNA as a template, the steps of reverse transcription were carried out following the specification of the Mir-X miRNA First-Strand Synthesis Kit (TaKaRa, China). A total of 10 miRNAs (miR-1-3p, miR-9a, miR-11, miR-184, miR-100-5p, miR-275, miR-252a, miR-279d, miR-277, and miR-624) and U6 snRNA, one commonly used reference gene, were set as the candidates for evaluation, according to the published database of B. tabaci miRNA-seq and our database (Wang et al, 2016;Li et al, 2018;Hasegawa et al, 2020). Primers of the candidate miRNA were designed in utilizing the software of Primer 5.0 based on the specification of the Mir-X miRNA First-Strand Synthesis Kit (TaKaRa, China), and the reverse primer of all miRNAs was a universal reverse primer (mRQ 3′Primer) from the kit.…”

“…Previously, the screening of suitable reference genes for mRNA in B. tabaci had been conducted (Li et al, 2013), and the results were contributed to the studies on mechanisms of insecticide resistance, plant virus-host interactions, chemical sensing, and host preference in whitefly (Wei et al, 2017;Xu et al, 2019;Zeng et al, 2019;He et al, 2020;Wang et al, 2020a,b;Yang et al, 2020). In recent years, several microRNA profiles of B. tabaci under different treatments have been published (Wang et al, 2016;Li et al, 2018;Hasegawa et al, 2020), but as an essential precondition, suitable reference genes of B. tabaci for analyzing the expression of miRNA have not been selected and evaluated.…”

The miR‐184‐3p promotes rice black‐streaked dwarf virus infection by suppressing Ken in Laodelphax striatellus (Fallén)

“…Introduction of microRNA‐184 that targeting the dengue virus type 4 genome results in a significant restriction of virus replication in mosquitoes 14 . The miR‐184‐3p has been identified as an abundant conserved miRNA in insects that transmit plant viruses, such as Laodelphax striatellus (Fallén), S ogatella furcifera (Horváth), and Bemisia tabaci 15–18 . Although the function of microRNA‐184 in regulating animal viruses has been studied, its function in the plant virus–insect interaction has not been well investigated.…”

Improving Whitefly Management

“…An understanding of the regulatory gene networks of whiteflies can help identify targets for RNA interference control of whiteflies. Therefore, Hassagawa et al conducted research which revealed a comprehensive microRNA regulatory system in the whitefly B. tabaci and this may be involved in virus acquisition and transmission [ 10 ].…”