Comparative Transcriptomics Reveals Key Gene Expression Differences between Diapausing and Non-Diapausing Adults of Culex pipiens

Abstract

Diapause is a critical eco-physiological adaptation for winter survival in the West Nile Virus vector, Culex pipiens, but little is known about the molecular mechanisms that distinguish diapause from non-diapause in this important mosquito species. We used Illumina RNA-seq to simultaneously identify and quantify relative transcript levels in diapausing and non-diapausing adult females. Among 65,623,095 read pairs, we identified 41 genes with significantly different transcript abundances between these two groups. Transcriptome divergences between these two phenotypes include genes related to juvenile hormone synthesis, anaerobic metabolism, innate immunity and cold tolerance.

Induction of long-lived potential aestivation states in laboratoryAn. gambiaemosquitoes

“…Additional fine tuning of priming and maintenance conditions may further push longevity. Future work based on the treatments described here is necessary to validate the state induced in mosquitoes in these conditions through analysis of transcriptional changes [15,53,54] , ovary follicle length [55][56][57] , lipid content [55] , and sugar utilization [58] . These should be contrasted with field-collected samples which may better represent the full expression of the aestivation phenotype.…”

“…Culicidae such as Culex pipiens and Aedes albopictus in response to relatively simple approximations of winter conditions of reduced temperature and photoperiod [15,16] . However, multiple studies performed to induce aestivation via oviposition deprivation [17] , adult photoperiod and temperature modulation [18] , and adult dietary restriction [19] , have failed to produce the dramatic lifespan extension typical of aestivation with only a modest increase in median lifespan from 20 to 30 days and maximum life spans of up to 64 days.…”

Omics approaches to study juvenile hormone synthesis

“…The transcripts for most JH biosynthetic enzymes are highly enriched or exclusively expressed in the CA, and their expressions are often coordinated with JH titers [20,7,23]. In addition, transcriptomes from whole body of dipteran and coleopteran species have shown differential expression of genes encoding JH biosynthetic enzymes during diapause [25,26]. …”

Absence of juvenile hormone signalling regulates the dynamic expression profiles of nutritional metabolism genes during diapause preparation in the cabbage beetle Colaphellus bowringi

“…As acetyl-CoA is the basic unit of fatty acid synthesis, we think it likely that upregulation of ADH and PDHE2 may promote lipid synthesis in DD females. In diapausing adults of the mosquito Culex pipiens (Kang et al, 2016), brine shrimp A. franciscana (Qiu et al, 2007) and Ca. elegans (McElwee et al, 2006), ADH was always highly expressed relative to NDD larvae.…”