Genome-wide characterization, evolutionary analysis of WRKY genes in Cucurbitaceae species and assessment of its roles in resisting to powdery mildew disease

Abstract

The WRKY proteins constitute a large family of transcription factors that have been known to play a wide range of regulatory roles in multiple biological processes. Over the past few years, many reports have focused on analysis of evolution and biological function of WRKY genes at the whole genome level in different plant species. However, little information is known about WRKY genes in melon (Cucumis melo L.). In the present study, a total of 56 putative WRKY genes were identified in melon, which were randomly distributed on their respective chromosomes. A multiple sequence alignment and phylogenetic analysis using melon, cucumber and watermelon predicted WRKY domains indicated that melon WRKY proteins could be classified into three main groups (I-III). Our analysis indicated that no recent duplication events of WRKY genes were detected in melon, and strong purifying selection was observed among the 85 orthologous pairs of Cucurbitaceae species. Expression profiles of CmWRKY derived from RNA-seq data and quantitative RT-PCR (qRT-PCR) analyses showed distinct expression patterns in various tissues, and the expression of 16 CmWRKY were altered following powdery mildew infection in melon. Besides, we also found that a total of 24 WRKY genes were co-expressed with 11 VQ family genes in melon. Our comparative genomic analysis provides a foundation for future functional dissection and understanding the evolution of WRKY genes in cucurbitaceae species, and will promote powdery mildew resistance study in melon.

Comparative analysis of powdery mildew resistant and susceptible cultivated cucumber (Cucumis sativus L.) varieties to reveal the metabolic responses to Sphaerotheca fuliginea infection

“…A number of cucumber genes and proteins responsive to S. fuliginea infection have been reported recently [ 14 , 31 ]. Our previous study has mined several candidate genes associated with PM resistence in cucumber by specific length amplified fragment sequencing.…”

“…Several TFs were reported to be involved in PM resistence in various plants. For examples, MED25 and JAZ1 from wheat, WRKY52 from Arabidopsis , ERF1-V in Harnaldia villosa , TIFY9 and NAC042 from Vitis vinfera , were responsive to PM resistance [ 31 , 55 – 60 ]. In our study, a large number of differentially expressed TFs were identified in the two cucumber varieties, providing some potential TFs for the improvement of PM resistance.…”

Genome-Wide Identification of WRKY Transcription Factors in the Asteranae

“…Compared with paralogous pairs, WRKY genes may be purified by whole genome duplication or species differentiation in carrot, sunflower, lettuce, and globe artichoke. In a comparison of WRKY orthologous pairs of watermelon, melon, and cucumber, strong purifying selection pressure was inferred to have operated during the evolution of these three species of Cucurbitaceae [47]. A similar conclusion has been drawn for the evolution of pineapple WRKY genes [44].…”

Comparative transcriptome analysis of Powdery mildew Resistance between two Melon (Cucumis melo L) with Different Thickness Peel

“…There were also some DEGs that were TFs that related to disease resistance like MYB (Katlyar et al, 2012; Li et al, 2013; Wang et al, 2013; Yang et al, 2019), ERF (Xiang et al, 2018; Debbarma et al, 2019) and WRKY (Line et al, 2011; Jiao et al, 2018; Yang et al, 2018). In plants, MYB TFs were related to plant development, secondary metabolism, hormone signal transduction, disease resistance and abiotic stress tolerance (Katlyar et al, 2012); the ERF TFs plays an important role in plant development processes and stress responses such as salt, drought, heat, and cold with well-conserved DNA-binding domain (Xiang et al, 2018; Debbarma et al, 2019); The WRKY TFs were widely implicated in defense responses and various other physiological processes (Yang et al, 2018); it could evolve diverse functions with different biochemical properties and implicated to modulate seed development, flowering, fruit ripening, senescence and various metabolic processes (Jiao et al, 2018).…”

“…There were also 46 genes were TFs, among them, four were the MYB (Li et al, 2013; Wang et al, 2013; Yang et al, 2019), six were the ERF (Xiang et al, 2018; Debbarma et al, 2019) and two were the WRKY (Line et al, 2011; Jiao et al, 2018; Yang et al, 2018);. This TFs were all related to disease resistance (Ling et al, 2010; Li et al, 2013; Wang et al, 2013; Jiao et al, 2018; Xiang et al, 2018; Yang et al, 2018; Debbarma et al, 2019; Yang et al, 2019). All this research could provide information for breeding muskmelon cultivars that were resistant to powdery mildew.…”