Comparative transcriptome analysis of melon (Cucumis melo L.) reveals candidate genes and pathways involved in powdery mildew resistance

Abstract

Powdery mildew is a major disease in melon, primarily caused by Podosphaera xanthii (Px). Some melon varieties were resistant to powdery mildew, while others were susceptible. However, the candidate genes associated with resistance and the mechanism of resistance/susceptibility to powdery mildew in melon remain unclear. In this study, disease-resistant melon cultivar TG-1 and disease-susceptible melon cultivar TG-5 were selected for comparative transcriptome analysis. The results suggested that the numbers of differentially expressed genes (DEGs) in TG-5 was always more than that in TG-1 at each of the four time points after Px infection, indicating that their responses to Px infection may be different and that the active response of TG-5 to Px infection may be earlier than that of TG-1. Transcription factors (TFs) analysis among the DEGs revealed that the bHLH, ERF, and MYB families in TG-1 may play a vital role in the interaction between melon and powdery mildew pathogens. GO enrichment analysis of these DEGs in TG-5 showed that the SBP, HSF, and ERF gene families may play important roles in the early stage of melon development after Px infection. Finally, we speculated on the regulatory pathways of melon powdery mildew and found PTI and ABA signaling genes may be associated with the response to Px infection in melon.

Genetic Diversity and Molecular Breeding of Melon (Cucumis melo L.): A review

“…Moreover, this study shed light on the potential role of the underlying signaling pathways such as PTI (PAMP-triggered immunity) and ABA (Abscisic acid) pathways that establishing the powdery mildew resistance in melon. 14 Another recent study was focused on developing the molecular marker required for the marker-assisted selection of melon hybrids resistant to powdery mildew. The molecular analysis of the resistant genotype (PMR 6) of melon for the race 5 of P. xanthii identified one major QTL named Pm-R.…”

“…(a) Extraction of the total RNA of an individual plant, (b) cDNA libraries construction and resequencing, (c) Quantitative Reverse Transcription PCR (qRT-PCR) using the primers designed for candidate genes based on the known genome sequence, (d) Identification and annotation of differentially expressed genes. [13][14][15][16][17] Altogether, these molecular studies would provide valuable genetic resources that can be directly used in molecular breeding for melon crop improvement.…”

Comparative transcriptome revealed the molecular responses of Aconitum carmichaelii Debx. to downy mildew at different stages of disease development

“…Rajarammohan [ 10 ] identified the differentially expressed genes (DEGs) in Brassica juncea associated with the pathogenicity of Alternaria brassicae via transcriptome sequencing. Based on the comparative transcriptomic analysis of Cucumis melo powdery mildew infection between a disease-resistant cultivar and a disease-susceptible cultivar, Zhao [ 11 ] conducted identification of DEGs and enrichment analysis, and ultimately speculated on the main disease-resistant regulatory pathways including the xyloglucan metabolic process, response to oxidative stress and hydrolase activity. RNA-seq can help us understand the host–pathogen interactions.…”

Comparative Transcriptome Analysis Identified Key Pathways and Genes Regulating Differentiated Stigma Color in Melon (Cucumis melo L.)

“…In the last decade, this approach has been widely used for an in-depth molecular understanding of various adaptive evolutions, the host immune system, and stress responses in many living organisms [ 15 ], e.g., rainbow trout ( Salmo gairdneri ) [ 16 ], fish species [ 17 ], sea bream ( Sparu aurata ) [ 18 ], sea bass ( Lateolabrax japonicas ) [ 19 ], and large yellow croaker ( Larimichthy crocea ) [ 20 ]. RNA-seq has been similarly used for a comparative transcriptomic analysis of the morphology and significant, quality-related traits of cucurbit fruit crops, e.g., the climacteric behavior and hardness of watermelon flesh in relation to fruit ripening ( Citrulus lanatus L.) [ 14 , 21 ], and the powdery mildew resistance mechanism in melon ( Cucumis melo L.) [ 22 ].…”