Genome-wide identification, evolution, and expression analysis of MLO gene family in melon ( Cucumis melo L.)

• Published in: Frontiers in plant science Vol. 14; p. 1144317
• Main Authors: Zhang, Taifeng, Xu, Nan, Amanullah, Sikandar, Gao, Peng
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 24-02-2023
• Subjects: Cucumis melo L; expression analysis; gene clone; genome-wide; MLO gene family; Plant Science; gene clone; Cucumis melo L; MLO gene family; genome-wide; expression analysis
• ISSN: 1664-462X; 1664-462X
• DOI: 10.3389/fpls.2023.1144317

Powdery mildew (PM) is one of the main fungal diseases that appear during the cultivation of the melon fruit crop. Mildew Resistance Locus "O" (MLO) is known as a gene family and has seven conserved transmembrane domains. An induced functional loss of a specific
gene could mainly confer PM resistance to melons. However, the genomic structure of
genes and its main role in PM resistance still remain unclear in melon. In this study, bioinformatic analysis identified a total of 14
gene family members in the melon genome sequence, and these genes were distributed in an uneven manner on eight chromosomes. The phylogenetic analysis divided the
genes into five different clades, and gene structural analysis showed that genes in the same clade had similar intron and exon distribution patterns. In addition, by cloning the
gene sequence in four melon lines, analyzing the
gene expression pattern after infection, and making microscopic observations of the infection pattern of PM, we concluded that the
(
) gene plays a negative role in regulating PM-resistance in the susceptible melon line (Topmark), and the critical time point for gene function was noticed at 24 and 72 hours after PM infection. The mutational analysis exhibited a single base mutation at 572 bp, which further results in loss of protein function, thus conferring PM resistance in melon. In summary, our research evidence provides a thorough understanding of the
gene family and demonstrates their potential role in disease resistance, as well as a theoretical foundation for melon disease resistance breeding.