# Morphology and Comparative Transcriptome Analysis of Resistant and Susceptible Bitter Gourd (Momordica charantia L.) Reveals the Molecular Response Related to Powdery Mildew Resistance

## TL;DR

This study identifies genes and pathways involved in powdery mildew resistance in bitter gourd using transcriptome analysis and morphology.

## Contribution

The study reveals specific genes and pathways linked to powdery mildew resistance in bitter gourd through comparative transcriptome analysis.

## Key findings

- Resistant and susceptible bitter gourd cultivars showed distinct gene expression patterns after powdery mildew infection.
- DEGs were enriched in plant-pathogen interaction and hormone signaling pathways.
- MLO gene Moc10g30350.1 is potentially involved in powdery mildew resistance.

## Abstract

Powdery mildew (PM) is a major disease affecting bitter gourd cultivation, and resolving the molecular regulatory mechanisms underlying PM resistance is important for bitter gourd molecular breeding for resistance. In this study, morphological and molecular methods were used to identify the PM pathogen in bitter gourd, and comparative transcriptome analysis was performed on leaves of the resistant cultivar R and the susceptible cultivar S after PM infection. The morphological and molecular identification results showed that the PM pathogen in bitter gourd was Podosphaera xanthii. Scanning electron microscopy results revealed that the P. xanthii exhibited distinct growth patterns in the R and S after P. xanthii infection. Compared to the S, the R exhibited 3966, 2729, 5891, and 3878 differentially expressed genes (DEGs) at 0, 2, 3, and 4 days after P. xanthii infection, respectively. KEGG enrichment analysis showed that DEGs were primarily enriched in plant–pathogen interactions, MAPK signaling pathway plants, and plant hormone signal transduction pathways. Transcription factor (TF) analysis of differentially expressed genes revealed that MYB, bHLH, and ERF family members could be involved in the defense process against the P. xanthii infection. Moreover, the analysis of the MLO genes revealed that Moc10g30350.1 could be involved in regulating PM resistance. These findings could enrich the molecular theoretical basis for resistance to PM, and provide new insights for the molecular breeding process of bitter gourd resistance to PM.