Functional characterization of DHCR7 and ERG3 sterol pathway genes in Phytophthora capsici for novel fungicide targets

Overview

This project investigates two conserved genes in the sterol synthesis pathway of Phytophthora capsici, namely DHCR7 and ERG3. Although Phytophthora species are sterol auxotrophs and cannot synthesize sterols independently, these two genes are conserved across multiple Phytophthora species, suggesting they serve important functions beyond sterol biosynthesis. The research aims to reveal the molecular basis of DHCR7 function through protein subcellular localization and identification of interacting proteins, providing insights into Phytophthora biology and enabling development of novel fungicides for managing Phytophthora diseases in agricultural crops.

Technical specifications

Key research activities:

• Protein subcellular localization of DHCR7 in P. capsici to determine its functional site within the cell
• Identification and characterization of proteins that interact with DHCR7 and ERG3
• Investigation of how interacting proteins participate in signal transduction and regulate P. capsici development
• Bioinformatics and lipidomics analysis to support functional characterization

Established baseline findings:

• P. capsici confirmed as a sterol auxotroph via GC-MS analysis
• DHCR7 enzyme activity validated, demonstrating 7-dehydrocholesterol reductase activity when expressed in Saccharomyces cerevisiae
• DHCR7 and ERG3 expression highly up-regulated in mycelium compared to other developmental stages
• CRISPR/Cas9-mediated DHCR7 knockout transformants display developmental defects from germ tube to mycelium
• DHCR7 disruption results in loss of ability to transform ergosterol into brassicasterol

Technology readiness level

This research is at an early-to-mid stage of basic investigation. Preliminary work has established the sterol auxotroph status of P. capsici, validated DHCR7 enzyme activity, generated homozygous knockout transformants via CRISPR/Cas9, and documented developmental defects in mutant strains. The current proposal seeks to advance understanding by characterizing protein localization and interaction networks over a 12-18 month timeline. The project seeks partnership support specifically in bioinformatics and lipidomics analysis to complement the team's molecular biology expertise. Outcomes may provide implications for new fungicide development targeting Phytophthora diseases.