Monitoring maize and Ustilago maydis RNA and protein expression during tassel infections

Stanford University, Stanford CA

Investigators

Abstract

The fungal pathogen Ustilago maydis infects many plants, however, only in corn (Zea mays L.) does infection cause cancer. The fungus proliferates outside plant cells and elicits tumors through predicted secreted proteins that interact with maize cells. To date the plant-fungal interaction has been studied using fungal mutants and little is known about maize contributions that confer the tumor outcome. In this project changes in maize and Ustilago gene expression will be monitored during the early stages of infection/cancer induction by cataloguing the genes expressed and production of new proteins by each partner. Data will be collected from infected, immature maize tassels (the organ responsible for producing pollen), because they are readily infected and maize mutants with defective anthers in an otherwise normal tassel block tumor formation specifically in the anther tissues. RNA and protein responses will be analyzed comparing susceptible wild-type anthers to a male-sterile mutant for additional insight into the maize anther proteins required for tumor growth. The potential impacts are a novel approach to understanding steps in anther development in maize and by extension other cereal crops and better understanding of how pathogens exploit host properties that are specific to one organ type. The long-term aim is define the individual steps in tumor elicitation, using as a working model production of fungal molecules that bind to maize receptors to alter development. As cereal crops are the most important contributor to agricultural productivity in the US and worldwide, this new knowledge is important for crop improvement and protection. In the course of the project, a postdoctoral fellow will receive training in high throughput mass spectrometric protein identification, an emerging technology applicable to many complex biological problems.