Characterization of the maize (Zea mays)-Ustilago maydis interaction in a warming climate

Abstract

Maize is among the most grown crops worldwide. Concurrently, infections with Ustilago maydis, causing corn smut disease, occur in all major growing regions. This is accompanied by loss of biomass, yields, and silage quality. As global warming increases, modeling analysis predicts an increase in pathogen infestation. Nevertheless, there are no maize lines resistant to U. maydis and no effective fungicides available. Based on the evaluation of climate data for the State of Bavaria (Germany), maize-U. maydis infection trials and RNAseq analysis were conducted on a variety of maize cultivars under different temperature conditions generating a large phenotypic and transcriptomic dataset to determine the influence of temperature changes and differences in plant susceptibility. Even a minimal increase in temperature resulted in increased symptoms and significant variances in expression. Infection-gene expression association analysis followed by in vivo tests identified GIBBERELLIC ACID STIMULATED TRANSCRIPT-LIKE4 (GSL4) and{gamma} -aminobutyric acid as important factors for the infection.