Zea mays Transcriptome or Gene expression. Zea mays

Anthocyanin induction in plant is considered a general defense response against biotic and abiotic stresses. The infection by Ustilago maydis, the corn smut pathogen, is accompanied with anthocyanin induction in leaf tissue. We revealed that anthocyanin is intentionally induced by the virulence promoting secreted effector protein Tin2. Tin2 protein functions inside plant cells where it interacts with cytoplasmic maize protein kinase ZmTTK1. Tin2 masks an ubiquitin-proteasome degradation motif in ZmTTK1 leading to a more stable active kinase. Active ZmTTK1 controls transcriptional activation of genes in the anthocyanin biosynthesis pathway rerouting phenylalanine away from lignin biosynthesis. Therefore, we performed microarray analysis to understand how maize gene transcription in phenylpropanoid pathway is differentially changed after infection with Ustilago maydis SG200 (wild type) and SG200Dtin2 (anthocyanin-inducing effector mutant). Overall design: We prepared three biological replicates for mock-inoculated maize (control), SG200-infected maize and SG200Δtin2-infected maize. For 1 sample, we harvested the leaves (1-3cm below injection hole) from 20 plants and pooled them. At 4 days post inoculation, total RNA was extracted.