Genetic analysis of cyp72a enzymes involved in corn acclimation to environmental stress

Abstract

Climate change impacts crop productivity due to worsening stressful environmental conditions. To combat stress, such as heat, chilling, drought, salinity, and/or caterpillar feeding, plants evolved a variety of physical or chemical defense mechanisms and growth modulations. Cytochrome P450 enzymes (CYPs) are involved in regulating the production of secondary metabolites that contribute to defense against biotic and abiotic stresses. CYP72As are a diverse subfamily of enzymes that are differentially expressed by abiotic stress. CYP72A genes have been implicated in gibberellin (GA) inactivation in rice, suggesting a role in defense-related growth modulation. We hypothesize that some CYP72As in maize are involved in GA inactivation as part of the growth/defense trade-off. To examine the individual biochemical contributions of each gene, we overexpressed maize CYP72As in Arabidopsis. Some CYP72A genes undergo alternative splicing, specifically intron retention as part of gene regulation. We hypothesize that alternative splicing varies between maize lines and stress conditions. We measured gene expression with reverse transcriptase PCR (RT-PCR) to understand the role stress plays in intron retention.