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ARS Home » Southeast Area » Gainesville, Florida » Center for Medical, Agricultural and Veterinary Entomology » Chemistry Research » Research » Publications at this Location » Publication #386242
Research Project: Molecular and Biochemical Characterization of Biotic and Abiotic Stress on Plant Defense Responses in Maize

Location: Chemistry Research

Title: Metabolite analysis of Arabidopsis CYP79A2 overexpression lines reveals turnover of benzyl glucosinolate and an additive effect of different aldoximes on phenylpropanoid repression

Author
item PEREZ, VERONICA - University Of Florida
item DAI, RU - University Of Florida
item Block, Anna
item JEONGIM, KIM - University Of Florida

Submitted to: Plant Signaling and Behavior
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/5/2021
Publication Date: 8/24/2021
Publication URL: https://handle.nal.usda.gov/10113/7538980
Citation: Perez, V.C., Dai, R., Block, A.K., Jeongim, K. 2021. Metabolite analysis of Arabidopsis CYP79A2 overexpression lines reveals turnover of benzyl glucosinolate and an additive effect of different aldoximes on phenylpropanoid repression. Plant Signaling and Behavior. 16, 1966586. https://doi.org/10.1080/15592324.2021.1966586.
DOI: https://doi.org/10.1080/15592324.2021.1966586

Interpretive Summary: The spicy taste of mustard plants is due to chemicals called glucosinolates. These chemicals help protect the plants from pests as their breakdown products are toxic to insects and microbes. The biochemical pathways that make these chemicals are interwoven with those for hormones that regulate plant growth. Scientists from from the ARS Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, Florida and the University of Florida are studying these pathways to uncover why breeding plants with increased pest resistance often leads to reduced growth and yield. In this study these scientists have revealed that the increased production of glucosinolates can lead to their activation into toxic chemicals even in the absence of pests, and that the building blocks for glucosinolate production can act to suppress plant growth. This increased understanding can help breeders develop more pest resistance plant varieties while maintaining good yield.

Technical Abstract: Amino acid derived aldoximes can serve as precursors for the growth regulating auxins indole-3-acetic acid (IAA) and phenylacetic acid (PAA) and defense related glucosinolates in Brassicales. Aldoximes also impact growth through their function as phenylpropanoid pathway inhibitors. Arabidopsis transgenic lines overexpressing AtCYP79A2, a phenylacetaldoxime (PAOx)-production enzyme, accumulate not only the PAOx-derived compounds benzyl glucosinolate and PAA, but also the benzyl glucosinolate hydrolysis product benzyl isothiocyanate, which indicates the turnover of benzyl glucosinolate can occur in intact tissues. Myrosinases or beta-glucosidases are known to catalyze glucosinolate breakdown. However, transcriptomics analysis detected no substantial increase in expression of known myrosinases or putative beta-glucosidases in AtCYP79A2 overexpressing lines. Furthermore, overexpression of AtCYP79A2 in the aldoxime accumulating ref2 background resulted in darker green leaves, delayed flowering and a decrease in sinapoylmalate content. These phenotypes indicate that accumulation of PAOx has an additive effect on phenylpropanoid pathway suppression mediated by other aldoximes.