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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 #423201
Research Project: Regulation, Biosynthesis, and Function of Plant Chemical Defenses and their Role in Climate-Resilient Agriculture

Location: Chemistry Research

Title: Transcriptomic and metabolomic analyses of oxylipin-deficient maize mutants

Author
item Hunter Iii, Charles
item Gorman, Zachary
item HAYFORD, RITA - Orise Fellow
item Li, Qin Bao
item Andorf, Carson
item CHRISTENSEN, SHAWN - Brigham Young University
item Block, Anna
item Woodhouse, Margaret

Submitted to: Maize Genetics Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 2/6/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The lipoxygenase (LOX) pathway produces several oxylipins that regulate plant defense against insect herbivores, including the phytohormone jasmonic acid (JA). To gain a better understanding of the impact of JA and other oxylipins on maize defense response to herbivory by fall armyworm (FAW), we performed transcriptomic and metabolomic analyses on two CRIPSR-induced mutants in the oxylipin pathway, lipoxygenase 10 (lox10) and allene oxide cyclase 1 and 2 (aoc1/2), both of which are highly susceptible to FAW. Targeted metabolomic analysis show reductions in most 13-oxylipin products in both mutants, yet they differentially accumulate herbivory-induced jasmonic acid (JA), but not its precursor, 12-OPDA. Despite producing similar levels of 12-OPDA, aoc1/2 mutants produce almost no JA in response to herbivory while lox10 produces around 50% of wildtype levels. Comparison of aoc1/2 and lox10 in the same genetic background provides an opportunity to differentiate the roles of JA and other 13-LOX derived oxylipins. An expanded untargeted metabolomics approach to compare the FAW-induced responses of these mutants showed approximately 7,500 metabolic features between FAW-treated and untreated plants in WT, aoc1/2, and lox10 genotypes. Substantial differences in metabolic responses to FAW were seen in both mutants, though this was more dramatic in the JA-deficient aoc1/2 than in lox10 mutants. Transcriptomic analyses (RNAseq) of these same tissues revealed major impacts of herbivory on gene expression in both mutants, though again, a greater affect was seen in aoc1/2 than in lox10 mutants. Our work provides a rich source of metabolomic and transcriptomic data on maize responses to FAW herbivory and helps to distinguish the impact of LOX10-derived oxylipins from JA. Additionally, this can help to differentiate JA-dependent vs. independent defenses, and possibly help identify novel JA-independent sources of FAW resistance in maize.