P-429 - APPLYING COMBINED METABOLOMICS AND X-RAY PHOTOELECTRON SPECTROSCOPY TO ANSWER THE COMPLEX INTERACTION BETWEEN BEECH LEAF NEMATODE AND AMERICAN BEECH.

Beech leaf nematode- a plant-parasitic nematode responsible for beech leaf disease spread rapidly across the Northeastern states. Little is known about the molecular interactions between the nematode and its host and how they may affect tree development. This study focused on a comparative metabolomics analysis and identified molecular differences between asymptomatic and symptomatic trees. Leaves were collected from symptomatic and asymptomatic trees and analyzed using Liquid Chromatography-Mass Spectrometry. Using X-ray photoelectron spectroscopy (XPS), the carbon chemical behavior of the same trees was observed by analyzing their twigs. Results show abscisic acid present at significantly higher levels in the banded portion of the leaves of symptomatic trees. It plays a vital role in multiple processes of plants- stomatal closure, osmotic regulation, growth inhibition, and leaf senescence. Other metabolites, such as quinic acid and malic acid, were found in higher concentrations in the leaves of asymptomatic trees. Quinic acid is a precursor for synthesizing antioxidant compounds, while malic acid regulates stomatal opening and closing. Using XPS, an increased oxygenated carbon response, coupled with an increased oxygen-to-carbon ratio, was found in the symptomatic trees. Traces of phosphorus (~0.3%) were detected and attributed to C-PO3 chemical species. This study integrates and connects the compositional and metabolomic changes with the carbon oxidation mechanism as a response to nematode activity, providing a better understanding of nematode-host interactions.