GC-MS Untargeted Comparative Metabolomics between Healthy and Phytophthora palmivora infected Theobroma cacao Pod Husk

Abstract

Pod rot in T. cacao is overwhelming cacao orchards in the Philippines as the disease reduces the productivity of farms. Investigating the metabolite concentration of healthy and infected cacao pods to provide metabolomic information of the pathogenesis is the aim of this study. Metabolites extracted using chloroform:methanol:water solution of healthy and P. palmivora infected T.cacao were treated using untargeted GCMS. Ripe pods T. cacao were freshly collected from selected cacao orchard and were immediately preserved in liquid nitrogen before transported to the laboratory for further analyses. Analyte extraction was done following the protocols of metabolomic profile studies with some modifications. Data processing of the GC-MS results recorded the compounds suggested by the library with at least a similarity score of 70. The retention times of the compounds were manually aligned and their height were compared with the ribitol internal standard to obtain the relative quantification of the metabolites. The processed data were tabulated using MS Excel™ then subjected to Metaboloanalyst™ for PCA analysis. A total of 55 metabolites were observed in healthy pods while 59 for the infected pods. 28 of the combined metabolites were identified to be statistically different. These 28 metabolites are prime candidates for possible targeted metabolomic analysis or metabolomic markers for future studies on the pathogenesis and control of P. palmivora in cacao in the Philippines.

https://doi.org/10.26803/MyRes.2024.07