Identification of a gene encoding polyphenol oxidase (PPO) in Theobroma cacao L. (cacao) from Ecuador

Abstract

In Ecuador, cocoa plantations have low production averages due to the diversity of pathogens, especially the infection by Moniliophthora roreri (monilia). It is believed that there is a relationship between the attack of the fungus and increased levels of expression of genes encoding polyphenol oxidases (PPOs) as a defense mechanism against pathogens and herbivores in different plants. For the identification of genes that code for PPOs, National cocoa leaves were selected, from resistant and susceptible plants to monilia, located in the Finca Experimental La Represa, property of the Universidad Técnica Estatal de Quevedo. A high-quality total RNA extraction protocol was recalculated for recalcitrant cocoa leaves. After its retrotranscription to cDNA, PCR amplification assays will be carried out with different primers, from the conserved sequences of PPOs. The amplification products allowed the identification of a 961 bp gene, similar to a gene that codes for the predictive PPO of Theobroma cacao deposited in NCBI (XP_017978715.1). The identification of this gene is essential to evaluate future levels of expression and quantification in different stages of fruit development. This reading quantification will propose control tools for monilia and build the bases for the genetic improvement of the National cacao.