Candidatus Phytoplasma trifolii (16Sr VI ) infection modifies the polyphenols concentration in pepper ( Capsicum annuum ) plant tissues

Of late, the presence of Candidatus Phytoplasma trifolii was reported as a serious threat to the pepper crop in Zacatecas, México; therefore, asymptomatic and symptomatic pepper plants were collected from a commercial field among three samplings after the fruit set stage was reached. Total DNA was extracted using the CTAB ‐based method and tested for phytoplasma using a nested PCR assay, followed by a BLAST , and restriction fragment length polymorphism ( RFLP ) analysis of 16S rDNA sequences, which confirmed the presence of phytoplasma group 16Sr VI , “ Candidatus Phytoplasma trifolii” in the symptomatic plants. As the metabolic pathways of pathogen‐infected plants tend to change, resulting in a biochemical differentiation with the noninfected plants, the polyphenolic compound concentrations were quantified from the vegetative tissues (root, stem, leaves and developed fruit/big bud) and were analysed based on a principal component analysis ( PCA ). Results revealed that, in general, plants tend to a progressive increase in total phenols, flavonoids, condensed tannins and anthocyanins related to the plants exposure to “ Ca . P. trifolii” infection, and PCA demonstrated that almost 90% of the observed variance was explained by the first two components. Hence, the phenolic content of the plants increases as a response of the defence mechanism, which reflects its condition and resistance.