Use of biological control agents against Penicillium expansum: Evaluation of the mycelial growth and patulin production

LAMBRESE, YESICA; DI MASI SUSANA; RABA JULIO; SANSONE GABRIELA; BENUZZI DELIA; CALVENTE VIVIANA; FERNÁNDEZ GASTÓN; SANZ FERRAMOLA MARIA I.

San Luis

Congreso; XIII Congreso Argentino de Microbiología General; 2018

Asociación Civil de Microbiología General

Penicillium expansum is the cause of blue rot and production of patulin in pome fruits. Patulin is a mycotoxin that causes acute and chronic intoxication. Synthetic fungicides are commonly used to control this disease but pose a risk to the environment and the health of both the consumer and the animals. An alternative is the use of biological control agents (BCAs). For this reason, the objective of the work was to evaluate in vitro effect of biological control agents on mycelial growth and the production of patulin in two strains of P. expansum from INTA, Alto Valle (Rio Negro), INTA-5 and INTA-10, previously selected for their high production of patulin. While the antagonists (BCAs)assayed were Rhodosporidium fluviale, Cryptococcus laurentii, and Kosakonia radicincitans. The mentioned microorganisms were isolated in the Laboratory of Industrial Microbiology (UNSL) from the epiphytic microbiota of apples. The assays were carried out in PDA medium confronting antagonist versus pathogen and incubating at 25 º C for 7, 14 and 21 days. The effect of antagonism of BCAswas evaluated in a semiquantitative manner, by observing the growth of both antagonist and pathogen. The extraction and determination of patulin were carried out following the protocol of the AOAC with modifications, the measure the concentration of patulin was performed by HPLC-UV. The results were expressed in ppm of patulin and percentage of reduction thereof as [(patulin control ? patulin treatment) / patulin control].100. The results showed a decrease in mycelial growth in both phytopathogenic strains in the presence of the antagonists, being the most effective K. radicincitans.Likewise, the production of patulin decreased in the presence of all antagonists; K. radicincitans and C. laurentii showed the most significant reduction. For the INTA-5 strain, the percentage of mycotoxin reduction by K. radicincitans was 89% and 61% with C. laurentii and for the INTA-10 strain of 94% with K. radicincitans and 88% with C. laurentti at 21 days. It is concluded that the application in vitro of BCAs reduced mycelial growth, but also considerably decrease the production of patulin in strains of P. expansum extremely toxicogenics, which allows supposing a reduction of rot and decrease in the toxin in fruits. The application of these BCAs could be healthier and environmentally friendly option to be used in fruit conservation chambers.