Chitosan biostimulant controls infection of cucumber by Phytophthora capsici through suppression of asexual reproduction of the pathogen

The biopolymer chitosan is a derivative of chitin, which can promote plant growth and protect plants from phytopathogens. This study aimed to evaluate the efficacy of chitosan as a biostimulant and a biorational agent to protect cucumber plants from damping-off disease caused by Phytophthora capsici. Cucumber seeds were treated with a range of chitosan concentrations, viz. 0, 125, 250, and 500 ppm, to evaluate effect on seed germination and fresh root and shoot weight of the seedlings. Chitosan significantly (p ≤ 0.05) enhanced seed germination and root and shoot growth of cucumber in a dose-dependent manner up to 500 ppm. Application of in vitro chitosan suspension onto P. capsici mycelial plug suppressed growth of mycelia, formation of sporangia, and release of P. capsici zoospores at 125–500 ppm concentrations. Cucumber seedlings from chitosan-treated seeds showed enhanced resistance to damping-off disease caused by P. capsici compared to untreated control. Cucumber seedlings from 500 ppm chitosan seed treatment showed 100% disease resistance against damping off caused by P. capsici. These results suggest that chitosan could be used as a natural and environmentally safe alternative to a synthetic growth promoter and pesticide for sustainable production of cucumber

Biostymulant chitozan kontroluje zakażenie ogórka przez Phytophthora capsici poprzez hamowanie bezpłciowego rozmnażania patogen

The biopolymer chitosan is a derivative of chitin, which can promote plant growth and protect plants from phytopathogens. This study aimed to evaluate the efficacy of chitosan as a biostimulant and a biorational agent to protect cucumber plants from damping-off disease caused by Phytophthora capsici. Cucumber seeds were treated with a range of chitosan concentrations, viz. 0, 125, 250, and 500 ppm, to evaluate effect on seed germination and fresh root and shoot weight of the seedlings. Chitosan significantly (p ≤ 0.05) enhanced seed germination and root and shoot growth of cucumber in a dose-dependent manner up to 500 ppm. Application of in vitro chitosan suspension onto P. capsici mycelial plug suppressed growth of mycelia, formation of sporangia, and release of P. capsici zoospores at 125–500 ppm concentrations. Cucumber seedlings from chitosan-treated seeds showed enhanced resistance to damping-off disease caused by P. capsici compared to untreated control. Cucumber seedlings from 500 ppm chitosan seed treatment showed 100% disease resistance against damping off caused by P. capsici. These results suggest that chitosan could be used as a natural and environmentally safe alternative to a synthetic growth promoter and pesticide for sustainable production of cucumber.Biopolimer chitozan jest pochodną chityny, może on stymulować wzrost roślin i chronić je przed fitopatogenami. Celem badań była ocena skuteczności chitozanu jako biostymulatora i „bioracjo-nalnego” środka ochrony ogórka przed zgorzelą wywołaną przez Phytophthora capsici. Nasiona ogórka poddano działaniu różnych stężeń chitozanu tj. 0, 125, 250 i 500 ppm w celu oceny ich wpływu na kiełkowanie nasion oraz świeżą masę korzeni i pędów siewek. Chitozan istotnie (p ≤ 0,05) stymulował kiełkowanie nasion oraz wzrost korzeni i pędów ogórka w sposób zależny od dawki do 500 ppm. Zastosowanie zawiesiny chitozanu w zakresie stężeń 125–500 ppm w warunkach in vitro hamowało wzrost grzybni P. capsici, tworzenie sporangiów i uwalnianie zoospor P. capsici. Siewki roślin uzyskanych z nasion traktowanych chitozanem charakteryzowały się zwiększoną odpornością na zgorzel wywołaną przez P. capsici w porównaniu z nietraktowanych chitozanem. Siewki ogórków z nasion traktowanych 500 ppm chitozanu wykazywały 100% odporność na zgorzel powodowaną przez P. capsici. Wyniki te sugerują, że chitozan może być stosowany jako naturalna i bezpieczna dla środowiska alternatywa dla syntetycznych stymulatorów wzrostu oraz pestycydów w zrównoważonej produkcji ogórka