Compost bacteria provide antifungal activity against grey mold andAlternariarot on bell pepper fruit

Abstract

Bell pepper (Capsicum annuum L.) fruit are susceptible to various molds, including grey mold and Alternaria rot. In this work, antagonistic bacteria isolated from disease-suppressive composts were assessed for their ability to reduce the mycelial growth of Botrytis cinerea Persoon and Alternaria alternata (Fries) Keissler as well as to suppress grey mold and Alternaria rot on bell pepper. Results showed that different bacterial antagonists reduced mycelial growth of B. cinerea and A. alternata by up to 49% and 53%, respectively. The bacteria provided inhibition of grey mold, reducing incidence and severity by as much as 43% and 67%, respectively. The isolates also provided strong inhibitory effects against Alternaria rot, decreasing incidence and severity by as much as 77% and 80%, respectively. Pseudomonas and Arthrobacter spp. were particularly suppressive to Alternaria rot. Results of this study suggest antagonistic bacteria may represent a potential method for controlling fruit rot of bell pepper.

Biological and chemical characterization of antimicrobial activity in Arthrobacter spp. isolated from disease‐suppressive compost

“…group G strain 87‐202‐3 [31,32]. Previous studies from our lab showed that A. humicola inhibited the growth of R. stolonifer , A. alternata , B. cinerea , and V. dahliae whereas A. psychrophenolicus inhibited B. cinerea and V. dahliae [8,9,18]. To the best of our knowledge, this is the first report of A. humicola inhibiting R. solani , and S. sclerotiorum and A. psychrophenolicus inhibiting the growth of R. solani , R. stolonifer , and S. sclerotiorum .…”

“…To mitigate the health risks, environmental concerns, and pathogen resistance associated with synthetic chemical pesticides, microbial antagonists have been previously tested to determine their antagonistic properties against plant pathogens [8,9,18]. In this study, the antifungal and antioomycetal activity of A. humicola strains M9‐1A, M9‐2, and M9‐8, and A. psychrophenolicus M9‐17 were tested against several important crop pathogens.…”

“…A promising alternative to fungicides is biological control. Among biological control methods, antagonistic bacteria have previously demonstrated effective suppression of postharvest plant diseases caused by pathogenic fungi [8–10]. Biological control agents typically combat phytopathogens through induced plant resistance, competition for nutrients and space, parasitism, and/or antibiosis [11–13].…”

“…For example, our previous work has indicated the four Arthrobacter spp. strains isolated from a disease‐suppressive marine compost inhibit the growth of Botrytis cinerea , Alternaria alternata , Fusarium sambucinum , Verticillium dahliae , and Pythium sulcatum [9,18]. Furthermore, these same Arthrobacter spp.…”

“…Furthermore, these same Arthrobacter spp. have demonstrated suppression of gray mold and Alternaria rot disease on bell peppers [9]. Similar to other actinomycetes (e.g., Streptomyces spp.…”