Streptomyces griseocarneus R132 controls phytopathogens and promotes growth of pepper ( Capsicum annuum )

Endophytic actinomycetes are important for the prospection of biologically active compounds and the development of biotechnological processes in agriculture for the biological control of plant diseases and phytopathogens. Eleven endophytic actinobacteria species isolated from Paullinia cupana were screened for in vitro antibiosis against five phytopathogens and control of anthracnose in pepper ( Capsicum annuum ) fruits. Cultures of the most active actinobacteria were fractionated with methanol and ethyl acetate, and the anthracnose control capacity of the resulting extracts was evaluated. Actinobacteria-mediated growth promotion and control of root pathogens in pepper plants were evaluated in a greenhouse. Streptomyces griseocarneus R132 (i) inhibited the growth of phytopathogens the most strongly, ranging from 57.24 ± 4.54% ( Fusarium oxysporum 46.7) to 73.93 ± 3.71% ( Botryosphaeria dothidea CFMAC3); (ii) markedly controlled the development of anthracnose symptoms caused by Colletotrichum gloeosporioides MPU99 in pepper fruits and plants; and (iii) promoted growth of pepper plants, increasing 42% of shoot dry mass. Actinobacteria extracts effectively controlled the anthracnose symptoms and reduced the lesion size by 30% in pepper fruits. Streptomyces griseocarneus R132 is a promising tool for the biological control of both pre- and post-harvest plant pathogens and growth promotion in pepper.