Selecting bacterial strains for use in the biocontrol of diseases caused by Phytophtora capsici and Alternaria alternata in sweet pepper plants

• Published in: Biologia plantarum Vol. 47; no. 4
• Main Authors: Sid, A.(University of Murcia, Espinardo (Spain). Dept. of Plant Physiology), Ezziyyani, M.(University of Murcia, Espinardo (Spain). Dept. of Plant Physiology), Egea-Gilabert, C.(Polytechnic Univ. of Cartagena (Spain). Dept. of Agrarian Production), Candela, M.E.(University of Murcia, Espinardo (Spain). Dept. of Plant Physiology)E-mail:mcandela@um.es
• Format: Journal Article
• Language: English
• Subjects: AGENT PATHOGENE; ALTERNARIA ALTERNATA; ANTAGONISM; ANTAGONISME; ANTAGONISMO; BIOLOGICAL COMPETITION; CAPSICUM ANNUUM; COMPETENCIA BIOLOGICA; COMPETITION BIOLOGIQUE; EXPERIMENTAL INFECTION; INFECCION EXPERIMENTAL; INFECTION EXPERIMENTALE; MANCHAS; MICELIO; MYCELIUM; ORGANISMOS PATOGENOS; PATHOGENS; PHYTOPHTHORA CAPSICI; PODREDUMBRE DE LA RAIZ; POURRITURE DES RACINES; RHIZOBACTERIA; RHIZOBACTERIE; RHIZOSPHERE; RIZOBACTERIAS; RIZOSFERA; ROOT ROTS; SPOTS; TACHE; ULTRAESTRUCTURA; ULTRASTRUCTURE
• ISSN: 0006-3134; 1573-8264

More than 500 isolates of bacteria were obtained from the aerial part and rhizosphere of sweet pepper (Capsicum annuum) plants harvested from different places in the Region of Murcia (Spain). The isolates were purified and assayed in vitro against Phytophthora capsici and Alternaria alternata. Sixty isolates produced an inhibition zone against at least one of the pathogens, whereas ten had a strong inhibitory effect on both pathogens assayed. Microscopic observation of interactions zone showed cell vacuolisation, hyphae lysis and spilling of cytoplasm content of the pathogens in the culture media. These ten isolates were then chosen for biocontrol of Phytophthora root rot and Alternaria leaf spots of pepper plants in vivo. Four of them denominated HS93, LS234, LS523 and LS674 reduced P. capsici root rot by 80, 51, 49 and 54%, respectively, and A. alternaria leaf spots by 54, 74, 62 and 53%. HS93 belongs to the genus Bacillus and probably the species subtilis, whereas LS234, LS523 and LS674 belong to the genus Bacillus and probably the species licheniformis. Dry mass of plants treated with these bacteria was significantly higher than that of non-treated and inoculated plants.