Fungal endophytes in germinated seeds of the common bean, Phaseolus vulgaris

Authors: PARSA, SOROUSH - International Center For Tropical Agriculture (CIAT); GARCIA-LEMOS, A - International Center For Tropical Agriculture (CIAT); CASTILLO, KATHERINE - International Center For Tropical Agriculture (CIAT); ORTIZ, VIVIANA - International Center For Tropical Agriculture (CIAT); BRAUN, J - Consultant; Vega, Fernando

Submitted to: Fungal Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2016
Publication Date: 4/20/2015
Citation: Parsa, S., Garcia-Lemos, A.M., Castillo, K., Ortiz, V., Braun, J., Vega, F.E. 2015. Fungal endophytes in germinated seeds of the common bean, Phaseolus vulgaris. Fungal Biology. 120:783-790.

Interpretive Summary: The common bean (Phaseolus vulgaris) is the most important food legume in the world, with yields being significantly constrained by biotic and abiotic stressors, top among them plant pathogens and drought. In order to gain a better understanding of fungi that live within the plant without causing any apparent symptoms (endophytes), we conducted a survey in 582 germinated seeds belonging to 11 cultivars from Colombia. The survey yielded 394 endophytic isolates belonging to 42 taxa, with one particular beneficial fungus (Aureobasidium pullulans) being quite common. This information will be of use to mycologists, microbiologists, and practitioners of biological control of plant pathogens.

Technical Abstract: The common bean (Phaseolus vulgaris) is the most important food legume in the world, but its production is severely limited by several biotic and abiotic stressors. In search of a sustainable solution to this problem, we conducted a survey of fungal endophytes in 582 germinated seeds belonging to 11 cultivars of the common bean. The survey yielded 394 endophytic isolates belonging to 42 taxa, as identified by sequence analysis of the ribosomal DNA internal transcribed spacer (ITS) region. The biological control agent, Aureobasidium pullulans, was the dominant species found, and it was isolated from 46.7% of the evaluated samples. Also common were Fusarium oxysporum, Xylaria aff. berteri and Cladosporium cladosporioides, but found in only 13.4%, 11.7% and 7.6% of seedlings, respectively. Endophytic colonization differed significantly among common bean cultivars and seedling parts, with the highest colonization observed in the first true leaves of the seedlings. Our results demonstrate a high compatibility between A. pullulans and the common bean, suggesting significant potential for endophytic biological control of this crop’s biotic stressors. Future empirical work should focus on seed inoculation trials exploring this potential.