Populations, diversity and identities of bacterial endophytes in potato (Solanum tuberosum L.) cropping systems

Abstract

Pageni, B. B., Lupwayi, N. Z., Larney, F. J., Kawchuk, L. M. and Gan, Y. 2013. Populations, diversity and identities of bacterial endophytes in potato ( Solanum tuberosum L.) cropping systems. Can. J. Plant Sci. 93: 1125–1142. Most plants host endophytic bacteria, but their identities and functions are usually unknown. Bacterial endophytes associated with potato grown after dry bean (Phaseolus vulgaris L.) or wheat (Triticum aestivum L.) were isolated, quantified and identified in a field study that compared crop rotations (3 to 6 yr in length) and soil management (CONV, conventional; CONS, conservation) for dry bean, potato, sugar beet (Beta vulgaris L.) and spring wheat. Populations of culturable endophytes ranged from 2.83×103 to 7.65×103 colony-forming units g−1 of root dry matter. The populations and diversity of the endophytes were greater with CONS than CONV soil management, and tended to be greater in longer than shorter rotations. The community structures of the endophytes were different between CONV and CONS soil management. A terminal-restriction fragment length polymorphism assay targeting the 16S rRNA gene, and its sequencing, showed that CONS management systems contained more Proteobacteria than CONV management systems, and vice-versa for Acidobacteria. Bacteriodetes were found only in long CONS rotations. This phylogenetic characterization of potato endophytes is important for further studies on their effects on the host plants.