Submitted to: American Journal of Plant Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/7/2016
Publication Date: 3/1/2017
Citation: Dombrowski, J.E., Hollenbeck, V.G., Martin, R.C. 2017. Isolation and identification of bacterial endophytes from grasses along the Oregon coast. American Journal of Plant Sciences. 8(3):574.
Interpretive Summary: Discovery of novel plant endophytes for improved stress tolerance. Endophytes are microorganisms that live symbiotically within plants and may improve plant tolerance to abiotic and biotic stresses. One hundred and thirty three different bacterial endophytes comprising 36 taxonomic groups of which 94 were found to be unique isolates, were isolated from 8 different grass genera growing in saline environments and sandy soils along the Oregon Coast. Fourteen of the bacterial isolates were found to possess ACC deaminase activity, an enzyme that has been demonstrated to be directly involved with improved plant growth under wide range of abiotic and biotic stresses. These newly discovered endophytes have the potential to improve the health and productivity of grasses and other crop species grown in marginal or stressful conditions.
Technical Abstract: Bacterial endophytes have been shown to improve abiotic and biotic stress responses in plants. Grasses growing along the Oregon coast are exposed to harsh conditions and may harbor endophytes that enable them to survive and grow under these conditions. Bacterial endophytes were isolated from thirty-four grass plants representing eight different grass species at four different locations along the Oregon coast. A portion of the 16S rRNA ITS regions of each isolate was amplified, sequenced, and used to perform a BLAST search against the nucleotide database collection at National Center for Biotechnology Information. One-hundred and thirty-three different bacterial isolates, ninety-four of which were unique, representing thirty-six different taxonomic groups were found. Over 50% of the total bacteria isolates were in just five taxonomic groups. Pseudomonads were the most predominate bacteria isolated, making up 20.3% of the total isolates, followed by Curtobacterium and Microbacterium, each at 8.2%, Bacillus at 7.5% and Xanthomomas at 6%. Forty-seven percent (17 of 36) of the taxonomic groups contained only a single isolate. Fourteen bacterial isolates from five taxonomic groups, nine of which were from the genus Pseudomonas, were found to have ACC deaminase activity, an enzyme associated with improving plant growth under stress. These endophytes will be investigated to determine their potential for improving the adaptability of grasses and other crop plants to grow in diverse environments where they are subjected to multiple biotic and abiotic stresses.