TITLE:
Isolation and Identification of Bacterial Endophytes from Grasses along the Oregon Coast
AUTHORS:
James E. Dombrowski, Vicky G. Hollenbeck, Ruth C. Martin
KEYWORDS:
Endophyte, Grasses, ACC Deaminase, Bacteria, Abiotic Stress, Salt Stress
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.8 No.3,
February
28,
2017
ABSTRACT: Bacterial endophytes have been shown to improve
abiotic and biotic stress responses in plants. Plants growing under harsh
conditions along the Oregon Coast could contain bacterial endophytes that
improve persistence and growth of grasses in this environment. Thirty-four
plants consisting of eight different species were collected along the Oregon
coast from four different sites. Bacterial endophytes were isolated from root
crown, stem and leaf tissues. 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 predominant 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
1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, an enzyme associated with
improving plant growth under stress. These newly discovered bacterial
endophytes will be a valuable biological resource to develop approaches to increase
the yield and adaptability of grasses and other crops grown in diverse
environments and to meet the challenges associated with an unpredictable
climate.