Diazotrophic endophytes of native black cottonwood and willow

Abstract

Poplar and willow are economically-important, fast-growing tree species with the ability to colonize nutrient-poor environments. To initiate a study on the possible contribution of endophytes to this ability, we isolated bacteria from within surface-sterilized stems of native poplar (Populus trichocarpa) and willow (Salix sitchensis) in a riparian system in western Washington state. Severalof the isolatesgrew well in nitrogen-limited medium. The presenceof nifH, a gene encodingone of the subunits of nitrogenase, was confirmed in several of the isolates including species of Burkholderia, Rahnella, Sphingomonas, and Acinetobacter. Nitrogenase activity (as measuredby the acetylene reduction assay) was also confirmed in someof the isolates. The presenceof these diazotrophic microorganisms may help explain the ability of these pioneering tree species to grow under nitrogen limitation.

The Resurrection Plant Tripogon Spicatus (Poaceae) Harbors a Diversity of Plant Growth Promoting Bacteria in Northeastern Brazilian Caatinga

“…isolate ESA 0014. These results corroborate results from other studies, in which efficient diazotrophic and phytohormone producing bacteria were isolated from cultivated (Kuss et al, 2007;Ferrara et al, 2012;Silva et al, 2013;Santos et al, 2015) and wild species (Doty et al, 2009;Jha et al, 2012).…”

“…Regarding wild non-legume species, the search for bacterial isolates able to promote plant growth has been carried out worldwide since the 1980's (Reinhold et al, 1987;Bilal et al, 1990;Doty et al, 2009;Lopez et al, 2011;Jha et al, 2012;Zahid et al, 2015). In Brazil, few plant groups have been studied only in the last few years (Costa and Melo, 2012;Fernandes Júnior et al, 2013;Kavamura et al, 2013).…”

Culturable bacteria community development in postglacial soils of Ecology Glacier, King George Island, Antarctica

“…Sphingomonas spp. (Alphaproteobacteria) also are often found in association with plants (in the rhizosphere) (White et al 1996); some are nitrogen fixers, suggesting a potential role as plant symbionts (Doty et al 2009). Pedobacter spp.…”

Innovative Biological Solutions to Challenges in Sustainable Biofuels Production

“…In switchgrass, inoculation of the seedlings by a consortium of different rhizosphere microbes increased N-uptake up to 6-fold (Brejda et al, 1998). In poplar and willow, there is a role for endophytes in fixing atmospheric nitrogen (Doty et al, 2009). Several genera of bacteria including Bacillus, Enterobactor, Pseudomonas and Azotobactor have been shown to mineralize or solubilize phosphate in the rhizosphere making it available to the plant (Vassilev et al, 2006 and references therein).…”