Suchergebnisse

After a forest wildfire, the microbial communities have a transient alteration in their composition. The role of the soil microbial community in the recovery of an ecosystem following such an event remains poorly understood. Thus, it is necessary to understand the plant-microbe interactions that occur in burned soils. By high-throughput sequencing, we identified the main bacterial taxa of burnt holm-oak rhizosphere, then we obtained an isolate collection of the most abundant genus and its growth promoting activities were characterised. 16S rRNA amplicon sequencing showed that the genus Arthrobacter comprised more than 21% of the total community. 55 Arthrobacter strains were isolated and characterized using RAPDs and sequencing of the almost complete 16S rRNA gene. Our results indicate that isolated Arthrobacter strains present a very high genetic diversity, and they could play an important ecological role in interaction with the host plant by enhancing aerial growth. Most of the selected strains exhibited a great ability to degrade organic polymers in vitro as well as possibly presenting a direct mechanism for plant growth promotion. All the above data suggests that Arthrobacter can be considered as an excellent PGP rhizobacterium that may play an important role in the recovery of burned holm-oak forests. ; This work was funded by the following grants: P08-CVI-03549 from The Department of Innovation, Science and Enterprise of the Autonomous Government of Andalusia; OAPN 021/2007 from The National Parks Autonomous Body (Ministry of the Environment) and 20134R069, RECUPERA 2020 from the Spanish Ministry of Economy and Competitiveness and CSIC, including ERDF (European Regional Development Fund). The work conducted by the U.S. Department of Energy Joint Genome Institute, a DOE Office of Science User Facility, is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. AJFG was awarded a pre-doctoral fellowship (FPU) from the Spanish Ministry of Education; JFCD was awarded a pre-doctoral fellowship from the Junta de Andalucía, and both with a postdoctoral contract from RECUPERA 2020. PMH was awarded a postdoctoral fellowship from Ramón Areces foundation ; Peer Reviewed

11 páginas, 3 tablas, 1 figura ; Canola (Brassica napus L. var. oleracea) is the third most common oil-producing crop worldwide after palm and soybean. Canola cultivation requires the use of chemical fertilizers, but the amount required can be reduced by applying plant growth-promoting bacteria (PGPB). Among PGPB, endophytic bacteria have certain advantages as biofertilizers, but canola endophytic bacteria have rarely been studied. In this work, we identified a collection of bacterial endophytes isolated from canola roots using MALDI-TOF MS, a technique that is still rarely used for the identification of such bacteria, and rrs gene sequencing, a methodology that is commonly used to identify canola endophytes. The results demonstrated that some bacterial isolates from canola roots belonged to the genera Bacillus, Neobacillus, Peribacillus (Pe.), and Terribacillus, but most isolates belonged to the genera Paenibacillus (P.) and Pseudomonas (Ps.). Inoculation of these isolates indicated that several of them could efficiently promote canola seedling growth in hydroponic conditions. These results were then confirmed in a microcosm experiment using agricultural soil, which demonstrated that several isolates of Pseudomonas thivervalensis, Paenibacillus amylolyticus, Paenibacillus polymyxa, Paenibacillus sp. (Paenibacillus glucanolyticus/Paenibacillus lautus group), and Peribacillus simplex (previously Bacillus simplex) could efficiently promote canola shoot growth under greenhouse conditions. Among them, the isolates of Paenibacillus and Peribacillus were the most promising biofertilizers for canola crops as they are sporulated rods, which is an advantageous trait when formulating biofertilizers ; This work was supported by JCyL (Junta de Castilla y León, Spanish Regional Government) Grant SA058U16 to EMM and Project "CLU-2019-05—IRNASA/CSIC Unit of Excellence", funded by the Junta de Castilla y León and cofinanced by the European Union (ERDF "Europe drives our growth"). ; Peer reviewed