Diazotrophic bacteria isolated from Brachiaria spp.: genetic and physiological diversity

Ciencia e Investigación Agraria

Júlia Kuklinsky-Sobral¹  João Tiago Correia Oliveira¹  Gilka Talita Silva¹  Danubia Ramos Moreira de Lima¹  Everthon Fernandes Figueredo¹  Williane Patrícia da Silva Diniz¹  Fernando José Freire¹  Isaneli Batista dos Santos²  Maria Caroline Quecine Verdi² 

[1] Rural Federal University of Pernambuco;University of São Paulo

关键词: N-Acyl homoserine lactones;    plant-microbe interactions;    plant growth promoting bacteria.;   

DOI  :  10.7764/rcia.v45i3.1949

学科分类：农业科学（综合）

来源: Pontificia Universidad Catolica de Chile

【 摘 要 】

Grass from the genusBrachiariaspp. predominates in pastures with low fertile soils. This scenario highlights the importance of the association with microorganisms to foster plant growth, which becomes essential to the successful establishment of this forage in such environments. This study aimed to evaluate the genetic variability and identify the mechanisms of plant growth promotion, in vitro, of bacteria associated withBrachiaria decumbensStapf. andBrachiaria humidicola(Rendle.) Schweickerdt in Pernambuco, Brazil. We evaluated 20 isolates of diazotrophic bacteria obtained from the endophyte or rhizosphere communities. The genetic characteristics were determined via sequencing the 16S rRNA region, which allowed us to identify ten different bacterial genera:  Bacillussp.,Burkholderiasp.,Enterobactersp.,Klebsiellasp.,Microbacteriumsp.,Pantoeasp.,  Ralstoniasp.,Rhizobiumsp.,Sinomonassp., andSphingomonassp., with a specificity of the genus  Rhizobiumsp. toBrachiaria decumbensStapf.. The phenotypic and functional characteristics revealed that 100% of the bacterial strains produced indol-3-acetic acid (IAA) with the addition of L-tryptophan, and 60% presented IAA production independent of the L-tryptophan pathway. We also detected that 70% of the isolated bacteria possessed the capacity to solubilize phosphorus. The analysis of the enzymatic output revealed that 30% of the bacterial isolates produced cellulase, 60% produced pectate lyase, 15% produced polygalacturonase, and 30% produced amylase. We also detected the production of N-acyl homoserine lactones in 65% of bacterial strains. In summary, our results showed that plants ofB. decumbensStapf. andB. humidicola(Rendle.) Schweickerdt interacted with different bacterial genera capable of promoting plant growth.

【 授权许可】

Unknown