Bacterial endophytes of tree legumes from Argentina

ALCANTARA, VIRGINIA; GAUNA, JUAN; MEDINA, ROCIO; BALATTI, PEDRO

Montevideo

Congreso; X Encuentro Latinoamericano y del Caribe de biotecnología agropecuaria y xi simposio REDBIO Argentina.; 2019

REDBIO

Nitrogen fixing tree legumes (Fabaceae) as well as actinoricic plants provide nitrogen to thesoils, so they are used managing silvicultural systems to prevent soil degradation and Ndepletion as well as to improve production. Nodules of leguminous plants might be occupiedby Gram (+) as well as Gram (-) endophytic bacteria that often promote growth. In SouthAmerica several studies have been, regarding the systematic and phylogenetic relationshipsof bacterial symbionts, particularly rhizobia, of tree legumes, as well as their ability to nodulateand fix nitrogen. The objective of this work is to study the bacteria isolated from the nodules ofnative tree legumes like Poecilanthe parviflora (Benth), Vachellia caven (Molina) Seigler &Ebinger and Enterolobium contortisiliquum (Vell.) Morong.Isolates obtained from surface sterilized nodules were characterized by Gram staining, pHalteration of culture media supplemented with bromothymol blue, phosphorussolubilization, fungal growth inhibition and by PCR amplification by means with BOX1AR(5´-CTACGGCAAGGCGACGCTGACG-3´) primer. Similarity and clustering based onband patterns were made using the DICE coefficient and the UPGMA algorithm of theNTSYS-pc software. The 16S rDNA gene sequence of selected organisms were amplifiedby using primers 27F (5´-AGAGTTTGATCMTGGCTCAG-3´) and 1492R (5´-ACGGTTACCTTGTTACGACTT-3´) and were then analized.Among 23 isolates, four alkalized the culture medium while the other ones did not modified pH;2 isolates solubilized phosphorus and 4 inhibited growth of Stemphylium lycopersici, a fungusthat provokes disease on tomato. Based on the genetic analysis the isolates were clustered intwo groups, one corresponded to Bradyrhizobium sp. and the other one to Bacillus sp. Thecurrent study contributes to knowing about the interactions that native tree legumesestablished with microorganisms which might contribute to the development of biological toolsto promote plant growth and health.