Rhizobia genetic polymorphisms and symbiosis with Prosopis flexuosa in saline environments in Chaqueña Region

ESPINOSA HERLEIN, MARIA DE LOS ANGELES; MELCHIORRE, MARIANA; GONZALEZ, PABLO; LOPEZ LAUENSTEIN, DIEGO

Rosario

Congreso; XXXIII Reunión Argentina de Fisiología Vegetal; 2021

Soc Argentina de Fisiologia Vegetal

In the salt flates, Pipanaco (Catamarca) and La Antigua (La Rioja), Parque Chaqueño, Prosopis flexuosa provides the ecosystem services and contributes with soil fertility by fixing N2 in symbiosis with soil rhizobia. The aim of this work was to characterize genetic diversity and symbiotic performance of indigenous rhizobial populations able to nodulate P. flexuosa.Soils samples were collected from four locations which showed different electric conductivity, and used to sown P. flexuosa seeds as trap plants in order to recover soil rhizobia. Conductivity in samples from Pipanaco_1 and Pipanaco_2 was 25 and 20 dS/m, whereas in samples from La Antigua_1 and La Antigua_2 conductivity was 9.7 and 62.5 dS/m respectively. P. flexuosa cultivated in soils from La Antigua_1 showed the highest leave and nodule number, on the contrary no nodules and the lowest plant height and leave number were observed in plants grown in extreme salinity (La Antigua_2). Nodules were collected and crushed to isolate rhizobia. From 73 strains, DNA was obtained and used to analyze genetic polymorphisms from BOX A1R PCR amplification. Cluster analysis was performed with the UPGMA algorithm using the binary matrix based on DNA BOX A1R electrophoretic patterns. Principal coordinate analysis (PCO) was performed. Strains from La Antigua_1 had the highest variability, almost homogeneously distributed along both PCO axes, whereas the strains from Pipanaco_1 and Pipanaco_2, were grouped on the left of the orthogonal axis in PCO1. These results showed that rhizobia diversity as well as their contribution to P. flexuosa growth were negatively affected by salinity increases.