Amelioration of Saline Stress on Chia (Salvia hispanica L.) Seedlings Inoculated With Halotolerant Plant Growth-Promoting Bacteria Isolated From Hypersaline Environments

YAÑEZ-YAZLLE, MARÍA FLORENCIA; ROMANO-ARMADA, NELI; RAJAL, VERÓNICA BEATRIZ; IRAZUSTA, VERÓNICA PATRICIA

Frontiers in Agronomy

Frontiers

Año: 2021 vol. 3

The rhizosphere and microbiome of halotolerant plants could be crucial for alleviatingsalinity stress during plant growth. The aims of this work were (1) to isolate bacteriafrom rhizosphere and bulk soil samples from the Salar del Hombre Muerto (Catamarca,Argentina), (2) to characterize different plant growth-promoting (PGP) activities producedby these bacterial isolates, and (3) to evaluate their effect on the initial growth ofchia (Salvia hispanica L.) under saline stress. A total of 667 microorganisms wereisolated, using different culture media with NaCl, and their abilities for nitrogenfixation, phosphate solubilization, siderophores production, and indole-3-acetic acidproduction were evaluated. Thirteen strains were selected for showing all the testedPGP activities; they belonged to the genera Kushneria, Halomonass, Pseudomonas,Planomicrobium, and Pseudarthrobacter. The strains Kushneria sp. and Halomonassp. showed the highest salinity tolerance (from 50 to 2,000mM NaCl) and biomassand biofilm production. Chia seeds were treated with six of the first 13 selectedstrains to evaluate their plant growth-promoting effect under saline stress (without andwith 50 and 100mM NaCl). Halomonas sp. 3R.12 and Kushneria sp. T3.7 producedheavier seedlings with a balanced shoot/root length ratio, while Pseudomonas sp. AN23showed the best effect upon chia seedlings, with a morphological response similar tonon-stressed seedlings. On the other hand, seedlings displayed no responses wheninoculated with Planomicrobium sp. 3S.31 and Pseudarthrobacter sp. ER25. This studycontributes to the knowledge on microorganisms from hypersaline environments as plantgrowth promoters for their use in the production of salt-sensitive crops, among otherpotential uses.