PLANT GROWTH-PROMOTING TRAITS OF ANTARCTIC ENDOPHYTIC BACTERIA

Successful colonization of Antarctic lands by vascular plants Deschampsia antarctica and Colobanthus quitensis and their adaptation to stressful environments is associated not only with climate change but also with the functioning of microbial groups of phylo- and endosphere of these plants. The aim of our study was to screen plant growth-promoting traits in endophytic bacteria of antarctic vascular plants. Materials and methods. We have studied 8 bacterial cultures isolated from D. antarctica collected during the 25th Ukrainian Antarctic Expedition (January-April 2020) along the Western part of the Antarctic Peninsula. Overnight liquid cultures were obtained on Nutrient Broth medium (HiMedia, Ltd.) in a shaking incubator (26 ℃, 160 rpm). Bacterial isolates were grown on Ashby's combined-nitrogen-free medium with sucrose. Drop collapse assay for cyclic lipopeptide production (CLP), motility assay, exoprotease production and phosphate solubilizing ability were performed using generally accepted methods. Results. All studied isolates have shown plant growth-promoting traits. The most abundant were nitrogen-fixing activity and motility. Both these play important role in plant colonization and promoting the growth of plants in harsh environments. The evidences of CLP were shown by two strains only. There was no notice of phosphate solubilizing ability and exoprotease production. Conclusions. Endophytic bacteria of antarctic vascular plants could support the growth and nutrition needs of the plants.