Exiguobacterium sp. as a bioinoculant for plant-growth promotion and Selenium biofortification strategies in horticultural plants

MARFETAN, JORGE; ANA LAURA GALLO; MARIA EUGENIA FARIAS; MARIA LAURA VÉLEZ; MICAELA PESCUMA; OMAR F. ORDOÑEZ

World Journal of Microbiology and Biotechnology

Springer

Año: 2023

Plant growth-promoting bacteria (PGPB) have a positive effect on plant development, and the substitution  of  chemical  fertilizers  by  PGPB  is  a  promising  way  to  enhance  crop  productivity.  Selenium  (Se)  i s  an important trace element and its intake is usually  lower than the  daily minimum amount required for humans; hence, Se biofortification  strategies  are  being  studied.  Here,  the  genetic  traits  known  to  be  associated  with  Plant-Growth Promotion (PGP) of Exiguobacterium sp. S17  were evaluated through genome analysis. Its growth-promoting capacity was  tested  through  plant-growth  promotion  assays  in  controlled  and  horticultural  conditions,  using  Brassica  juncea (indian mustard),  Beta vulgaris  (chard), and  Lactuca sativa  (lettuce) as plant models. Additionally, selenized bacteria were obtained and tested in horticultural conditions,  and extracts obtained from mustard plants grown with or without the selenized bacteria were screened for their possible antioxidant activities. The  sequenced  bacteria genome revealed the  presence  of  multiple  genes  involved  in  important  functions  regarding  soil  and  plant  colonization  and  PGP. Moreover,  Exiguobacterium  sp.  S17  enhanced  plant  growth  to  a  greater  extent  in  comparison  with  the  control,  and plants  showed  greater antioxidant activities in comparison with the control plants. Thereby,  Exiguobacterium  sp.  S17 might be used for developing new, sustainable, and environmentally friendly agro-technological strategies.