Production of Plant Beneficial and Antioxidants Metabolites by Klebsiellavariicola under Salinity Stress

Abstract

Bacteria that surround plant roots and exert beneficial effects on plant growth are known as plant growth-promoting rhizobacteria (PGPR). In addition to the plant growth-promotion, PGPR also imparts resistance against salinity and oxidative stress and needs to be studied. Such PGPR can function as dynamic bioinoculants under salinity conditions. The present study reports the isolation of phytase positive multifarious Klebsiella variicola SURYA6 isolated from wheat rhizosphere in Kolhapur, India. The isolate produced various plant growth-promoting (PGP), salinity ameliorating, and antioxidant traits. It produced organic acid, yielded a higher phosphorous solubilization index (9.3), maximum phytase activity (376.67 ± 2.77 U/mL), and copious amounts of siderophore (79.0%). The isolate also produced salt ameliorating traits such as indole acetic acid (78.45 ± 1.9 µg/mL), 1 aminocyclopropane-1-carboxylate deaminase (0.991 M/mg/h), and exopolysaccharides (32.2 ± 1.2 g/L). In addition to these, the isolate also produced higher activities of antioxidant enzymes like superoxide dismutase (13.86 IU/mg protein), catalase (0.053 IU/mg protein), and glutathione oxidase (22.12 µg/mg protein) at various salt levels. The isolate exhibited optimum growth and maximum secretion of these metabolites during the log-phase growth. It exhibited sensitivity to a wide range of antibiotics and did not produce hemolysis on blood agar, indicative of its non-pathogenic nature. The potential of K. variicola to produce copious amounts of various PGP, salt ameliorating, and antioxidant metabolites make it a potential bioinoculant for salinity stress management.

Bacillus tequilensis strain ‘UPMRB9’ improves biochemical attributes and nutrient accumulation in different rice varieties under salinity stress

“…It has been reported that multifarious halotolerant K . variicola SURYA6 acted as an effective bioinoculants for promoting plant growth by protecting plants from excess salt-induced damages, thus helped in accumulating higher soil nutrients in plants [ 49 ].…”

“…These findings are in line with Dodd and Pe´rez-Alfocea [48] who illustrated that microbes could modify host plant physiology by producing a physical barrier around the roots and modifying the absorption of nutrients and toxic ions by roots (extensive rhizosheaths formation by bacterial exo-polysaccharides), or reduction of foliar noxious ions (Na + , Cl -) absorption; thus, improve the quantity of micro and macronutrients. It has been reported that multifarious halotolerant K. variicola SURYA6 acted as an effective bioinoculants for promoting plant growth by protecting plants from excess salt-induced damages, thus helped in accumulating higher soil nutrients in plants [49].…”

Psychrotolerant Mesorhizobium sp. Isolated from Temperate and Cold Desert Regions Solubilizes Potassium and Produces Multiple Plant Growth Promoting Metabolites

“…Microorganisms produce ammonia via the hydrolyzation of urea into ammonia and CO 2 [ 54 ], or through the fixation of atmospheric nitrogen into ammonia that inhibits the growth of pathogenic microbes [ 55 ]. Several rhizobacterial strains have been found capable of producing many volatile compounds such as hydrogen cyanide (HCN) to control some soil-borne diseases like root rots in various crop plants [ 56 , 57 , 58 ]. Microorganisms such as Pseudomonas , Bacillus , Bradyrhizobium , Klebsiella Rhizobium sp.…”

Variation in Peperomia pellucida growth and secondary metabolism after rhizobacteria inoculation

“…asburiae was reported to improve maize [ 58 ], peppers, lettuces, cucumbers and tomatoes development [ 26 ] while K . variicola is well-known for promoting soybean [ 59 ], maize [ 60 ] and wheat growth [ 61 ]. Both E .…”

“…The genera Enterobacter and Klebsiella are well-known for their potential for plant growth promotion and biocontrol of agricultural diseases [51][52][53][54][55][56][57]. E. asburiae was reported to improve maize [58], peppers, lettuces, cucumbers and tomatoes development [26] while K. variicola is well-known for promoting soybean [59], maize [60] and wheat growth [61]. Both PLOS ONE E. asburiae and K. variicola indicated potential to increase sugarcane growth [25,28].…”