Screening of plant growth-promoting attributes bearing endogenous bacteria from abiotic stress resisting high altitude plants

The microorganisms that live in the host are known as endophytes. They help in plant development by secreting numerous plant growth-promoting compounds like IAA, gibberellin, siderophore, and cytokinin. They also provide resistance to plants against many pathogen attacks. The present research focuses on isolating and screening PGP endophytic bacteria from six stress-bearing plants named Commiphora wightii, Salvia rosmarinus, Lantana camara, Phoenix dactylifera, Haemerocallis fulva, and Abutilon indicum. Lantana camara, Phoenix dactylifera, Hemerocallis fulva, and Salvia rosmarinus samples were collected from the Himachal Pradesh district Kangra village Noushera, Commiphora wightii from Chandigarh Botanical garden and Abutilon indicum from Jalandhar near city wastewater outlet. There were 50 isolates, i.e., eleven endophytic bacteria from Commiphora wightii, four from Rosemary, nine from Lantana,11 from Phoenix dactylifera, eight from Haemerocallis fulva, and seven from Abutilon indicum were isolated. Isolates obtained were further tested for IAA, gibberellin, cytokinin, and siderophore production. It was found that the three isolates, L1L2, G2R1, and DL3R2, isolated from Lantana leaves, Commiphora wightii roots, and Hemerocallis fulva roots, have shown IAA production. The maximum amount of IAA was produced by bacterial isolate DL3R2, i.e., 29.5 μg/ml at 10% tryptophan concentration. The maximum amount of gibberellic acid is 550 μg/ml produced by the isolate A1S1S. 16srRNA sequencing analysis has identified isolate A1S1S as Pelomonas aquatica AIS1S and DL3R2 as Solibacillus silvestris DL3R2. The isolates obtained can enhance plant growth and biofertilizers, thus suggesting an alternative approach to sustainable agriculture.