Priming Apoplast-Associated Bacillus Amyloliquefaciens LAS10 Enhances Growth and Yield Attributes of Little Millet Under Drought Stress

Abstract

Little millet plant, in general, withstands various climatic changes and environmental stresses. The endophytic bacterial communities associated with these plants help the plant to develop enduring harsh conditions. Priming seeds with endophytic bacteria helps the host plant grow under adverse environments. The present study aimed to prime the seeds with apoplastic endophytic bacteria, Bacillus amyloliquefaciens LAS10 from little millet (var. ATL1) and to evaluate the efficiency to tolerate an osmotic potential of -10 bars (-1MPa). The seeds were primed with B. amyloliquefaciens LAS10 to investigate the plant growth attributes in vitro and in vivo. Induced drought stress was imposed using different concentrations of PEG6000 in vitro and by withholding the irrigation for ten days during panicle initiation in vivo. Biometric observations were recorded. The results showed significant differences both in vegetative growth parameters as well as yield attributes compared with the control under moisture stress. During the panicle initiation stage (20 DAS), the shoot length (32.26, and 28.36 cm), root length (19.1, and 17.7 cm), total plant biomass (4.61, and 2.47 g), number of productive tillers plant-1 (5, and 3), the total number of panicles plant1 (15.63, and 13.69), panicle length (9.9 cm, and 9.1 cm) and 1000 grain weight (12.91, and 11.92 g), grain yield plant-1 (16.92, and 12.24g), straw yield (21.65, and 19.31) registered more in B. amyloliquefaciens LAS10 primed plants compared to uninoculated control under both irrigated and drought stressed conditions, respectively. Thus, the present study confirmed that the inoculation of little millet with the apoplastic bacterium B. amyloliquefaciens LAS10 could promote plant growth and productivity under moisture stress. Further, the apoplastic bacterium B. amyloliquefaciens LAS10 can be recommended as a bio-inoculant for alleviating drought stress in little millet and enhancing crop fitness and sustainable little millet production.