Influence of Pseudomonas sp. NEEL19 Expelled Volatile Compounds on Growth and Development of Crop Seedlings

This research intended to investigate the airborne chemical communication that occurs via volatile substances released by phyllosphere-associated bacteria, and it has been investigated whether it is beneficial to plants. The composition of halotolerant Pseudomonas sp. NEEL19 volatiles and impact on mung bean and fenugreek growth and metabolism were examined through co-culture in PPD. NEEL19 volatile mixtures (NEEL19 V⁺) enhanced the shoot and root length and chlorophyll content of mung bean under different saline conditions on short-term exposure. In particular, total chlorophyll a + b showed percentage increases of 58.15%, 67.00%, and 29.5% at 0, 50, and 100 mM NaCl, respectively. Furthermore, fenugreek seedlings' biomass, shoot length, and chlorophyll content significantly increased while exposed to NEEL19 V⁺. In order to identify the range of volatile organic compounds (VOCs) that NEEL19 released, SPME-GCMS was utilized. The predominant VOC was dimethyl disulfide, while volatile inorganic compounds (VICs), including CO₂ and NH₃, were examined using the volatile trapping method. Saline stress of 100 mM NaCl influences the quantity and composition of both VOCs and VICs production in NEEL19. The consequences of aqueous NH₄OH (1-5 μL) exposure seed PPD assay disclosed that NH₃ is one of the responsible volatile substances that trigger substantial alterations in shoot length, root length, total chlorophyll, and stomatal structure in mung bean seedlings. Whereas, fenugreek seedlings exhibited a high chlorophyll content overall. This study indicates that the release of volatile mixtures from NEEL19 promotes the growth and development of mung bean and fenugreek seedlings.