Enhancing Melon Growth and Nutrient Uptake with Plant-Growth-Promoting Microorganisms from Cucumis melo

Abstract

In an effort to mitigate the environmental impact of chemical fertilizers while promoting soil sustainability, this study investigated the potential of rhizosphere-associated microorganisms to augment nutrient uptake and growth in melon crops. Soil samples were procured from three distinct melon fields and subjected to serial dilution techniques for microbial isolation on Nutrient Agar (NA) and Potato Dextrose Agar (PDA) media. Subsequent screening identified select isolates with capabilities for nitrogen fixation, phosphorus and potassium solubilization, indole-3-acetic acid (IAA) production, and antagonism against pathogens. Two bacterial isolates, designated BS 1A and BK 1, and one fungal isolate, FW 2B, were earmarked for their plant growth-promoting microorganism (PGPM) potential. Sequence analysis revealed homology of BS 1A with Pseudochrobactrum sp., BK 1 with Bacillus cereus, and FW 2B with Trametes polyzona. A greenhouse experiment employing a completely randomized design evaluated the effects of these isolates on melon growth. Control treatments included a positive control (C+), receiving the recommended dosage of NPK fertilizer, and a negative control (C-), devoid of both NPK and microbial treatments. The application of B. cereus, Pseudochrobactrum sp., and T. polyzona was observed to significantly elevate plant biomass and nutrient acquisition, with B. cereus demonstrating the most pronounced effect, rivalling that of chemical fertilization. The results of this study highlight the potential of utilizing select soil microorganisms as biostimulants, which could play a significant role in increasing the productivity of melon crops, thereby supporting the advancement of sustainable agricultural methodologies.