Challenges faced by plant growth-promoting bacteria in field-level applications and suggestions to overcome the barriers

Zero hunger is a significant sustainable development goal to ensure food access by all people in vulnerable situations by 2030. However, climate change-mediated possible threats (drought, salinity, and submergence) are adversely impacting our crop yield, which would eventually jeopardize our ability to feed ourselves. Pathogenic attacks caused by nematodes, fungi, bacteria, and viruses are examples of biotic stresses that also result in lower food yields for human consumption. Despite the immense potential for plant growth-promoting bacteria (PGPB) to reduce biotic and abiotic stressors, very few PGPB have been effectively registered as biofertilizers in the commercial sector. The biofertilizer market share includes a tiny fraction of the synthetic agrochemical market share. Specific obstacles hamper field-level applications of PGPB that were effective in laboratories. The preparation of formulations faces numerous difficulties, including issues with shelf life, viability upkeep, biofilm formation, and risks to human health. Different regions have different weather patterns and soil compositions. The full image of microbial interactions is still largely unknown. This review aims to explore the recent advancements in biofertilizer formulations and their in vivo monitoring techniques to correlate with the mitigation of the obstacles. At the same time, possible ways for creating effective, reliable, and affordable PGPB formulations are also discussed.