New frontiers in agriculture productivity: Optimised microbial inoculants and in situ microbiome engineering.

Increasing agricultural productivity is critical to feed the ever-growing human population. Being linked intimately to plant health, growth and productivity, harnessing the plant microbiome is considered a potentially viable approach for the next green revolution, in an environmentally sustainable way. In recent years, our understanding of drivers, roles, mechanisms, along with knowledge to manipulate the plant microbiome, have significantly advanced. Yet, translating this knowledge to expand farm productivity and sustainability requires the development of solutions for a number of technological and logistic challenges. In this article, we propose new and emerging strategies to improve the survival and activity of microbial inoculants, including using selected indigenous microbes and optimising microbial delivery methods, as well as modern gene editing tools to engineer microbial inoculants. In addition, we identify multiple biochemical and molecular mechanisms and/approaches which can be exploited for microbiome engineering in situ to optimise plant-microbiome interactions for improved farm yields. These novel biotechnological approaches can provide effective tools to attract and maintain activities of crop beneficial microbiota that increase crop performance in terms of nutrient acquisition, and resistance to biotic and abiotic stresses, resulting in an increased agricultural productivity and sustainability.