Microbial Communities in Rice: Their Role in Nutrient Dynamics and Yield Enhancement

Abstract

Plants are in a dynamic web of biotic and abiotic associations, commonly called the phytobiome. Of the biotic components, the plant microbiome is at the core of managing plant health, growth, and productivity. Understanding the structure and function of microbial populations that live in association with plants is key to understanding plant-microbe interactions and their influence on crop performance. Rice (Oryza sativa L.), a food source for over half the world's population, is faced with mounting production issues with limited arable land, soil erosion and hence unsustainable agriculture. This has led to amplified application of chemical fertilizers, which is environmentally costly and has generated interest in microbial alternatives as sustainable inputs. Research indicates microbial consortia (e.g., Azospirillum brasilense, Pseudomonas fluorescens) reduce Nitrogenous fertilizer requirements by 25–40% while increasing yield by 8–12% through biological fixation and phytohormone modulation. Another study showed that inoculation of Rhizobium leguminosarum pv. Trifolii significantly promoted grain yield in rice by 47%. Despite significant research on microbial inoculants, their effective utilization is sporadic with only ~10-30% of biofertilizer trials showing reproducible yield improvements. This review considers the diversity and functional importance of the rice microbiome, in terms of its function in agricultural quality and yield. It also considers the prospect of harnessing microbial communities as sustainable biofertilizers to enhance rice productivity as opposed to dependence on inorganic means. A comprehensive understanding of the rice microbiome in a range of environmental conditions may make it feasible to design optimized microbial interventions tailored to a specific agricultural environment.