Endophytes have recently garnered importance worldwide and multiple studies are being conducted to understand their important role and mechanism of interaction inside plants. But before we indulge in their functions it is necessary to dig into the microbiome. This will help to get a complete picture of the microbes intrinsic to their host and understand changes in community composition with respect to their habitats. To ful l this requirement in our study we have attempted to dissect the endophytic diversity in roots of rice plant grown across the various agro-ecological zones of West Bengal by undergoing amplicon analysis of their 16S rRNA gene. We found that the agro-ecological zones can be divided into two groups: nutrient dense (GAZ, NHZ and TTAZ) and nutrient low groups (CSZ, RLZ and VAZ). Few genera (Aeromonas, Sulfurospirillum, Uliginosibacterium, etc.) are present in samples cultivated in all the zones representing the core microbiome of rice in West Bengal while some other genera like Lactococcus, Dickeya, Azonexus, Pectobacterium, etc. are unique to speci c zone. It can be concluded that understanding which particular endophytes cohabit with the internal plant environment can play an important role in endophyte-based stress management strategy.
Introduction:Rice is the most important staple food for more than half the world's population. India is one of the leading producers and consumer of rice and the state of West Bengal is one of the highest producers of rice in India (Kunda et al., 2018). However, rice production is impeded by several abiotic and biotic factors. Therefore, to improve the productivity of crops, farmers apply a wide range of chemical fertilizers and pesticides which in excess leave eco-toxic residues in the soil and in longer term, decrease crop productivity (Kumar Bag, 2011). These toxic chemicals are also responsible for global warming and groundwater pollution (Mashiane et al., 2017). To combat these problems, recent developments are being made to use potential microorganisms to manage biotic and abiotic stress and improve plant growth for a healthier environment (Edwards et al., 2015;Mashiane et al., 2017). Microbiomes associated with plants roots are known to play a signi cant role in hastening plant growth, development and can alter plant health as well as their stress tolerance abilities (Lareen et al., 2016). These microbes can reside either in the rhizopsheric soil in close association with the roots or can remain inside the plant as endophytes (Olanrewaju et al., 2017). Symbiotic bacterial endophytes of rice provide multiple bene ts to their host. They adapt different mechanisms to protect plants from various stressful conditions like drought, salinity, pathogen attack (Khare et al., 2018;Mukhtar et al., 2019). They do so by increasing carbon and nitrogen metabolism, enhancing photosynthetic activity as well as detoxifying enzymes activities, reducing damage caused by reactive oxygen species, producing osmotic regulators, ACC deaminase enzyme, various phytohormones and also...