Biopriming Using Rhizospheric Actinobacteria- A Promising Tool in Paddy (Oryza Sativa) Farming

Abstract

The germination of paddy seeds plays a critical role in the establishment of seedlings and their subsequent developmental processes. However, Impaired rice seed germination results from reduced levels of bioactive gibberellins (GAs), due to environmental stress. This inhibitory effect can be mitigated through hormone priming, nutrient priming, and Osmo priming. These pretreatments stimulate the α-amylase activity and initiate other developmental processes. Currently, new biopriming trends are emerging. Biopriming is the application of seed pre-treatment with diverse plant growth-promoting rhizospheric microbes.Reports show that actinobacteria are the least studied biopriming agents. In this study, around 43 actinomycete isolates were isolated from various rhizospheric soils cultivated with the rice variety, Indrayani. Data revealed a significant improvement in the germination process due to the biopriming of seeds using four multifunctional isolates. Streptomyces ardesiacus strain I7 marked the highest vigor index. Streptomyces antibioticus strain I4 showed  significant antimicrobial activity against Xanthomonas oryzae subspecies oryzae (Xoo).Colonization of actinomycetes at surface of paddy roots was observed using a scanning electron microscope. These actinomycete isolates can be further taken up for commercial consortium development.