Effect of indole acetic acid (IAA)-overproducing mutants of Burkholderia cepacia (RRE25), a member of β-subclass of Proteobacteria and naturally occurring rice endophyte, was observed on the growth of rice (Oryza sativa L.) plants grown under greenhouse conditions. Nine mutants were characterized for altered biosynthesis of IAA after nitrous acid mutagenesis. These mutants were grouped into two classes: class I mutants have reduced production of IAA as compared to the wild type, while class II mutants showed overproduction of IAA. Mutants of both classes and RRE25, the parent (wild type), were inoculated on rice seedlings of two cultivars (Sarjoo-52 and NDR-97). Uptake of nitrogen, phosphorous, and potassium was estimated in these plants. Significant increase in the amount of uptake of all three elements was observed when inoculated with the IAA-overproducing mutants over control as well as in the plants inoculated with the wild type (RRE25). Effect of inoculation of IAA-overproducing mutants was more pronounced on the uptake of phosphorous in cultivar NDR-97 than Sarjoo-52, while it was opposite with respect to potassium uptake. Any significant difference was not observed in nitrogen uptake among the two cultivars. It shows that the host also plays an important role in the beneficial endophytic association. It was concluded from these results that one of the possible mechanisms of growth promotion of rice plants inoculated with bacterial endophytes is their effects on an increase in the capability of nutritional uptake possible through the effect of IAA production which results in proliferation of root system that could mine more nutrients from the soil.

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Abstract. Singh RK, Malik N, Singh S. 2013. Impact of rhizobial inoculation and nitrogen utilization in plant growth promotion of maize (Zea mays L.). Nusantara Bioscience 5: 8-14. During the course of growing population demands, there has been an increasing interest in exploring the possibility of extending the beneficial interaction between cereals and plant growth promoting rhizobacteria (PGPR). Endophytes are a group of microorganism that resides mostly in the intercellular space of various parts of plants including cereals. Assessment of plant growth promoting properties of the five-rhizobial strains belonging to α subclass i.e. Rhizobium leguminosarum bv. phaseoli RRE6 and R. undicola RRE36 and those belonging to β subclass i.e. Burkholderia cepacia (RRE3, RRE5, RRE25) was done by growing maize plants inoculated with these strains. Inoculated maize plants showed a significant increase in plant height, root length, shoot and root dry weight over uninoculated control. R. leguminosarum bv. phaseoli RRE6 and B. cepacia RRE5 among the α and β-subclass representatives respectively, gave the best inoculation response. Effect of nitrate supplementation upon maize-RRE6 and RRE5 association was also studied and a significant increase in all the growth parameters and colonization ability was recorded when nitrate was present as a supplement over uninoculated control and maize-RRE6 and RRE5 in absence of external nitrate.

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The sudden outbreak of coronavirus turned into a pandemic and resulted in huge socio-economic and human losses becoming a public health emergency. It took just 3-4 months to spread and encroach all over the world and not even a single country is left was unaffected by the coronavirus. WHO started clinical, epidemiological, and laboratory investigations in response to this outbreak to control the further spread of the virus. The coronaviruses are enveloped and pleomorphic. The spike proteins present on the virus surface mediate its entry into host cells. The vaccines recommended have been shown to reduce COVID-19 illness symptoms but somehow their role in the transmission of the disease is unclear. By contrast, immunomodulatory therapy has also benefitted patients. As long as SARS-CoV-2 spreads in the population there are chances of its mutation as RNA viruses mutate over time and its upcoming variants. The previous Delta variant and the latest Omicron variant may cause much more serious deaths and health issues. Variants reduce the effectiveness of monoclonal antibodies or antibodies generated by previously administered vaccines. This review focuses on the pathogenicity of coronavirus and various drug therapies available to date to cure the disease. The present study also highlights the target sites and side effects of available drugs for treating COVID-19. Article info