Scientist Namrata's Thesis Defense: A Brief Interview
What's your thesis about and why did you pick that topic?
My PhD thesis focused on understanding the mechanism of a potential endophytic bacterial strain, Methylorubrum extorquens DSM13060. This strain was isolated from Scots pine (Pinus sylvestris L.) in the forests of Northern Finland. It is known to promote growth and development in pine seedlings without producing any common plant hormones. This bacterium colonizes the plant throughout various seasons and stages of growth. It is intracellular in nature and can accumulate around the nucleus of pine cells, a mechanism not commonly observed in beneficial microbes. This novel interaction occurring in the Arctic environment differs from commonly found plant growth-promoting rhizobacteria, hence motivating me to pursue it as the topic for my PhD research work.
Why is your topic important?
Vegetation is a major global carbon store as plants consume CO2 during photosynthesis. Plants participate in the carbon budget by emitting monocarbon compounds, which play a key role in climate forcing and ozone depletion. Methanol is produced in plant tissue and they lack mechanisms for detoxifying it, which is mainly emitted through stomata. M. extorquens DSM13060, being a methylotroph, can consume the methanol released from plants and utilize it for the production of storage granules called polyhydroxybutyrate (PHB). PHB provides protection against oxidative stress for both host and endosymbiont cells through its protective oligomers. M. extorquens has the unique property of accumulating itself in the plant cell around the nucleus in Scots pine. A deeper knowledge of this symbiotic relationship has opened up the potential development of endosymbiotic bacteria as biofertilizers or biocontrol agents in agriculture.
What research did you do and what did you find?
One of the findings of this study showed that endosymbiotic strains such as M. extorquens must rely heavily on PHB metabolism to mitigate oxidative stress induced by the host and thus helping minimize the toxic effects of carbon-based compounds from the environment. Additionally, the bacterial nuclear effector protein, Ank_2, is a prerequisite for colonization, nuclear interaction, and plant growth promotion by M. extorquens. Bacterial nuclear effectors are the proteins responsible for hijacking or interfering with multiple nuclear processes of the host plant. Our research unearthed that the Ank_2 protein is also responsible for the transfer of carbon and nitrogen compounds to the actively dividing cells of Scots pine, aiding in plant development. This discovery of new cellular and molecular-level mechanisms plays a role in understanding endosymbiotic interactions and opens the potential for use in sustainable agricultural systems.
What's your next step?
As a senior scientist at ISC, I believe, with my years of experience and skills, I can make a difference. I have been proactive in my work with ISC from the beginning and will work hard to achieve groundbreaking discoveries. I plan to help the team drive biological innovations and aim to make the world around us safer, healthier, and more ecologically sustainable.