CCMB scientists decode bacterial blight in rice

The first barrier encountered by the bacterium when it comes in contact with the rice plant is the cell wall of the plant cells, which confers structural integrity and protection to the cell.

By Author  |  Published: 20th May 2019  9:29 pm

Hyderabad: The genetic researchers at Hyderabad-based Centre for Cellular and Molecular Biology (CCMB) have managed to understand the interplay between bacterium Xanthomonas and rice crop. The findings of the study were published in the Journal Molecular Plant Pathology, a publication of the British Society for Plant Pathology.

The bacterium Xanthomonas causes a bacterial blight infection in rice. The first barrier encountered by the bacterium when it comes in contact with the rice plant is the cell wall of the plant cells, which confers structural integrity and protection to the cell. In order to breakdown the cell wall, Xanthomonas secretes certain cell wall degrading enzymes.

This is sensed by the plant which then activates its innate immune responses to fight the bacterium. But the bacterium has also evolved to secrete specialised proteins (called the effector proteins) that can suppress the plant immune responses.

“It is the balance between the two that decides if the plant succeeds to protect itself from the bacterial attack. Understanding the molecular players in plant immune response pathway offers new ways of blocking the bacterial hijack as well as strengthening the defence responses of the plant cells,” said Dr Ramesh V Sonti along with Dr Hitendra K Patel and research scholar Sohini Deb.

The team has identified the principal players behind this process and discovered a new plant‐bacterial interaction which renders the plant to be resistant to bacterial infection. The researchers found that a bacterial effector, named XopQ, suppresses rice immune responses by interacting with certain class of proteins in the rice plant cells.

In an interesting experiment, researchers altered the sequence of the effector protein and consequently, they found that the mutant form of the bacterial effector protein, is now unable to suppress the plant immune responses but makes the plant resistant to bacterial infection, a press release said.