R. Sonti - Modulation of host innate immunity during bacterial infection of rice
Channel: Icgeb
Date: 2023-04-26

Ramesh Sonti, Director, ICGEB New Delhi Component, New Delhi, INDIA speaks on "Modulation of host innate immunity during bacterial infection of rice".

Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight, a serious rice disease. As part of its virulence repertoire, Xoo secretes a battery of cell wall degrading enzymes (CWDEs) that target different components of the rice cell wall. However, the CWDEs are double edged swords as the damage that they cause serves as a mark of infection and results in induction of Damage Triggered Immune responses that are part of pathogen triggered immunity (PTI). Xoo suppresses these defense responses using four different effector proteins that it secretes into rice cells via a type 3 secretion system (T3SS). Mutational analysis indicates that these four proteins function redundantly in suppression of PTI. Three of these T3SS effectors have 14-3-3 protein binding motifs. Each of these T3SS effectors interacts with different rice 14-3-3 proteins and this interaction is necessary for the ability of the effectors to suppress PTI. Some of the effectors that suppress PTI also appear to trigger a second layer of the plant immune response that is commonly referred to as Effector Triggered Immunity (ETI). Xoo is able to suppress ETI using five other T3SS effectors. At least for one of these effectors, the suppression of ETI appears to be due to physical interaction with effectors that elicit ETI and alteration of their intracellular localization. These results suggest a complex interplay of Xanthomonas T3SS effectors in suppression of both PTI and ETI to promote virulence on rice.