<i>In silico</i> characterization, molecular docking, and dynamic simulation of a novel fungal cell-death suppressing effector, MoRlpA as potential cathepsin B-like cysteine protease inhibitor during rice blast infection
Creators: name: Sarkar, Debrup
name: Majumder, Satyabrata
name: Giri, Kalyan
name: Sabnam, Nazmiara
Publisher: name: Taylor & Francis
Year: 2022
Subjects: subject: Medicine
subject: Microbiology
subject: FOS: Biological sciences
subject: Cell Biology
subject: Genetics
subject: Biological Sciences not elsewhere classified
subject: Information Systems not elsewhere classified
subject: Infectious Diseases
subject: FOS: Health sciences
subject: Plant Biology

description: The blast fungus <i>Magnaporthe oryzae</i> is one of the most notorious pathogens affecting rice production worldwide. The cereal killer employs a special class of small secreted proteins called effectors to manipulate and perturb the host metabolism. In turn, the host plants trigger effector-triggered immunity (ETI) via localized cell death and hypersensitive response (HR). We have identified and characterized a novel secreted effector MoRlpA from <i>M. oryzae</i> by extensive <i>in silico</i> methods. The localization studies suggested that it is exclusively secreted in the host apoplasts. Interestingly, MoRlpA interacts with a protease, cathepsin B from rice with highest affinity. The 3D structural models of both the proteins were generated. Cathepsin B-like cysteine proteases are usually involved in programmed cell death (PCD) and autophagy in plants which lead to generation of HR upon infection. Our results suggest that MoRlpA interacts with rice cathepsin B-like cysteine protease and demolish the host counter-attack by suppressing cell death and HR during an active blast infection. This was further validated by molecular docking and molecular dynamic simulation analyses. The important residues involved in the rice-blast pathogen interactions were deciphered. Overall, this research highlights stable interactions between MoRlpA-OsCathB during rice blast pathogenesis and providing an insight into how this novel RlpA protease inhibitor-cum-effector modulates the host’s apoplast to invade the host tissues and establish a successful infection. Thus, this research will help to develop potential fungicide to block the binding region of MoRlpA target so that the cryptic pathogen would be recognized by the host. HIGHLIGHTSFor the first time, a novel secreted effector protein, MoRlpA has been identified and characterised from <i>M. oryzae in silico</i>MoRlpA contains a rare lipoprotein A-like DPBB domain which is often an enzymatic domain in other systemsMoRlpA as an apoplastic effector interacts with the rice protease OsCathB to suppress the cell death and hypersensitive response during rice blast infectionThe three-dimensional structures of both the MoRlpA and OsCathB proteins were predictedMoRlpA-OsCathB interactions were analysed by molecular docking and molecular dynamic simulation studies For the first time, a novel secreted effector protein, MoRlpA has been identified and characterised from <i>M. oryzae in silico</i> MoRlpA contains a rare lipoprotein A-like DPBB domain which is often an enzymatic domain in other systems MoRlpA as an apoplastic effector interacts with the rice protease OsCathB to suppress the cell death and hypersensitive response during rice blast infection The three-dimensional structures of both the MoRlpA and OsCathB proteins were predicted MoRlpA-OsCathB interactions were analysed by molecular docking and molecular dynamic simulation studies Communicated by Ramaswamy H. Sarma