For those with green fingers, an unwelcome plant disease can potentially destroy your weeks, months or even years of gardening.
Plant diseases are not only a nuisance to neighbourhood gardeners, but more importantly, have a direct impact on a country’s agri-food industry. Food security and sustainability are extremely important to any country – making the understanding of plant disease and its accompanying immune response an important field of study.
Associate Professor Miao Yansong, a plant scientist from the NTU School of Biological Sciences, recently published a study that shed some light on the field of plant immune response against microbial pathogens.
Assoc Prof Miao Yansong
Infectious pathogens such as Xanthomonas campestris pv. campestris (Xcc) – a devastating bacteria that causes black rot in plants – produce bacterial virulence factors (VF) which trigger plant immune responses against bacterial infection. Plant actin cytoskeletons is a core of such plant defense mechanisms that respond to bacterial signals rapidly and remodel its polymerization to coordinate diverse cellular processes to fight against pathogen invasion.
The mechanisms by which plants sense and respond to bacterial VFs so swiftly to orchestrate plant immune signal transduction was unclear, that is until Assoc Prof Miao and his team managed to unravel the puzzle.
The recently published article found Type-I Formins – a protein family that initiates actin cytoskeleton polymerization – performing as a plant molecular sensor of bacterial VFs. Upon perception of two well-known types of VFs, pathogen-associated molecular pattern (PAMP) and Xcc quorum-sensing signal diffusible signal factor (DSF), formins are rapidly clustered into molecular condensates on the plasma membrane of plant cells. This resulted in an immediate increase in actin polymerization.
Assoc Prof Miao’s lab additionally identified the mechanical regulatory mechanism by which the formin condensation on the cell surface is largely regulated by their integrated plant scaffolding structure, cell wall-plasma membrane-actin cytoskeleton (CW-PM-AW) continuum, the front battlefield between plants and pathogens.
This work is supported by NTU Nanyang Assistant Professorship-start up grant, Singapore MOE Tier 1 and Tier 3 grants to Assoc Prof Miao. The plant signalling and phase separation studies are also recognized by European Molecular Biology Organization, and the EMBO Global Investigator awarded to Assoc Prof Miao.
Assoc Prof Miao and his team not only managed to discover a new mechanism to understand plant signalling, by being able to control plant development and defense mechanisms – this study can also be further translated into Singapore’s agri-food industry, such as urban farming, which in the long run, could boost Singapore’s food technology, food safety and sustainability.