Pathogen effectors: What do they do at plasmodesmata?

• Published in: Molecular plant pathology Vol. 23; no. 6; pp. 795 - 804
• Main Authors: Iswanto, Arya Bagus Boedi, Vu, Minh Huy, Pike, Sharon, Lee, Jihyun, Kang, Hobin, Son, Geon Hui, Kim, Jae‐Yean, Kim, Sang Hee
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.06.2022; John Wiley and Sons Inc
• Subjects: Bacteria; bacterial effectors; Bacterial infections; Cell interactions; Effectors; fungal effectors; Fungi; host defence mechanism; Host plants; Host-Pathogen Interactions; Immune system; Kinases; Life cycles; Microreview; Oomycetes - metabolism; Pathogens; Permeability; Plant Diseases - microbiology; Plant growth; plant immune response; Plant resistance; Plants - microbiology; Plasmodesmata; Plasmodesmata - metabolism; Proteins; Viruses; plasmodesmata; fungal effectors; bacterial effectors; host defence mechanism; plant immune response
• ISSN: 1464-6722; 1364-3703
• DOI: 10.1111/mpp.13142

Plants perceive an assortment of external cues during their life cycle, including abiotic and biotic stressors. Biotic stress from a variety of pathogens, including viruses, oomycetes, fungi, and bacteria, is considered to be a substantial factor hindering plant growth and development. To hijack the host cell's defence machinery, plant pathogens have evolved sophisticated attack strategies mediated by numerous effector proteins. Several studies have indicated that plasmodesmata (PD), symplasmic pores that facilitate cell‐to‐cell communication between a cell and neighbouring cells, are one of the targets of pathogen effectors. However, in contrast to plant‐pathogenic viruses, reports of fungal‐ and bacterial‐encoded effectors that localize to and exploit PD are limited. Surprisingly, a recent study of PD‐associated bacterial effectors has shown that a number of bacterial effectors undergo cell‐to‐cell movement via PD. Here we summarize and highlight recent advances in the study of PD‐associated fungal/oomycete/bacterial effectors. We also discuss how pathogen effectors interfere with host defence mechanisms in the context of PD regulation. Many pathogen effectors are delivered to the cytosol and suppress callose accumulation at the apoplast or plasmodesmata; some undergo cell‐to‐cell symplasmic trafficking and physically interact with plasmodesmata regulators.