Role of Stomata in Plant Innate Immunity and Foliar Bacterial Diseases

• Published in: Annual review of phytopathology Vol. 46; no. 1; pp. 101 - 122
• Main Authors: Melotto, M, Underwood, W, He, S.Y
• Format: Journal Article
• Language: English
• Published: Palo Alto, CA Annual Reviews 01-01-2008
• Subjects: Bacteria; Bacterial Infections - immunology; Bacterial plant pathogens; bacterial proteins; Biological and medical sciences; disease outbreaks; disease resistance; foliar diseases; Fundamental and applied biological sciences. Psychology; host plants; Immunity, Innate; infection; literature reviews; Lycopersicon esculentum; Pathology. Damages, economic importance; phylloplane; Phytopathology. Animal pests. Plant and forest protection; plant damage; Plant Diseases - immunology; Plant Diseases - microbiology; plant pathogenic bacteria; Plant Stomata - immunology; Plants - immunology; Plants - microbiology; Pseudomonas syringae; Pseudomonas syringae - immunology; Pseudomonas syringae - pathogenicity; Pseudomonas syringae pv. tomato; rain; relative humidity; resistance mechanisms; stomata; stomatal movement; virulence; Pseudomonadales; Pathogenesis; Biological model; Epiphyte; Organism defense; Epidemiology; Immunity; Guard cell; Arabidopsis thaliana; Signal transduction; Molecular signal; innate immunity; Pseudomonas syringae; Dicotyledones; Angiospermae; Associated microflora; Solanaceae; Phytotoxin; Biochemical compound; plant hormones; Infection; Penetration; plant defense; Vegetative apparatus; Phytohormone; Plant microorganism relation; Inborn; Plant pathology; Plant pathogen; Review; Allelochemicals; Cruciferae; Lycopersicon esculentum; Stomatal movement; Phyllosphere; Bacteria; Pseudomonadaceae; Plant growth substance; coronatine; Host agent relation; Stomata; Plant leaf; Bacteriology; Biological compound; Vegetable crop; Bacteriosis; Molecular recognition; Endophyte; Spermatophyta; Molecular biology
• ISSN: 0066-4286; 1545-2107
• DOI: 10.1146/annurev.phyto.121107.104959

Pathogen entry into host tissue is a critical first step in causing infection. For foliar bacterial plant pathogens, natural surface openings, such as stomata, are important entry sites. Historically, these surface openings have been considered as passive portals of entry for plant pathogenic bacteria. However, recent studies have shown that stomata can play an active role in limiting bacterial invasion as part of the plant innate immune system. As a counter-defense, the plant pathogen Pseudomonas syringae pv. tomato DC3000 uses the virulence factor coronatine to actively open stomata. In nature, many foliar bacterial disease outbreaks require high humidity, rain, or storms, which could favor stomatal opening and/or bypass stomatal defense by creating wounds as alternative entry sites. Further studies on microbial and environmental regulation of stomatal closure and opening could fill gaps in our understanding of bacterial pathogenesis, disease epidemiology, and microbiology of the phyllosphere.