Role of plant stomata in bacterial invasion

Abstract

SummaryStomata are microscopic pores in the epidermis of the aerial parts of terrestrial plants. These pores are essential for photosynthesis, as they allow CO2 to diffuse into the plant. The size of the stomatal pore changes in response to environmental conditions, such as light intensity, air humidity and CO2 concentrations, as part of the plant's adaptation to maximize photosynthetic efficiency and, at the same time, to minimize water loss. Historically, stomata have been considered as passive portal of entry for plant pathogenic bacteria. However, recent studies suggest that stomata can play an active role in restricting bacterial invasion as part of the plant innate immune system. Some plant pathogens have evolved specific virulence factors to overcome stomata-based defence. Interestingly, many bacterial disease outbreaks require high humidity, rain, or frost damage, which could promote stomatal opening and/or bypass stomatal defence by creating wounds as alternative entry sites. Further studies on microbial and environmental regulation of stomata-based defence should fill gaps in our understanding of bacterial pathogenesis, disease epidemiology and phyllosphere microbiology.

Light Regulation and Daytime Dependency of Inducible Plant Defenses in Arabidopsis: Phytochrome Signaling Controls Systemic Acquired Resistance Rather Than Local Defense

“…For pathogenic bacteria, however, besides a light-dependent effectiveness of plant defenses, a number of other factors can contribute to determine the timing of pathogen attack and the final outcome of a particular plantpathogen interaction in natural habitats (Colhoun, 1973). These include the necessity for bacteria to enter through open stomata, temperature influences on bacterial virulence, and humidity effects (van Dijk et al, 1999;Underwood et al, 2007).…”

Role of Stomata in Plant Innate Immunity and Foliar Bacterial Diseases

“…We thank K. Bird for assistance in preparation of this paper, and Wiley-Blackwell Publishing Ltd. for permission to use the content of the reference Underwood et al (110). Supported by grants from the U.S. Department of Energy and National Institutes of Health.…”

“…COR also plays roles in the late stages of the infection process, including suppression of local and systemic host defenses and promotion of disease symptoms (24,62,110,112). As disease progresses, Pst DC3000 heavily colonizes the sub-stomatal cavity (14) and it is possible that COR-induced stomatal opening is also important for the release of bacteria to the leaf surface to facilitate subsequent spread to nearby healthy plants.…”

Novel High-Throughput Detection Method To Assess Bacterial Surfactant Production

“…It is already known that once inside the leaf, bacteria such as Pseudomonas syringae use surfactants to cause plant cell leakage and disease symptoms (33). However, some studies have also implicated biosurfactants in the prepathogenic stages of plant-associated bacteria (16,24,36).…”