Biofilm-Forming Ability of Phytopathogenic Bacteria: A Review of its Involvement in Plant Stress

Abstract

Phytopathogenic bacteria not only affect crop yield and quality but also the environment. Understanding the mechanisms involved in their survival is essential to develop new strategies to control plant disease. One such mechanism is the formation of biofilms; i.e., microbial communities within a three-dimensional structure that offers adaptive advantages, such as protection against unfavorable environmental conditions. Biofilm-producing phytopathogenic bacteria are difficult to manage. They colonize the intercellular spaces and the vascular system of the host plants and cause a wide range of symptoms such as necrosis, wilting, leaf spots, blight, soft rot, and hyperplasia. This review summarizes up-to-date information about saline and drought stress in plants (abiotic stress) and then goes on to focus on the biotic stress produced by biofilm-forming phytopathogenic bacteria, which are responsible for serious disease in many crops. Their characteristics, pathogenesis, virulence factors, systems of cellular communication, and the molecules implicated in the regulation of these processes are all covered.

Keywords: bacteria-plant interactions; biofilm; biotic stress; phytopathogenic bacteria.

Figure 1

Cyclic model of disease by phytopathogenic bacteria consisting of several distinct stages: 1. Survival or source of inoculum: The bacteria survive outside the host by developing in another environment or by remaining dormant. 2. Dissemination: The bacteria spread. 3. Inoculation: The bacteria come into contact with the plant. 4. Penetration: The bacteria enter the plant. 5. Colonization: The bacteria disseminate within the plant. 6. Appearance of symptoms: This is the result of bacteria producing phytotoxins, EPS, exoenzymes, phytohormones, etc.

Figure 2

Involvement of biofilm in interactions between plants and phytopathogenic bacteria.