title: Green and Red Light Reduces the Disease Severity by Pseudomonas cichorii JBC1 in Tomato Plants via Upregulation of Defense-Related Gene Expression.
abstract: Light influences many physiological processes in most organisms. To investigate the influence of light on plant and pathogen interaction, we challenged tomato seedlings with Pseudomonas cichorii JBC1 by flood inoculation and incubated the seedlings under different light conditions. Tomato seedlings exposed to green or red light showed a significant reduction in disease incidence compared with those grown under white light or dark conditions. To understand the underlying mechanisms, we investigated the effects of each light wavelength on P. cichorii JBC1 and tomato plants. Treatment with various light wavelengths at 120 µmol m(-2) s(-1) revealed no significant difference in growth, swarming motility, or biofilm formation of the pathogen. In addition, when we vacuum-infiltrated P. cichorii JBC1 into tomato plants, green and red light also suppressed disease incidence which indicated that the reduced disease severity was not from direct influence of light on the pathogen. Significant upregulation of the defense-related genes, phenylalanine ammonia-lyase (PAL) and pathogenesis-related protein 1a (PR-1a) was observed in P. cichorii JBC1-infected tomato seedlings grown under green or red light compared with seedlings grown under white light or dark conditions. The results of this study indicate that light conditions can influence plant defense mechanisms. In particular, green and red light increase the resistance of tomato plants to infection by P. cichorii.
authors.affiliation: First author: Division of Biotechnology, Chonbuk National University, 194-5 Ma-Dong, Iksan, Jeonbuk 570-752, Republic of Korea; and second author: Advanced Institute of Environment and Bioscience, and Plant Medical Research Center, Chonbuk National University 194-5 Ma-Dong, Iksan, Jeonbuk 570-752, Republic of Korea.
authors.forename: Rajalingam
authors.initials: R
authors.lastname: Nagendran
authors.forename: Yong Hoon
authors.initials: YH
authors.lastname: Lee
mesh_terms: D018441:Biofilms / Q000254:growth & development; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects*; D008027:Light; D018551:Solanum lycopersicum / Q000235:genetics / Q000382:microbiology / Q000502:physiology / Q000528:radiation effects*; D010650:Phenylalanine Ammonia-Lyase / Q000235:genetics; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D057865:Plant Immunity; D018515:Plant Leaves / Q000235:genetics / Q000276:immunology / Q000528:radiation effects; D010940:Plant Proteins / Q000235:genetics*; D011549:Pseudomonas / Q000254:growth & development / Q000472:pathogenicity* / Q000502:physiology; D036226:Seedlings / Q000235:genetics / Q000276:immunology / Q000528:radiation effects; D015854:Up-Regulation
chemical_list: D010940:Plant Proteins; C053376:pathogenesis-related proteins, plant; D010650:Phenylalanine Ammonia-Lyase