Phytopathology (2015) 105, 412-418

Rajalingam Nagendran and Yong Hoon Lee (2015)
Green and red light reduces the disease severity by Pseudomonas cichorii JBC1 in tomato plants via upregulation of defense-related gene expression
Phytopathology 105 (4), 412-418
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^–2s^–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.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation
resistance/tolerance/defence of host

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Pseudomonas cichorii	Tomato (Solanum lycopersicum)