Nagendran Rajalingam, Lee Yong Hoon
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.
Phytopathology. 2015 Apr;105(4):412-8. doi: 10.1094/PHYTO-04-14-0108-R.
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.
光照影响大多数生物体的许多生理过程。为了研究光照对植物与病原体相互作用的影响，我们通过漫灌接种用菊苣假单胞菌JBC1对番茄幼苗进行挑战，并在不同光照条件下培养这些幼苗。与在白光或黑暗条件下生长的番茄幼苗相比，暴露于绿光或红光下的番茄幼苗发病率显著降低。为了了解其潜在机制，我们研究了每种光波长对菊苣假单胞菌JBC1和番茄植株的影响。在120 µmol m(-2) s(-1) 的各种光波长处理下，病原体的生长、群体运动性或生物膜形成没有显著差异。此外，当我们将菊苣假单胞菌JBC1真空渗入番茄植株时，绿光和红光也抑制了发病率，这表明病情严重程度降低并非源于光照对病原体的直接影响。与在白光或黑暗条件下生长的幼苗相比，在绿光或红光下生长的受菊苣假单胞菌JBC1感染的番茄幼苗中，防御相关基因苯丙氨酸解氨酶（PAL）和病程相关蛋白1a（PR-1a）显著上调。本研究结果表明光照条件可影响植物防御机制。特别是，绿光和红光可增强番茄植株对菊苣假单胞菌感染的抗性。
