UV-Induced cell death in plants.
Plants are photosynthetic organisms that depend on sunlight for energy. Plants respond to light through different photoreceptors and show photomorphogenic development. Apart from Photosynthetically Active Radiation (PAR; 400-700 nm), plants are exposed to UV light, which is comprised of UV-C (below 280 nm), UV-B  (280-320 nm) and UV-A (320-390 nm). The atmospheric ozone layer protects UV-C radiation from reaching earth while the UVR8 protein acts as a receptor for UV-B radiation. Low levels of UV-B exposure initiate signaling through UVR8 and induce secondary metabolite genes involved in protection against UV while higher dosages are very detrimental to plants. It has also been reported that genes involved in MAPK cascade help the plant in providing tolerance against UV radiation. The important targets of UV radiation in plant cells are DNA, lipids and proteins and also vital processes such as photosynthesis. Recent studies showed that, in response to UV radiation, mitochondria and chloroplasts produce a reactive oxygen species (ROS). Arabidopsis metacaspase-8 (AtMC8) is induced in response to oxidative stress caused by ROS, which acts downstream of the radical induced cell death (AtRCD1) gene making plants vulnerable to cell death. The studies on salicylic and jasmonic acid signaling mutants revealed that SA and JA regulate the ROS level and antagonize ROS mediated cell death. Recently, molecular studies have revealed genes involved in response to UV exposure, with respect to programmed cell death (PCD).
Division of Applied Life Sciences (BK21 program) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Korea. jacobgnu69@gnu.ac.kr.
Ganesh M
GM
Nawkar
Punyakishore
P
Maibam
Jung Hoon
JH
Park
Vaidurya Pratap
VP
Sahi
Sang Yeol
SY
Lee
Chang Ho
CH
Kang
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D016923:Cell Death / Q000235:genetics / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D008957:Models, Genetic; D010788:Photosynthesis / Q000235:genetics / Q000528:radiation effects; D059828:Plant Cells / Q000378:metabolism / Q000528:radiation effects*; D063245:Plant Development / Q000235:genetics / Q000528:radiation effects*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D010944:Plants / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D014466:Ultraviolet Rays
D010940:Plant Proteins