UV-B and UV-C pre-treatments induce physiological changes and artemisinin biosynthesis in Artemisia annua L. - an antimalarial plant.
Present study was undertaken to investigate if short-term UV-B (4.2 kJ m(-2) day(-1)) and UV-C (5.7 kJ m(-2) day(-1)), pre-treatments can induce artemisinin biosynthesis in Artemisia annua. Twenty-one day old Artemisia seedlings were subjected to short-term (14 days) UV pre-treatment in an environmentally controlled growth chamber and then transplanted to the field under natural conditions. Treatment of A. annua with artificial UV-B and UV-C radiation not only altered the growth responses, biomass, pigment content and antioxidant enzyme activity but enhanced the secondary metabolites (artemisinin and flavonoid) content at all developmental stages as compared to non-irradiated plants. The extent of oxidative damage was measured in terms of the activities of enzymes such as catalase, superoxide dismutase and ascorbate peroxidase. Reinforcement in the antioxidative defense system seems to be a positive response of plants in ameliorating the negative effects of UV-B and UV-C radiations. While the carotenoid content was elevated, the chlorophyll content decreased under UV-B and UV-C pre-treatments. The reverse transcription PCR analysis of the genes associated in artemisinin/isoprenoid biosynthesis like 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), cytochrome P450 oxidoreductase (CPR) and amorpha-4,11-diene synthase (ADS) genes at different growth stages revealed UV induced significant over-expression of the above protein genes. UV-B and UV-C pre-treatments, led to an increase in the concentrations of artemisinin at full bloom stage by 10.5% and 15.7% than that of the control respectively. Thus, the result of our study suggests that short term UV-B pre-treatment of seedlings in greenhouse prior to transplantation into the field enhances artemisinin production with lesser yield related damages as compared to UV-C radiation in A. annua.
Laboratory of Morphogenesis, Centre of Advance Study in Botany, Banaras Hindu University, Varanasi 221 005, India. rai.rashmi6@gmail.com
Rashmi
R
Rai
Ram Prasad
RP
Meena
Shachi Shuchi
SS
Smita
Aparna
A
Shukla
Sanjay Kumar
SK
Rai
Shashi
S
Pandey-Rai
D000962:Antimalarials / Q000378:metabolism*; D000975:Antioxidants / Q000378:metabolism; D031172:Artemisia annua / Q000201:enzymology / Q000378:metabolism* / Q000502:physiology / Q000528:radiation effects*; D037621:Artemisinins / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D005419:Flavonoids / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D006861:Hydrogen Peroxide / Q000378:metabolism; D018384:Oxidative Stress / Q000528:radiation effects; D010788:Photosynthesis / Q000528:radiation effects; D010860:Pigments, Biological / Q000378:metabolism; D011392:Proline / Q000378:metabolism; D036226:Seedlings / Q000201:enzymology / Q000378:metabolism / Q000502:physiology / Q000528:radiation effects; D013312:Stress, Physiological / Q000528:radiation effects; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D013997:Time Factors; D014466:Ultraviolet Rays / Q000009:adverse effects*
D000962:Antimalarials; D000975:Antioxidants; D037621:Artemisinins; D015415:Biomarkers; D005419:Flavonoids; D010860:Pigments, Biological; D017392:Thiobarbituric Acid Reactive Substances; D011392:Proline; C031327:artemisinin; D006861:Hydrogen Peroxide