Arsenic-induced changes in morphological, physiological, and biochemical attributes and artemisinin biosynthesis in Artemisia annua, an antimalarial plant

Abstract

Present study is the first to explore physiological, biochemical and molecular changes in the medicinal plant Artemisia annua under arsenic (As) stress. A. annua grown hydroponically in a nutrient solution was spiked with increasing doses of As (0, 1,500, 3,000 and 4,500 μg l(-1)) for 7 days. Plants accumulated As in a dose dependent manner with bioconcentration factor 13.4 and translocation factor 0.97. While a similar trend of As accumulation was observed under soil culture experiments, the transfer factor went up to 2.1, depicting high efficiency of As translocation from roots to shoots by A. annua. Plants raised in 0-3,000 μg l(-1) As containing nutrient solution registered increase in root length, biomass, and carotenoid contents without any visual toxicity symptoms. A dose dependent increase in the activities of enzymes such as superoxide dismutase, ascorbate peroxidase, glutathione reductase and guaiacol peroxidase followed by a gradual decline at higher concentrations suggested their role in alleviating oxidative stress. Significant increase in the levels of thiols, GSH, and pcs gene transcript up to 3,000 μg l(-1) As attested their roles in As detoxification. Enhanced artemisinin production (an antimalarial compound) under As stress and upregulation of the transcripts (measured by RT-PCR) of the genes HMGR, FDS, ADS, and CYP71AV1 involved in artemisinin biosynthesis reaffirmed induction of artemisinin biosynthesis in A. annua under As stress. The results of the present study vividly suggested that A. annua has considerable As tolerance, and thus can be successfully cultivated in As contaminated fields.

Enhanced Photosynthesis and Carbon Metabolism Favor Arsenic Tolerance inArtemisia annua, a Medicinal Plant as Revealed by Homology-Based Proteomics

“…Artemisia annua L (family: Asteraceae) plants were cultured hydroponically as described by Rai et al [11]. Briefly, seeds of A. annua were collected from Central Institute of Medicinal and Aromatic Plants (CIMAP), Lucknow, India, and grown in botanical garden, Banaras Hindu University, Varanasi, India.…”

“…Our previous study demonstrated a significant induction of artemisinin production under As stress. The high tolerance of A. annua against As stress was coupled with an appreciable increase in biomass and As accumulation capacity, thus enabling this plant to be worth cultivating in As contaminated soils [11]. …”

“…It requires mentioning that As (V) exposure (i) triggers ROS production causing alterations in the antioxidant pathways [11, 20], (ii) disturbs phosphate metabolism (e.g., ATP synthesis) and electron transport systems [12], and (iii) induces photoinhibitory conditions [25, 26]. In view of the above it was hypothesized that for survival under As stress, A. annua may (i) increase the accumulation of APX and DHAR to detoxify ROS, (ii) increase the electron transport to overcome the shortage of ATP and NADPH, and (iii) enhance phytochelatin synthase ( pcs ) and ABC transporter like protein genes for detoxification.…”

Arsenic accumulation in Brassicaceae seedlings and its effects on growth and plant anatomy

“…The first plant response to arsenic exposition is the increased production of reactive oxygen species, which, when in excess, cause oxidative stress. This might alter the structure and permeability of cell membranes and consequently cause breakdown and electrolyte leakage (Khan et al, 2009;Singh et al, 2009;Yadav, 2010;Rai et al, 2011). Electrolyte leakage causes a decrease in cytoplasmic content, which can anatomically be identified as protoplast retraction.…”

A different sequence of events than previously reported leads to arsenic-induced damage in Ceratophyllum demersum L.

“…20 However, most of the studies on plants have been done on As hyperaccumulators or tolerant plants, which can withstand higher levels of As through specific mechanisms. 9,11,21 Some studies concerning As toxicity in non-tolerant plants have been done as well, 16,20,[22][23][24] but they were mostly performed with short-term exposure (few hours or days) to high As concentrations (hundred micromolar to millimolar). Experiments with such high concentrations for plants that are not specifically As-tolerant do not adequately simulate As toxicity in the environment, where the level of As in water or in soil solution would almost never become so high.…”