Cadmium toxicity-induced proline accumulation is coupled to iron depletion.
Investigations were conducted to elucidate the key factor behind Cd2+-toxicity-induced proline accumulation in Indian mustard (Brassica juncea) by raising seedlings, independently in distilled water (DW) and mineral growth medium (MGM) in the presence of 0-500 μM CdCl2. Invariably, Cd2+-induced toxicity, measured in terms of growth, was significantly more prominent in seedlings raised in DW than those raised in MGM. Cd2+brought about a significant reduction in growth and photosystem II activity with a concomitant increase in proline levels, in a concentration-dependent manner. Interestingly, the level of iron in shoots of seedlings decreased proportionately with increase in Cd2+toxicity. Cd2+-promoted proline accumulation was significantly higher in seedlings raised in DW than those raised in MGM. Depletion of essential cations (viz. Ca2+, Mg2+, K+, and Fe2+) from MGM one at a time revealed that depletion of Fe2+leads to maximal proline accumulation under Cd2+toxicity. Interestingly, proline level in seedlings raised under Cd2+toxicity in DW supplemented with Fe2+was similar to that recorded in seedlings raised in MGM. Our results convincingly demonstrated that Cd2+-induced iron deficiency promotes proline accumulation.
Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India. sharmila_ps@rediffmail.com.
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P
Sharmila
Amity Institute of Biotechnology, Amity University, Noida, 201303, UP, India.
P Kusuma
PK
Kumari
Department of Environmental Studies, University of Delhi, Delhi, 110007, India.
Kavita
K
Singh
Department of Botany, Sri Venkateswara College, University of Delhi, South Campus, New Delhi, 110021, India.
N V S R K
NV
Prasad
Department of Environmental Studies, University of Delhi, Delhi, 110007, India. ppsaradhi@gmail.com.
P
P
Pardha-Saradhi
D018533:Biomass; D002104:Cadmium / Q000633:toxicity*; D007501:Iron / Q000378:metabolism*; D009149:Mustard Plant / Q000033:anatomy & histology / Q000187:drug effects / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism; D011392:Proline / Q000378:metabolism*; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism
D045332:Photosystem II Protein Complex; D002104:Cadmium; D011392:Proline; D007501:Iron
Brassica juncea; Cadmium toxicity; Iron; Photosystem II; Proline