Gupta Meetu, Sharma Pallavi, Sarin Neera Bhalla, Sinha Alok Krishna
Department of Biosciences, Jamia Millia Islamia, Maulana Mohammad Ali Jouhar Marg, Jamia Nagar, New Delhi-110025, India.
Chemosphere. 2009 Mar;74(9):1201-8. doi: 10.1016/j.chemosphere.2008.11.023. Epub 2008 Dec 19.
Present study showed the toxicity caused by Arsenite (As(III)) and its detoxification responses in two varieties (Varuna and Pusa Bold) of Brassica juncea. Comparisons were made in leaves and roots of both the varieties, which showed that the accumulation pattern in both the varieties were dose and duration dependent, being more in roots for two days and in leaves for four days. Increase/decrease of antioxidant enzymes activities (SOD, CAT, GPX) showed not much changes at the given concentrations except that the enzyme activities showed significant increase at the lower concentrations. Semi quantitative RT-PCR analysis of PCS showed more expression of its transcript in P. Bold as compared to Varuna variety due to As(III) stress. The analysis of isoenzyme pattern in leaves of P. Bold showed five and two major bands of SOD and GPX, respectively. As(III) treatment leads to the activation of MAPK activity indicating role of this important cascade in transducing As(III) mediated signals. The data presented indicates the differential responses in both the varieties and also that the increased tolerance in P. Bold may be due to the defensive role of antioxidant enzymes, induction of MAPK and up regulation of PCS transcript which is responsible for the production of metal binding peptides.
目前的研究表明了亚砷酸盐（As(III)）对芥菜两个品种（Varuna和Pusa Bold）造成的毒性及其解毒反应。对两个品种的叶片和根部进行了比较，结果表明两个品种中的积累模式均取决于剂量和持续时间，在两天内根部积累更多，四天内叶片积累更多。抗氧化酶活性（超氧化物歧化酶、过氧化氢酶、谷胱甘肽过氧化物酶）的增加/减少在给定浓度下变化不大，只是在较低浓度下酶活性显著增加。PCS的半定量逆转录聚合酶链反应分析表明，由于As(III)胁迫，与Varuna品种相比，其转录本在P. Bold中的表达更多。对P. Bold叶片同工酶模式的分析表明，超氧化物歧化酶和谷胱甘肽过氧化物酶分别有五条和两条主要条带。As(III)处理导致丝裂原活化蛋白激酶活性的激活，表明这一重要级联在转导As(III)介导的信号中的作用。所呈现的数据表明了两个品种中的差异反应，并且P. Bold中耐受性的增加可能归因于抗氧化酶的防御作用、丝裂原活化蛋白激酶的诱导以及负责金属结合肽产生的PCS转录本的上调。
