Full Length Research Paper

Application of inter simple sequence repeat (ISSR marker) to detect genotoxic effect of heavy metals on Eruca sativa (L.)

Fahad Al-Qurainy

Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia, 11451. E -mail: fahad_alqurainy@yahoo.com. Tel: 00966555234564. Fax: 009664678301.

Accepted 17 November, 2009

   Abstract

As an influence of the Mediterranean diet, Eruca sativa (rocket salad) is eaten all over the world in salads and soups. It belongs to plant order Capparales (glucosinolate-containing species) and it is from the family Brassicaceae. Predominantly, the leaves of this species is eaten raw or cooked, although flowers are also consumed. Assessment of environmental contamination on ecology (plant) at molecular and population levels is important in risk quantification and remediation study. Heavy metal toxicity in plants is to induce oxidative stress linked to oxidation of proteins and membrane lipids but also to alterations of DNA damage response. E. sativa has been investigated in our study which is of agronomical importance and widely used in European countries. We studied three heavy metals Zn, Pb and Cd which showed a dose-dependent effect on radicle and coleoptile lengths of E. sativa. The radicle length was more affected than the coleoptiles length under all concentration tested plant. The ranking of genotoxic potencies in all three heavy metals was in the descending order: Cd²⁺ > Pb²⁺ ≥ Zn²⁺. Among these heavy metals, high concentration of Cd (150 mg/l) and Pb (150 mg/l) generated mutations along with changed morphology of seedlings. The radicle and coleoptile lengths (cm) under high concentration of Cd were decreased as compared to low, medium and high concentrations treated seedlings with Pb and Zn. 20 ISSR primers were used, of which four did not amplify, three gave single band and the rest of thirteen primers generated upto six bands (an average of 4 bands per primer). Sixteen primers exhibiting amplified products gave monomorphic; only two primers (OPC-5 and OPC-7) gave unique extra band in seedlings treated with medium and high concentrations of heavy metals Cd and Pb, respectively. The dendrogram was constructed to evaluate the genetic distance generated among the seedling treated with various heavy metals at various concentrations. The similarity matrix values were found from 42.8 to 100% and these values showed the genetic divergence among the seedlings treated with various concentrations of heavy metals.

Key words: Bioindicator, environmental pollutant, genetic diversity, mutation.