Transgenic Spartina alterniflora for phytoremediation.

Area of Science:

• Environmental science
• Plant biotechnology
• Bioremediation

Background:

• Perennial grasses are crucial natural remediators of pollutants.
• Genetic modification can significantly enhance the pollutant remediation potential of grasses.
• Salt marsh cordgrass (Spartina alterniflora) is ecologically vital for coastal protection and nutrient cycling.

Purpose of the Study:

• To genetically engineer Spartina alterniflora for enhanced mercury phytoremediation.
• To co-introduce the organomercurial lyase (merB) and mercuric reductase (merA) genes into S. alterniflora.
• To assess the transformation efficiency and mercury resistance of the engineered plants.

Main Methods:

• Co-inoculation of S. alterniflora embryogenic callus with two Agrobacterium strains carrying merA and merB genes.
• Selection of geneticin resistant transgenic lines.
• Verification of transgene presence using PCR and Southern blotting.
• Analysis of transgene expression via Northern blotting.
• Assessment of mercury resistance (HgCl2 and PMA) in transgenic lines.

Main Results:

• Seven stable transgenic S. alterniflora lines were recovered.
• Co-introduction of both merA and merB genes from separate Agrobacterium strains was feasible.
• Transgenic lines showed varying levels of merA and merB gene expression.
• Significant mercury resistance was observed, with Line #7 highly resistant to HgCl2 and Line #3 to PMA.
• Wild-type callus exhibited sensitivity to mercury compounds at lower concentrations.

Conclusions:

• Co-introduction of two separate genes into S. alterniflora using Agrobacterium is effective for enhancing mercury phytoremediation.
• Engineered S. alterniflora demonstrates improved tolerance and remediation potential for mercury pollutants.
• This genetic improvement holds promise for bioremediation strategies in salt marsh ecosystems.