Phytoremediation

What are the four types of phytoremediation?

Photo extraction, phytodegradation, phytovolitisation, phytostabilisation

Why are heavy metals toxic?

They attach to sulphydryl groups of proteins, inhibiting or changing structure

They cause ROS and free radicals that can cause oxidative stress to cells (like corals)

They can displace essential elements and cause deficiencies

Why are plants good at up taking contaminants?

They are able to sense, transport and release essential metals whilst detoxifying metalloids and non-essential metals

What is the gene with potential for phytoremediation?

HMA4 - overexpressing the gene results in accumulation of zinc and cadmium in the leaves, ideal as leaves can be removed and grow again without removing whole plant (hyperaccumulators tend to store metals in shoots)

what is cadmium removed with in plants?

Phytochelatins, proteins which have sulphydryl groups and allows attachment of cadmium. It is then transported to vacuoles

What enzyme makes phytochelatin?

Phytochelatin synthase - there have been opposing results for over expressing this. Some say it’s good for metal uptake, others don’t

What is the reduction based strategy for iron uptake?

H+ ions moved into apoplast, reduction in pH increases solubility of Fe(3)

Fe (3) converted to Fe(2) with Fe(3) chelate reductase

Fe(2) transported to root by IRT1 transporter

What is chelation based strategy 2?

Tom 1 transporter releases PS

PS binds to Fe3 to create Fe3PS complex

Transported into symplasm with YSL transporter

What drives plant biotechnology?

• Phytoremediation

• Fertiliser concerns

• Synthesis of chemicals for medicine and other needs

• Answering biological questions

• Crop production efficiency

What is the malarial drug from sweet wormwood?

Artemisinin

Why is artemisinin anti malarial?

It forms bonds to malarial proteins, prevents digestion of haemoglobin

Issues with artemisinin

High cost but low yield - only 1% dry weight in leaf tissues

BUT there is potential for improvement

How can artemisinin production be improved?

Increased biomass, increased trichome count, increased production of artemisinin from the trichomes

How can the artemisinin pathway be modified to increase production?

Trichomes produce more than one metabolite, by removing this second pathway the production of artemisinin may be increased to compensate for the lack of the other

How was flavr savr tomatoes made?

downregulation of the gene creating polygalacturonase,(which shortens pectin in tomato cell walls and causes softening) reduced the activity of this enzyme to 1%

This kept tomatoes firm during transport and reduced waste. It also didn’t reduce flavour and reduced price too as didn’t have to be heat treated