Strains of drought-resistant GM plants to preserve crop yields and combat the effects of climate change have been announced by US scientists...

The experimental tobacco plants created by UC Davis researcher Eduardo Blumwald and his colleagues grew normally under ideal conditions, could still grow well when given only a fraction of their normal requirements and were even able to tolerate 15 days without water altogether.  Unmodified "control" tobacco exposed to the same conditions, however, all died. 

The team created the plants by blocking a process known as "leaf senescence" in which plants artifically age and drop their leaves in order to reduce their leaf area and hence their water requirements. 

Whilst this can help to preserve the growing cycle of the plant it reduces the yield of an annual crop.  So to prevent this from occurring the researchers used genetic techniques to switch on a gene called IPT - isopentenyltransferase - whenever and wherever the plant tissues became stressed by a lack of water. 

IPT boosts the production of a growth-related gene called cytokinin (CK), which helps to protect leaves against the effects of water shortage.

Encouragingly, the transgenic crops continued to grow well under conditions of severe water restriction.  Grown side by side with unmodified control plants and given only a third (0.3 litres) of their normal water requirement for 4 months to simulate a prolonged dry spell, the modified plants dropped their yield by only 8-14% compared with a 60% loss of yield for the unmodified plants.

The team hope that their results could be used to produce low-water tolerant crops that could be used to make arid-land more productive, or enable farmers to save irrigation water whilst maintaining higher crop yields.


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