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Clock gene could strengthen brassicas


American researchers from Dartmouth College in New Hampshire have identified a circadian clock gene in field mustard (Brassica rapa), which they say could help other brassica crops withstand extreme cold and salty conditions.

The circadian clock coordinates the timing of many aspects of plant growth and performance. The researchers identified a gene called GIGANTEA as being responsible for natural variation in the circadian clock in field mustard. Specifically, they identified the nucleotide (individual letter in the DNA encoding GIGANTEA) responsible for this alteration in circadian clock function. The researchers showed that different versions of the GIGANTEA gene affect many aspects of plant performance, including flowering timing, seedling development and resistance to environmental stresses like extreme cold and high salt.

One strategy to increase yield in the face of global population growth is to identify genetic variation in plant regulatory networks that limit yield in order to define targets for molecular breeding. One such target is the circadian clock, which affects influences plant development in both natural and cultivated settings.

“Our results show that different forms of the GIGANTEA gene can affect many aspects of plant performance, so our findings will enable plant breeders to select for improved stress tolerance or improved flowering characteristics by deliberately choosing a specific form of the GIGANTEA gene,” said senior author Rob McClung, a professor of biological sciences at Dartmouth. “We propose that our results can be generalized to other crops: Natural variation of clock genes in general offers an attractive target for breeders to develop crops with enhanced stress tolerance and improved yield.”