Some plant species have ingenious ways to survive floods. These plants prevent themselves from suffocating by temporarily producing energy without needing oxygen. In the 23 October issue of Nature, an international team including researchers from Utrecht University describe how a plant knows it is submerged. The new insights offer interesting leads for making agricultural crops less vulnerable to floods.
In addition to carbon dioxide, plants need oxygen for their energy supply. Consequently, many agricultural crops perish within a few days of flooding or torrential rains. However, some plant species can temporarily cope with this oxygen deficit. Up to now nobody knew how these plants are aware of the fact that they are submerged.
Energy from alcohol production
Plant biologists from the Netherlands, Italy and Germany discovered that one specific protein in the model plant species Arabidopsis thaliana immediately takes action in the event of oxygen deficiency. Imminent suffocation induces this protein RAP2.12 to detach itself from the cell membrane after which the plant's alcohol production is activated. That makes these plant cells capable of producing some energy despite the low oxygen levels due to flooding. When the suffocation risk is over, the proteins are broken down at once and the alcohol fermentation stops.
Different chances of survival
The results provide new insights into the divergent chances of survival for plant species in flood-prone environments. "We have found for instance that marsh dock, which can survive under water for months, has a lot of proteins that detect oxygen deficiency," says Professor Rens Voesenek of Utrecht University. "Common sorrel on the other hand, has relatively low quantities of these proteins so it already starts to rot after being flooded for just a few days."
Identifying this oxygen sensing mechanism in plants is a major step in breeding agricultural crops with increased resistance against water problems. “The increasing water problems caused by climate change make it ever more important to grow stronger crops”, Voesenek states. “I anticipate that within a few years of clever selection and crossbreeding, we will have potatoes that survive twice as long in torrential rains.”
Oxygen sensing in plants is mediated by an N-end rule pathway for protein destabilisation, Francesco Licause, et al., Nature, 23 October 2011
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