As we move to a warmer planet, animals are adapting by moving their preferred habitats. Every continent and region has reports of a bird or a frog or a fish that is now found in an area where it has never been seen before. Plants too are making habitat shifts, but their time scale is much slower.
Not such a bad thing if you are a forest tree, but if you are a farmer trying to grow a crop in hotter drier drought-prone, salt laden soils with a variety that is not salt-tolerant, temperature-tolerant or drought-resistant, then yields are low.
The standard option of plant breeding to select strains for these newly required traits is a slow one, and genetic manipulation in the laboratory to insert the requisite genes, although much faster, is expensive.
Excitingly, there appears to be a third technique to enable plants to thrive in hotter, saltier and drier times. University of Washington researchers have shown that repopulating the microbes associated with the plant roots with root microbes from a plant species that grows already in such adverse conditions can switch on pathways in the plant to enable it to survive and thrive where it once could not.
These symbiotic microbes provide nitrogen, phosphorus and other minerals to the plants as well as protect them from viruses in exchange for the plant providing them with nutrients derived from photosynthesis. When seeds of a grass that normally grew in the hot springs of Yellowstone were sterilised to remove the symbiotic root fungi, the plant could no longer grow at the hot temperature. Further when the fungus was isolated and fungal spores were sprayed on a variety of wheat seeds that could grow at 38 degrees the wheat could now grow at 70 degrees and needed 50 per cent less water to do so.
Rice sprayed with micro organisms from cold tolerant grasses and from salt tolerant grasses yielded 35 per cent more grain in salty and cold environments than the untreated rice control. The take home message for Australia, where salt will poison over 17 million hectares of Australian farmlands by the year 2050, is that the root microbiome may be the saviour of our future crops.
