Triticale grain is very important as a feed grain. It is also gaining attention as a potential energy crop – triticale grain eventually could be used to produce bioethanol. One of the advantages of triticale is its resistance to various diseases. However, some years ago it was resistant to fungal disease called mildew, but now it is not anymore. Scientists from the University of Zurich now demonstrated that this new fungal threat to the triticale is actually a genetic mix of existing mildew forms.
Resistance to fungal diseases was a big advantage of cultivating triticale since 1960s. It is a cross between wheat and rye, and, for example, when fungus can reduce the harvest of wheat by up to 45%, triticale is largely resistant to such diseases. Or at least it has been, because in 2001 fields of this grain has been infected by mildew for the first time. Now scientists managed to answer the question how did the fungus managed to spread to triticale.
Researches collected samples from different places in Europe in order to investigate genetic information of this fungus. They compared genome of the pathogens that attack triticale, rye and wheat and found that the new triticale fungus is a hybrid of the variants specialized in wheat and rye. In fact, scientists even managed to trace the exact proportion, noting that 12.5% of the genome comes from fungus attacking rye, and from 87.5% attacking wheat. This means that mildew underwent evolution in order to attack the triticale.
Study showed how the mildew can adapt to new host plants in a co-evolutionary way and eventually breaks down their resistance. This is not a unique phenomenon. In fact, it happens all the time. Thousands of years ago bread wheat was resistant to the mildew. Thomas Wicker, one of the authors of the study, said: “These results are of major significance for treating and preventing plant diseases. The more we know about the evolutionary mechanisms of mildew, the better we can keep new cultivated plants resistant to the pathogens”.
Little examples like this show how minute forms of life adapt themselves rather rapidly to new environmental conditions. Now scientists can start figuring out the ways to make triticale more resistant or at least can imagine future evolution scenarios of this fungus better.