Resistant plant pests, climate change & Co: Our crops are facing major challenges. In order to arm them against this, information from gene banks of old varieties could be the key, as breeding experiments suggest. Biologists specifically crossed genes from old, rare wheat lines into modern high-yield varieties. The resulting wheat plants were subsequently resistant to a major pest and even outperformed modern elite strains.
Gene banks worldwide store the genetic information of countless species and thus make an important contribution to the preservation of biological diversity. The genomes of many old and exotic crops are stored there, for example, which are no longer used in the fields today. But these plants contain a veritable wealth of information: In times when drought and heat are affecting our crops and aggressive plant pathogens are developing resistance to pesticides, new varieties have to be developed that make wheat, barley & Co more resistant to climate change and pests and so we can secure our food supply.
It's the crossing that does it
This is possible because the old varieties stored in the gene banks have some valuable properties that have been lost in modern varieties, but which may be crucial for future crop production. But how can this treasure of biological diversity be developed for agriculture? Albert Schulthess from the Leibniz Institute for Plant Genetics and Crop Plant Research in Gatersleben and his colleagues investigated this question. To do this, they developed a strategy in which they crossed modern useful plants, so-called elite plants, with old varieties from the gene bank.
The aim of these crossing attempts was to maintain the high yields of modern crops, but still introduce the desired characteristics of the old varieties into the resulting plants. "This required a logistical masterstroke and many creative tricks from everyone involved in the project in order to evaluate the potential of the old varieties without disruptive effects," emphasizes Schulthess. Through their crossing tests, the team was finally able to test the extensive collection of old wheat varieties in the federal central ex-situ gene bank at the Leibniz Institute in the laboratory and in field trials for their yield and resistance to yellow rust.
Resistant and still productive
The performance of the resulting bridging lines from crossing promising, old varieties with modern wheat plants surprised the scientists: "We observed higher yields for some bridging lines than for important current elite varieties," reports Schulthess. The researchers were thus able to show that genes from old varieties can actually help make modern crops more efficient. "Through the comprehensive sequencing of old and new varieties, but also varieties not native to this country, in combination with the valuable field data, we were able to identify possible new gene variants for resistance to yellow rust," says Schulthess.
This allows a big step towards an agriculture with less or no use of pesticides. The immune system of the local wheat can therefore be enriched and made more diverse with the help of the newly discovered genome regions from the old plants. But there are still considerable challenges to be overcome before the resistance genes from the old varieties can be used in plant production. The resistance genes must be validated and inserted into the background of elite lines without disturbing existing cell mechanisms. Nevertheless, senior author Jochen Reif is convinced that the biodiversity of the elite pool can be increased by exploiting new valuable genetic variation of the bridge lines: "This is of great importance to tackle the huge problems that climate change poses to agriculture".
Source: Leibniz Institute for Plant Genetics and Crop Plant Research, Article: Nature Genetics, doi: 10.1038/s41588-022-01189-7