This research project aims to develop wheat plants with improved, multiple and durable fungal tolerance through new breeding methods. This is reflected in the project name: Fungal tolerance of wheat by new breeding methods (“Pilztoleranz von Weizen mittels neuer Züchtungsmethoden” = PILTON).
New breeding methods are said to have great potential to shorten the development of plant varieties with improved characteristics for resource-efficient and productive agriculture. The project will investigate how fungus-tolerant wheat can significantly reduce the use of plant protection products. In addition, the project will also address the question of how currently available genome editing technologies, such as CRISPR/Cas, can be used by small and medium-sized plant breeding companies in particular in view of existing property rights.
You can find out more about the PILTON project in our flyer.
Right: Wheat leaf with fungal infestation
This research project aims to develop wheat plants with improved, multiple and durable fungal tolerance through new breeding methods. This is reflected in the project name: Fungal tolerance of wheat by new breeding methods (“Pilztoleranz von Weizen mittels neuer Züchtungsmethoden” = PILTON).
New breeding methods are said to have great potential to shorten the development of plant varieties with improved characteristics for resource-efficient and productive agriculture. The project will investigate how fungus-tolerant wheat can significantly reduce the use of plant protection products. In addition, the project will also address the question of how currently available genome editing technologies, such as CRISPR/Cas, can be used by small and medium-sized plant breeding companies in particular in view of existing property rights.
You can find out more about the PILTON project in our flyer.
The PILTON project is accompanied by the German Plant Breeders Association (Verband Deutscher Pflanzenzüchter = BDP). The basics and background of the research project are explained in the introductory film.
Continuous video updates will document the progress and results of the project.
The BDP press release on the project launch can be found here.
Dr. Dietmar Stahl, scientific director of the Pilton project, explains the current status in the video.
The expert interviews provide a deeper insight into the topic of genome editing and plant breeding.
Scientific, breeding and legal issues are examined.
About the first tests of susceptibility to fungal pathogens.
Plant breeder Dr. Stefan Streng on breeding, CRISPR and the benefits of new breeding methods.
CRISPR stands for “Clustered Regularly Interspaced Short Palindromic Repeats” These repeats were first discovered in bacteria and are part of the natural bacterial immune system that bacteria use to protect themselves against viruses.
Just like humans, bacteria can be attacked by viruses (so-called phages) and have developed sophisticated defenses against such an attack. When a phage docks on a bacterial cell and injects its genetic material, part of this viral genetic material is incorporated into the bacterial DNA as so-called spacers (hence the “interspaced” in CRISPR) (i. e., in the palindromic repeats). When the bacteria re-infect, these incorporated pieces allow them to identify and specifically cut the viral DNA to stop infection. This system is therefore something like a genetic memory of the bacterium.
Scientists have discovered that this mechanism can also be transferred to other organisms and can thus be used as a genome editing tool in plant breeding to recognise and cut DNA.
To find out exactly what palindromes are and how bacteria use CRISPR in combination with a protein to fight viruses, read on:
Cas9 is one of the proteins (endonucleases) that interact with the bacterial immune system CRISPR (Cas = CRISPR associated) and is used for genome editing.
Cas9 uses an RNA molecule to find a complementary DNA sequence. The complementary DNA sequence can be selected so that it occurs only once in the entire genome. Once this target DNA is identified, Cas9 cuts both DNA strands.
This precise cutting has led to the CRISPR technology being referred to as “molecular scissors” or “scalpel”. Many other endonucleases, such as Cpf1, are now available to scientists and breeders with a wide range of properties.
A CRISPR system with characteristics different from Cas9.
Like Cas9, Cpf1 is an endonuclease and also functions as a “molecular scissor”. However, it is smaller than Cas9, which facilitates its release into cells and tissues. And it cuts the DNA strands in a staggered fashion, leaving short overhangs at the exposed ends. Cpf1 is also referred to as Cas12a. Both terms refer to the same endonuclease.
In addition to Cas9 and Cpf1, there are many other nucleases used in CRISPR systems. Another variant is the MAD7 nuclease, which has other specific properties. The selection of the endonuclease usually depends on the objective.
In July 2018 (case C-528/16), the European Court of Justice (ECJ) generally classified plants from new breeding methods as genetically modified organisms (GMOs), irrespective of the type of modification. According to this ruling, all plants produced using methods of targeted mutagenesis, such as genome editing, shall be approved as GMOs in future and are subject to the strict requirements of genetic engineering law with regard to monitoring, labelling and traceability.
Genetic modifications such as those obtained by targeted mutagenesis can also result from natural processes or conventional breeding methods. As a result of the ECJ ruling, plants with identical characteristics and identical genetic make-up are assessed differently, solely on the basis of the method used in breeding.
Experimental releases (also known as field trials) of genetically modified plants must be approved by the competent authority before being sown. Following the ruling of the European Court of Justice (ECJ) in July 2018, this shall also apply to plants that have been bred using new breeding methods.
Release trials are necessary to test and compare the properties of the plants in the field under real environmental conditions. In a release experiment, preventive isolation measures are taken to minimise the spread of the test plants. The application documents are submitted to the competent federal authority, the Federal Office of Consumer Protection and Food Safety (BVL). The BVL then examines the project in consultation with the Federal Agency for Nature Conservation (BfN), the Federal Institute for Risk Assessment (BfR) and the Robert Koch Institute (RKI) and decides on a release. The Julius Kühn Institute – Federal Research Centre for Cultivated Plants (JKI), the Central Commission for Biological Safety (ZKBS) and the competent authority of the respective federal state then issue their opinions. The approval of the release may be subject to additional conditions and always refers to a defined duration and a defined location, which is listed in a public register.
A fungicide is a plant protection product which kills fungi and/or their spores harmful to plants and/or prevents their growth for the time of its activity. Fungicides are used as soon as it becomes apparent that the crop is affected by a fungal disease.
The main fungi affecting wheat are leaf rust, strip rust, septoria and fusarium.
Gene expression is the process by which the cell activates and reads a specific information stored in the genetic material (DNA). The most common result of this process is the production of a specific protein. To do this, the cell interprets the genetic code and adds one of 20 different amino acids for each group of three letters. The amino acids are the basic units needed to build proteins. This process can be specifically modified, for example by reducing gene expression.
Genome editing is the name given to a group of new breeding technologies that scientists can use to modify the DNA of an organism. These changes in the DNA sequence can be single base exchanges (as they can occur naturally) or the removal or insertion of genetic material. The best known of these technologies is called “CRISPR”, which stands for “Clustered Regularly Interspaced Short Palindromic Repeats”. The basis of CRISPR technology is a natural system that uses bacteria to protect against viruses.
With CRISPR technology, changes in the genome can be made more precisely and easily than with previous methods.
Just like us humans, plants are attacked by bacteria, viruses and fungi, and they have developed defence mechanisms to defend themselves against these pests. Even if they have no antibodies against pests, they can use immune receptors to recognise pathogens on their surface and then take specific defensive measures (for example, closing their stomata or strengthening the cell walls).
A permanent alteration of the genetic material. Mutations can occur spontaneously or be caused by external influences of mutagens such as radioactive radiation or chemicals. The change can be small (individual base pair exchanges, see also definition of “sequencing”), involve thousands of base pairs (insertions, deletions, translocations) or can affect entire chromosomes.
In breeding, people have for a long time deliberately created mutations in the genome of plants to create new variability in the genome, which can then produce new characteristics.
This term covers new methods of plant breeding that create very precise changes and variability in plants. This precision and efficiency distinguishes them from conventional breeding methods such as random mutagenesis using chemicals or radioactive radiation.
Examples of these methods are cisgenesis, agro-infiltration and the methods for targeted mutagenesis such as CRISPR, TALEN and zinc finger nuclease (ZFN).
Humans started changing plants more than 10,000 years ago. The aim of any plant breeding is to genetically modify plants in such a way that they are better adapted to the demands that humans make on them.
In cross-breeding, the breeder deliberately selects plants with the desired characteristics and crosses them with each other. The next generation resulting from this crossing is propagated and then further selected for the desired trait. This process is continued until a new variety with improved properties is finally produced.
Over time, depending on the crop, numerous breeding methods have developed, such as clone breeding (e.g. potato, apple, sugar cane), line breeding (e.g. cereals such as wheat), hybrid breeding (e.g. sugar beet, rape, maize) and population breeding (e.g. cabbage).
A repressor is a protein that negatively regulates the expression of one or more genes, i.e. usually suppresses expression. The repressor protein binds to the promoter region of the gene and thus prevents the production of messenger RNA (mRNA).
When DNA is sequenced, the sequence of the four DNA building blocks is determined by means of chemical analysis methods. The DNA building blocks are called bases. From the sequence, scientists can use computer models to determine the type of genetic information contained in a particular segment of DNA.
For example, scientists can use sequence information to determine which DNA segments contain genes or have regulatory functions.
A fungus-tolerant wheat variety can be infected by fungi such as leaf rust, strip rust, Septoria or Fusarium. However, the plant is so robust that there is no complete loss of vitality or atrophy of the ears, resulting in a significant loss of yield.
Common wheat (Triticum aestivum L.) is the most widespread crop on earth and is one of the most important protein resources. However, compared to other crops, the genome of wheat is large and extremely complicated, as it consists of three sub-genomes.
Website of the international consortium on the sequencing of the wheat genome
