Physical, chemical and biological mutagenic agents cause genes to mutate at rates above the spontaneous baseline, thus producing a range of novel traits and broadening the genetic diversity of plants. The use of induced mutants in breeding has had a profound impact on world agriculture and more than 2300 new crop varieties, all carrying novel induced variation, have now been officially registered (IAEA Mutant Variety Database). This has all been achieved largely in the absence of knowledge of the precise changes induced at the DNA level. Indeed there still is very little understanding of the nature of the mutations induced by different mutagens. With the advent of molecular genetics and genomics, induced mutations are finding new applications in modern plant breeding. Reverse genetics and deletion library methodologies capable of discovering new genes and their modes of action are often underpinned by variation induced by both physical and chemical mutagens. However the efficiency of these new methods will be enhanced only when the type, frequency and distribution of mutations in a range of crop species can be predicted, and ideally directed.
Today, with the range of technologies available to the scientific community to assay variation in DNA sequence and the availability of a vast amount of crop plant DNA sequence, including the complete sequences of both Arabidopsis and rice, these questions can now be approached. This Coordinated Research Project sets out to define the type, frequency and patterns of molecular changes induced by the range of physical and chemical mutagens in a range of crop species.
This Coordinated Research Project aimed to understand the mechanism of mutation induction in plants and to quantify the types (base pair changes or deletions), frequencies (rates of change relative to mutagens dose) and patterns (induction of changes in different parts of the genome) of changes in DNA induced by a range of physical and chemical mutagens in a range of key crop plant species. Knowledge obtained is bound to assist Member States in enhancing crop breeding programmes through the application of targeted induced mutations, complementary genomic approaches and knowledge for the identification and selection of mutants of specific genes with the objective of increasing agricultural sustainability, food security and economic stability.
1) Measure the microscopic characteristics of the spontaneous and induced mutation process at the molecular level using nucleic acid scanning methodologies at the whole genome/transcriptome level and mutation trap assays.
2) Determine the existence of mutation-induced heterogeneities.
3) Test if mutations are constrained by the structure of nucleic acids.
4) Assay the effect of different doses of physical and chemical mutagens
5) Compare different physical and chemical mutagens at equivalent doses
6) Develop a knowledge base for enlightened use and application of mutation induction, including the descriptions and definitions of
a) levels of DNA damage
b) effects of repair systems in plants following mutagenic treatment
c) types, frequencies, rates and patterns of molecular change
induced by the range of physical and chemical mutagens for use in crop plant breeding,
relative to background spontaneous mutation.
7) An up-to-date review of the present understanding of the mechanisms involved in and the effects of mutation induction in plants
• Enhancement of capacity in techniques to generate and analyse mutant germplasm in developing countries .
• Guidance tools on the use of appropriate mutagens to achieve mutation breeding objectives developed.
• Development of a repository of knowledge on mutagens and their efficacy.
• Two rice varieties suitable for diabetics and obesity patients commercialized.
• Mutant lines tolerant to postharvest physiological deterioration (PPD) in cassava identified.
• Drought tolerant soybean variants characterized
1) Provide guidelines to Member States for the informed application of induced mutation to crop improvement;
2) Characterize DNA damage, repair mechanisms and types of lesions in plants induced by treatment with physical and chemical mutagens.
3) Promote efficient and safer crop improvement by defining thresholds for environmental protection;
4) Produce and communicate research results that enhance the quality and relevance of mutation breeding;
5) Foster implementation regional collaboration, knowledge transfer, technology, and genetic and molecular resources between all participating research groups for their mutual benefit;
6) To produce guidelines and publish methods on the application induced mutations to various crops.
7) Contribute to the development of enhanced germplasm with traits that are essential for crop breeding programmes in developing countries;