[en] Phytic acid (PA, myo-inositol 1,2,3,4,5,6-hexakisphosphate) is an important anti-nutritional component in cereal and legume grains. PA forms of phosphorus (P) and its salts with micronutrient cations, such as iron and zinc, are indigestible in humans and non-ruminant animals, and hence could affect food/feed nutritional value and cause P pollution of ground water from animal waste. We previously developed a set of low phytic acid (LPA) rice mutants with the aim to increase their nutritional quality. Among them, one line, i.e., Os-lpa -XQZ-1 (hereafter lpa 1-2), was identified to have a mutation allelic to the KBNT lpa 1-1 mutation (hereafter lpa 1-1), which was already delimited to a 47-kb region on chromosome 2. In this study, we searched the candidate gene for these two allelic LPA mutations using T-DNA insertion mutants, mutation detection by CEL I facilitated mismatch cleavage, and gene sequencing. The TIGR locus LOC_Os02g57400 was revealed as the candidate gene hosting these two mutations. Sequence analysis showed that the lpa 1-1 is a single base pair substitution mutation, while lpa 1-2 involves a 1,475-bp fragment deletion. A CAPS marker (LPA1_CAPS) was developed for distinguishing the lpa 1-1 allele from lpa 1-2 and WT alleles, and InDel marker (LPA1_InDel) was developed for differentiating the lpa 1-2 allele from lpa 1-1 and WT ones. Analysis of two populations derived from the two mutants with wild-type varieties confirmed the complete co-segregation of these two markers and LPA phenotype. The LOC_Os02g57400 is predicted to encode, through alternative splicing, four possible proteins that are homologous to the 2-phosphoglycerate kinase reported in hyperthermophilic and thermophilic bacteria. The identification of the LPA gene and development of allele-specific markers are of importance not only for breeding LPA varieties, but also for advancing genetics and genomics of phytic acid biosynthesis in rice and other plant species. (author)

[en] Induced crop mutation strategies have, since the seminal article of Stadler (1928), in the past over 50 years played a major role in the development of superior crop varieties. With over 2700 officially released crop mutants in more than 170 plant species, translating into a tremendous economic impact valued in billions of dollars and tens of millions of cultivated hectares. The Joint FAO/IAEA Programme has for over 40 years been promoting the efficient use of mutation techniques as a complementary tool for developing superior crop varieties. The Joint FAO/IAEA Programme through research coordination provides a global platform for scientists to work on common induced crop mutagenesis related themes. Through the Technical Cooperation Project mechanism of the IAEA, direct technical input and guidance have been provided to scientists, especially in the Least Developed Countries (LDC) of the world and have contributed immensely to capacity building and the development of mutant crop varieties that address specific production constraints. The Joint FAO/IAEA Programme has a training, service and research and development (R and D) unit dedicated exclusively to induced crop mutagenesis at the IAEA Laboratories in Seibersdorf, Austria. In addition to the traditional roles of supporting capacity building in LDC member states of both FAO and IAEA, the R and D activities of this laboratory component addresses the enhancement of the efficiency of processes related to induced crop mutagenesis. This paper while presenting an overview of the contributions of induced mutagenesis to sustainable agricultural productivity also posits that the technology has great potentials for adding value to high yielding, stable crop varieties through the development of hardy variants that being adaptable to extreme abiotic stresses are important for addressing the constraints of climate change. Also, through the subtle modification of quality traits in otherwise good varieties, induced crop mutants enrich the crop germplasm useful for mitigating micronutrient deficiencies and meeting the requirements of niche industries. We also present the status of work on the use of a suite of integrated bio-/molecular technologies in enhancing the efficiency levels of induced crop mutagenesis. The paper highlights the central role of cellular biology in the rapid production of histonts as well as the innovative adaptation of the reverse genetics technology, Targeting Induced Local Lesions IN Genomes (TILLING) as a methodology for the high throughput detection of mutation events and hence significant reductions in the sizes of mutant populations for field trials. Reports on TILLING will include progress on the development of platforms for under-researched vegetative crops like banana and cassava. Perspectives for the future direction for the application of induced crop mutagenesis both as crop improvement and functional genomics tools are also provided. (author)

[en] The International Symposium on Induced Mutations in Plants was held from 12-15 August, 2008 at the Vienna International Centre. Almost 500 participants, more than half of them from developing countries, attended the Symposium. Nine international organizations and 82 member countries, among these 60 developing countries, were represented at the Symposium. The Symposium was opened by IAEA's Dr. W. Burkart, Deputy Director General, Department of Nuclear Sciences and Applications. Dr. S. Pandey, Director, delivered opening remarks on behalf of the Food and Agriculture Organization of the United Nations. Also in the opening session, Professor R. Phillips (USA), Vice President of the International Crop Science Society, delivered a keynote address on 'Expanding the Boundaries of Gene Variation for Crop Improvement', and Dr. P.J.L. Lagoda, Head of the Plant Breeding and Genetics Section in the IAEA, introduced the role of the Joint FAO/IAEA Programme on Nuclear Techniques in Food and Agriculture in networking and fostering of cooperation in plant mutation genetics and breeding. Dr. T. Ishige, President of the Japanese National Institute of Agrobiological Sciences summarized the opportunities and the way forward for plant mutagenesis in the genomics era, and Dr. A.M. Cetto, Deputy Director General of the Department of Technical Cooperation in the IAEA, officially closed the Symposium after highlighting the role of technical cooperation in promoting the use of mutation techniques in Member States. Apart from opening and closing session, the Symposium was organized into two Plenary Sessions, 10 Concurrent Sessions, and one Workshop. Four hundred twenty-four abstracts were submitted for the Symposium - out of these, 129 papers were selected for oral presentation (including invited talks) and 184 for poster presentation. The Symposium was organized by the International Atomic Energy Agency (IAEA) and the Food and Agriculture Organization (FAO) of the United Nations through the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture. The great cooperation and support of the following organizations contributed to the success of the Symposium and is highly commended: Bhabha Atomic Research Centre (BARC, India); Chinese Society of Agricultural Biotechnology, European Association for Research and Plant Breeding, Indian Society of Genetics and Plant Breeding, and National Institute of Agrobiological Sciences (Japan). Overview of topics of the Symposium. The year 2008 marked the 80th anniversary of mutation induction in crop plants. Although induction of mutations had often been considered as accidental for a long time since it was discovered, it has been globally explored and has significantly contributed to increased agricultural production over the past half century. During the past 10 years, more and more molecular biological studies have proven that mutations are not mere 'accidents', but that they could be deliberately induced, using various methods. Meanwhile, induced mutations have become more and more useful and important in modern genetic studies, such as gene discovery and function elucidation. By integrating molecular techniques, such as high throughput mutation screening techniques, induced mutations are now widely expected to play an even greater role in plant improvement than ever before. Progress in all those fields was repeatedly reported by various groups at the Symposium, which not only demonstrated the recent renaissance of mutation techniques but also outlined a bright future for these classic techniques

[en] The advance in molecular genetics and DNA technologies has brought plant breeding including mutation breeding into a molecular era. With the ever increasing molecular genetics and genomics knowledge and rapidly emerging molecular techniques, breeders can now more wisely and efficiently than ever before using mutation techniques in breeding new varieties. Plant molecular mutation breeding is here defined as mutation breeding in which molecular or genomic information and tools are used in the development of breeding strategies, in the screening, selection and verifying of induced mutants, and in the utilization of mutated genes in the breeding process. It is built upon the science of DNA damage, repair and mutagenesis, plant molecular genetics and genomics of important agronomic traits as well as induced mutations. Mutagenic treatment, super-mutable genetic lines, molecular markers and high throughput DNA technologies for mutation screening such as TILLING (Targeting Induced Limited Lesions IN Genomes) are the key techniques and resources in molecular mutation breeding. Molecular mutation breeding will significantly increase both the efficiency and efficacy of mutation techniques in crop breeding. A perspective molecular mutation breeding scheme is proposed for discussion. (author)

[en] The year 2008 marks the 80th anniversary of mutation induction in plants. The application of mutation techniques, i.e. Gamma-rays and other physical and chemical mutagens, has generated a vast amount of genetic variability and has played a significant role in plant breeding and genetic studies. The widespread use of induced mutants in plant breeding programmes throughout the world has led to the official release of more than 2,700 plant mutant varieties. A large number of these varieties (including cereals, pulses, oil, root and tuber crops, and ornamentals) have been released in developing countries, resulting in enormous positive economic impacts. During the last decade, with the unfolding of new biological fields such as genomics and functional genomics, bioinformatics, and the development of new technologies based on these sciences, there has been an increased interest in induced mutations within the scientific community. Induced mutations are now widely used for developing improved crop varieties and for the discovery of genes, controlling important traits and understanding the functions and mechanisms of actions of these genes. Progress is also being made in deciphering the biological nature of DNA damage, repair and mutagenesis. To this end, the International Symposium on Induced Mutations in Plants was organized by the International Atomic Energy Agency (IAEA) and the Food and Agriculture Organization (FAO) of the United Nations through the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture. The Symposium comprised an open session, two plenary sessions and ten concurrent sessions, covering topics from induced mutations in food and agriculture, plant mutagenesis, genetic diversity, biofortification, abiotic stress tolerance and adaptation to climate changes, crop quality and nutrition, seed and vegetatively propagated plants, gene discovery and functional genomics. A workshop on low phytate rice breeding was also organized. About 500 participants from 82 Member States of the IAEA and FAO, and nine international organizations/institutions attended the Symposium, with a good balance between the private and public sector, as well as developing and developed Member States. The Symposium received valuable assistance from the cooperating organizations and generous support from the private sector, for which the sponsoring organizations are most grateful. This publication is a compilation of peer-reviewed full papers contributed by participants. They were either oral or poster presentations given in different sessions. These papers not only provide valuable information on the recent development in various fields related to induced mutations, but also on the social and economic impact of mutant varieties worldwide. Therefore, these Proceedings should be an excellent reference book for researchers, students and policy makers for understanding applications of induced mutations in crop improvement and biological research.

[en] Gelatinization temperature (GT) is an important cooking quality character of rice grains. Low GT rice is preferred for easy cooking with less energy intake. The physical-chemical properties of a low GT mutant, induced by gamma irradiation, were investigated through molecular mapping. The gene controlling the GT was identified to be located on chromosome 6. Through candidate gene sequencing and expression analysis, the GT gene was identified to be the SSIIa gene, which affects GT through amylopectin structure. The GC/TT_2340-41 SNPs of SSIIa gene, which results in a Leu to Phe change, appeared to be the causative factor of the reduced SSIIa activity. Analysis of a set of 67 rice varieties showed the SNP GC/TT₂₃₄₀ of SSIIa play a role in GT and most low GT varieties have the homozygous SNP genotype of TT/TT. (author)

[en] Advances in molecular genetics and DNA technologies have brought plant breeding, including mutation breeding, into a molecular era. With ever-increasing knowledge of molecular genetics and genomics and rapidly emerging molecular techniques, breeders can now use mutation techniques in breeding new varieties more wisely and efficiently than ever before. Plant molecular mutation breeding is here defined as mutation breeding, in which molecular or genomic information and tools are used in the development of breeding strategies, screening, selection and verification of induced mutants, and in the utilization of mutated genes in the breeding process. It is built upon the science of DNA damage, repair and mutagenesis, plant molecular genetics and genomics of important agronomic traits as well as induced mutations. Mutagenic treatment, super-mutable genetic lines, molecular markers and high throughput DNA technologies for mutation screening such as TILLING (Targeting Induced Limited Lesions IN Genomes), are the key techniques and resources in molecular mutation breeding. Molecular mutation breeding will significantly increase both the efficiency and efficacy of mutation techniques in crop breeding. A perspective molecular mutation breeding scheme is proposed for discussion. (author)

[en] Physical availability and economic accessibility of food are the most important criteria of food security. Induced mutations have played a great role in increasing world food security, since new food crop varieties embedded with various induced mutations have contributed to the significant increase of crop production at locations people could directly access. In this paper, the worldwide use of new varieties, derived directly or indirectly from induced mutants, was reviewed. Some highlights are: rice in China, Thailand, Vietnam, and the USA; barley in European countries and Peru, durum wheat in Bulgaria and Italy, wheat in China, soybean in China and Vietnam, as well as other food legumes in India and Pakistan. An exact estimate of the area covered by commercially released mutant cultivars in a large number of countries is not readily available, but the limited information gathered clearly indicates that they have played a very significant role in solving food and nutritional security problems in many countries. (author)

[en] Diabetes is a major socio-economic cost and is a predisposing factor for early onset coronary heart disease and peripheral vascular disease. Type II diabetes reflects a failure of blood glucose regulation, leading to sustained high blood glucose concentrations that have numbers of metabolic effects predisposing to pathology. The risk of Type II diabetes is related to diet, especially the availability of readily digested, highly refined foods and excess energy intake. In the case of diabetes, the ready digestion of carbohydrates (particularly starches) leads to a rapid rise in blood glucose and a greater demand on the pancreas for insulin to normalize concentrations. Starch that is not absorbed in the small intestine but passes into the large bowel (Resistant starch, RS) is a key protector against serious disease (including cancer) in the latter region of the intestines, being fermented by the large bowel microflora yielding short chain fatty acids (SCFA) that promote normal colonic function. Multiple approaches were suggested to obtain high amounts of resistant starch, and most of is to physically modify starch structure through processing technology. Diabetes is also increasing in the Third World and Least Developed Countries (LDCs). The current rice varieties low in resistant starch available to these individuals are not low in GI and the production of high resistant starch rices will be an attractive consumer option to this section of the population. The ability of subsistence farmers to be able sell high-RS rice lines will enable such farmers to continue to survive in those in these countries. The largest producers in the world are China and India with production at 120 and 80 million tonnes per annum respectively. The contents of RS in the hot cooked and processed rice are always below 3% by the traditionally domestic manners. This might lead to a higher glycemic index (GI) and lower butyrate content, subsequently increase the potential risk of metabolic syndrome. To execute the dietary-prevention strategy and the non-insulin-dependent diabetes treatment, developing for rice high in RS is of particular interest and an accepted means of preventing diet-related disease. Serial of mutants high in RS in the hot cooked rice and processed was induced from the leading commercial rice varieties in China i.e. R7954, 9311, II-32B, Zhongzhe B, K17B, Gang46B. Despite obviously low RS content in the raw milled rice, RS content in the cooked an processed rice of mutants were 10-100 times higher than that of the wild type and common rice, the highest RS content is about 15% in mutants. Obvious differences in physicochemical properties, starch granule morphology, pasting properties, thermal properties, and X-ray diffraction pattern were observed among mutants, wild type, and common rice. The high-RS mutants were unique in natural starch structure and were characterized by the higher λmax of absorbance and blue value of iodine-binding starch complex, higher percentage of oval-shaped granules and bigger oval size, lower onset temperature, peak temperature, final temperature, and enthalpy of gelatinization, lower crystallinity, containing a higher percentage of intermediate chains of amylopectin and displaying a mixture of B- and V-type that was more resistant to starch hydrolysis by alpha-amylase. Starch hydrolysises in vitro by porcine pancreatic α-amylase tends to be incomplete with a lower rate and extent in the cooked or processed high-RS rice. In practically consumed as the staple foods by diabetes and animal-feeding test, the GI levels in two hours after eating were significantly lower than that of common rice, and the increased satiety sensation was clearly felt, which is the key important for the diabetes to eat the enough to meet the basic 'Always hungry' problem. The reduction in the amount of inhibiting-digestion chemicals and insulin and improvement of health body were quickly observed in the long-term eating testing. Based on the protocols developed, mutants high in RS with 10∼50 times increases were also induced from the commercial Chinese and Australia wheat varieties. (author)

[en] Nutritional quality is an important component of the rice grain. Development of low phytic acid (lpa) crops, in which the PA phosphorus (Pi) content is significantly reduced in grains, has recently been considered as a potential way to increase bioavailability of Zn²⁺ and Fe³⁺ in the rice grain. Another potential approach to improve nutritional quality is to express ferritin gene from legume crops to increase iron content in rice grain. We have isolated a low phytic acid rice mutant (lpa- XS110-1) and obtained transgenic rice expressing the ferritin gene from pea. Two transgenic lines (Fer34 and Fer65) had iron content about five times that of the parent XS110 (Ye et al 2007). To pyramid the low phytic acid mutation and ferritin gene into one line, two crosses were made between Fer34 and lpa-XS110-1 and between Fer65/ lpa-XS110-1. The F₁ anthers were subjected to anther culture to obtain stable homozygous plants. A total of 43 doubled haploid (DH) lines were obtained from the Fer34/ lpa-XS110-1 cross, and 86 DH lines from Fer65/ lpa-XS110-1. For individual trait, both low phytic acid and the Ferritin gene (indirectly assayed with Gus) were inherited as a single locus. In combination, four recombinant traits were obtained, i.e high inorganic pi (lpa)/Gus+, lpa/Gus-, low inorganic pi/Gus+, and low inorganic pi/Gus-, the ratio of each recombinant was in accordance with the ratio of 1: 1: 1; 1, , indicating that lpa and Fer gene were not linked, and segregated as a single locus. The results suggest doubled haploid production is a rapid approach to pyramid useful genes from different origin for rice improvement. This study was jointly supported by funds from IAEA (12229), the Science and Technology Department of Zhejiang Province. (author)