In soybean, EMS is commonly used, and diverse mutant phenotypes have been reported (reviewed in ).

Ethyl methanesulfonate (EMS), N-nitroso-N-methylurea (NMU), and ethyl nitrosourea (ENU) constitute 64 % of all agents used for chemical mutagenesis (reviewed in ). One of the reverse genetics approaches, induction of point mutations by chemical mutagenesis, known as TILLING (targeting-induced local lesions in genomes), has been widely used to discover the biological functions of sequenced genes and to develop novel alleles associated with specific traits in several crop species such as maize, wheat, rice, sorghum, soybean, tomato, and canola. Gamma ray is the most commonly used physical mutagens in plant mutation breeding and induces deletions. Retention of the ancestral function by one of the duplicated genes and acquisition of a novel function by the other may result in phenotypic changes despite the high genetic redundancy in the soybean genome. However, RNA-seq analysis of transcriptional divergence of duplicated genes by neo-functionalization has shown that approximately 50 % of duplicated genes were differentially expressed in soybean. Compared with diploids, polyploid species can better withstand higher mutation densities because of compensation by other genome copies, as additional gene copies may mask the phenotypic effect of a mutation. Soybean has a paleopolyploid genome and nearly 75 % of predicted soybean genes are present in multiple copies due to two duplication events at 13 and 59 mya. A mutant library with a high mutation density would be helpful for obtaining such functional evidence. The functions of most of these predicted genes have not been clarified. The reference genome sequence (975 Mb) comprises 54,175 predicted protein-coding loci. Soybean is a major source of the world’s protein, oil, and animal feed. Thus, our mutant library and the indexed amplicon sequencing will be useful for functional studies of soybean genes and have a potential to yield useful mutant alleles for soybean breeding. The mutation density of our library is sufficiently high to obtain a plant in which a gene is nonsense mutated. A high mutation density (1 mutation/74 kb) was achieved by repeating the EMS treatment. ConclusionsĪ soybean mutant library with a high mutation density was developed. In comparison with HRM screening of several genes, indexed amplicon sequencing allows one to scan a longer sequence range and skip screening steps and to know the sequence information of mutation because it uses systematic DNA pooling and the index of NGS reads, which simplifies the discovery of mutants with amino acid substitutions. Two screening strategies for high resolution melting (HRM) analysis and indexed amplicon sequencing were designed to retrieve the mutants the mutations were confirmed by Sanger sequencing as the final step. On average, 691 and 35 per line were missense and nonsense mutations, respectively. Based on whole-genome re-sequencing analysis of 12 mutant lines, the average number of base changes was 12,796 per line. The resultant library, which consisted of DNA and seeds from 1536 plants, revealed large morphological and physiological variations. To increase the mutation density, seeds of the Japanese elite soybean cultivar Enrei were treated with the chemical mutagen ethyl methanesulfonate (EMS) M2 seeds produced by M1 plants were treated with EMS once again. Development of cost-effective and high-throughput protocols using next generation sequencing (NGS) technologies is expected to simplify the retrieval of mutants with mutations in genes of interest. A mutant library with a high mutation density would be helpful for functional studies and for identification of novel alleles useful for breeding. Labs supporting Ukrainian Scientists is an expansive list of labs and PIs offering support at this time.Functions of most genes predicted in the soybean genome have not been clarified.Science for Ukraine provides an overview of labs offering a place for researchers and students who are affected to work from, as well as offers of employment, funding, and accommodation:.Personally, I have found the messages of support from scientists everywhere to be truly heartfelt, and I would like to highlight some of the community initiatives I’ve seen here: We also want to use our platform to highlight the response from the scientific community.

Clc sequence viewer 7.5 workflow