Discovering and verifying DNA polymorphisms in a mung bean [V. radiata (L.) R. Wilczek] collection by EcoTILLING and sequencing.

BACKGROUND: Vigna radiata, which is classified in the family Fabaceae, is an important economic crop and a dietary staple in many developing countries. The species radiata can be further subdivided into varieties of which the variety sublobata is currently acknowledged as the putative progenitor of radiata. EcoTILLING was employed to identify single nucleotide polymorphisms (SNPs) and small insertions/deletions (INDELS) in a collection of Vigna radiata accessions. FINDINGS: A total of 157 DNA polymorphisms in the collection were produced from ten primer sets when using V. radiata var. sublobata as the reference. The majority of polymorphisms detected were found in putative introns. The banding patterns varied from simple to complex as the number of DNA polymorphisms between two pooled samples increased. Numerous SNPs and INDELS ranging from 4-24 and 1-6, respectively, were detected in all fragments when pooling V. radiata var. sublobata with V. radiata var. radiata. On the other hand, when accessions of V. radiata var. radiata were mixed together and digested with CEL I relatively few SNPs and no INDELS were detected. CONCLUSION: EcoTILLING was utilized to identify polymorphisms in a collection of mung bean, which previously showed limited molecular genetic diversity and limited morphological diversity in the flowers and pod descriptors. Overall, EcoTILLING proved to be a powerful genetic analysis tool providing the rapid identification of naturally occurring variation.

Genetic diversity of cultivated and wild-type peanuts evaluated with M13-tailed SSR markers and sequencing.

Thirty-one genomic SSR markers with a M13 tail attached were used to assess the genetic diversity of the peanut mini core collection. The M13-tailed method was effective in discriminating almost all the cultivated and wild accessions. A total of 477 alleles were detected with an average of 15.4 alleles per locus. The mean polymorphic information content (PIC) score was 0.687. The cultivated peanut (Arachis hypogaea L.) mini core produced a total of 312 alleles with an average of 10.1 alleles per locus. A neighbour-joining tree was constructed to determine the interspecific and intraspecific relationships in this data set. Almost all the peanut accessions in this data set classified into subspecies and botanical varieties such as subsp. hypogaea var. hypogaea, subsp. fastigiata var. fastigiata, and subsp. fastigiata var. vulgaris clustered with other accessions with the same classification, which lends further support to their current taxonomy. Alleles were sequenced from one of the SSR markers used in this study, which demonstrated that the repeat motif is conserved when transferring the marker across species borders. This study allowed the examination of the diversity and phylogenetic relationships in the peanut mini core which has not been previously reported.

DNA technology, interstate commerce, and the likely origin of formosan subterranean termite (Isoptera: Rhinotermitidae) infestation in Atlanta, Georgia.

This study was the first to use DNA sequencing data to infer the origin of a Formosan subterranean termite, Coptotermes formosanus Shiraki, infestation. Cytochrome oxidase II gene sequence was used to define eight specific maternal lineages from 14 geographic locations across the southeastern United States, Hawaii, and China. One maternal lineage, A, was unique to all the Atlanta collections and one New Orleans collection, which indicated that termites at these sites shared a common maternal ancestor. The impact of interstate commerce in terms of Formosan subterranean termite introductions is addressed as is the industry response needed to arrest the spread of these termites via commercial traffic in used railroad cross ties.