Genetic evaluation of domestic walnut cultivars trading on Korean tree markets using microsatellite markers

Walnut (Juglans regia L.) is regarded as a healthy food because of its high nutritional composition and various health benefits. Although several walnut cultivars are being actively traded for domestic plantation or ornament in Korea, no particular effort has been made to evaluate genetic quality management of walnut cultivars in domestic tree markets. In this study, as an effort to evaluate the status of walnut seedling trade, we collected walnut seedlings of diverse cultivars from domestic tree markets and several locations in Korea and performed genotype analysis for the collections using microsatellite markers (76 individuals belonging to eight domestic cultivars). We used 12 markers that were previously reported to be informative and polymorphic in walnuts. The number of alleles that was detected from the collections using these markers ranged from 6 to 16, with heterozygosity values ranging from 0.03 to 0.75. Dendrogram revealed that the domestic walnut cultivars trading on tree markets could be genotypically distinguished from various foreign cultivars. However, genotyping data also showed that individual plants belonging to identical cultivars were sporadically distributed on the dendrogram, indicating that walnut cultivars trading on domestic tree markets seem to be poorly managed.Keywords: Walnut (Juglans regia L.), microsatellite markers, tree market, seedling trade, domestic cultivars, foreign cultivars, cultivar managementAfrican Journal of Biotechnology Vol. 11(29), pp. 7366-7374, 10 April, 201

Isolation and characterization of a G protein alpha subunit gene from Stentor coeruleus

Stentor coeruleus is a unicelluar heterotrich ciliate that can exhibit a step-up photophobic response and a negative phototactic response. The photoreceptor, stentorin, is located in the pigment granule just below the cell membrane. Proton transfer from the excited state stentorin is thought to be an initial process and subsequent calcium influx induces the ciliary beat reversal. Recent evidence suggests that cGMP and heterotrimeric G proteins are involved in this light signal transduction pathway as in the vertebrate visual system. Furthermore, a 39 kDa protein from the Stentor membrane fraction was detected by immunoblot analysis with the AS/7 antisera against the carboxyl decapeptide of transducin $\alpha$ subunit. As a first step to trace each molecule in the light signal transduction pathway, a G protein $\alpha$ subunit gene from Stentor was cloned by the PCR approach. Even though just part of the G$\alpha$ subunit gene was cloned, it is homologous to the mammalian Gi type $\alpha$ subunit (amino acid sequence identity is 60%). To check the possibility that stentorin may interact with a G protein directly, the location of the G protein $\alpha$ subunit was investigated by immunogold labeling of the AS/7 antisera. The result indicated that the G protein is located in the myoneme and the kinetosome fibre. These organelles are responsible for cell contraction and cell extension

Characterization of Genes for a Putative Hydroxycinnamoyl-coenzyme A Quinate Transferase and <i>p</i>‑Coumarate 3′-Hydroxylase and Chlorogenic Acid Accumulation in Tartary Buckwheat

Tartary buckwheat (Fagopyrum tataricum Gaertn.) contains a high level of flavonoid compounds, which have beneficial and pharmacological effects on health. In this study, we isolated full-length cDNAs encoding hydroxycinnamoyl-coenzyme A quinate hydroxycinnamoyltransferase (HQT) and <i>p</i>-coumarate 3′-hydroxylase (C3H), which are involved in chlorogenic acid (CGA) biosynthesis. We examined the expression levels of HQT and C3H using real-time RT-PCR in different organs and sprouts of two tartary buckwheat cultivars (Hokkai T8 and T10) and analyzed CGA content using high-performance liquid chromatography. Among the organs, the flowers in both cultivars showed the highest levels of CGA. We concluded that the expression pattern of <i>FtHQT</i> and <i>FtC3H</i> did not match the accumulation pattern of CGA in different organs of T8 and T10 cultivars. Gene expression and CGA content varied between the cultivars. We presume that <i>FtHQT</i> and <i>FtC3H</i> levels might be controlled by multiple metabolic pathways in different organs of tartary buckwheat. Probably, <i>FtC3H</i> might have a greater effect on CGA biosynthesis than <i>FtHQT</i>. Our results will be helpful for a greater understanding of CGA biosynthesis in tartary buckwheat

Generation and Analysis of End Sequence Database for T-DNA Tagging Lines in Rice

We analyzed 6,749 lines tagged by the gene trap vector pGA2707. This resulted in the isolation of 3,793 genomic sequences flanking the T-DNA. Among the insertions, 1,846 T-DNAs were integrated into genic regions, and 1,864 were located in intergenic regions. Frequencies were also higher at the beginning and end of the coding regions and upstream near the ATG start codon. The overall GC content at the insertion sites was close to that measured from the entire rice (Oryza sativa) genome. Functional classification of these 1,846 tagged genes showed a distribution similar to that observed for all the genes in the rice chromosomes. This indicates that T-DNA insertion is not biased toward a particular class of genes. There were 764, 327, and 346 T-DNA insertions in chromosomes 1, 4 and 10, respectively. Insertions were not evenly distributed; frequencies were higher at the ends of the chromosomes and lower near the centromere. At certain sites, the frequency was higher than in the surrounding regions. This sequence database will be valuable in identifying knockout mutants for elucidating gene function in rice. This resource is available to the scientific community at http://www.postech.ac.kr/life/pfg/risd