OsDREB1D, a special DREB (dehydration responsive element binding protein) homologous gene, whose transcripts cannot be detected in rice (Oryza sativa L), either with or without stress treatments, was amplified from the rice genome DNA. The yeast one-hybrid assay revealed that OsDREB1D was able to form a complex with the dehydration responsive element/C-repeat motif. It can also bind with a sequence of LTRE (low temperature responsive element). To analyze the function of OsDREB1D, the gene was transformed and over-expressed in Arabidopsis thaliana cv. Columbia. Results indicated that the over-expression of OsDREB1D conferred cold and high-salt tolerance in transgenic plants, and that transgenic plants were also insensitive to ABA (abscisic acid). From these data, we deduced that this OsDREB1D gene functions similarly as other DREB transcription factors. The expression of OsDREB1D in rice may be controlled by a special mechanism for the redundancy of function.

Using PCR-RFLP analysis, a comparative study on the restriction site polymorphism within 8 genes and regions of the Abies chloroplast DNA has been conducted covering 15 Asian, 6 North American and 7 Mediterranean species. A variable degree of divergence was observed among individual species of a given region as well as between geographical groups. A group of the Mediterranean firs, consisting of closely related species, differed profoundly from both Asian and North American representatives. Although a higher level of restriction site variants was detected among the Asian firs, two thirds of them were allocated to the difference between A. mariesii and the other Asian firs. The North American species exhibited the highest level of polymorphism resulting in several subgroups on a cladogram. At the individual species level, the Asian species A. mariesii and the North American species A. lasiocarpa diverged conspicuously from their counterparts in their respective regions. The results of restriction site polymorphism analysis are discussed with ragard to crossability and taxonomic status of individual species.

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Diversity arrays technology (DArT) is a microarray hybridization-based molecular marker technique, and a novel method to discover genetic polymorphic markers. DArT has recently been applied in genetic research of plants because of its characteristics of sequence-independent, high-throughput, fast, low-cost. We briefly introduce the principle, characteristics, protocol of DArT and its application in genetic research of plants.

To monitor the level and distribution pattern of genetic diversity in countrywide populations of Japanese red pines in Korea, 80 I-SSR variants were analyzed from 192 individuals in 11 populations. The previously reported data, obtained from the 8 populations of this species, were incorporated into the estimation of the population genetic statistics. Relatively higher level of genetic diversity was observed in 19 populations of Japanese red pines (mean of 0.453) than those in other tree species. From the results of AMOVA, majority of genetic diversity (92%) was allocated within populations, which brought about the moderate degree of population differentiation (ϕST= 0.08). Two genetic groups were observed from the dendrogram reconstructed by UPGMA. Overall correlation between genetic relationships and geographic affinity was inconsistent among the 19 populations. Some probable genetic disturbances, induced by either human interference or the natural process of regeneration for the species after devastation, might be responsible for the discrepancy between genetic relationships and geographical distribution of the populations. These results suggested that simple geographic or ecological grouping might not represent the genetic zone of the Korean populations of Japanese red pines, and that more careful approach should be made for designating in situ gene conservation of this species in Korea.