Sweetpotato whitefly (Bemisia tabaci), especially Q biotype, has been recognized one of the most destructive insect pests worldwide because of increased resistance to some insecticide groups requiring alternative strategies for its control. We studied the conidia production of entomopathogenic fungus Isaria javanica Pf04, which had been reported high virulence isolate against Q biotype of B. tabaci, using grain. Brown rice was most suitable for conidia mass production of the isolate of I. javanica. Conidia was produced high at 25 ~ 27.5℃. The isolate produced more spores when conidia suspension directly inoculated onto media than two-phase fermentation. When concentration of inoculum was high spore production was high, but increasing rate of conidia production was highest at low inoculum concentration (1×105 conidia/ml) as 6,700 times increase compared with 20 times increase at high inoculum concentration (1×108 conidia/ml). These results indicated that the isolate can produce more conidia with cheap agricultural product and can develop as a microbial pesticide to control sweetpotato whitefly.

Soybean is a crop of importance economically and nutritionally in many parts of the world. Thanks to many new genes brought from genomic research, It is possible to introduce various candidate genes through genetic transformation to see the performance of the genes in field. In our lab, soybean transformations have been tried for last 10 years to probe the possibility of traits improvement by transformation of new gene into soybean. For this purpose, three different genes were transformed into Korean soybean variety, Kwangan. First, the gene that controls early flowering of plant was transformed into Kwangan. Second, a candidate gene for soybean mosaic virus (SMV) resistance was transformed to produce transgenic plants. Third, another candidate gene for drought tolerance was transformed. All the transgenic plants from three genes transformation were produced for their gene insertion and their expression using PCR, qRT-PCR. Further analysis including harvesting seeds is currently undertaken.

ORE7 gene incorporated into 3 different promoters including pCKLSL-35S, pCKLSL-TP and pCSENIF was transformed to Korean soybean variety Kwangan using highly efficient soybean transformation system. The gene is known to exhibit a delayed leaf senescence phenotype in Arabidopsis. Fourteen, Fifteen and nine transgenic plants were produced from pCKLSL-35S::ORE7, pCKLSL-TP::ORE7 and pCSENIF::ORE7, respectively. Moreover, transgenic plants were confirmed for gene introduction and their expression using PCR, qRT-PCR and RT-PCR. To identify the transgene insertion events, the analysis of flanking sequence was determined. As a results, T-DNA was integrated intergenically in transgenic line 1 of pCKLSL-35S::ORE7 and line 1 of pCSENIF::ORE7. Currently, flanking sequence analysis with pCKLSL-35S::ORE7, pCKLSL-TP::ORE7 and pCSENIF::ORE7 is carrying out to investigate the stable T-DNA insertions.

The direct use of mutation is a valuable approach to generate variability in crops. The electron beam, one of the ionizing radiations, has been applied to evaluate its effect on seed germination and early seedling growth of creeping bentgrass (Agrostis palustris Huds., cv Penn-A1). The mature dry seeds were irradiated with various electron beam energies (0.3, 1.0, 1.3, and 2 MeV) and current levels (0.03 and 0.06 mA). Although large variability was existed within each dose, distinct difference of germiability and seedling vigor were not found at 0.3 MeV / 0.03 mA and 0.3 MeV / 0.06 mA beam condition. However, 1.0 MeV / 0.06 mA application most effectively inhibited and retarded seed germination and most severely restricted cotyledon and root growth in early seedling growth. The direct use of electron beam would be a valuable supplementary approach to generate mutants suitable for breeding purposes.