Transgenic chickens have been spotlighted as an highly potent bioreactor for their fecundity, short generation time, and eggs associated with mass production of protein. In this study, we generated transgenic chickens exhibiting oviduct specific expression of human growth hormone fused to human transferrin for oral administration. Gene of the modified growth hormone located at downstream ovalbumin promoter (∼3.6 kb) was introduced to stage X blastodermal cell employing retrovirus vector system. Several transgenic chickens were successfully generated. However, genomic analyses showed unexpected deletion within the transgene. The modification of the transgene seemed to occur during germ cell formation because the deletion was detected only from the sperm DNA of the G0 founder animal. There was no evidence of deletion in the somatic cell DNA samples of the same chicken. Consequently, same pattern of the deletion was confirmed in both somatic and germ cells of the G1 progeny.

Safflower (Carthamus tinctorius L.) seeds have long been clinically used in Korea to promote bone formation and prevent osteoporosis. In addition, the safflower buds (SB) were found to have more useful functional ingredients than safflower seed. Thus, we investigated the preventive effects of SB diet in ovariectomized (OVX) rats. The rats were divided into five groups; sham operated group, OVX alone group, OVX plus 17β-estradiol (E2 10 ㎍/㎏, i.p.) and OVX plus SB diet feeding group (0.3% or 1%). Feeding of SB diet (0.3% or 3%) to OVX rats markedly increased trabecular formation in femur compared to OVX rats. Feeding of SB diet (0.3% or 3%) to OVX rats also decreased TRAP activity compared to OVX rats. These results suggest that SB diets have bone sparing effects by the decrease of osteoclast activity. We also observed that OVX rats fed with SB diet (0.3% or 3%) exhibited the decrease of calcium and phosphorus in serum compared to OVX-induced rats. Therefore, SB may be beneficial for the patients of osteoporosis, especially in postmenopausal women.

Citrus canker caused by Xanthomonas citri is a notorious disease affecting a decrease in fruit productivity and quality. Citrus export to USA is also prohibited by the disease. Therefore, development of citrus canker resistant variety is essential and exploitation of markers for molecular breeding is urgent. To develop DNA molecular markers, we performed whole genome resequencing for 8 varieties: 4 citrus canker resistant varieties including C. hybrid ‘Kioymi’ and 4 citrus canker susceptible varieties including C. iyo ‘Miyauchiiyokan’. In total, 642 polymorphic SNPs were detected between resistant and susceptible varieties. Of the 642 SNPs, 50 SNPs were preferably selected based on integrative genomics viewer. To apply the markers in a broad range of citrus variety, we performed genotyping with 6 other varieties very well known as citrus canker resistant and susceptible varieties in addition to previous mentioned 8 varieties. Three of the 50 SNPs were identified as a marker to distinguish citrus canker resistant varieties from susceptible varieties. Secondly, we developed molecular markers to apply for F1 lines crossed by ‘Kiyomi’ and ‘Miyauchiiyokan’. Of the 50 SNPs, we identified 2 SNP markers to distinguish between F1 resistant and susceptible lines. One of them is a resistance gene that plays a role in plant defense mechanism. In this study, we developed 5 molecular marker candidates possible to apply for molecular breeding to develop citrus canker resistant variety. We are working on development of candidate markers related to citrus canker.

Citrus canker caused by Xanthomonas citri pv. citri is one of economically important diseases in the citrus industry. The devastating bacterial disease results in unattractive quality and a significant reduction in fruit production. Citrus growers and industry in Korea has been struggling with the serious disease causing the prohibition of export market. Korea also became the top import market for oranges. The development of markers linked to citrus canker resistance is strongly needed. In this study, we investigated molecular markers between ‘Kiyomi’ (Citrus unshiu ｘ C. sinensis), a resistant cultivar, and Natsudaidai (C. natsudaidai), a susceptible cultivar. To develop markers, we focused on structural variation (copy number variation, CNV, and presence/absence variation, PAV). It has been well documented that CNV and PAV of defense-related genes are associated with resistant cultivars. Using a read depth approach following next-generation sequencing, we performed genome-wide analysis of CNV and PAV in two varieties. As a result, 633 genes showing at least two times difference between the mapping reads from two varieties and 61 genes showing presence of the mapping reads in only either one of them were screened. Visual inspection using the Integrative Genomics Viewer (IGV) was performed and experimental validation is being investigated. Interestingly, one of PAV candidates showed polymorphism in ‘Kiyomi’ and ‘Natsudaidai’ as well as other resistant and susceptible cultivars. Our results suggest a necessity for the detection of structural variation and indicate that the candidates may be useful for molecular breeding for citrus canker resistance and understanding disease resistance mechanism.