내혼계 배추에서 BrSOS1 (3,432개 뉴클레오티드), BrSOS2 (1,341개 뉴클레오티드), BrSOS3 (666개뉴클레오티드) 유전자들을 동정하였으며, 담배를 대상으로 BrSOS3 완전장이 전이되는 pSO3 계통과 RNA interference(RNAi) 기법으로 담배 SOS3(NtSOS3) 유전자의 발현을 억제하는 pSI3 계통을 생산하였다. 두 계통을 200mM NaCl에서 5일동안 염 스트레스 처리를 한 결과, pSO3 계통은 NtSOS3의 발현이 비형질전환체 대비 2.5배 이상 증가하였고, pSI3 계통에서는 4배까지 감소하였다. 표현형 분석에서도 pSO3 계통은 정상적인 생육을 보임으로써 염 스트레스에 저항성을 가지는 것으로 나타났지만, pSI3 계통은 그렇지 못하였다. 위 결과들을 근거로 BrSOS3 유전자의 발현은 작물의 염 저항성 향상에 매우 밀접하게 연관된 것으로 판단된다.

The C-repeat/dehydration-responsive element binding transcription factors (CBF/DREBs) are involved in an important pathway for abiotic stress-response in plants. We have identified CBF/DREB1 gene family from Brassica rapa whole genome sequence and designated them as BrDREB1s. They contain conserved nucleus localization signal, AP2/EREBP domain, and CBF/DREB1 signature, as other known plant CBF/DREB1s. By comparative genomics, we found that nine of ten BrDREB1 genes were present in seven macro-synteny blocks co-linear to four Arabidopsis counterpart blocks and also genomic organizations of their flanking regions were very similar to those for co-linear Arabidopsis CBF/DREB1 genes. In particular, three genes, BrDREB1A, BrDREB1B1, and BrDREB1C1, were closely located within a 59 kb genomic sequence, which was similar to that of their Arabidopsis counterpart genes. However, the genomic regions of those BrDREB1 genes contained additional sequences, compared to their co-linear regions in A. thaliana. The expression of BrDREB1 genes under abiotic stresses were examined by searching microarray database and by RT-PCR analysis. All of eight genes tested were highly up-regulated during cold treatment and some of them were also responsive to salt, drought, and ABA treatment. Taken together, these results indicate that CBF/DREB1-mediated stress signaling pathway is also functioning in B. rapa. On the other hand, differences in genomic organization and gene number for CBF/DREB1 are thought to cause different response to stress between B. rapa and A. thaliana. In this presentation, we will introduce more detailed results for CBF/DREB1 gene family in B. rapa.