Flavonoids are divided into several structural classes, including anthocyanins, which provide flower and leaf colors and other derivatives with diverse roles in plant development and interactions with the environment. This study characterized four Anthocyanidin Synthase (ANS) genes of Brassica rapa, a structural gene of anthocyanin biosynthetic pathway, and investigated their association with cold and freezing tolerance in B. rapa. Sequences of these genes were analyzed and compared with similar types of gene sequences of other species and found a high degree of homology with their respective functions. In the organ specific expression analysis, these genes showed expression only in the colored portion of leaves of different lines of B. rapa. On the other hand, BrANS genes also showed differential expression with certain time course of cold stress treatment in B. rapa. Thus, the above results suggest probable association of these genes with anthocyanin biosynthesis and cold and freezing tolerance and might be useful resources for developing cold resistant Brassica crops with desirable colors as well. The present work may help explore the molecular mechanism that regulates anthocyanin biosynthesis and its response to abiotic stress at the transcriptional level in plants.

Flavonoids including anthocyanins provide flower and leaf colors and other derivatives that play diverse roles in plant development and interactions with the environment and dihydroflavonol 4-reductase (DFR) is part of an important step in the flavonoid biosynthesis pathway of anthocyanins. This study characterized 12 DFR genes of Brassica rapa and investigated their association with anthocyanin coloration, cold and freezing tolerance in several genotypes of B. rapa. Sequences of these genes were analyzed and compared with DFR gene sequences from other species and a high degree of homology was found. Constitutive expression of them in several pigmented and non-pigmented lines of B. rapa showed a correlation with anthocyanin accumulation only for BrDFR8 and 9. Conversely, BrDFR genes also showed responses to cold and freezing stress treatment in B. rapa. BrDFRs were also shown to be regulated by two transcription factors, BrMYB2-2 and BrTT8, contrasting with anthocyanin accumulation and cold and freezing stress. Thus, the above results suggest the association of these genes with anthocyanin biosynthesis and cold and freezing stress tolerance and might be useful resources for development cold and/or freezing resistant Brassica crops with desirable colors as well. The findings presented here may also help explore the molecular mechanism that regulates anthocyanin biosynthesis and its response to abiotic stress at the transcriptional level in plants.

비닐피복을 이용, 보리, 밀 품종의 봄철 저온장해의 대규모 유도와 품종간 차이로 선발 가능성을 구명하고자 포장의 비닐 피복을 이용한 저온처리시험을 실시하였다. 저온에 대해 보리, 밀 모두 가장 민감한 생육시기는 수잉기였고 영화 분화기 > 화기발육기 순이었다. 같은 생육정도라도 맥종간 장해정도에 차이를 보였는데 보리, 밀 각각 고사이삭비율 28%, 59%, 고사개체비율 10%, 44%, 퇴화이삭비율 18%, 44%였다. 저온장해 저항성 품종은 없었으나 품종간 장해 정도는 차이를 보여 보리에서는 찰보리가, 밀에서는 그루밀, 조광밀 등이 안정적인 수량을 보였다. 저온스트레스는 수량구성요소중 주로 수수와 일수립수에 큰 영향을 미치는 것으로 나타났으며 보리품종중 수원 259호와 강보리 수량이 수수와 밀접한 상관을 보였으나 일수립수와는 상관이 없었다. 밀은 대부분의 품종들이 세 시기 모두 수수와 밀접한 상관을 보였고 생육이 진전된 시기에는 일수립수와도 상관을 보였다. 저온장해에 대한 유전자형을 구분하기 위해 포장에서 비닐피복이라는 간단한 처리에 의해 저온저항성 품종이나 계통의 선발이 가능할 것으로 생각되나 시험기간의 2~4 월의 저온내습일수와 온도하강 정도에 변이가 있어 최소 2년 정도의 검정기간이 필요하다.