甘蓝型油菜光敏色素(PHY)家族基因的鉴定及表达分析

Genome-wide identification and expression analysis of PHY gene family in Brassica napus

光敏色素(phytochrome,PHY)作为植物体内感受红光和远红光的受体,在植物的避荫反应及生物、非生物胁迫响应中起重要的调节作用。鉴定甘蓝型油菜中PHY家族基因并解析其分子机理,有助于提高油菜光能利用率,培育抗逆性强、适合密植直播和机收的油菜品种。为了研究PHY基因在甘蓝型油菜(Brassica napus L.)中的家族特征,以5个拟南芥(Arabidopsis thaliana)AtPHY基因为基础序列,在甘蓝型油菜、甘蓝(B.oleracea)、白菜(B.rapa(Lour.)Rupr.)、黑芥(B.nigra)、芥菜型油菜(B.juncea)和埃塞俄比亚芥(B.carinata)中分别鉴定出11个、6个、5个、5个、10个和9个PHY基因。生物信息学分析结果显示PHY基因在芸薹属中高度保守。在甘蓝型油菜11个BnaPHY基因中,PHYA亚组成员主要在根中表达,PHYB亚组主要在叶片中表达。此外PHYA和PHYB均显著受高温和低温胁迫的调控,而非生物胁迫和激素处理对PHY基因表达的影响不明显。春化处理中的PHYB亚组表达量下调,PHYC和PHYE亚组表达量则上调,而在PHYA亚组只有部分基因表达量上调。大部分PHY基因表达明显受核盘菌抑制,有两个PHYA成员的表达明显受核盘菌诱导。

Phytochrome(PHY), as a receptor for red and far-red light sensing in plants, plays an important role in the regulation of response to shade, biological and abiotic stress. Identification of PHY family genes in Brassica napus and analysis of their molecular mechanism are helpful to improve the light energy utilization rate of B. napus, and to cultivate varieties with resistance to stress, and suitable for dense planting and machine harvesting. In order to study the family characteristics of PHY genes in B. napus, five AtPHY genes were used as reference sequences, 11, 6, 5, 5, 10 and 9 PHY genes in Brassica napus, B. oleracea, B. rapa, B. nigra, B. juncea and B. carinata were identified, respectively. Results of bioinformatics analysis showed that the sequences and gene structures of PHY were highly conserved in Brassicaceae species. In B. napus, PHYA(subgroup)members were mainly expressed in roots, while PHYB members were mainly expressed in leaves. PHYA and PHYB were regulated by heat and cold stresses, but the effect of abiotic and hormone treatments on PHY genes expression were not obvious. During vernalization, the expression levels of PHYB subgroup were down-regulated, while PHYC and PHYE expressions were up-regulated. In PHYA subgroup, only a few genes were up-regulated after vernalization treatment. Most PHY genes were strongly repressed by infection of S. sclerotiorum, while 2 members of PHYA subgroup were induced.