CAJ | 학술논문

CBF转录因子属于AP2/EREBP转录因子家族，是植物特有的一类转录因子，在植物应对外界非生物胁迫的过程中起了非常重要的作用。在前期克隆河北杨PhCBF4a、PhCBF4b基因的基础上，通过同源克隆方法，从河北杨中继续分离出其它CBF类基因：PhDREB66、PhDREB67-1、PhDREB67-2、PhDREB68、PhDREB69、PhDREB70。与PhCBF4a、PhCBF4b基因相似，这6个基因包含AP2区域、核定位位点（ NLS）以及AP2区域侧翼的两个CBF类基因所特有的基序。与相应毛果杨基因比对分析发现，这8个河北杨基因可分为3个Groups （旁系同源基因群），其中2个各包括3个基因，1个包含2个基因，河北杨旁系同源基因及其与毛果杨直系同源物之间在氨基酸水平上表现出了较高的序列一致性。进化分析结果显示，CBF基因可分为真双子叶植物分支与单子叶植物分支。真双子叶植物分支又可以分为3个分支，可分别由3个河北杨CBF旁系同源基因群所代表，显示在从共同的双子叶祖先分离之前或分离过程中，杨树CBF基因经历了复制与趋异的进化过程。 PAML分析检测到PhCBF4 a基因在进化过程中承受了正向的选择压力，表明其在河北杨响应并适应外界胁迫中的重要作用。表达分析结果显示河北杨CBF类基因能够应答干旱、低温、高温、盐及ABA胁迫，显示了其在调控河北杨胁迫抗性中的作用。
CBF전록인자속우AP2/EREBP전록인자가족，시식물특유적일류전록인자，재식물응대외계비생물협박적과정중기료비상중요적작용。재전기극륭하북양PhCBF4a、PhCBF4b기인적기출상，통과동원극륭방법，종하북양중계속분리출기타CBF류기인：PhDREB66、PhDREB67-1、PhDREB67-2、PhDREB68、PhDREB69、PhDREB70。여PhCBF4a、PhCBF4b기인상사，저6개기인포함AP2구역、핵정위위점（ NLS）이급AP2구역측익적량개CBF류기인소특유적기서。여상응모과양기인비대분석발현，저8개하북양기인가분위3개Groups （방계동원기인군），기중2개각포괄3개기인，1개포함2개기인，하북양방계동원기인급기여모과양직계동원물지간재안기산수평상표현출료교고적서렬일치성。진화분석결과현시，CBF기인가분위진쌍자협식물분지여단자협식물분지。진쌍자협식물분지우가이분위3개분지，가분별유3개하북양CBF방계동원기인군소대표，현시재종공동적쌍자협조선분리지전혹분리과정중，양수CBF기인경력료복제여추이적진화과정。 PAML분석검측도PhCBF4 a기인재진화과정중승수료정향적선택압력，표명기재하북양향응병괄응외계협박중적중요작용。표체분석결과현시하북양CBF류기인능구응답간한、저온、고온、염급ABA협박，현시료기재조공하북양협박항성중적작용。
CBF transcription factor, belonging to AP2/EREBP family and specific to plant, plays an important role in plant re-sponse and adaptation to abiotic stress.Previously, PhCBF4a/4b genes were characterized from Populus hopeiensis.The other six CBF-like genes, PhDREB66, PhDREB67-1, PhDREB67-2, PhDREB68, PhDREB69 and PhDREB70 were cloned.Similar to PhCBF4a/4b, the cloned genes contain all conserved domains in other CBF transcription factor, such as AP2 domain, nuclear location signals, the CBF signature sequences which bracket the AP2 domain, and the hydrophobic clusters which contribute towards the total trans-activating potential of CBF.Eight CBF genes of P.hopeiensis were as-signed into three paralogous groups, two genes inone group and three genes in each of the other two.The paralogs and the genes withtheir orthologs in P.trichocarpa show higher amino acid sequence identity.The phylogenetic analysis using known CBF homologs reveals that all Eudicot CBF genes are separately clustered from Monocot CBF genes.The Eudicot CBF family with three clades, represented by above three paralogous groups, shows that the Populus CBF genes are duplica-ted and diverged before or during speciation from the common Eudicot ancestor .Moreover , positive selection is detected in PhCBF4a with PAML, and the expression profiles show that the CBF genes of P.hopeiensis can respond to drought, cold, heat, NaCl and ABA stress.All these reveal their important roles responsive to environmental stresses in P.hopeiensis.