Taking Ammopiptanthus mongolicus(Maxim. ex Kom.)Cheng f. seedlings as experimental materials,its transcriptome was sequenced, the differentially expressed transcription factor genes were selected under simulated drought stress with mass volume fraction of 18% polyethylene glycol 6000. On this basis,phylogenetic relationships of differentially expressed bHLH transcription factors under drought stress, and expression patterns of differentially expressed bHLH genes under drought stress and 100 mmol·L-1NaCl stress were analyzed.The results show that there are 49 transcription factor gene families from A. mongolicus, including 1 575 transcription factor genes. Under drought stress, fold change of expression level of 44 transcription factor genes from above?ground part of A. mongolicus is greater than or equal to two times, in which, there are 33 transcription factor genes with up?regulated expression, and 11 transcription factor genes with down?regulated expression; fold change of expression level of 57 transcription factor genes from under?ground part is greater than or equal to two times,in which,there are 50 transcription factor genes with up?regulated expression,and 7 transcription factor genes with down?regulated expression. Differentially expressed transcription factor genes from A. mongolicus in responding to drought stress are mainly existed in AP2?EREBP, MYB, WRKY, NAC, and bHLH gene families. Numbers of differentially expressed transcription factor genes from above?and under?ground parts with up?regulated(down?regulated)expression levels of 2-5,5(including 5)-10(including 10)and more than 10 times are 28,7 and 9,and 11,27 and 19,respectively.The result of cluster analysis shows that there are similarities with different degrees in amino acid sequences encoded by six differentially expressed bHLH genes from A. mongolicus and those encoded by bHLH genes from Arabidopsis thaliana(Linn.) Heynh. Under drought stress and NaCl stress,six differentially expressed bHLH genes from A. mongolicus are induced with different degrees.These results offer resource of abundant transcription factor genes to do research on regulatory mechanism of A. mongolicus during process of abiotic stress.%以沙冬青〔Ammopiptanthus mongolicus(Maxim. ex Kom.)Cheng f.〕幼苗为实验材料,对其转录组进行测序,筛选出质量体积分数18%聚乙二醇6000模拟干旱胁迫下差异表达的转录因子基因;在此基础上,对干旱胁迫下差异表达bHLH转录因子的系统进化关系以及干旱胁迫和100 mmol·L-1NaCl胁迫下差异表达bHLH基因的表达模式进行分析.结果表明:沙冬青中存在49个转录因子基因家族,共包含1575个转录因子基因.干旱胁迫下沙冬青地上部有44个转录因子基因表达量的差异倍数大于等于2倍,其中33个转录因子基因上调表达,11个转录因子基因下调表达;地下部有57个转录因子基因表达量的差异倍数大于等于2倍,其中50个转录因子基因上调表达, 7个转录因子基因下调表达.沙冬青响应干旱胁迫的差异表达转录因子基因主要分布于 AP2-EREBP、MYB、WRKY、NAC和bHLH基因家族.沙冬青地上部和地下部表达量上(下)调2~5、5(含5)~10(含10)及10倍以上的差异表达转录因子基因数分别为28、7和9个,以及11、27和19个.聚类分析结果显示:沙冬青6个差异表达bHLH基因编码的氨基酸序列与拟南芥〔Arabidopsis thaliana(Linn.)Heynh.〕bHLH基因编码的氨基酸序列有不同程度的相似性.干旱胁迫和NaCl胁迫下,沙冬青6个差异表达bHLH基因的表达受到不同程度的诱导.本结果为研究非生物胁迫过程中沙冬青调控机制提供了大量的转录因子基因资源.
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