关键词: 芹菜, AgHAT4, 基因表达, 组织, 非生物胁迫

Abstract: The transcription factor gene，AgHAT4，was cloned from two celery varieties of‘Liuhe Huangxinqin’and‘Ventura’，respectively. The amino acid composition，protein structure，physicochemical characterizations，and phylogenetic tree were analyzed using bioinformatics methods. Results showed that AgHAT4 contains an open reading frame（ORF）with the length of 900 bp，encoding 299 amino acids. One nucleotide site of AgHAT4 and an amino acid residue were different between the two celery varieties. The relative molecular weights of AgHAT4 protein of‘Liuhe Huangxinqin’and‘Ventura’were 33.71 kD and 33.68 kD respectively，with theoretical pI both about 9.12. Phylogenetic analysis demonstrated that the HAT4 proteins in celery and carrot belonged to the same branch. Protein structure prediction indicated that AgHAT4 protein was mainly composed of three α-helixes and some random coils，and no signal peptide was there. It was detected that AgHAT4 gene was most highly expressed in the petiole，followed by the root and lowest in the leaf blade by real-time quantitative PCR. The results also showed that multiple abiotic stresses induced the expression levels of AgHAT4 in celery. Compared with the control group，the expression levels of AgHAT4 in‘Liuhe Huangxinqin’up-regulated at 24 h under high temperature treatment. The expression response of AgHAT4 to salt stress in‘Ventura’was similar to that in‘Liuhe Huangxinqin’. The transcription levels of AgHAT4 increased first and then decreased in general，which reached the peak after 2 h of treatment. In ‘Ventura’，the expression of AgHAT4 exhibited the highest at 4 h under high temperature treatment，and it exhibited the highest expression at 2 h of low temperature treatment.

Key words: Apium graveolens, AgHAT4, gene expression, tissue；abiotic stress