Abstract:

【Objective】This study aimed to clone a full length cDNA of MhWRKY1 from Malus hupehensis and analyze the expression pattern of MhWRKY1 in different tissues (leaf, stem and root) and the expression pattern after treatment with the elicitors salicylic acid (SA), methyl jasmonate (MeJA), 1-aminocyclopropane-1-carboxylic acid (ACC) and apple ring spot pathogens (Botryosphaeria berengeriana de Not. f. sp. Parabola Nise Koganezawa et Sakuma), respectively.【Method】The full length cDNA sequence of MhWRKY1 from the M. hupehensis was isolated using the method of in silico cloning combined with the RT-PCR validation. Real-time quantitative RT-PCR (qRT-PCR) was performed to determine the expression pattern of MhWRKY1 in different tissues (leaf, stem and root) and the expression pattern in leaf, stem and root after treatment with SA, MeJA and ACC, respectively. And the expression of this gene after treatment with apple ring spot pathogens was also performed using qRT-PCR.【Result】 1 338 bp full-length cDNA sequence of MhWRKY1 was cloned and the GenBank database accession number was FJ598139. Bioinformatics analysis showed that the open reading frame of this gene was 993 bp, encoding 330 amino acids. The deduced amino acid sequence shares 68%, 68%, 66%, 60%, 59%, 49% and 43% identity with poplar WRKY26, WRKY20, soybean WRKY, potato WRKY2, tobacco WRKY, arabidopsis WRKY7, and rice WRKY53. MhWRKY1 protein contains one conserved WRKY domains that is composed of about 60 amino acid residues with the WRKYGQK sequence followed by a C2H2 zinc finger motif, belongs to the second type of transcription factor. Expression analysis showed that the expression of MhWRKY1 in leaves and stems were high and the expression in leaves and stem were 4.81-fold and 3.75-fold than that in root, respectively. SA, MeJA and ACC induced the expression of MhWRKY1 gene in leave, stem and root, respectively. In addition, the expression of this gene was enhanced and up to the peak at 12 h (9-fold than untreated materials) after treatment with apple ring rots pathogens during the first 72 h.【Conclusion】MhWRKY1 could be involved in SA, MeJA and ET-mediated basic signaling pathway of plant defense responses and disease resistance signal transduction network. MhWRKY1 was involved in defense responses mediated by apple ring rot pathogen. It might be play a key role in disease resistance in M. hupehensis.

Key words: Malus hupehensis (Pamp.) Rehd, MhWRKY1, expression pattern, SA, MeJA, ACC, apple ring rot pathogen (Botryosphaeria berengeriana de Not. f. sp. Parabola Nise Koganezawa et Sakuma)