Abstract：WRKY is a class of transcription factor superfamilies found in higher plants. Many studies have shown that WRKY transcription factors play a critical role in biotic and abiotic stress of plants. However, these studies are mainly concentrated in arabidopsis and other model plant species and also have been reported in melon(Cucumis melo) and pepper(Capsicum annuum) and other vegetable crops, while the research of WRKY transcription factor about browning from luffa (Luffa cylindrical) has not been reported in present. The transcriptome database of luffa Fushi-3 fresh-cut browning flesh were obtained by using the transcriptome sequencing (RNA-seq)technology in early , and a total of four Unigene sequences that shared high homology with WRKY protein were screened from the transcriptome databases in this study. Sequence analysis showed that full length of these four luffa WRKY genes (Unigene0018509, Unigene0021412, Unigene0025291 and Unigene0034271) were 2,189、1,990、2,365 and 2,274 bp, respectively, and they all contained an open reading frame(ORF), and the GenBank accession numbers were from KY621843 to KY621846. Wolf Psort prediction indicated that WRKY proteins encoded by the four Unigene were located in the nuclear. Gene phylogenetic analysis and conservative domains analysis showed that four luffa WRKY transcription factors all had a WRKY conserved domain and C2H2 type zinc finger, which suggested that these four WRKY protein were members of the second category of WRKY protein family. The expression levels of these four WRKY genes in different tissues (root, stem, leaf,flower and fruit) and different storage periods of postharvest flesh were analyzed by quantitative Real-time PCR, and the expression patterns and RNA-seq results of four WRKY genes during different time points of fresh-cut browning flesh have also been analyzed. The results showed that all of the four WRKY genes had the tissue-specific expression, and their expression patterns were different. The variation trends of these four WRKY genes on the expression of quantitative Real-time PCR and RNA-seq databases (i.e.，FPKM value) in luffa fresh-cut browning fruit were almost same, and the expression of Unigene0018509, Unigene0021412 and Unigene0025291 were significantly up-regulated from 0 h to 6 h after fresh-cut browning, and the expression of Unigene0034271 was up-regulated during 0 ~ 3 h and then decreased in 6 h. Overall, the expression trends of four WRKY genes were up-regulated in different postharvest and storage browning periods and their expression patterns were not the same. This study may provide a theoretical foundation for further expounding the luffa browning mechanism and breeding of varieties.
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