Cloning and Expression Analysis of Transcription Factor LcWRKY21 Gene from Luffa cylindrical

Abstract: A length of 1 809 bp cDNA was isolated from Luffa cylindrical by rapid amplification of cDNA ends (RACE) and reverse transcription-polymerase chain reaction (RT-PCR) techniques， which contained a 1 044 bp open reading frame (ORF) that encoded 347 amino acids， with a predicted molecular weight of 38.61 kDa and a hypothetical isoelectric point of 9.46. It shared over 84% identity with the homologous proteins from Cucumis melo and Cucumis sativus， proving that it was highly conservative. The acquired gene was named LcWRKY21. Wolf Psort protection indicated that LcWRKY21 protein was located in the nucleus， and Motif Scan analysis showed that LcWRKY21 protein had the domains of conserved WRKY， DNA binding and zinc finger in the position of 274-340， 279-399 and 325-337 sites， respectively. Homology analysis suggested that LcWRKY21 protein was a member of the WRKY group II transcription factors. The Real-time quantitative polymerase chain reaction (qPCR) revealed that LcWRKY21 exhibited a tissue specific expression， and the expression level in Luffa ‘Fusi-2’ fruits was the highest， following by roots and stems， and the expression levels of flowers and leaves were lower. The levels of LcWRKY21 were different among six Luffa varieties， and the expression in browning sensitive Luffa cylindrical cultivar ‘Fusi-2’ was higher than that in ‘Fusi-3’， ‘Fusi-4’ and Luffa acutangula Roxb (‘Fusi-5’ and ‘Fusi-6’) and browning resistance Luffa cylindrical cultivar ‘Fusi-1’. The expression level of LcWRKY21 gene in different mature period of ‘Fusi-2’ was up-regulated from the day after pollination of 7 d to 35 d， then decreased. Furthermore， the relative expression level of LcWRKY21 in ‘Fusi-2’ was up-regulated during fresh-cut browning processes， suggesting that LcWRKY21 gene may play aregulatory role in Luffa browning process.

CSTR: 32200.14.cjcb.2017.10.0002