Abstract:

Polygalacturonase-inhibiting proteins (PGIPs), a group of plant defense proteins, play a crucial role in plant defense reaction. In order to excavate the important function of AhPGIPs, the study cloned AhPGIP1 and AhPGIP2 from H.11648 by PCR. The expression levels of AhPGIP1 and AhPGIP2 were analyzed in sisal H.11648 under several treatments, including Phytophthora nicotianae Breda, methyl jasmonate (MeJA), salicylic acid (SA), salt, low temperature and wounding by fluorescence quantitative PCR (qRT-PCR) technique. The results showed that the full-length cDNA of AhPGIP1 contained 1008 bp and was predicted to encode a protein of 335 amino acids with a theoretical molecular mass of 36.7 kDa and pI of 8.65. The full-length cDNA of AhPGIP2 contained 981 bp, and was predicted to encode a protein of 326 amino acids with a theoretical molecular mass of 35.8 kDa and pI of 8.98. The expression level of AhPGIP1 was not changed at 24 h and then significantly up-regulated by Phytophthora nicotianae Breda, and reached the max value after inoculating 48 h, and was up-regulated by MeJA, SA, salt, and wounding, and reached the max value after stresses 3, 12, 3 and 12 h, respectively. The expression level of AhPGIP1 was not changed by low temperature at 6 h and significantly down-regulated at 3, 12 and 24 h. The expression level of AhPGIP2 was significantly down-regulated at 24, 36 and 48 h and up-regulated at 72 h by Phytophthora nicotianae Breda, was significantly up-regulated by salt, low temperature, SA and MeJA, and reached the max value after stresses 3, 24, 3 and 12 h respectively. The expression level of AhPGIP2 was significantly up-regulated and reached the max value after stress 12 h by wounding, and significantly down-regulated after stress 3, 6, and 24 h. The study laid a solid foundation for further exploration of the function of AhPGIPs.

Key words: sisal, qRT-PCR, gene expression, PGIP