Cloning and Expression Analysis of Serine Carboxypeptidases in Maize ( Zea mays L.)

Abstract

Serine carboxypeptidases play important roles in regulating the growth, development and disease resistance in plants. Reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) were applied to clone the serine carboxypeptidase gene named ZmSCP using cDNA of the high resistant maize inbred line R15 induced by Rhizoctonia solani. The cDNA full length of serine carboxypeptidase gene is 1874 bp (GenBank accession number: JF682634) containing a 999 bp complete open reading frame, encode 333 amino acids, with the molecular weight of 36.505 kD for the expected encoded proteins, and the isoelectric point of 4.75. The homology analysis indicated that the homology percentage were from 42% to 81% between the deduced amino acids from Zea mays L. and those from other plants. Phylogenetic analysis revealed that ZmSCP showed closer kinship with that of Oryza sativa and sorghum, indicating that they belong to the same evolutionary branch. ZmSCP protein has S10 conserved domain and belongs to S10 superfamily. The ZmSCP mRNA expression was analyzed by semi-quantitative and quantitative methods under different stress conditions. It is showed that the ZmSCP gene expression was basically up-regulated after ABA, JA, low temperature, and salt treatments, and showed two-step trend under induction of Rhizoctonia solani, with the first peak at 24h after inoculation, and the second peak at 60 h, showing significant differences compared with the case of non-inoculated. In addition, the expression level of ZmSCP gene increased under the ABA, JA, low tem- perature, and salt stresses with an expression peak at 48 h.