StPUB17, a novel potato UND/PUB/ARM repeat type gene, is associated with late blight resistance and NaCl stress

StPUB17, a novel UND/PUB/ARM repeat type gene, was isolated from leaves of potato (Solarium tuberosum L.) clone 386209.10 using the rapid amplification of cDNA ends strategy with the primers designed according to a potato EST fragment up-regulated by Phytophthora infestans. StPUB17 was confirmed intron-free by comparison of the cDNA and genomic DNAs. The RT-PCR analysis showed that StPUB17 was constitutively and differentially expressed in all tissues, and was significantly induced in detached leaves subjected to P. infestans, signal molecules such as salicylic acid, methyl jasmonate, ethylene, abscisic acid and wounding. The gene expression was also strongly up-regulated when in vitro plantlets were exposed to high (40 degrees C) and low (4 degrees C) temperatures and dehydration induced by polyethylene glycol and NaCl. The function of StPUB17 was further clarified by silencing it in potato using RNAi-based post-transcriptional gene silencing (PTGS). The results demonstrated that StPUB17-silenced plants exhibited more susceptible to the infection of P. infestans and more sensitive to the stress of NaCl. Present data indicated that StPUB17 is a gene harboring broad-spectrum responses to both biotic and abiotic stresses in the potato and may play crucial roles in late blight resistance and salt tolerance of the crop. (C) 2009 Elsevier Ireland Ltd. All rights reserved.