Functional characterization of the silenced potato cysteine proteinase inhibitor gene (PCPI) in Phytophthora infestans resistance

Construct carrying dsRNA of the potato cysteine proteinase inhibitor (PCPI) was transiently expressed in Phythophthora resistance potato cultivar White Lady. Expression was strongly reduced as indicated by a reduction of up to 93.94% in PCPI transcript levels. Silencing of PCPI resulted in a marked increase in lesion size and water soaking, indicating that cysteine proteinase inhibitor plays a role in limiting lesion expansion. This analysis sheds light on the transcriptional changes that accompany plant infection by P. infestans, and will aid in identifying potential gene targets that could be used to generate stable resistant transgenic plants of the sensitive genotypes.