Insight on genes affecting tuber development in potato upon potato spindle tuber viroid (PSTVd) infection

Abstract

Potato (Solanum tuberosum L) is a natural host of Potato spindle tuber viroid (PSTVd) which can cause characteristic symptoms on developing plants including stunting phenotype and distortion of leaves and tubers. PSTVd is the type species of the family Pospiviroidae, and can replicate in the nucleus and move systemically throughout the plant. It is not well understood how the viroid can affect host genes for succeful invasion and which genes show altered expreion levels upon infection. Our primary focus in this study is the identification of genes which can affect tuber formation since viroid infection can strongly influence tuber development and especially tuber shape. In this study, we used a largescale method to identify differentially expreed genes in potato. We have identified defence, stre and sugar metabolism related genes having altered expreion levels upon infection. Additionally, hormone pathway related genes showed significant up- or down-regulation. DWARF1/DIMINUTO, Gibberellin 7-oxidase and BEL5 transcripts were identified and validated showing differential expreion in viroid infected tiues. Our study suggests that gibberellin and brainosteroid pathways have a poible role in tuber development upon PSTVd infection.