Comparative analysis of gene expression in tomato roots during mild and severe potato spindle tuber viroid infection.

We employed microarray analysis to observe dynamic changes of gene expression profiles in response to mild and severe potato spindle tuber (PSTVd) infection in the roots of tomato cv ‘Rutgers’. Solanum lycopersicum cv 'Rutgers' was infected with mild (M) and severe (S23) PSTVd isolates. Root samples were collected at three phases of disease: i) early stage of symptoms -17 dpi; ii) full spectrum of symptoms – 24 dpi; iii) recovery - 49 dpi. Three independent biological replicates of PSTVd-M, PSTVd-S23 and pUC9 (control) were analised at every time point but two replicates of PSTVd-S23 at 17dpi. Totally 26 samples of RNA were analysed.