Comparative analysis of gene expression in tomato leaves 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 leaves of tomato cv ‘Rutgers’. Solanum lycopersicum cv 'Rutgers' was infected with mild (M) and severe (S23) PSTVd isolates. Leaf samples were collected at four phases of disease: i) symptomless – 8 days post inoculation (dpi); ii) early stage of symptoms -17 dpi; iii) full spectrum of symptoms – 24 dpi; iiii) 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-M at 8dpi. Totally 35 samples of RNA were analysed.