The endosymbiont Methylorubrum extorquens DSM13060 reprograms development and stress responses of Scots pine seedlings

The meristem-associated endosymbiont M. extorquens DSM13060 significantly increases needle and root growth of Scots pine (Pinus sylvestris L.) seedlings without producing plant hormones, but by aggregating around host nuclei. Here we studied gene expression of the pine host induced by M. extorquens DSM13060 infection. We selected the time point of 90 days post-inoculation for our analysis based, because at this point, Methylorubrum extorquens DSM13060 has systemically colonized the pine seedlings, being found throughout tissues of roots and shoots. Analysis used total RNA of the untreated pine seedlings as control samples for comparison to the experimental samples, seedlings inoculated with M. extorquens DSM13060, harvested at 90 days post-inoculation. cDNAs of the treatment/control were hybridized with custom microarray chips in total of six times (n=6) with two-color dye-swap approach to minimize technical variability and dye bias.