Mycorrhization phenotype of wild-type, nts382, and nts1007 in the split-root experiment I used for Affymetrix GeneChip analysis. (a, b) Colonization of initially inoculated root-parts at time-point of first harvest (= 19 days after inoculation with R. irregularis). (c) Colonization of both root-parts at time-point of second harvest (= 40 days after previous and 21 days after subsequent inoculation with R. irregularis) in either pre-inoculated ('treatment') or non-pre-inoculated ('control') plants. Crosses indicate the missing previous inoculation in case of control plants. The colonization of root-parts by R. irregularis was analyzed microscopically after staining of roots (a) and/or by transcript analysis of the fungal marker gene RiBTub1 (b, c). Transcript levels of RiBTub1 were determined by RT-qPCR and calculated in relation to GmSUBI-1 as plant reference gene. All data are given as mean values of six to seven plants + SD. Data of previously inoculated root-parts (a-c) were statistically analyzed by multiple Student's t-tests with Bonferroni correction. Different letters designate significant differences with P ≤0.05. Data of subsequently inoculated root-parts (c) were pairwise compared between control plants and mycorrhizal plants ('treatment'), each for wild-type (wt), nts382, and nts1007, by the Student's t-test. **P ≤0.01. n.d.: not detected.
Schaarschmidt et al. Genome Biology 2013 14:R62 doi:10.1186/gb-2013-14-6-r62