Figure 7.

Functional analysis of GmNF-YA1 in transgenic roots of chimeric soybean plants inoculated with R. irregularis. Gene expression of GmNF-YA1a/b was suppressed by an RNAi approach in A. rhizogenes-transformed roots of wild-type, nts382, and nts1007. Plants were harvested for analysis 3 weeks after AM fungal inoculation. (a, b) Analysis of the RNAi effect and the root colonization by R. irregularis in transformed roots. Transcript levels of GmNF-YA1 (gray columns) and RiBTub1 (black columns) were determined by RT-qPCR and are given in relation to GmSUBI-1 (a). For gene-specific transcript levels of GmNF-YA1a and GmNF-YA1b see Table 2. AM fungal colonization of roots was in addition analyzed microscopically after staining of roots (b). RNAi: roots transformed with A. rhizogenes carrying the RNAi construct. EV: empty vector control. Data are presented as means + SD with n ≥30 and n ≥15 for wild-type and nark mutants, respectively, coming from two independent experiments. Data of EV control and RNAi plants were pairwise compared by the Student's t-test. *P ≤0.05, **P ≤0.01, ***P ≤0.001. (c) AM fungal colonization caused by individual infection events. Bar represents 100 µm.