Figure 5.

The bHLH476 Cytokinin Primary Response Transcription Factor Positively Regulates Symbiotic Nodulation.

(A) Quantification of the number of nodules formed under greenhouse conditions 30 DAI with S. meliloti on roots expressing RNAi constructs targeting CKX1, bHLH476, or GUS (as control), respectively.

(B) Real-time RT-PCR analysis of CKX1 and bHLH476 expression in roots expressing RNAi constructs targeting each gene or GUS (as control), respectively. The GUS RNAi control was set to 1 (dotted line). Error bars represent sd (n = 5 independent transgenic roots/construct), and a Kruskal-Wallis test was performed to assess significant differences (α < 0.05).

(C) Quantification of the nodulation efficiency under in vitro conditions (14 DAI) of roots expressing RNAi constructs targeting bHLH476 (two independent RNAi constructs) or GUS (as control), respectively.

(D) Quantification of the number of nodules formed under greenhouse conditions (14 DAI) on roots of a Tnt1 insertional mutant affecting the bHLH476 gene. WT, wild type.

In [(A), (C), and (D)], error bars represent confidence interval (α = 0.05; n > 30 independent transgenic roots/genotype), and a Kruskal-Wallis (A) or Mann-Whitney [(C) and (D)] test was performed to assess significant differences (α < 0.05).