However, despite clear-cut infection thread defect phenotypes, many transcription factors mutants, such as ern1, ipd3, nf-ya1, are still able to partially initiate early symbiotic signaling to form nodule primordia (Middleton et al., 2007; Yano et al., 2008; Horváth et al., 2011; Ovchinnikova et al., 2011; Cerri et al., 2012, 2016; Laloum et al., 2014; Laporte et al., 2014). This evidence concerns the gene ERN1 and infection.