Silencing in Soybean Results in Activated Defense Responses.

Receptor-like kinases (RLKs) are a large group of pattern recognition receptors (PRRs) and play a critical role in recognizing pathogens, transducing defense signals, and mediating the activation of immune defense responses. Although extensively studied in the model plant Arabidopsis, studies of RLKs in crops, including soybean, are limited. When a () homolog (referred to as hereafter) was silenced by the BPMV ()-induced gene silencing (BPMV-VIGS), it resulted in phenotypes that were reminiscent of constitutively activated defense responses, including a significantly stunted stature with observable cell death on the leaves of the silenced plants. In addition, both SA and HO were over-accumulated in the leaves of the -silenced plants. Consistent with this autoimmune phenotype, -silenced plants exhibited significantly enhanced resistance to both () and (SMV), two different types of pathogens, compared to the vector control plants. Together, our results indicated that BIR1 is a negative regulator of immunity in soybean and the function of BIR1 homologs is conserved in different plant species.