Dan-Dan Liu, Hu-Jiao Lan, Hashimi Said Masoud, Mei-Yan Ye, Xian-Yong Da, Chen-Li Zhong, Sheng-Nan Tian, Jian-Zhong Liu

Int J Mol Sci.; 2022 Jul 5;23(13):7450.  doi: 10.3390/ijms23137450.

Abstract

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 BAK1-interacting receptor-like kinase (BIR1) homolog (referred to as GmBIR1 hereafter) was silenced by the BPMV (Bean pod mottle virus)-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 H₂O₂ were over-accumulated in the leaves of the GmBIR1-silenced plants. Consistent with this autoimmune phenotype, GmBIR1-silenced plants exhibited significantly enhanced resistance to both Pseudomonas syringae pv. glycinea (Psg) and Soybean mosaic virus (SMV), two different types of pathogens, compared to the vector control plants. Together, our results indicated that GmBIR1 is a negative regulator of immunity in soybean and the function of BIR1 homologs is conserved in different plant species.

See https://pubmed.ncbi.nlm.nih.gov/35806456/

Figure 5

Silencing GmBIR1 reduces the activation of GmMPK3/GmMPK6 in response to flg22 treatment. Leaf discs from indicated soybean plants were incubated on moist filter paper for 24 h to allow recovery from wounding before being treated with 10 μM flg22 or diluted DMSO. The kinase activities were detected by Western blotting using Phosph-p44/p42 MAP Erk1/2 antibody. Coomassie Blue–stained gel (CBS) used as loading controls. The experiment was repeated 3 times with similar results.