Nt‐Sd‐RLK encodes an S‐domain lectin receptor‐like kinase that is induced in response to microbe‐associated molecular pattern molecules (MAMPs) such as lipopolysaccharide (LPS). In this study, we investigated the alternative splicing of Nt‐Sd‐RLK in response to LPS stimulation. Our data indicate that in nonstimulated cells, a shorter transcript of Nt‐Sd‐RLK is generated and that in response to LPS, alternative splicing produces the full‐length transcript. We propose that the extracellular domain of Nt‐Sd‐RLK encoded by the shorter transcript functions in pathogen surveillance. Once this domain binds LPS, alternative splicing generates the kinase domain‐containing Nt‐Sd‐RLK that activates downstream signalling leading to a defence response. Thus, our findings suggest that plant defence signalling may be regulated through the alternative splicing of receptor‐like kinases involved in pathogen recognition.