Alternative splicing of the receptor-like kinase Nt-Sd-RLK in tobacco cells responding to lipopolysaccharides: suggestive of a role in pathogen surveillance and perception?

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.