ROS-mediated plasmodesmal regulation requires a network of an Arabidopsis receptor-like kinase, calmodulin-like proteins, and callose synthases

Abstract

Plasmodesmata (PD) play a critical role in symplasmic communication, coordinating plant activities related to growth & development, and environmental stress responses. Most developmental and environmental stress signals induce reactive oxygen species (ROS)-mediated signaling in the apoplast that causes PD closure by callose deposition. Although the apoplastic ROS signals are primarily perceived at the plasma membrane (PM) by receptor-like kinases (RLKs), such components involved in PD regulation are not yet known. Here, we show that an Arabidopsis NOVEL CYS-RICH RECEPTOR KINASE (NCRK), a PD-localized protein, is required for plasmodesmal callose deposition in response to ROS stress. We identified the involvement of NCRK in callose accumulation at PD channels in either basal level or ROS-dependent manner. Loss-of-function mutant (ncrk) of NCRK induces impaired callose accumulation at the PD under the ROS stress resembling a phenotype of the PD-regulating GLUCAN SYNTHASE-LIKE 4 (gsl4) knock-out plant. The overexpression of transgenic NCRK can complement the callose and the PD permeability phenotypes of ncrk mutants but not kinase-inactive NCRK variants or Cys-mutant NCRK, in which Cys residues were mutated in Cys-rich repeat ectodomain. Interestingly, NCRK mediates plasmodesmal permeability in mechanical injury-mediated signaling pathways regulated by GSL4. Furthermore, we show that NCRK interacts with calmodulin-like protein 41 (CML41) and GSL4 in response to ROS stress. Altogether, our data indicate that NCRK functions as an upstream regulator of PD callose accumulation in response to ROS-mediated stress signaling pathways.

The multifarious role of callose and callose synthase in plant development and environment interactions

“…(B) Typical images of aniline blue stained callose in different tissues and plant species. (B1) Callose deposition at the plasmodesmata of Arabidopsis leaf epidermal cells, scale bar = 20 µm ( Vu et al., 2022 ). (B2) Callosic cell plate formation (indicated by arrow) during cytokinesis of rice pollen mother cells, scale bar = 10 μm ( Zhang et al., 2018 ).…”

Péptidos pequeños bioactivos en plantas y su papel en el desarrollo y la defensa

“…La familia RLK contiene varias proteínas que participan en el desarrollo de las hojas. El receptor ERECTA (ER) pertenece a la subfamilia LRR-RLK, que incluye también a ERECTA-LIKE 1 (ERL1) y ERL2, dichas proteínas desempeñan un papel importante en la regulación de la morfología foliar, desarrollo de los estomas y respuesta al estrés biótico y abiótico (Fischer y Teichmann, 2017;Chen et al, 2019;Vu et al, 2023). El receptor tipo cinasa mejor conocido y ampliamente estudiado, se denomina BRASSINOSTEROID RESPONSE 1 (BRI 1).…”

Roles of ROS and redox in regulating cell-to-cell communication: Spotlight on viral modulation of redox for local spread

“…These rapid defenses were absent in plants where CML41 expression was knocked down, and there was constitutively elevated callose levels at PD in plant overexpressing CML41 . CML41 interacts with the receptor-like kinase NOVEL CYS-RICH RECEPTOR KINASE (NCRK) as part of a module that causes ROS-induced callose accumulation at PD (Vu et al, 2022). This interaction is crucial because NRCK phosphorylates CML41, which is necessary for the accumulation of callose at the PD mediated by GLS4.…”

“…Phosphorylation modifications can alter the conformation and interactions of these proteins, affecting their ability to regulate plasmodesmal permeability. For example, ROS application intensifies the interaction between PD proteins (CML41) and NCRK [described above; (Vu et al, 2022)]. ROS can also induce redox modifications in proteins, forming disulfide bonds or other covalent modifications.…”

“…In some cases, viral control of TRX can help establish a microenvironment rich in ROS that facilitates viral accumulation and spread. In other cases, virus-mediated reduction of ROS hampers SA-related defenses, including those regulating PD permeability (Table 1) (Wu et al, 2018;Wang et al, 2021;Vu et al, 2022).…”