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

C-Type LECTIN receptor-like kinase 1 and ACTIN DEPOLYMERIZING FACTOR 3 are key components of plasmodesmata callose modulation

Plasmodesmata (PDs) are intercellular organelles carrying multiple membranous nanochannels that allow the trafficking of cellular signalling molecules. The channel regulation of PDs occurs dynamically and is required in various developmental and physiological processes. It is well known that callose is a critical component in regulating PD permeability or symplasmic connectivity, but the understanding of the signalling pathways and mechanisms of its regulation is limited. Here, we used the reverse genetic approach to investigate the role of C-type lectin receptor-like kinase 1 (CLRLK1) in the aspect of PD callose-modulated symplasmic continuity. Here, we found that loss-of-function mutations in CLRLK1 resulted in excessive PD callose deposits and reduced symplasmic continuity, resulting in an accelerated gravitropic response. The protein interactome study also found that CLRLK1 interacted with actin depolymerizing factor 3 (ADF3) in vitro and in plants. Moreover, mutations in ADF3 result in elevated PD callose deposits and faster gravitropic response. Our results indicate that CLRLK1 and ADF3 negatively regulate PD callose accumulation, contributing to fine-tuning symplasmic opening apertures. Overall, our studies identified two key components involved in the deposits of PD callose and provided new insights into how symplasmic connectivity is maintained by the control of PD callose homoeostasis.

Enhancing climate change resilience in agricultural crops

Climate change threatens global food and nutritional security through negative effects on crop growth and agricultural productivity. Many countries have adopted ambitious climate change mitigation and adaptation targets that will exacerbate the problem, as they require significant changes in current agri-food systems. In this review, we provide a roadmap for improved crop production that encompasses the effective transfer of current knowledge into plant breeding and crop management strategies that will underpin sustainable agriculture intensification and climate resilience. We identify the main problem areas and highlight outstanding questions and potential solutions that can be applied to mitigate the impacts of climate change on crop growth and productivity. Although translation of scientific advances into crop production lags far behind current scientific knowledge and technology, we consider that a holistic approach, combining disciplines in collaborative efforts, can drive better connections between research, policy, and the needs of society.

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

Callose is an important linear form of polysaccharide synthesized in plant cell walls. It is mainly composed of β-1,3-linked glucose residues with rare amount of β-1,6-linked branches. Callose can be detected in almost all plant tissues and are widely involved in various stages of plant growth and development. Callose is accumulated on plant cell plates, microspores, sieve plates, and plasmodesmata in cell walls and is inducible upon heavy metal treatment, pathogen invasion, and mechanical wounding. Callose in plant cells is synthesized by callose synthases located on the cell membrane. The chemical composition of callose and the components of callose synthases were once controversial until the application of molecular biology and genetics in the model plant Arabidopsis thaliana that led to the cloning of genes encoding synthases responsible for callose biosynthesis. This minireview summarizes the research progress of plant callose and its synthetizing enzymes in recent years to illustrate the important and versatile role of callose in plant life activities.