Topic:

An Evolutionarily Conserved Long-Distance Migrating Peptide Regulates Lignin Biosynthesis and Plant Immunity

Abstract: 

Peptides act as hormones to deliver intercellular signals to govern intracellular transcriptional networks during complex developmental processes. Lignin in vascular tissues plays a critical role in plant terrestrialization for water-conducting and structural-supporting functions. Lignin also forms physical barriers against pathogen invasion. Comprehensive knowledge has been established on the transcriptional networks for the regulation of lignin biosynthesis. However, the long-distance migrating peptides transported by vascular sap for regulating monolignol biosynthesis remain unknown. Here, we used high throughput peptidomic analyses to reveal a group of evolutionarily conserved long-distance migrating peptides in vascular sap of five angiosperms, Cinnamomum kanehirae, Populus trichocarpa, Eucalyptus grandis, Glycine max and Zea mays. We found one of the conserved peptides, named Angiosperm Sap Peptide (ASAP), can strengthen the plant cell wall through the enhancement of the S-lignin pathway and trigger the salicylic acid-mediated immune responses to resist root-knot nematodes. The phosphoproteomic analyses exhibited that the ASAP rapidly induced protein phosphorylation involved in lignin biosynthesis and xylem development. Sequence identity analysis showed that ASAP emerged in land plants, suggesting its evolutionarily conserved role on regulation of lignin biosynthesis to facilitate plant terrestrialization and resistance to pathogens.

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