OsTCP19 coordinates lignin suppression and cellulose biosynthesis activation to modify lodging resistance in rice.

Lignin and cellulose are two essential elements of plant secondary cell walls that shape the mechanical characteristics of the culm to prevent crop lodging. However, the mechanisms of combinatorial regulation of lignin and cellulose composites to achieve optimal mechanical characteristics are unclear. Here, we showed that increasing OsTCP19 expression coordinately repressed lignin biosynthesis and promoted cellulose biosynthesis, resulting in enhanced lodging resistance. Repression of OsTCP19, on the contrary, coordinately activated lignin biosynthesis and inhibited cellulose biosynthesis, leading to lodging susceptibility. We revealed that OsTCP19 binds to the promoters of both MYB108 and MYB103L to activate their expression. MYB108 and MYB103L were responsible for repressing lignin biosynthesis and promoting cellulose biosynthesis, respectively. Moreover, up-regulation of OsTCP19 in fibers improved grain yield and lodging resistance. This study identified the OsTCP19-OsMYB108/OsMYB103L module as a key regulator of lignin and cellulose production in rice. The discovery opens up a new avenue for precisely manipulating lignin-cellulose composition to improve culm mechanical properties for lodging resistance.