The WAK-like protein RFO1 acts as a sensor of the pectin methylation status in Arabidopsis cell walls to modulate root growth and defense
Résumé
Most organisms adjust their development according to their environmental conditions. For the majority, this implies sensing the alterations caused to their cell walls by different cues. Despite the relevance of this process, few molecular players involved in cell wall-sensing are known and characterized. Here, we show that the wall-associated kinase-like protein RESISTANCE TO FUSARIUM OXYSPORUM 1 (RFO1) is required for plant growth and early defense to F. oxysporum by sensing changes in the pectin-methylation levels at the cell wall. RFO1 dwell time at the plasma membrane is affected by that cell wall pectin-methylation-status, regulating MITOGEN ACTIVATED PROTEIN KINASE and gene expression pathways. We show that the extracellular domain of RFO1 binds de-methylated pectin in vitro, whose distribution at the cell wall is altered during F. oxysporum infection. Our data also indicate that RFO1 is required for the BR-dependent plant growth alteration in response to inhibition of pectin de-methyl-esterase activity at the cell wall. This work demonstrates that RFO1 is a novel pectin sensor that plays a unique dual role in plant growth and defense against vascular pathogens.