Arabidopsis thaliana constitutively active ROP11 interacts with the NADPH oxidase respiratory burst oxidase homologue F to regulate reactive oxygen species production in root hairs.

Reactive oxygen species (ROS) play a key signalling role in cells. Plant NADPH oxidases, also known as respiratory burst oxidase homologues (Rbohs), are well characterised ROS-generating systems. In this study, we found that the constitutively active small guanosine triphosphatase (GTPase) ROP11 (CA-ROP11) interacted with RbohF by using a yeast two-hybrid analysis, a pull-down assay and an in vivo bimolecular fluorescence complementation assay. The mutation of amino acid L336 or L337 in RbohF abolished its interaction with CA-ROP11. Coexpression of CA-ROP11 and wild-type RbohF in Nicotiana benthamiana Domin enhanced ROS production compared with coexpression of CA-ROP11 and mutant RbohF or of dominant negative ROP11 and wild-type RbohF. Moreover, CA-ROP11 overexpression resulted in ROS accumulation and a swollen root hair phenotype in Arabidopsis thaliana (L.) Heynh. The deletion of RbohF partially reduced the increase in ROS in Arabidopsis plants overexpressing CA-ROP11. These results suggest that Arabidopsis ROP11 modulates ROS production by interacting with RbohF in root hairs.