In:
New Phytologist, Wiley, Vol. 224, No. 2 ( 2019-10), p. 833-847
Abstract:
The phosphoinositide kinase PIP 5K6 has recently been identified as a target for the mitogen‐activated protein kinase ( MAPK ) MPK 6. Phosphorylation of PIP 5K6 inhibited the production of phosphatidylinositol 4,5‐bisphosphate (PtdIns(4,5)P 2 ), impacting membrane trafficking and cell expansion in pollen tubes. Here, we analyzed whether MPK 6 regulated PIP 5K6 in vegetative Arabidopsis cells in response to the pathogen‐associated molecular pattern ( PAMP ) flg22. Promoter‐β‐glucuronidase analyses and quantitative real‐time reverse transcription polymerase chain reaction data show PIP 5K6 expressed throughout Arabidopsis tissues. Upon flg22 treatment of transgenic protoplasts, the PIP 5K6 protein was phosphorylated, and this modification was reduced for a PIP 5K6 variant lacking MPK 6‐targeted residues, or in protoplasts from mpk6 mutants. Upon flg22 treatment of Arabidopsis plants, phosphoinositide levels mildly decreased and a fluorescent reporter for PtdIns(4,5)P 2 displayed reduced plasma membrane association, contrasting with phosphoinositide increases reported for abiotic stress responses. Flg22 treatment and chemical induction of the upstream MAPK kinase, MKK 5, decreased phosphatidylinositol 4‐phosphate 5‐kinase activity in mesophyll protoplasts, indicating that the flg22‐activated MAPK cascade limited PtdIns(4,5)P 2 production. PIP 5K6 expression or PIP 5K6 protein abundance changed only marginally upon flg22 treatment, consistent with post‐translational control of PIP 5K6 activity. PtdIns(4,5)P 2 ‐dependent endocytosis of FM 4‐64, PIN 2 and the NADPH ‐oxidase RbohD were reduced upon flg22 treatment or MKK 5 induction. Reduced RbohD‐endocytosis was correlated with enhanced ROS production. We conclude that MPK 6‐mediated phosphorylation of PIP 5K6 limits the production of a functional PtdIns(4,5)P 2 pool upon PAMP perception.
Type of Medium:
Online Resource
ISSN:
0028-646X
,
1469-8137
Language:
English
Publisher:
Wiley
Publication Date:
2019
detail.hit.zdb_id:
208885-X
detail.hit.zdb_id:
1472194-6
