Skip to main content
SLU publication database (SLUpub)

Research article2021Peer reviewedOpen access

The AtCRK5 Protein Kinase Is Required to Maintain the ROS NO Balance Affecting the PIN2-Mediated Root Gravitropic Response in Arabidopsis

Cseplo, Agnes; Zsigmond, Laura; Andrasi, Norbert; Baba, Abu Imran; Labhane, Nitin M.; Peto, Andrea; Kolbert, Zsuzsanna; Kovacs, Hajnalka E.; Steinbach, Gabor; Szabados, Laszlo; Feher, Attila; Rigo, Gabor


The Arabidopsis AtCRK5 protein kinase is involved in the establishment of the proper auxin gradient in many developmental processes. Among others, the Atcrk5-1 mutant was reported to exhibit a delayed gravitropic response via compromised PIN2-mediated auxin transport at the root tip. Here, we report that this phenotype correlates with lower superoxide anion (O-2(center dot-)) and hydrogen peroxide (H2O2) levels but a higher nitric oxide (NO) content in the mutant root tips in comparison to the wild type (AtCol-0). The oxidative stress inducer paraquat (PQ) triggering formation of O-2(center dot-) (and consequently, H2O2) was able to rescue the gravitropic response of Atcrk5-1 roots. The direct application of H2O2 had the same effect. Under gravistimulation, correct auxin distribution was restored (at least partially) by PQ or H2O2 treatment in the mutant root tips. In agreement, the redistribution of the PIN2 auxin efflux carrier was similar in the gravistimulated PQ-treated mutant and untreated wild type roots. It was also found that PQ-treatment decreased the endogenous NO level at the root tip to normal levels. Furthermore, the mutant phenotype could be reverted by direct manipulation of the endogenous NO level using an NO scavenger (cPTIO). The potential involvement of AtCRK5 protein kinase in the control of auxin-ROS-NO-PIN2-auxin regulatory loop is discussed.


auxin transport; Calcium-Dependent Protein Kinase-Related Kinase (CRK); reactive oxygen species; superoxide anion; hydrogen peroxide; nitric oxide; paraquat; oxidative stress; root gravitropism; Arabidopsis

Published in

International Journal of Molecular Sciences
2021, Volume: 22, number: 11, article number: 5979
Publisher: MDPI

    UKÄ Subject classification

    Biochemistry and Molecular Biology

    Publication identifier


    Permanent link to this page (URI)