Annexin 1 Is a Component of eATP-Induced Cytosolic Calcium Elevation in Arabidopsis thaliana Roots.

Amirah Mohammad-Sidik,Zhizhong Song,Ryoung Shin,Elsa Matthus,Katie A Wilkins,Youzheng Ning,Julia M Davies,Jian Sun

doi:10.3390/ijms22020494

Abstract

Extracellular ATP (eATP) has long been established in animals as an important signalling molecule but this is less understood in plants. The identification of Arabidopsis thaliana DORN1 (Does Not Respond to Nucleotides) as the first plant eATP receptor has shown that it is fundamental to the elevation of cytosolic free Ca2+ ([Ca2+]cyt) as a possible second messenger. eATP causes other downstream responses such as increase in reactive oxygen species (ROS) and nitric oxide, plus changes in gene expression. The plasma membrane Ca2+ influx channels involved in eATP-induced [Ca2+]cyt increase remain unknown at the genetic level. Arabidopsis thaliana Annexin 1 has been found to mediate ROS-activated Ca2+ influx in root epidermis, consistent with its operating as a transport pathway. In this study, the loss of function Annexin 1 mutant was found to have impaired [Ca2+]cyt elevation in roots in response to eATP or eADP. Additionally, this annexin was implicated in modulating eATP-induced intracellular ROS accumulation in roots as well as expression of eATP-responsive genes.

Highlights

Extracellular ATP is implicated as an apoplastic signal molecule in the abiotic and biotic stress responses of plants, their cellular viability, growth and stomatal regulation [1,2,3,4,5,6]
In Arabidopsis thaliana, Extracellular ATP (eATP) can act as a damage-associated molecular pattern (DAMP) and activates immunity signalling through the plasma membrane purinoreceptor AtDORN1 (Does Not Respond to Nucleotides1, known as P2K1) [7]
The touch response was similar between genotypes (p > 0.5) and the first eATP peak was lower in Atann1 it was not significantly different to Col-0 (p > 0.05) (Figure 1d)

Summary

Introduction

Extracellular ATP (eATP) is implicated as an apoplastic signal molecule in the abiotic and biotic stress responses of plants, their cellular viability, growth and stomatal regulation [1,2,3,4,5,6]. In Arabidopsis thaliana, eATP can act as a damage-associated molecular pattern (DAMP) and activates immunity signalling through the plasma membrane purinoreceptor AtDORN1 (Does Not Respond to Nucleotides, known as P2K1) [7]. A plasma membrane co-receptor P2K2 has recently been identified and both DORN1/P2K1 and. EATP perception triggers increase in root and leaf free cytosolic Ca2+ ([Ca2+ ]cyt ) [5] that can lead to the production of reactive oxygen species (ROS) as further putative signalling agents [11,12,13,14]. Many eATP-responsive genes contain the CAM-box motif, which suggests that CAMTAs (Calmodulin-binding Transcription Activators) are important components [18].

Methods

Results

Discussion

Conclusion