Annexin 1 Is a Component of eATP-Induced Cytosolic Calcium Elevation in <i>Arabidopsis thaliana</i> Roots

• Main Authors: Amirah Mohammad-Sidik, Jian Sun, Ryoung Shin, Zhizhong Song, Youzheng Ning, Elsa Matthus, Katie A. Wilkins, Julia M. Davies
• Format: Article
• Language: English
• Published: MDPI AG 2021-01-01
• Series: International Journal of Molecular Sciences
• Subjects: extracellular ATP; ADP; root; <i>Arabidopsis</i>; annexin 1; calcium
• Online Access: https://www.mdpi.com/1422-0067/22/2/494

Extracellular ATP (eATP) has long been established in animals as an important signalling molecule but this is less understood in plants. The identification of <i>Arabidopsis thaliana</i> 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. <i>Arabidopsis thaliana</i> 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.