Original Article

Planta

, Volume 227, Issue 3, pp 659-669

The Arabidopsis cax3 mutants display altered salt tolerance, pH sensitivity and reduced plasma membrane H+-ATPase activity

  • Jian ZhaoAffiliated withUnited States Department of Agriculture/Agricultural Research Service Children’s Nutrition Research Center, Baylor College of Medicine
  • , Bronwyn J. BarklaAffiliated withInstituto de Biotecnología, Universidad Nacional Autónoma de México
  • , Joy MarshallAffiliated withDepartment of Biology, Prairie View A&M University
  • , Jon K. PittmanAffiliated withFaculty of Life Sciences, University of Manchester
  • , Kendal D. HirschiAffiliated withUnited States Department of Agriculture/Agricultural Research Service Children’s Nutrition Research Center, Baylor College of MedicineVegetable and Fruit Improvement Center, Texas A&M University Email author 

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Abstract

Perturbing CAX1, an Arabidopsis vacuolar H+/Ca2+ antiporter, and the related vacuolar transporter CAX3, has been previously shown to cause severe growth defects; however, the specific function of CAX3 has remained elusive. Here, we describe plant phenotypes that are shared among cax1 and cax3 including an increased sensitivity to both abscisic acid (ABA) and sugar during germination, and an increased tolerance to ethylene during early seedling development. We have also identified phenotypes unique to cax3, namely salt, lithium and low pH sensitivity. We used biochemical measurements to ascribe these cax3 sensitivities to a reduction in vacuolar H+/Ca2+ transport during salt stress and decreased plasma membrane H+-ATPase activity. These findings catalog an array of CAX phenotypes and assign a specific role for CAX3 in response to salt tolerance.

Keywords

Arabidopsis Antiporter Calcium Salt tolerance Transport