The Mitochondrial Phosphate Transporters Modulate Plant Responses to Salt Stress via Affecting ATP and Gibberellin Metabolism in <em>Arabidopsis thaliana</em>

<div><p>The mitochondrial phosphate transporter (MPT) plays crucial roles in ATP production in plant cells. Three <em>MPT</em> genes have been identified in <em>Arabidopsis thaliana</em>. Here we report that the mRNA accumulations of <em>AtMPTs</em> were up-regulated by high salinity stress in <em>A. thaliana</em> seedlings. And the transgenic lines overexpressing <em>AtMPTs</em> displayed increased sensitivity to salt stress compared with the wild-type plants during seed germination and seedling establishment stages. ATP content and energy charge was higher in overexpressing plants than those in wild-type <em>A. thaliana</em> under salt stress. Accordingly, the salt-sensitive phenotype of overexpressing plants was recovered after the exogenous application of atractyloside due to the change of ATP content. Interestingly, Genevestigator survey and qRT-PCR analysis indicated a large number of genes, including those related to gibberellin synthesis could be regulated by the energy availability change under stress conditions in <em>A. thaliana</em>. Moreover, the exogenous application of uniconazole to overexpressing lines showed that gibberellin homeostasis was disturbed in the overexpressors. Our studies reveal a possible link between the ATP content mediated by AtMPTs and gibberellin metabolism in responses to high salinity stress in <em>A. thaliana</em>.</p>