Calcium-binding mitochondrial GTPase involved in calcium signaling during salt stress response (PubMed:16832621). May play a role in the progression of embryonic cell division, development of haploid male and female gametes, and pollen tube growth (PubMed:21494602). Activated by calcium. Expressed roots, rosette and cauline leaves, stems, flowers and siliques. By abscisic acid (ABA) and NaCl. No visible phenotype under normal growth conditions (PubMed:16832621, PubMed:18344283). Mutant plants show increased sensitivity to ABA, NaCl or mannitol during germination (PubMed:16832621). Belongs to the mitochondrial Rho GTPase family.