Cytochrome c and the ABA signaling pathway interact to regulate root cell elongation in Arabidopsis

FACUNDO ROLDAN; NATANAEL MANSILLA; ELINA WELCHEN; DANIEL GONZALEZ

Santa Fe

Congreso; XXXIII Argentinian Meeting Of Plant Physiology (RAFV 2021); 2021

Sociedad Argentina de Fisiología Vegetal

Cytochrome c (CYTc) is a soluble protein responsible for the transport of electrons between complexes III and IV of the inner mitochondrial membrane. It has been shown that plants with reduced CYTc levels show low growth rate and late flowering. These phenotypes are due to an altered cellular energy status which impacts on different hormonal pathways to fine-tune plant growth. In this work, we studied the role of CYTc in Arabidopsis root growth. Mutants in CYTC-1, one of the genes that encode CYTc, showed a decreased root growth rate, with shorter mature elongated cells and a reduced number of meristematic cells. Abscisic acid (ABA) is a known player in root cell elongation, with either stimulatory or inhibitory roles depending on the concentration. Roots of cytc-1 mutants were more sensitive than the wild-type to treatment with stimulatory amounts of ABA, which largely reverted the elongation deficiency of these mutants. In addition, the activity of a fluorescent reporter of the ABA signaling pathway was increased in a cytc-1 mutant background. These findings suggests that CYTc deficiency affects ABA responses to regulate root cell elongation.