NRGA1, a putative mitochondrial pyruvate carrier, mediates ABA regulation of guard cell ion channels and drought stress responses in Arabidopsis.
Abscisic acid (ABA) regulates ion channel activity and stomatal movements in response to drought and other stresses. Here, we show that the Arabidopsis thaliana gene NRGA1 is a putative mitochondrial pyruvate carrier which negatively regulates ABA-induced guard cell signaling. NRGA1 transcript was abundant in the A. thaliana leaf and particularly in the guard cells, and its product was directed to the mitochondria. The heterologous co-expression of NRGA1 and AtMPC1 in yeast complemented a loss-of-function mitochondrial pyruvate carrier (MPC) mutant. The nrga1 loss-of-function mutant was very sensitive to the presence of ABA in the context of stomatal movements, and exhibited a heightened tolerance to drought stress. Disruption of NRGA1 gene resulted in increased ABA inhibition of inward K(+) currents and ABA activation of slow anion currents in guard cells. The nrga1/NRGA1 functional complementation lines restored the mutant's phenotypes. Furthermore, transgenic lines of constitutively overexpressing NRGA1 showed opposite stomatal responses, reduced drought tolerance, and ABA sensitivity of guard cell inward K(+) channel inhibition and anion channel activation. Our findings highlight a putative role for the mitochondrial pyruvate carrier in guard cell ABA signaling in response to drought.
Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan, 250100, China.
Chun-Long
CL
Li
Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan, 250100, China.
Mei
M
Wang
Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan, 250100, China.
Xiao-Yan
XY
Ma
Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan, 250100, China weizhang@sdu.edu.cn.
Wei
W
Zhang
D000040:Abscisic Acid / Q000494:pharmacology*; D000222:Adaptation, Physiological / Q000187:drug effects; D000595:Amino Acid Sequence; D027321:Anion Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002465:Cell Movement / Q000187:drug effects; D055864:Droughts; D005816:Genetic Complementation Test; D015640:Ion Channel Gating / Q000187:drug effects; D026901:Membrane Transport Proteins / Q000378:metabolism*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D024101:Mitochondrial Proteins; D008954:Models, Biological; D008969:Molecular Sequence Data; D027501:Monocarboxylic Acid Transporters; D009154:Mutation / Q000235:genetics; D010802:Phylogeny; D054046:Plant Stomata / Q000166:cytology*; D030821:Plants, Genetically Modified; D015221:Potassium Channels / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D013312:Stress, Physiological / Q000187:drug effects*; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects
D027321:Anion Transport Proteins; D029681:Arabidopsis Proteins; C000595629:At4g05590 protein, Arabidopsis; C573715:FMP37 protein, S cerevisiae; C000629172:MPC1 protein, Arabidopsis; D026901:Membrane Transport Proteins; D033681:Mitochondrial Membrane Transport Proteins; D024101:Mitochondrial Proteins; D027501:Monocarboxylic Acid Transporters; D015221:Potassium Channels; D029701:Saccharomyces cerevisiae Proteins; D000040:Abscisic Acid
ABA; NRGA1; drought stress.; guard cell; inward K+ channel; mitochondrial pyruvate carrier; slow anion channel; stomata