S-nitrosylation triggers ABI5 degradation to promote seed germination and seedling growth.
Plant survival depends on seed germination and progression through post-germinative developmental checkpoints. These processes are controlled by the stress phytohormone abscisic acid (ABA). ABA regulates the basic leucine zipper transcriptional factor ABI5, a central hub of growth repression, while the reactive nitrogen molecule nitric oxide (NO) counteracts ABA during seed germination. However, the molecular mechanisms by which seeds sense more favourable conditions and start germinating have remained elusive. Here we show that ABI5 promotes growth via NO, and that ABI5 accumulation is altered in genetic backgrounds with impaired NO homeostasis. S-nitrosylation of ABI5 at cysteine-153 facilitates its degradation through CULLIN4-based and KEEP ON GOING E3 ligases, and promotes seed germination. Conversely, mutation of ABI5 at cysteine-153 deregulates protein stability and inhibition of seed germination by NO depletion. These findings suggest an inverse molecular link between NO and ABA hormone signalling through distinct posttranslational modifications of ABI5 during early seedling development.
Dpto. de Microbiología y Genética, Instituto Hispano-Luso de Investigaciones Agrarias (CIALE), Facultad de Biología, Universidad de Salamanca, C/ Río Duero 12, Salamanca 37185, Spain.
Pablo
P
Albertos
Dpto. de Bioquímica, Biología Celular y Molecular de Plantas, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Profesor Albareda 1, Granada E-18008, Spain.
María C
MC
Romero-Puertas
Laboratory of Plant Organ Development, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki 444-8585, Japan.
Kiyoshi
K
Tatematsu
Dpto. de Microbiología y Genética, Instituto Hispano-Luso de Investigaciones Agrarias (CIALE), Facultad de Biología, Universidad de Salamanca, C/ Río Duero 12, Salamanca 37185, Spain.
Isabel
I
Mateos
Dpto. de Microbiología y Genética, Instituto Hispano-Luso de Investigaciones Agrarias (CIALE), Facultad de Biología, Universidad de Salamanca, C/ Río Duero 12, Salamanca 37185, Spain.
Inmaculada
I
Sánchez-Vicente
Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S3B2.
Eiji
E
Nambara
Dpto. de Microbiología y Genética, Instituto Hispano-Luso de Investigaciones Agrarias (CIALE), Facultad de Biología, Universidad de Salamanca, C/ Río Duero 12, Salamanca 37185, Spain.
Oscar
http://orcid.org/0000-0001-9523-0789
O
Lorenzo
D000040:Abscisic Acid / Q000378:metabolism*; D017360:Arabidopsis; D029681:Arabidopsis Proteins / Q000378:metabolism*; D050976:Basic-Leucine Zipper Transcription Factors / Q000378:metabolism*; D044842:Cullin Proteins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018525:Germination; D006706:Homeostasis; D009569:Nitric Oxide / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D026422:S-Nitrosoglutathione; D036226:Seedlings / Q000254:growth & development; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism
C409743:ABI5 protein, Arabidopsis; D029681:Arabidopsis Proteins; D050976:Basic-Leucine Zipper Transcription Factors; C514806:CULLIN4 protein, Arabidopsis; D044842:Cullin Proteins; D009569:Nitric Oxide; D026422:S-Nitrosoglutathione; D000040:Abscisic Acid; C518495:KEG protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases