title: Nitric oxide suppresses the inhibitory effect of abscisic acid on seed germination by S-nitrosylation of SnRK2 proteins.
abstract: Nitric oxide (NO) plays important roles in plant development, and biotic and abiotic stress responses. In a recent study, we showed that endogenous NO negatively regulates abscisic acid (ABA) signaling in guard cells by inhibiting sucrose nonfermenting 1 (SNF1)-related protein kinase 2.6 (SnRK2.6)/open stomata 1(OST1) through S-nitrosylation. Application of NO breaks seed dormancy and alleviates the inhibitory effect of ABA on seed germination and early seedling growth, but it is unclear how NO functions at the stages of seed germination and early seedling development. Here, we show that like SnRK2.6, SnRK2.2 can be inactivated by S-nitrosoglutathione (GSNO) treatment through S-nitrosylation. SnRK2.2 and the closely related SnRK2.3 are known to play redundant roles in ABA inhibition of seed germination in Arabidopsis. We found that treatment with the NO donor SNP phenocopies the snrk2.2snrk2.3 double mutant in conferring ABA insensitivity at the stages of seed germination and early seedling growth. Our results suggest that NO negatively regulates ABA signaling in germination and early seedling growth through S-nitrosylation of SnRK2.2 and SnRK2.3.
authors.affiliation: a Department of Horticulture and Landscape Architecture; Purdue University ; West Lafayette , IN , USA.
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Wang
authors.forename: Jian-Kang
authors.initials: JK
authors.lastname: Zhu
authors.forename: Zhaobo
authors.initials: Z
authors.lastname: Lang
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D018525:Germination / Q000187:drug effects*; D008969:Molecular Sequence Data; D009569:Nitric Oxide / Q000378:metabolism / Q000494:pharmacology*; D015538:Nitrosation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D026422:S-Nitrosoglutathione / Q000494:pharmacology; D036226:Seedlings / Q000254:growth & development / Q000378:metabolism; D012639:Seeds / Q000187:drug effects / Q000254:growth & development*
chemical_list: D029681:Arabidopsis Proteins; C492978:SnRK2 protein, Arabidopsis; D009569:Nitric Oxide; D026422:S-Nitrosoglutathione; D000040:Abscisic Acid; D017346:Protein Serine-Threonine Kinases
keywords: ABA; NO; S-nitrosylation; SnRK2.2; SnRK2.3; seed dormancy; signaling