title: SnRK1A-interacting negative regulators modulate the nutrient starvation signaling sensor SnRK1 in source-sink communication in cereal seedlings under abiotic stress.
abstract: In plants, source-sink communication plays a pivotal role in crop productivity, yet the underlying regulatory mechanisms are largely unknown. The SnRK1A protein kinase and transcription factor MYBS1 regulate the sugar starvation signaling pathway during seedling growth in cereals. Here, we identified plant-specific SnRK1A-interacting negative regulators (SKINs). SKINs antagonize the function of SnRK1A, and the highly conserved GKSKSF domain is essential for SKINs to function as repressors. Overexpression of SKINs inhibits the expression of MYBS1 and hydrolases essential for mobilization of nutrient reserves in the endosperm, leading to inhibition of seedling growth. The expression of SKINs is highly inducible by drought and moderately by various stresses, which is likely related to the abscisic acid (ABA)-mediated repression of SnRK1A under stress. Overexpression of SKINs enhances ABA sensitivity for inhibition of seedling growth. ABA promotes the interaction between SnRK1A and SKINs and shifts the localization of SKINs from the nucleus to the cytoplasm, where it binds SnRK1A and prevents SnRK1A and MYBS1 from entering the nucleus. Our findings demonstrate that SnRK1A plays a key role regulating source-sink communication during seedling growth. Under abiotic stress, SKINs antagonize the function of SnRK1A, which is likely a key factor restricting seedling vigor.
authors.affiliation: Graduate Institute of Life Sciences, National Defense Medical Center, Neihu, Taipei 114, Taiwan, Republic of China.
authors.forename: Chien-Ru
authors.initials: CR
authors.lastname: Lin
authors.forename: Kuo-Wei
authors.initials: KW
authors.lastname: Lee
authors.forename: Chih-Yu
authors.initials: CY
authors.lastname: Chen
authors.forename: Ya-Fang
authors.initials: YF
authors.lastname: Hong
authors.forename: Jyh-Long
authors.initials: JL
authors.lastname: Chen
authors.forename: Chung-An
authors.initials: CA
authors.lastname: Lu
authors.forename: Ku-Ting
authors.initials: KT
authors.lastname: Chen
authors.forename: Tuan-Hua David
authors.initials: TH
authors.lastname: Ho
authors.forename: Su-May
authors.initials: SM
authors.lastname: Yu
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000595:Amino Acid Sequence; D050260:Carbohydrate Metabolism / Q000187:drug effects; D015687:Cell Hypoxia / Q000187:drug effects; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D017124:Conserved Sequence; D056625:Endosperm / Q000187:drug effects / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D001467:Hordeum / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D008954:Models, Biological; D008969:Molecular Sequence Data; D005810:Multigene Family; D012275:Oryza / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000187:drug effects; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013213:Starch / Q000378:metabolism; D013312:Stress, Physiological / Q000187:drug effects
chemical_list: D010940:Plant Proteins; D000040:Abscisic Acid; D013213:Starch; C071570:SNF1-related protein kinases; D017346:Protein Serine-Threonine Kinases