title: The EPIP peptide of INFLORESCENCE DEFICIENT IN ABSCISSION is sufficient to induce abscission in arabidopsis through the receptor-like kinases HAESA and HAESA-LIKE2.
abstract: In Arabidopsis thaliana, the final step of floral organ abscission is regulated by INFLORESCENCE DEFICIENT IN ABSCISSION (IDA): ida mutants fail to abscise floral organs, and plants overexpressing IDA display earlier abscission. We show that five IDA-LIKE (IDL) genes are expressed in different tissues, but plants overexpressing these genes have phenotypes similar to IDA-overexpressing plants, suggesting functional redundancy. IDA/IDL proteins have N-terminal signal peptides and a C-terminal conserved motif (extended PIP [EPIP]) at the C terminus (EPIP-C). IDA can, similar to CLAVATA3, be processed by an activity from cauliflower meristems. The EPIP-C of IDA and IDL1 replaced IDA function in vivo, when the signal peptide was present. In addition, synthetic IDA and IDL1 EPIP peptides rescued ida and induced early floral abscission in wild-type flowers. The EPIP-C of the other IDL proteins could partially substitute for IDA function. Similarly to ida, a double mutant between the receptor-like kinases (RLKs) HAESA (HAE) and HAESA-LIKE2 (HSL2) displays nonabscising flowers. Neither overexpression of IDA nor synthetic EPIP or EPIP-C peptides could rescue the hae hsl2 abscission deficiency. We propose that IDA and the IDL proteins constitute a family of putative ligands that act through RLKs to regulate different events during plant development.
authors.affiliation: Department of Molecular Biosciences, University of Oslo, N-0316 Oslo, Norway.
authors.forename: Grethe-Elisabeth
authors.initials: GE
authors.lastname: Stenvik
authors.forename: Nora M
authors.initials: NM
authors.lastname: Tandstad
authors.forename: Yongfeng
authors.initials: Y
authors.lastname: Guo
authors.forename: Chun-Lin
authors.initials: CL
authors.lastname: Shi
authors.forename: Wenche
authors.initials: W
authors.lastname: Kristiansen
authors.forename: Asbjørn
authors.initials: A
authors.lastname: Holmgren
authors.forename: Steven E
authors.initials: SE
authors.lastname: Clark
authors.forename: Reidunn B
authors.initials: RB
authors.lastname: Aalen
authors.forename: Melinka A
authors.initials: MA
authors.lastname: Butenko
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid
chemical_list: D029681:Arabidopsis Proteins; C512213:IDA protein, Arabidopsis; C000589322:HSL2 protein, Arabidopsis; C089427:RLK5 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases