title: Novel insights of ethylene role in strawberry cell wall metabolism.
abstract: Due to its organoleptic and nutraceutical qualities, strawberry fruit (Fragaria x ananassa, Duch) is a worldwide important commodity. The role of ethylene in the regulation of strawberry cell wall metabolism was studied in fruit from Toyonoka cultivar harvested at white stage, when most changes associated with fruit ripening have begun. Fruit were treated with ethephon, an ethylene-releasing reagent, or with 1-methylcyclopropene (1-MCP), a competitive inhibitor of ethylene action, maintaining a set of non-treated fruit as controls for each condition. Ethephon treated-fruit showed higher contents of hemicelluloses, cellulose and neutral sugars regarding controls, while 1-MCP-treated fruit showed a lower amount of those fractions. On the other hand, ethephon-treated fruit presented a lower quantity of galacturonic acid from ionically and covalently bound pectins regarding controls, while 1-MCP-treated fruit showed higher contents of those components. We also explored the ethylene effect over the mRNA accumulation of genes related to pectins and hemicelluloses metabolism, and a relationship between gene expression patterns and cell wall polysaccharides contents was shown. Moreover, we detected that strawberry necrotrophic pathogens growth more easily on plates containing cell walls from ethephon-treated fruit regarding controls, while a lower growth rate was observed when cell walls from 1-MCP treated fruit were used as the only carbon source, suggesting an effect of ethylene on cell wall structure. Around 60% of strawberry cell wall is made up of pectins, which in turns is 70% made by homogalacturonans. Our findings support the idea of a central role for pectins on strawberry fruit softening and a participation of ethylene in the regulation of this process.
authors.affiliation: IIB-INTECH (CONICET-UNSAM), Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, Avenida Intendente Marino km 8,2 (B7130IWA) Chascomús, Pcia, Buenos Aires, Argentina.
authors.forename: Natalia M
authors.initials: NM
authors.lastname: Villarreal
authors.affiliation: IIB-INTECH (CONICET-UNSAM), Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, Avenida Intendente Marino km 8,2 (B7130IWA) Chascomús, Pcia, Buenos Aires, Argentina.
authors.forename: María
authors.initials: M
authors.lastname: Marina
authors.affiliation: IIB-INTECH (CONICET-UNSAM), Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, Avenida Intendente Marino km 8,2 (B7130IWA) Chascomús, Pcia, Buenos Aires, Argentina.
authors.forename: Cristina F
authors.initials: CF
authors.lastname: Nardi
authors.affiliation: INFIVE (CONICET-UNLP), Instituto de Fisiología Vegetal, Diag. 113 y Calle 61, n°495-C.c 327, 1900 La Plata, Argentina; Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), 47 y 115, 1900 La Plata, Argentina.
authors.forename: Pedro M
authors.initials: PM
authors.lastname: Civello
authors.affiliation: IIB-INTECH (CONICET-UNSAM), Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, Avenida Intendente Marino km 8,2 (B7130IWA) Chascomús, Pcia, Buenos Aires, Argentina; Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), 47 y 115, 1900 La Plata, Argentina. Electronic address: gmartinez@intech.gov.ar.
authors.forename: Gustavo A
authors.initials: GA
authors.lastname: Martínez
mesh_terms: D050260:Carbohydrate Metabolism / Q000187:drug effects; D002473:Cell Wall / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism / Q000494:pharmacology*; D031985:Fragaria / Q000378:metabolism* / Q000382:microbiology / Q000648:ultrastructure; D005638:Fruit / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D054884:Host-Pathogen Interactions / Q000187:drug effects; D010368:Pectins / Q000235:genetics / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism / Q000494:pharmacology*; D011134:Polysaccharides / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D005030:Ethylenes; D010937:Plant Growth Regulators; D011134:Polysaccharides; D012333:RNA, Messenger; C007916:hemicellulose; D010368:Pectins; D002482:Cellulose; C036216:ethylene
keywords: Cell wall; Ethylene; Gene expression; Middle lamella; Pectins; Strawberry