Novel insights of ethylene role in strawberry cell wall metabolism

MARINA MARÍA; MARTÍNEZ GUSTAVO A.; VILLARREAL NATALIA M.; CIVELLO PEDRO M.; NARDI CRISTINA F.

PLANT SCIENCE

ELSEVIER IRELAND LTD

Lugar: Amsterdam; Año: 2016 vol. 252 p. 1 - 11

0168-9452

Dueto its organoleptic and nutraceutical qualities, strawberry fruit (Fragaria xananassa, Duch) is a worldwide important commodity. The role of ethylene in theregulation of strawberry cell wall metabolism was studied in fruit fromToyonoka cultivar harvested at white stage, when most changes associated with fruitripening have begun. Fruit were treated with ethephon, an ethylene-releasingreagent, or with 1- methylcyclopropene (1-MCP), a competitive inhibitorofethylene action, maintaining a set of non-treated fruit as controls for eachcondition. Ethephon treated-fruit showed higher contents of hemicelluloses,cellulose and neutral sugars regarding controls, while 1-MCP-treated fruitshowed a lower amount of those fractions. On the other hand, ethephon-treatedfruit presented a lower quantity of galacturonic acid from ionically andcovalently bound pectins regarding controls, while 1-MCP-treated fruit showedhigher contents of those components. We also explored the ethylene effect overthe mRNA accumulation of genes related to pectins and hemicellulosesmetabolism, and a relationship between gene expression patterns and cell wall polysaccharides contents was shown. Moreover, we detected thatstrawberry necrotrophic pathogens growth more easily on plates containing cellwalls from ethephon-treated fruit regarding controls, while a lower growth ratewas observed when cell walls from 1-MCP treated fruit were used as the onlycarbon source, suggesting an effect of ethylene on cell wall structure. Around60% of strawberry cell wall is made up of pectins, which in turns is 70% madeby homogalacturonans. Our findings support the idea of a central role for pectinson strawberry fruit softening and a participation of ethylene in the regulationof this process.