Novel insights of ethylene role in strawberry cell wall metabolism.

NATALIA VILLARREAL; MARIA MARINA; CRISTINA F. NARDI; MARCOS CIVELLO; GUSTAVO MARTINEZ

PLANT SCIENCE

ELSEVIER IRELAND LTD

Lugar: Amsterdam; Año: 2016

0168-9452

AbstractDue to its organoleptic and nutraceutical qualities, strawberry fruit (Fragaria x ananassa, Duch) is a worldwide important commodity. The aim of this work was to provide new insights into the regulation of strawberry cell wall metabolism by ethylene. The potential ability of ethylene to modify the contents of each strawberry cell wall fraction 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 correspondence between gene expression patterns and cell wall polysaccharides contents was revealed. Moreover, we detected that strawberry necrotrophic pathogens can 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. 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 that ethylene participates of the regulation of this process.