Expression profiling of endo-xylanases during ripening of strawberry cultivars with contrasting softening rates. Influence of postharvest and hormonal treatments.

HIRSCH, MAILÉN; LANGER, SILVIA E.; MARINA, MARÍA; ROSLI, HERNÁN; CIVELLO, PEDRO M.; MARTINEZ, GUSTAVO .; VILLARREAL, NATALIA M.

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE

JOHN WILEY & SONS LTD

Lugar: Londres; Año: 2021 vol. 101 p. 3676 - 3684

0022-5142

BACKGROUND: Softening is one of the main features that determine fruit quality during strawberry (Fragaria x ananassa, Duch.) ripening and storage. Being closely related to textural changes, the molecular and biochemical bases underlying strawberry cell wall metabolism is still a matter of interest. Here, we investigated the abundance of transcripts encoding putative strawberry endo-xylanases in various plant tissues, during fruit ripening and under hormonal and postharvest treatments. Total xylanase activity and expression of related genes in strawberry varieties with contrasting softening rates were analyzed.RESULTS: FaXynA and FaXynC mRNA abundance were significantly higher than FaXynB in each plant tissue studied. Higher total xylanase activity was detected at the end of the ripening of the softer cultivar (Toyonoka) in comparison with the firmer one (Camarosa), correlating with the abundance of FaXynA and FaXynC transcripts. Postharvest 1-methylcyclopropene treatment up-regulated FaXynA and FaXynC expressions in ripe strawberry fruit. FaXynC mRNA abundance decreased by heat treatment while the opposite was observed for FaXynA. Calcium chloride treatment down-regulated FaXynA and FaXynC expression. Both genes responded differently to plant growth regulators´ exposure. FaXynC expression was down-regulated by auxins and gibberellins treatment and up-regulated by abscisic acid. FaXynA was up-regulated by auxins, while no changes in mRNA levels were evident by abscisic acid and gibberellins exposure. CONCLUSION: New knowledge about the presence of xylanases in ripening strawberry fruit and their response to postharvest and hormonal treatments is provided. Our findings suggest a role for endo-xylanases on hemicelluloses depolymerization and possibly in strawberry fruit softening.