Effect of Exogenous Auxin Treatment on Cell Wall Polymers of Strawberry Fruit.

Ricardo I Castro,Luis Morales-Quintana,Carolina Parra-Palma,Felipe Valenzuela-Riffo,Ana González-Feliu,Marcelo Muñoz-Vera

doi:10.3390/ijms22126294

Abstract

The role of auxin in the fruit-ripening process during the early developmental stages of commercial strawberry fruits (Fragaria x ananassa) has been previously described, with auxin production occurring in achenes and moving to the receptacle. Additionally, fruit softening is a consequence of the depolymerization and solubilization of cell wall components produced by the action of a group of proteins and enzymes. The aim of this study was to compare the effect of exogenous auxin treatment on the physiological properties of the cell wall-associated polysaccharide contents of strawberry fruits. We combined thermogravimetric (TG) analysis with analyses of the mRNA abundance, enzymatic activity, and physiological characteristics related to the cell wall. The samples did not show a change in fruit firmness at 48 h post-treatment; by contrast, we showed changes in the cell wall stability based on TG and differential thermogravimetric (DTG) analysis curves. Less degradation of the cell wall polymers was observed after auxin treatment at 48 h post-treatment. The results of our study indicate that auxin treatment delays the cell wall disassembly process in strawberries.

Highlights

Auxin has been described as important for fruit growth, playing notable roles from flower formation to fruit ripening [1,2]
Fruit development is an irreversible process that ends with the ripe stage of the fruit; this process alters the cell wall architecture when it is possible to divide it into two phases in most fruits [16]
In strawberries, the two phases make it difficult to establish the functional separation of these phases [32], because in the strawberry, the development and ripening process are two events that occur in parallel [33]

Summary

Introduction

Auxin has been described as important for fruit growth, playing notable roles from flower formation to fruit ripening [1,2]. At the early stage of fruit development, auxin is believed to participate in the cell expansion associated with fruit growth [3,4]. The role of auxin in the ripening of strawberry (Fragaria x ananassa) fruits has been limited to the early stages of development, in which the delivery of auxin from achenes is responsible for receptacle growth [5]. Fragaria x ananassa (commercial strawberry) is an economically important fruit species that is consumed around the world for its pleasant aroma, flavor, and nutritional value [17,18]. Texture is an important attribute for consumer acceptability, and it is related with fruit softening during ripening and postharvest [21]. Fruit softening is partly explained by cell wall breakdown [21]

Objectives

Methods

Results

Conclusion