Metabolism of Stone Fruits: Reciprocal Contribution Between Primary Metabolism and Cell Wall.

Monica Canton,Robert P Walker,María V Lara,Claudio Bonghi,María F Drincovich,Giannina Vizzotto,Franco Famiani

doi:10.3389/fpls.2020.01054

Abstract

Cell wall turnover and modification in its composition are key factors during stone fruit development and patterning. Changes in cell wall disassembly and reassembly are essential for fruit growth and ripening. Modifications in cell wall composition, resulting in the formation of secondary cell walls, are necessary for producing the most distinctive trait of drupes: the lignified endocarp. The contribution of primary metabolism to cell wall synthesis has been investigated in detail, while the knowledge on the contribution of the cell wall to primary metabolites and related processes is still fragmented. In this review, starting from peculiarities of cell wall of drupes cells (in mesocarp and endocarp layers), we discuss the structure and composition of cell wall, processes related to its modification and contribution to the synthesis of primary metabolites. In particular, our attention has been focused on the ascorbate synthesis cell wall-related and on the potential role of cyanogenic compounds in the deposition of the secondary cell wall.

Highlights

Cell wall metabolism is an integral part of the primary metabolism since the cell wall is the primary carbon sink in many plant tissues
Worthy of note is the fact that the action of xyloglucan endotransglucosylase/hydrolases (XTHs) is induced by xyloglucan oligosaccharides (XGOs) and that, during peach fruit ripening, Pei et al (2019) observed the down-regulation of two esterase/ lipase proteins (GELPs) known for their action against XGOs
A quantitative trait locus (QTL) analysis allowed the identification of five regions and two of them included genes annotated with terms related to the known D-Man/L-Gal and AsA/glutathione pathways (Stevens et al, 2007)

Summary

INTRODUCTION

Cell wall metabolism is an integral part of the primary metabolism since the cell wall is the primary carbon sink in many plant tissues. In addition to polysaccharides (cellulose, hemicelluloses, and pectins), cell walls are composed by other, quantitatively minor but functionally important components, such as polyphenols and proteins, many of which are glycosylated (Somerville et al, 2004). Cell walls are classified as primary walls, which are surrounding the cell driving its growth and its morphology, and secondary walls, whose rigidity and strength is necessary to fulfill specialized cell functions (Somerville et al, 2004). In stone fruits (or drupes), cell wall changes resulting in the formation of secondary cell walls are important because they are necessary for producing the most distinctive trait of drupes: the lignified endocarp

PRIMARY METABOLISM AND PRIMARY CELL WALL

Contribution of Cell Wall Disassembly to Primary Metabolites in Ripening Fruit

PRIMARY METABOLISM AND FORMATION OF THE LIGNIFIED ENDOCARP

Structural Characteristics of Drupe Pit

Contribution of Primary Metabolism to the Formation of a Lignified Endocarp

FUTURE PERSPECTIVES