Cell wall structures leading to cultivar differences in softening rates develop early during apple Malus x domestica fruit growthReport as inadecuate

Cell wall structures leading to cultivar differences in softening rates develop early during apple Malus x domestica fruit growth - Download this document for free, or read online. Document in PDF available to download.

BMC Plant Biology

, 13:183

Biochemistry and physiology


BackgroundThere is a paucity of information regarding development of fruit tissue microstructure and changes in the cell walls during fruit growth, and how these developmental processes differ between cultivars with contrasting softening behaviour. In this study we compare two apple cultivars that show different softening rates during fruit development and ripening. We investigate whether these different softening behaviours manifest themselves late during ethylene-induced softening in the ripening phase, or early during fruit expansion and maturation.

Results‘Scifresh’ slow softening and ‘Royal Gala’ rapid softening apples show differences in cortical microstructure and cell adhesion as early as the cell expansion phase. ‘Scifresh’ apples showed reduced loss of firmness and greater dry matter accumulation compared with ‘Royal Gala’ during early fruit development, suggesting differences in resource allocation that influence tissue structural properties. Tricellular junctions in ‘Scifresh’ were rich in highly-esterified pectin, contributing to stronger cell adhesion and an increased resistance to the development of large airspaces during cell expansion. Consequently, mature fruit of ‘Scifresh’ showed larger, more angular shaped cells than ‘Royal Gala’, with less airspaces and denser tissue. Stronger cell adhesion in ripe ‘Scifresh’ resulted in tissue fracture by cell rupture rather than by cell-to-cell-separation as seen in ‘Royal Gala’. CDTA-soluble pectin differed in both cultivars during development, implicating its involvement in cell adhesion. Low pectin methylesterase activity during early stages of fruit development coupled with the lack of immuno-detectable PG was associated with increased cell adhesion in ‘Scifresh’.

ConclusionsOur results indicate that cell wall structures leading to differences in softening rates of apple fruit develop early during fruit growth and well before the induction of the ripening process.

KeywordsApple Cell adhesion Cell wall Fruit firmness Immunofluorescence labelling Microstructure Pectin AbbreviationsCDTATrans-1,2-diaminocyclohexane-N,N,N-,N-tetraacetic acid

DAFBDays after full bloom

DEDegree of methyl esterification



LMLeeds monoclonal antibody

PBS-TPhosphate-buffered saline containing 0.1% Tween80


PMEPectin methylesterase

SDStandard deviation

SEStandard error

UAUronic acid.

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2229-13-183 contains supplementary material, which is available to authorized users.

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Author: Jovyn KT Ng - Roswitha Schröder - Paul W Sutherland - Ian C Hallett - Miriam I Hall - Roneel Prakash - Bronwen G Smit

Source: https://link.springer.com/

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