Fruit Softening: Revisiting the Role of Pectin

Abstract

Fruit softening, which is a major determinant of shelf life and commercial value, is the consequence of multiple cellular processes, including extensive remodeling of cell wall structure. Recently, it has been shown that pectate lyase (PL), an enzyme that degrades de-esterified pectin in the primary wall, is a major contributing factor to tomato fruit softening. Studies of pectin structure, distribution, and dynamics have indicated that pectins are more tightly integrated with cellulose microfibrils than previously thought and have novel structural features, including branches of the main polymer backbone. Moreover, recent studies of the significance of pectinases, such as PL and polygalacturonase, are consistent with a causal relationship between pectin degradation and a major effect on fruit softening.

Calcium chloride treatment modifies cell wall metabolism and activates defense responses in strawberry fruit (Fragaria × ananassa, Duch)

“…Besides turgor pressure, pectins metabolism is central to determine strawberry fruit texture . Pectin is a structural heteropolysaccharide, consisting of homogalacturonan (HG) and type I and type II rhamnogalacturonan regions (RG‐I and RG‐II, respectively) .…”

“…Besides turgor pressure, pectins metabolism is central to determine strawberry fruit texture . Pectin is a structural heteropolysaccharide, consisting of homogalacturonan (HG) and type I and type II rhamnogalacturonan regions (RG‐I and RG‐II, respectively) . PMEs catalyzed the de‐esterification of GalA from HG backbone, allowing calcium bridges formation and also providing the substrate of pectinases such as PGs and PLs .…”

Differential metabolism of pectic galactan in tomato and strawberry fruit: detection of the LM26 branched galactan epitope in ripe strawberry fruit

“…Tomato and strawberry are leading model systems for the study of fruit ripening (Seymour et al , Posé et al , Wang et al ). Although much is known about cell wall disassembly during fruit ripening, a full molecular description of events has not yet been achieved (Brummell , Mercado et al , Posé et al , Wang et al ). In both fruits, several studies demonstrate a correlation between pectin depolymerisation, loss of neutral sugars from pectin side chains and firmness changes, together with transpirational water loss due to cuticle changes (Saladié et al ).…”

“…Extensive cell wall disassembly is considered to be the major determinant of fruit softening during the ripening process in fleshy fruits (Mercado et al , Posé et al , Wang et al ). This cell wall disassembly has been widely studied for potentially extending the shelf life of soft fruits therefore reducing agronomical losses, and a firmer fruit phenotype has been produced in several cases (Jiménez‐Bermúdez et al , Smith et al , Quesada et al , Paniagua et al , Uluisik et al ).…”

Caracterización de indicadores de la calidad del fruto en líneas de fresa transgénicas con genes silenciados que codifican para enzimas pectinolíticas

“…La textura es función de la estructura de los tejidos, del contenido de agua, la turgencia de las célu-las y la composición de la pared celular (Bourne, 2002). Las modificaciones en la textura que tienen lugar durante la maduración del fruto implican alteraciones genéti-camente programadas en la estructura de la pared celular (Posé et al, 2018;Wang et al, 2018). Las enzimas involucradas en el desensamblado de la pared celular y por ende la pérdida de firmeza son, entre otras, la poligalacturonasa (PG), pectato liasa (PL), pectin metil esterasa, endo-β-1,4-D-glucanasa y otras hidrolasas, así como otras proteínas como las expansinas (Brummell, 2006).…”