Annals of Botany🎊Great news! The newly published paper ‘Fruit softening: evidence for rhamnogalacturonan lyase action in vivo in ripe fruit cell walls’ in @AnnBot by Thurayya Al-Hina and co-authors is now #free for a limited time. (1/7)
Fruit softening involves the breakdown of cell-wall pectin through enzymic hydrolysis, enzymic elimination, and non-enzymic oxidative scission. But the question remained: Does RGL actually act in vivo? (2/7)
Authors developed a sensitive method to detect in-vivo RGL activity. They found a characteristic unsaturated tetrasaccharide fingerprint product, indicating RGL action, in diverse ripe fruits like dates, mangoes, and strawberries. (3/7)
The method involved Driselase digestion of cell walls, followed by electrophoresis and thin-layer chromatography to separate and identify the RGL fingerprint compound. (4/7)
The fingerprint compound, 8ΔUA-Rha-GalA-Rha9, was confirmed by mass spectrometry and acid hydrolysis. This compound was found in various ripe fruits, suggesting widespread RGL activity in fruit softening. (5/7)
Intriguingly, the ratio of galacturonate to rhamnose in digests from ripe dates indicated that around 1.4% of the backbone Rha➔GalA bonds in endogenous RG-I had been cleaved by in-vivo RGL action. (6/7)
🍓🥭🍇These findings provide the first direct evidence that RGL, previously known from gene expression and in-vitro studies, actively contributes to fruit softening by cleaving pectin in the cell walls of ripe fruits. (7/7)