Analysis of rhamnogalacturonan I fragments as elicitors of the defense mechanism in tomato fruit

Abstract

The rhamnogalacturonan I (RGI) is part of pectin plant cell wall, and currently there is scarce information about the elicitor effect of its fragments in the fruit defense mechanism. In this work, the effect of the fragments of RGI on the defense mechanism in tomato (Solanum lycopersicum L.) fruits was evaluated. Three fragments of RGI released from enzymatic degradation by RG lyase were characterized according to their physical-chemical and structural characteristics. Two of RGI fragments (F-1 and F-2) were selected and applied on tomato fruits during 48 h. At different exposure times (0, 0.5, 1, 6, 24, and 48 h) tomato samples were taken, and the enzymatic activity of chitinase was assessed by fluorometry, and β-1,3glucanase and peroxidase by spectrophotometry (UV-visible). The absorption bands determined by Fourier transform infrared (FT-IR) spectroscopy in the RGI fragments, was different concerning RGI no fragmented. The RGI had a molecular weight of 64 kDa and an intrinsic viscosity of 40.9 mL g-1 ; while the molecular weight of F-1 and F-2 fragments were 20 and 16 kDa, and an average intrinsic viscosity of 27 and 26 mL g-1 , respectively. The content of galacturonic acid decreased, and the neutral sugars increased concerning the time of enzymatic degradation. F-1 and F-2 fragments induced an increase in the level of β-1,3-glucanase activity in tomato fruits; however, an increase in the enzymatic activity of chitinase and peroxidase was observed after 0.5 h of exposure to F-2 fragment. It was concluded that the RGI fragments were structurally different from the RGI no fragmented and induced the natural defense mechanism of the tomato fruit.

Rhamnogalacturonan lyase: a pectin modification enzyme of higher plants

“…The findings of that research concluded that Solyc04g076660 and Solyc04g076630 genes are involved in the early stages of tomato fruit development in which it is growing mainly by cell expansion and the Solyc11g011300 gene plays a role in the fruit softening phenomena during tomato fruit ripening. Furthermore, Jiménez-Maldonado et al (2018) assessed the effect of RG-I fragments from potato on the defense mechanism in tomato fruits. Two fragments of RG-I with a molecular weight of 20 and 16 kDa (F-1 and F-2 fragments respectively) induced the enzymatic activity of β-1,3-glucanase at 6 h after treatment.…”

Análisis De Expresión De Genes Codificantes De Isoenzimas De Ramnogalacturonano Liasa Durante El Desarrollo Y La Madurez Del Fruto De Tomate

“…The activity of the RGL enzyme has been reported to be involved in cell wall enlargement by changing the cohesion network in cotton cotyledons (Gossypium hirsutum L.) (Naran et al, 2007), the activation of the defense system in tomato (Jiménez-Maldonado et al, 2018), the regulation of cell division and periderm development (Oomen et al, 2002) and the control of cell wall architecture in potato (Solanum tuberosum) (Huang et al, 2017). Recently, it was reported that RGL isoenzymes are involved in the deposition of tertiary cell wall fibers in flax (Linum usitatissimum) (Mokshina et al, 2019).…”