Redox and Wall-Restructuring

Decrease in Fruit Moisture Content Heralds and Might Launch the Onset of Ripening Processes

“…Oxidative coupling of wall‐bound hydrocinnamic acid derivatives, a peroxidase‐catalyzed and H 2 O 2 ‐dependent process (Fry 1986; 2004; Lindsay and Fry 2007), is apparently a common molecular basis for the wall tightening and resultant structural strain (Gregor 1951; Gregor and Frederick 1953). It is noteworthy, however, that in cell wall of ripening tomato cross‐linked phenolic acids consist mostly of ferulate residues or coniferyl alcohol, a molecular kin of ferulate (Figure 9), despite low relative abundance of ferulate residue in tomato cell wall (Figure 8).…”

“…It is noteworthy, however, that in cell wall of ripening tomato cross‐linked phenolic acids consist mostly of ferulate residues or coniferyl alcohol, a molecular kin of ferulate (Figure 9), despite low relative abundance of ferulate residue in tomato cell wall (Figure 8). Cinnamic acid, although abundant in tomato cell wall (Figure 8), was sparsely used for cross‐linking, apparently because the compound is lacking in hydroxyl groups that facilitate oxidative coupling (Lindsay and Fry 2007). Importantly, the observed increase in the content of cross‐linked and wall‐bound ferulate or coniferyl alcohol residues appears to be inversely related to swelling efficacy of cell wall preparations from on‐the‐vine ripening tomato fruit (Figure 7A).…”

Reactive oxygen species are involved in regulation of pollen wall cytomechanics

“…). It should be noted that functions of the wall peroxidases depend on the reaction conditions; these enzymes can produce • OH and thus loosen the wall, but they can also catalyse cross‐linking of the phenolic residues by H 2 O 2 and stiffen the wall (Lindsay & Fry ; Bunzel ).…”

The imbalance of redox homeostasis in arthropod-induced plant galls: Mechanisms of stress generation and dissipation

“…The new patterns of cell elongation are directly linked to the reorientation of cellulose microfibrils, which requires loosening and tightening mechanisms. Several of these mechanisms involve redox reactions, with the control of wall extensibility orchestrated by low-molecular-weight oxidants and antioxidants in the apoplast [59]. This premise is supported by the work of Miller [66], who demonstrated experimentally that H 2 O 2 is responsible for the rapid breakdown of the cell-wall polysaccharides.…”