Abscisic acid mediates the formation of a suberized stem scar tissue in tomato fruits

Abstract

Summary• During harvest, fleshy berry tomato fruits (Solanum lycopersicum) were wounded at their stem scar. Within 3 d, this wound was rapidly sealed by a process covering the wound site with a membranous layer which effectively protects the tomato fruit from excessive water loss, nutrient elution and the entry of pathogens.• Chemical analysis of the de novo synthesized stem scar tissue revealed the presence of aromatic and aliphatic components characteristic of the biopolyester suberin.• Gene expression patterns associated with suberization were identified at the stem scar region. Changes in the relative abundance of different transcripts suggested a potential involvement of the plant hormone abscisic acid (ABA) in the wound-healing processes.• The amount of ABA present in the stem scar tissue showed a significantly increased level during wound healing, whereas ABA-deficient mutants notabilis, flacca and sitiens were largely devoid of this rise in ABA levels. The mutant fruits showed a retarded and less efficient suberization response at the stem scar wound, whereas the rate and strength of this response were positively correlated with ABA content. These results clearly indicate in vivo the involvement of ABA in the suberization-based wound-healing processes at the stem scar tissue of tomato fruits.

Three Transcription Activators of ABA Signaling Positively Regulate Suberin Monomer Synthesis by Activating Cytochrome P450 CYP86A1 in Kiwifruit

“…The 20-24 w-hydroxyacids mainly generated by CYP86B1 were also significantly induced by the three TF genes. The a, w-diacids were probably produced by CYP94C1 and CYP94A5 (Le Bouquin et al, 2001;Kandel et al, 2007). In agreement with the expression of CYP94C1 and CYP94A5, a, w-diacids were significantly elevated by overexpressing the three TF genes.…”

“…Additionally, the long-chain a, w-diacids were also significantly increased. The long-chain a, w-diacids accumulation could be performed in two different ways including that through dehydrogenase reactions of long-chain w-hydroxyacids to generate the corresponding a, w-diacids, and AchnCYP86A1 probably acted as a multifunctional w-hydroxylase, similar to CYP94A5 and CYP94C1 catalyzing the multi-step oxidation of fatty acids to corresponding a, w-diacids (Le Bouquin et al, 2001;Kandel et al, 2007). In kiwifruit, the expression of AchnCYP86A1 and the accumulation of w-hydroxyacids were highly induced by wounding (Figure 9).…”

“…Additionally, gene encoding a VLCFA w-hydroxylase (NbCYP86B1) (Compagnon et al, 2009) was also significantly elevated. The AtCYP94C1 and NtCYP94A5 proteins have been reported catalyzing the oxidation of fatty acids to corresponding a, w-diacids in vitro (Le Bouquin et al, 2001;Kandel et al, 2007). NbCYP94C1 and NbCYP94A5, the homologs of AtCYP94C1 and NtCYP94A5, were strongly induced.…”

The Nonspecific Lipid Transfer Protein AtLtpI-4 Is Involved in Suberin Formation of Arabidopsis thaliana Crown Galls

“…The air-dried material was weighed, and the soluble wax-like compounds were extracted using chloroform (Roth) at 40°C for 1 h. The insoluble crown gall material was transesterified with methanolic boron trifluoride (1.3 M boron trifluoride in methanol; Fluka) at 70°C overnight to release ester-bound suberin compounds. Depolymerized methyl ester monomers were extracted with chloroform from an aqueous two-phase system (Leide et al, 2012). Before gas chromatographic analysis, solvent-soluble and transmethylated components from crown galls and stems were transformed into the corresponding trimethylsilyl derivatives using N,O-bis-trimethylsilyl-trifluoroacetamide (Macherey-Nagel) dissolved in pyridine (Merck).…”

Mechanistic understanding of temperature-driven water and bacterial infiltration during hydrocooling of fresh produce

“…Overall, temperature differential is not the only important factor. A dried stem scar, the opening for liquid water and bacterial infiltration, can act as a wick to absorb water via capillary action (demonstrated by the age of the stem scar (Smith et al, 2006, Leide et al, 2012. This observation neglects the hydrophobicity of a dry stem scar that would repel water (Smith et al, 2006, Bartz et al, 2015 and assumes it is congested enough with water to absorb water via capillary forces.…”