Microscopic and metabolic investigations disclose the factors that lead to skin cracking in chili-type pepper fruit varieties

Abstract

The hydrophobic cuticle encasing the fruit skin surface plays critical roles during fruit development and post-harvest. Skin failure often results in the fruit surface cracking and forming a wound-periderm tissue made of suberin and lignin. The factors that make the fruit skin susceptible to cracking have yet to be fully understood. Herein, we investigated two varieties of chili peppers (Capsicum annuum L.), Numex Garnet, whose fruit has intact skin, and Vezena Slatka, whose fruit has cracked skin. Microscopical observations, gas chromatography-mass spectrometry, biochemical and gene expression assays revealed that Vezena Slatka fruit form a thicker cuticle with greater levels of cutin monomers and hydroxycinnamic acids, and highly express key cutin-related genes. The skin of these fruit also had a lower epidermal cell density due to cells with very large perimeters, and highly express gene involved in epidermal cell differentiation. We demonstrate that skin cracking in the Vezena Slatka fruit is accompanied by a spatial accumulation of lignin-like polyphenolic compounds, without the formation of a typical wound-periderm tissues made of suberized cells. Lastly, we establish that skin cracking in chili-type pepper significantly affects fruit quality during post-harvest storage in a temperature-dependent manner. In conclusion, our data highlight cuticle thickness and epidermal cell density as two critical factors determining fruit skin susceptibility to cracking in chili-type pepper fruit.

Transcriptome Analysis Reveals the Molecular Mechanisms of BR Negative Regulatory Factor StBIN2 Maintaining Tuber Dormancy

“…In previous studies, it was found that the roughness and cracking of the pericarp are correlated with lignin content. When the pericarp cracks, water loss becomes severe, leading to a shorter fruit lifespan [49]. The skin of potato tubers serves as the primary barrier for water retention.…”

Comparative metabolomics reveals complex metabolic shifts associated with nitrogen-induced color development in mature pepper fruit

“…Therefore, targeted carotenoid metabolomics using saponification has the potential to expand our knowledge of specific classes of carotenoid metabolites contributing to color expression. Additionally, non-targeted metabolomics can help to identify a broader spectrum of metabolic products and understand their metabolism in relation to fruit color development ( Luo et al., 2022 ; Marinov et al., 2023 ). Until now, such comprehensive saponification-assisted targeted carotenoid metabolomics and non-targeted secondary metabolomics studies on pepper fruit color development have not been reported.…”