Del Olmo Ivan, Romero Irene, Alvarez Maria Dolores, Tarradas Rosa, Sanchez-Ballesta Maria Teresa, Escribano Maria Isabel, Merodio Carmen
Laboratory of Biotechnology and Postharvest Quality, Department of Characterization, Quality and Security, Institute of Food Science, Technology and Nutrition (ICTAN-CSIC), Madrid, Spain.
Front Plant Sci. 2022 Aug 19;13:983976. doi: 10.3389/fpls.2022.983976. eCollection 2022.
One of the greatest threats to wild strawberries ( Mara des Bois) after harvest is the highly perishability at ambient temperature. Breeders have successfully met the quality demands of consumers, but the prevention of waste after harvest in fleshy fruits is still pending. Most of the waste is due to the accelerated progress of senescence-like process after harvest linked to a rapid loss of water and firmness at ambient temperature. The storage life of strawberries increases at low temperature, but their quality is limited by the loss of cell structure. The application of high CO concentrations increased firmness during cold storage. However, the key genes related to resistance to softening and cell wall disassembly following transference from cold storage at 20°C remain unclear. Therefore, we performed RNA-seq analysis, constructing a weighted gene co-expression network analysis (WGCNA) to identify which molecular determinants play a role in cell wall integrity, using strawberries with contrasting storage conditions, CO-cold stored (CCS), air-cold stored (ACS), non-cold stored (NCS) kept at ambient temperature, and intact fruit at harvest (AH). The hub genes associated with the cell wall structural architecture of firmer CO-treated strawberries revealed xyloglucans stabilization attributed mainly to a down-regulation of , , and the maintenance of expression levels of nucleotide sugars transferases such as and as well as improved lamella integrity linked to a down-regulation of , and . The preservation of cell wall elasticity together with the up-regulation of , , and , required to maintain cell turgor, is the mechanisms controlled by high CO. In stressed air-cold stored strawberries, in addition to an acute softening, there is a preferential transcript accumulation of genes involved in lignin and raffinose pathways. Non-cold stored strawberries kept at 20°C after harvest are characterized by an enrichment in genes mainly involved in oxidative stress and up-expression of genes involved in jasmonate biosynthesis. The present results on transcriptomic analysis of CO-treated strawberries with enhanced resistance to softening and oxidative stress at consumption will help to improve breeding strategies of both wild and cultivated strawberries.
采收后，野生草莓（玛拉·德·布瓦）面临的最大威胁之一是其在常温下极易腐烂。育种者已成功满足了消费者对品质的要求，但如何防止肉质果实采收后的浪费问题仍悬而未决。大部分浪费是由于采收后类似衰老过程的加速进行，这与常温下水分和硬度的快速丧失有关。草莓在低温下的储存期会延长，但其品质会因细胞结构的丧失而受到限制。高浓度二氧化碳的应用可在冷藏期间提高硬度。然而，从20°C冷藏转移后，与抗软化和细胞壁分解相关的关键基因仍不清楚。因此，我们进行了RNA测序分析，构建了加权基因共表达网络分析（WGCNA），以确定哪些分子决定因素在细胞壁完整性中起作用，使用了具有不同储存条件的草莓，即二氧化碳冷藏（CCS）、空气冷藏（ACS）、常温下非冷藏（NCS）以及采收时的完整果实（AH）。与经过二氧化碳处理后更硬的草莓的细胞壁结构相关的枢纽基因显示，木葡聚糖的稳定主要归因于、、的下调，以及核苷酸糖转移酶如和的表达水平的维持，同时与、和的下调相关的片层完整性得到改善。高浓度二氧化碳控制的机制包括维持细胞壁弹性以及上调、和，以维持细胞膨压。在空气冷藏的应激草莓中，除了急剧软化外，参与木质素和棉子糖途径的基因会优先转录积累。采收后在20°C下保存的非冷藏草莓的特征是主要参与氧化应激的基因富集，以及参与茉莉酸生物合成的基因上调表达。目前关于经过二氧化碳处理的草莓在食用时抗软化和抗氧化应激能力增强的转录组分析结果，将有助于改进野生草莓和栽培草莓的育种策略。
