Roses (Rosa hybrida) are the most popular cut flower plants worldwide, accounting for over a third of the global cut flower industry. Gray mold, caused by Botrytis cinerea, is often referred to as the postharvest "cancer" of cut roses and represents the most significant disease impacting the postharvest preservation of these flowers in China. Currently, research progress in this area has been limited. Our study utilized single-cell RNA sequencing (scRNA-seq) technology to elucidate the mechanisms underlying B. cinerea resistance in R. hybrida 'Jumilia'. We identified seven distinct cell groups within rose petals. The rose epidermis acts as the physical barrier of defense against B. cinerea, while the infection rate may be accelerated through vascular tissues. Furthermore, we identified several key genes, including pectin methylesterases (PMEs), pathogenesis-related proteins (PRPs), glutathione S-transferase, and endochitinase EP3, which may play crucial roles in the stress response. The biosynthesis of secondary metabolites temporarily mitigates the infection process, and pathogenesis-related proteins (FRAs) have been recognized as key regulatory genes. This preliminary study elucidates the cellular changes and molecular mechanisms involved in B. cinerea infection in rose petals at the single-cell level. Our findings provide new insights into the defense mechanisms of roses against fungal diseases.

Rootstocks are vital in cucumber production. Although figleaf gourd (Cucurbita ficifolia) is among the species used, its application remains limited due to the perception that white-seeded pumpkin (C. maxima × C. moschata) offers superior commercial traits. This perception is partly due to the insufficient collection and evaluation of local figleaf gourd germplasm, which has obscured its potential as a rootstock. Based on prior screening, four wild figleaf gourd genotypes from Yunnan Province were selected and compared with seven commercial white-seeded pumpkin rootstocks. Scions grafted onto figleaf gourd exhibited vegetative growth (stem diameter, plant height, and leaf area) and fruit morphology (length, diameter, biomass, and surface bloom) comparable to the top-performing white-seeded pumpkin genotypes. Fruits from figleaf gourd rootstocks also displayed comparable or significantly higher nutritional quality, including vitamin C, total soluble solids, soluble sugars, and proteins. Notably, figleaf gourd itself showed significantly greater intrinsic resistance to Fusarium wilt than white-seeded pumpkin. When used as a rootstock, it protected the scion from pathogen stress by triggering a stronger antioxidant response (higher SOD and POD activity) and mitigating cellular damage (lower MDA levels and electrolyte leakage). These results provide evidence that these figleaf gourd genotypes are not merely viable alternatives but are high-performing rootstocks, particularly in enhancing nutritional value and providing elite disease resistance.

Chrysanthemum is one of the world’s four main cut flowers. However, postharvest drought stress severely disrupts water homeostasis, triggering reactive oxygen species burst and membrane lipid peroxidation, thereby reducing its ornamental quality and vase life. Melatonin serves as a multifunctional antioxidant and stress regulator. This study demonstrated that 200 μmol L⁻¹ melatonin effectively alleviated drought-induced leaf wilting, maintained relative water content, decreased the accumulation of MDA, H₂O₂, and O₂^•−, and enhanced the activities of SOD, CAT, POD, and APX. Concurrently, non-enzymatic antioxidants (proline, GSH, ASA) accumulated to high levels. RNA-seq analysis revealed that drought affects pathways closely related to the production of antioxidant and osmoprotectant metabolites, while melatonin initiated extensive transcriptional reprogramming and responded to drought stress through distinct pathways at the early (12 h) and late (24 h) treatment stages. Melatonin also modulated key transcription factor families, including bHLH, NAC, ERF, MYB, and bZIP. Collectively, exogenous MT mitigates drought damage in chrysanthemum cut flowers by coordinating antioxidant systems and complex transcriptional regulatory networks. This study provides a theoretical foundation for improving postharvest drought tolerance and prolonging the vase life of cut flowers.

Fusarium wilt, caused by Fusarium oxysporum f. sp. cucumerinum (FOC), poses a major threat to economically important crops worldwide. Figleaf gourd (Cucurbita ficifolia) has been widely adopted as a rootstock for FOC-susceptible cucumber (Cucumis sativus) due to its strong resistance, although the underlying molecular mechanisms remain elusive. In this study, we leveraged the contrasting FOC resistance between C. ficifolia and C. sativus to perform a comparative analysis aimed at elucidating the molecular basis of Fusarium wilt resistance in C. ficifolia. Compared to C. sativus, resistant C. ficifolia exhibited milder wilting, enhanced antioxidant enzyme activities, and reduced oxidative damage. Transcriptome profiling revealed 1,599 species-specific expressed genes and 3,379 orthologous genes with interspecies expression divergence. Several key defense-related pathways, such as MAPK signaling and plant-pathogen interaction, contained critical node genes that exhibited species-specific regulation, potentially contributing to the enhanced resistance of C. ficifolia. This global divergence in gene expression was associated with distinct metabolic shifts, leading to the specific activation of defense-related metabolic pathways in C. ficifolia and the subsequent accumulation of protective compounds such as brassinosteroids, phenylpropanoids, and flavonoids. These findings indicate that C. ficifolia's superior FOC resistance is not attributable to a single factor but emerges from a sophisticated orchestration of gene expression and metabolic output. This study provides novel molecular insights into Fusarium wilt resistance and offers candidate genes and metabolic targets for breeding disease-resistant cucurbit crops.

Cucumber Fusarium wilt, which is induced by the soil-borne pathogen Fusarium oxysporum f. sp. Cucumerinum (FOC), represents a highly destructive disease. Cucumber seedling grafted onto figleaf gourd (Cucurbita ficifolia Bouché) rootstock (CFC) demonstrated better resistance to FOC. However, the molecular mechanism underlying this enhanced disease resistance capability is largely unknown. To elucidate this, we performed transcriptome, small RNA, and degradome sequencing for leaves from CFC and self-grafted cucumbers (SGC) as controls, with and without FOC infections, respectively. Our results indicated that three NAC genes, all predicted as targets of csa-miR164, were significantly up-regulated in CFC after FOC infection. Co-transformation assay in Nicotiana benthamiana confirmed that csa-miR164f directly inhibits NAC2, and transient overexpression of NAC2 in cucumber enhanced resistance to FOC, supporting its positive role in defense. Therefore, our results suggest that three NACs, upregulated in CFC, as an alternative pathway, enhance the reactive oxygen species burst and hypersensitive response, which further elevates the resistance to FOC infection. These results provide new insights into the molecular basis for improved FOC resistance in CFC.

Background/Objectives: The 3-ketoacyl-CoA synthase (KCS) enzyme is a key and rate-limiting component in the biosynthesis of very long-chain fatty acids (VLCFAs). Through controlling VLCFA production, KCS plays an essential role in plant cuticle formation. The necrotrophic fungus Botrytis cinerea can infect all aboveground parts of rose plants (flowers, leaves, and stems), causing severe economic losses. KCS restricts pathogen invasion by influencing cuticle formation and enhances tolerance to environmental stresses. While the KCS gene family has been well-studied in some plants, it remains unexplored in rose (Rosa × hybrida Hort.), a species of significant ornamental and economic value. Methods: In this study, we conducted a genome-wide analysis of the RcKCS gene family in rose, identifying 18 non-redundant genes. Phylogenetic, structural, and synteny analyses were performed to investigate the evolutionary relationships, gene architecture, and duplication events. The expression patterns of RcKCS genes in rose petals during B. cinerea infection were examined, and transient overexpression and silencing of RcKCS6 were used to study its function. Results: RcKCS6 was found to be upregulated during gray mold infection, and transient overexpression reduced lesion size on infected petals. Conclusions: Our study provides the first comprehensive analysis of the RcKCS gene family in rose and highlights RcKCS6 as a potential candidate for improving resistance to gray mold in rose through molecular breeding.