Cucumber (Cucumis sativus L.) is an important horticultural crop worldwide. Sodium (Na⁺) and chloride (Cl⁻) in the surface soil are the major limiting factors in coastal areas of Shandong Province in China. Therefore, to understand the mechanism used by cucumber to adapt to sodium chloride (NaCl), we analyzed the phenotypic and physiological indicators of eighteen cucumber germplasms after three days under 100 and 150 mM NaCl treatment. A cluster analysis revealed that eighteen germplasms could be divided into five groups based on their physiological indicators. The first three groups consisted of seven salt-tolerant and medium salt-tolerant germplasms, including HLT1128h, Zhenni, and MC2065. The two remaining groups consisted of five medium salt-sensitive germplasms, including DM26h and M1-2-h-10, and six salt-sensitive germplasms including M1XT and 228. A principal component analysis revealed that the trend of comprehensive scores was consistent with the segmental cluster analysis and survival rates of cucumber seedlings. Overall, the phenotype, comprehensive survival rate, cluster analysis, and principal component analysis revealed that the salt-tolerant and salt-sensitive germplasms were Zhenni, F11-15, MC2065, M1XT, M1-2-h-10, and DM26h. The results of this study will provide references to identify or screen salt-tolerant cucumber germplasms and lay a foundation for breeding salt-tolerant cucumber varieties.

High carbohydrate availability promotes malic acid accumulation in fleshy fruits, but the underlying mechanism is not known. Here, we show that antisense repression of ALDOSE-6-PHOSPHATE REDUCTASE in apple (Malus domestica) decreases the concentrations of sorbitol and malate and the transcript levels of several genes involved in vacuolar malate transport, including the aluminum-activated malate transporter (ALMT) gene MdALMT9 (Ma1), the P-ATPase gene MdPH5, the MYB transcription factor gene MdMYB73, and the cold-induced basic helix-loop-helix transcription factor gene MdCIbHLH1, in fruit and leaves. We identified a linker histone H1 variant, MdH1.1, which complements the Arabidopsis (Arabidopsis thaliana) H1 deficient mutant and functions as a transcription factor. MdH1.1 activates MdMYB73, MdCIbHLH1, and MdPH5 expression by directly binding to their promoters. MdMYB73, in return, binds to the promoter of MdH1.1 to enhance its transcription. This MdH1.1-MdMYB73 feedback loop responds to sorbitol, regulating Ma1 expression. Antisense suppression of either MdH1.1 or MdMYB73 expression significantly decreases whereas overexpression increases Ma1 expression and malate accumulation. These findings demonstrate that MdH1.1, in addition to being an architectural protein for chromatin structure, operates as a transcription factor orchestrating malic acid accumulation in response to sorbitol, revealing how sugar signaling modulates vacuolar malate transport via a linker histone in plants.

Flower color, a critical phenotypic trait of ornamental plants, is an essential indicator for flower variety classification. Many physical and internal factors that affect flower color have been widely investigated; however, the effects of internal factors during the flowering period remain unknown. In this study, we evaluated the effects of internal factors on floral coloration during the flowering period of four chrysanthemum cultivars of different colors. colorimetric measurements showed that L*, a*, and b* were in correlation with the lightness and color development in the four chrysanthemum cultivars. The distinctive shape of upper epidermal cells was observed in each flowering stage of different colored chrysanthemums. With progression of the flowering process, the content of anthocyanins and carotenoids increased during early stages, decreased at the senescence stage, and was the highest at the full-bloom stage. The vacuolar pH of flowers gradually decreased as the flower bloomed. Metal contents in flowers varied across different chrysanthemum varieties. Anthocyanins biosynthesis genes, such as CmCHS and CmCHI, were expressed and responsible for pigment changes in red chrysanthemums. Moreover, the expression pattern of cytosol pH-related genes, such as CmVHA-a1, CmVHA-C, and CmVHA-C″1, was in accordance with a decrease in pH during flowering stages. Our results revealed the effects of main internal factors on floral color during the flowering period in four Chrysanthemum varieties, providing insights into the introcellular and molecular regulatory mechanisms of flower coloration and laying key foundations for the improvement of color breeding in chrysanthemums.

Apples, as respiratory climacteric fruit, undergo postharvest ripening and senescence, impacting commodity value. Cuticular wax protects against environmental stresses. Here, gas chromatography-mass spectrometry (GC-MS) analysis revealed a decline in fatty alcohol levels in apple wax during storage, correlating with fruit quality deterioration. Notably, octacosanol content significantly decreased with storage, suggesting that it is a primary cause of wax and fruit quality decline. Octacosanol treatment improved fruit quality and delayed softening by enhancing wax synthesis and antioxidant levels and suppressing cell wall-degrading enzymes. Transcriptome sequencing and real-time quantitative polymerase chain reaction (RT-qPCR) assays indicated increased expression of wax, peroxidase, sucrose, and starch genes and decreased expression of cell wall degradation genes, explaining octacosanol’s benefits. This study provides a theoretical basis for octacosanol application in fruit preservation.

Chrysanthemum, one of the most popular ornamental plants in the world, is renowned for its brilliant colors and multifarious flower types. Thousands of gorgeous chrysanthemum cultivars exist thanks to both traditional breeding techniques and its characteristic bud sporting. In this study, we identified a pink-to-yellow flower color-changed bud sport of the edible chrysanthemum cultivar ‘Pink Candy’. The bud variant and its parent plant bloomed at the same time, but with yellow- and pink-colored flowers, respectively. However, the two flower types exhibited strikingly different combinations and concentrations of primary and secondary metabolites, aromatic compounds, and pigments. Additionally, the expression patterns of key pigment biosynthesis genes, such as CmPAL (phenylalanineammonialyase), CmDFR (dihydroflavonol 4-reductase), CmF3H (flavanone 3′-hydroxylase), CmNXS (neoxanthin synthase) and CmCCD4 (carotenoid cleavage dioxygenase 4) were distinct between both flower types, helping to explain the color transformation of the mutant to some extent. Taken together, our results suggest a mechanism explaining the transformation of pink flowers to yellow flowers in the mutant bud sport. These results provide the foundation for the production of a novel chrysanthemum cultivar.