Anthocyanins play crucial roles in conferring multicolored characteristics to higher plant organs. Previous studies have investigated the absence of anthocyanin accumulation in white cornflower petals, where the anthocyanin biosynthesis pathway was obstructed by CcF3H. However, the genetic regulation mechanism underlying anthocyanin absence remained unclear. In the present study, the full-length sequences of two transcription activators CcMYB6-1 and CcbHLH1 were isolated in white cornflower petals. The multi-sequence alignment analysis revealed that there was no difference in the CcMYB6-1 sequence between the blue and white petals, while CcbHLH1 was truncated to a length of 1,125 bp on account of alternative splicing, resulting in a frame-shift mutation and premature codon, leading to the loss of basic, helix-loop-helix domains. The truncated CcbHLH1 could still interact with CcMYB6-1 as demonstrated by yeast-two hybrid and bimolecular luminescence complementary assays but lost the ability to enhance the trans-activation of CcDFR promoter using dual-luciferase assay. Transient over-expression of mutated CcbHLH1 in tobacco leaves resulted in a significant decrease in anthocyanin production. These results suggested the alternative splicing of CcbHLH1 caused the incapacity of trans-activating the anthocyanin biosynthetic pathway together with CcMYB6-1, finally leading to anthocyanin absence in white cornflower. The present findings further shed light on the genetic regulation mechanism of anthocyanin biosynthesis in cornflower and enrich the knowledge underlying the white color transition in higher plants.

The mastication trait of citrus fruit is a key determinant of consumer preference and market value, which is influenced by a combination of genetic, environmental, and postharvest factors. This review focuses on analyzing these factors and their impacts on citrus fruit quality, with a particular emphasis on masticatory properties. The biochemical and molecular mechanisms underlying mastication traits are examined, focusing on cell wall metabolism (pectin, cellulose, lignin), cytoplasmic and intercellular matrix changes, and molecular regulation. Strategies for improving citrus quality and mastication traits are discussed, emphasizing varietal improvement through gene editing technologies, optimized cultivation practices, and advanced postharvest handling techniques. Despite significant progress, challenges remain in elucidating the complex genetic and environmental interactions governing these traits and developing sustainable management practices. Future research should integrate multiomics approaches, gene–environment interaction studies, and precision agriculture to address these challenges. This review provides a comprehensive synthesis of the current knowledge and prospective directions, aiming to guide the development of high-quality citrus varieties with enhanced mastication traits.

The winter pot kalanchoe (Kalanchoe blossfeldiana) is an ornamental plant with succulent leaves and clustered flowers in Crassulaceae, widely used as a potted flower or garden decoration. In nature, the bicolor petal is an interesting phenomenon, and breeders have succeeded in cultivating the winter pot kalanchoe with bicolored petals. However, its potential molecular mechanism of pigmentation is poorly understood. This study collected a yellow-red colored winter pot kalanchoe to investigate the molecular mechanism underlying its bicolor formation using the integrative analyses of metabolome and transcriptome. The metabolome results showed that both flavonoid and carotenoid co-existed in the winter pot kalanchoe petals, whereas only anthocyanin accumulation showed significant differences—about nineteen times higher in the red region than that in the yellow region. The differentially expressed genes were significantly enriched in the anthocyanin biosynthesis pathway, and the expression level of biosynthetic genes, including KbCHS, KbCHI, KbF3H, KbDFR, KbANS and KbGTs, were significantly upregulated in the red region. Moreover, transcription factors potentially regulating anthocyanin biosynthesis were predicted, and KbMYB2 and KbbHLH1 might play important roles in positively regulating anthocyanin biosynthesis in the red region. The findings reported here provide new insights into the understanding of petal bicolor formation mechanisms and will assist cultivar innovation in winter pot kalanchoe.

The sepal color of Fuchsia hybrida is colorful instead of green and usually varies from the petal colors, which greatly increases its ornamental value and attract customers’ preference. However, the potential molecular mechanism underlying the color variation between sepals and petals remains unclear. The present study collected F. hybrida with red sepals and purple petals to explore the key pigments and genes involved in color development using a targeted metabolome and transcriptome. A total of 43 metabolites with diverse hydroxylation, glycosylation, methylation and acylation patterns were isolated and identified by UPLC-MS/MS. The quantification analysis showed that peonidin-3,5-O-diglucoside and malvidin-3,5-O-diglucoside were the most abundant anthocyanins accumulating in the sepals and petals, respectively. Then, six libraries from the sepals and petals were constructed for the transcriptome and 70,135 unigenes were generated. The transcript level of FhF3′H was significantly higher in the sepals, while Fh3′5′H showed more abundant expression in the petals, which can account for the abundant peonidin and malvidin accumulation in the sepals and petals, respectively. The subsequent multiomics analysis showed that both the differentially accumulated anthocyanins and expressed unigenes were enriched in the anthocyanin biosynthesis pathway. Additionally, FhMYBs potentially regulating anthocyanin biosynthesis were screened out by correlation analysis and protein interaction prediction. These findings help to elucidate the molecular mechanisms underlying the color variation between the sepals and petals in F. hybrida.

Chrysanthemum (Chrysanthemum × morifolium Ramat.) is a globally popular ornamental plant, but most cultivars lack efficient petal-based transient transformation systems, limiting floral trait molecular mechanism exploration. Protoplasts are versatile tools for gene localization, interaction, and functional characterization. Here, we established a petal protoplast isolation and transient transformation system for C. morifolium ‘Wandai Fengguang’ via L₉(3⁴) orthogonal design: optimal isolation (0.6 M mannitol, 8 h enzymatic digestion time, 0.4% macerozyme R-10, 4% cellulase R-10) and transformation (40% PEG4000, 12 μg plasmid, 10 min transfection, a protoplast density of 1 × 10⁶ protoplasts mL⁻¹). Under these conditions, protoplast yield was 5.14 × 10⁶ protoplasts g⁻¹·FW, viability 87.41%, and transformation efficiency 51.50%, with good applicability for six additional germplasms. We further analyzed CmVIT1 protein localization. Compared with the previous system, this system significantly improved protoplast yield and transformation efficiency, facilitating the transient transformation of genes related to floral traits in chrysanthemum and providing a methodological framework for other horticultural crops.