Understanding the global transcriptomic and metabolic changes during mulberry growth and development is essential for the enhancing fruit quality and optimizing breeding strategies. By integrating phenotypic, metabolomic, and transcriptomic data across 18 developmental and ripening stages of Da10 mulberry fruit, a global map of gene expression and metabolic changes was generated. Analysis revealed a gradual progression of morphological, metabolic, and transcriptional changes throughout the development and ripening phases. In this study, a new transcriptome transition, which was highly related to stress resistance, was observed after the full ripening stage. Moreover, a novel method was devised by integrating metabolome and phenotypic data to assess fruit quality and determine optimal harvest times early in the supply chain. Phase-specific co-expression networks involved in photosynthesis, quality regulation, and plant immunity were also constructed. Notably, eight flavonoids and six hub genes emerged as potential natural edible coatings or gene-editing targets for mulberry fruit to enhance resistance against biotic and abiotic stress. These findings should facilitate further research on stress resistance, post-harvest management, and sustainable agricultural development.

The development of floral organs, crucial for the establishment of floral symmetry and morphology in higher plants, is regulated by MADS-box genes. In sunflower, the capitulum is comprised of ray and disc florets with various floral organs. In the sunflower long petal mutant (lpm), the abnormal disc (ray-like) floret possesses prolongated petals and degenerated stamens, resulting in a transformation from zygomorphic to actinomorphic symmetry. In this study, we investigated the effect of MADS-box genes on floral organs, particularly on petals, using WT and lpm plants as materials. Based on our RNA-seq data, 29 MADS-box candidate genes were identified, and their roles on floral organ development, especially in petals, were explored, by analyzing the expression levels in various tissues in WT and lpm plants through RNA-sequencing and qPCR. The results suggested that HaMADS3, HaMADS7, and HaMADS8 could regulate petal development in sunflower. High levels of HaMADS3 that relieved the inhibition of cell proliferation, together with low levels of HaMADS7 and HaMADS8, promoted petal prolongation and maintained the morphology of ray florets. In contrast, low levels of HaMADS3 and high levels of HaMADS7 and HaMADS8 repressed petal extension and maintained the morphology of disc florets. Their coordination may contribute to the differentiation of disc and ray florets in sunflower and maintain the balance between attracting pollinators and producing offspring. Meanwhile, Pearson correlation analysis between petal length and expression levels of MADS-box genes further indicated their involvement in petal prolongation. Additionally, the analysis of cis-acting elements indicated that these three MADS-box genes may regulate petal development and floral symmetry establishment by regulating the expression activity of HaCYC2c. Our findings can provide some new understanding of the molecular regulatory network of petal development and floral morphology formation, as well as the differentiation of disc and ray florets in sunflower.

As an ornamental organ, petal plays an important role in attracting insect pollination, it’s development attracts the attention of many researchers. In this study, a sunflower mutant line with ligulate-like tubular petal (lpm) was screened out, and its disc tubular florets were characterized with elongated ligulate-like petals, longer filaments size, fewer anthers and lower seed setting rate, compared with wide type (WT) plants. From the suppression subtractive hybridization library constructed using inflorescence of lpm and WT plants, the HaYABBY was identified with expressing differentially. The cDNA and structural sequences of HaYABBY gene were 997 and 4339 bp, respectively, encoding a peptide with 219 amino acids. The analysis of HaYABBY expression showed that it presented higher transcription level in flower than root, stem and leaf of sunflower. The expression level of YABBY in disc florets of lpm was significantly higher than those of WT, especially at early floral developmental stage. The results suggested that HaYABBY could impact the floral development at early stage, particularly on petal elongation and floral symmetry morphogenesis in sunflower. Furthermore, the results implied that HaYABBY would be involved in the regulation of reproductive system development and affect their fertility. Our findings will provide some insight to understand the regulating network of floral development in sunflower, and help to cultivate new sunflower varieties with high ornamental value.

Sunflower (Helianthus annuus L.) is a major oilseed crop in the world, but recently it has become a popular ornamental flower in China (Kaya ET AL., 2012). Notably, stem rot was frequently observed...