MADS-box is a class of transcriptional regulators that are ubiquitous in plants and plays important roles in the process of plant growth and development. Identification and analysis of blueberry MADS-box genes can lay a foundation for their function investigations. In the present study, 249 putative MADS-box genes were identified in the blueberry genome. Those MADS-box genes were distributed on 47 out of 48 chromosomes. The phylogenetic and evolutionary analyses showed that blueberry MADS-box genes were divided into 131 type I members and 118 type II members. The type I genes contained an average of 1.89 exons and the type II genes contained an average of 7.83 exons. Motif analysis identified 15 conserved motifs, of which 4 were related to the MADS domain and 3 were related to the K-box domain. A variety of cis-acting elements were found in the promoter region of the blueberry MADS-box gene, indicating that the MADS-box gene responded to various hormones and environmental alterations. A total of 243 collinear gene pairs were identified, most of which had a Ka/Ks value of less than 1. Nine genes belonging to SEP, AP3/PI, and AGL6 subfamilies were screened based on transcriptomic data. The expression patterns of those nine genes were also verified using quantitative PCR, suggesting that VcMADS6, VcMADS35, VcMADS44, VcMADS58, VcMADS125, VcMADS188, and VcMADS212 had potential functions in blueberry fruit ripening. The results of this study provide references for an in-depth understanding of the biological function of the blueberry MADS-box genes and the mechanism of blueberry fruit ripening.

The glutathione S-transferases (GSTs, EC 2.5.1.18) constitute a versatile enzyme family with pivotal roles in plant stress responses and detoxification processes. Recent discoveries attributed the additional function of facilitating anthocyanin intracellular transportation in plants to GSTs. Our study identified 178 VcGST genes from 12 distinct subfamilies in the blueberry genome. An uneven distribution was observed among these genes across blueberry’s chromosomes. Members within the same subfamily displayed homogeneity in gene structure and conserved protein motifs, whereas marked divergence was noted among subfamilies. Functional annotations revealed that VcGSTs were significantly enriched in several gene ontology and KEGG pathway categories. Promoter regions of VcGST genes predominantly contain light-responsive, MYB-binding, and stress-responsive elements. The majority of VcGST genes are subject to purifying selection, with whole-genome duplication or segmental duplication serving as key processes that drive the expansion of the VcGST gene family. Notably, during the ripening of the blueberry fruit, 100 VcGST genes were highly expressed, and the expression patterns of 24 of these genes demonstrated a strong correlation with the dynamic content of fruit anthocyanins. Further analysis identified VcGSTF8, VcGSTF20, and VcGSTF22 as prime candidates of VcGST genes involved in the anthocyanin intracellular transport. This study provides a reference for the exploration of anthocyanin intracellular transport mechanisms and paves the way for investigating the spectrum of GST functions in blueberries.

Leaf senescence is a key developmental process influencing photosynthesis, carbon allocation, and crop productivity, all tightly regulated by source–sink balance. In maize (Zea mays), abscisic acid signaling and nonstructural carbohydrate partitioning have been proposed as major determinants of senescence timing under sink limitation. Through multiyear, multigenotype analyses, we refine the current understanding by identifying starch-induced chloroplast disruption as the primary trigger of sink-removal-induced senescence, whereas abscisic acid acts mainly as a secondary, modulatory signal. We also reveal a respiration-linked metabolic compensation mechanism that stabilizes leaf function in genotypes with delayed senescence. In early-senescing genotypes, ear removal induced significant chlorophyll loss, anthocyanin accumulation, and severe sugar/starch overaccumulation that disrupted chloroplast ultrastructure, coinciding with reduced leaf protein contents and impaired photosynthesis. By contrast, genotypes with delayed senescence maintained pigment stability, displaying enhanced dark respiration, balanced carbohydrate metabolism, and chloroplast integrity. Shading experiments further confirmed that starch overaccumulation, rather than abscisic acid elevation, is the dominant driver of sink-removal-induced senescence. Metabolomic analyses showed that early-senescing genotypes accumulate soluble sugars and phosphoenolpyruvate-pathway intermediates, whereas genotypes with delayed senescence exhibited reduced tricarboxylic acid cycle activity and elevated aspartate-family amino acids. Transcriptomics revealed downregulation of sucrose transporters (eg ZmSUT7) and starch degradation genes (eg ZmBmy3) alongside upregulation of anthocyanin and carbohydrate metabolism genes in early-senescing genotypes. Coexpression network analysis further identified hub genes associated with carbohydrate and amino acid metabolism, linking transcriptional regulation to genotype-specific metabolic adjustments. Together, these findings refine current source–sink regulatory models and offer potential physiological and metabolic targets for improving source–sink coordination and enhancing yield resilience in maize.