In plants, SPL is a distinct family of transcription factors. Its protein structure possesses a highly conserved SBP domain comprising two zinc finger structures and nuclear localization regions, and microRNAs (miR156) control the transcriptional expression of the majority of SPL genes. SPLs are key TFs in regulating organ morphogenesis, phase transition/floral induction, and yield-related traits in agronomic and horticultural crops. These biomolecules have been functionally characterized for their role in augmenting plant responses to abiotic and biotic stresses. Present research gaps and viewpoints are addressed herein. Using these extensive data, researchers can more comprehensively understand how SPL genes modulate agronomic features in different ways.

Fruits are an important source of a healthy diet due to their essential nutrients for daily intake. Melon is known as a significant fruit crop of the Cucurbitaceae family based on its various dietary benefits, but its shelf life needs to be maintained for long-term usage. 1-Methylcyclopropene (1-MCP) is a cyclopropene-derived synthetic plant growth regulator (PGR) that is used for significantly delaying the ripening process and maintaining the shelf life of climacteric fruits during storage. In this study, freshly harvested melon fruits were fumigated with various concentrations (1.0 µL·L⁻¹, 2.0 µL·L⁻¹, and 3.0 µL·L⁻¹) of 1-MCP treatment for 12 h (h) and stored at low temperature (8 ± 1 °C) for 30 days (d). The obtained results showed that 1-MCP fumigation coupled with low-temperature treatment maintains the postharvest shelf life of melon fruit. It was noticed that the increase in color hue (a* (red/green), b* (blue/yellow), L* (lightness)) was slowed down and the external fresh color was effectively maintained. At the same time, the firmness, soluble solids, titratable acids (TAs), and vitamin C (VC) content seemed to be maintained at a high level; weight loss and cell permeability were reduced; respiratory intensity and ethylene emission were inhibited; and the accumulation of superoxide anions and malondialdehyde (MDA) was also reduced. In addition, an upsurge in the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) was noticed in melon fruits under the combined treatment of 1-MCP and low-temperature storage as compared with the control group (CK, without treatment), indicating that 1-MCP treatment can effectively enhance the antioxidant metabolism of melon fruits during storage. Overall, we can recommend that the 3.0 µL·L⁻¹ concentration of 1-MCP had the best effect on maintaining the internal and external quality of sweet melon fruit during storage.

Rind hardness is a significant horticultural trait that directly determines sensory quality and postharvest shelf life. Lignin deposition in the stone cell layer is the primary biochemical determinant of fruit rind, yet the genetic regulatory basis of lignin biosynthesis in watermelon has been studied less. Cinnamic acid 4-hydroxylase (C4H) is a rate-limiting enzyme in the phenylpropanoid metabolic cycle, essential for lignin biosynthesis in plants and the formation of robust fruit rinds. However, the in-depth genetic regulatory basis of rind hardness in many fruits has not been investigated. Herein, we conducted the first genome-wide bioinformatics analysis to identify the characterization of the C4H gene family and to explore its potential functions through physiological and molecular experiments in watermelon. The retrieved results exposed a total of 4 ClC4H members, and phylogenetic analysis classified them into two closely associated branches: Class I and Class II. The gene promoter analysis revealed that the upstream region of the ClC4H gene not only contains a large number of essential core elements for basic transcription but also is densely enriched with cis-acting elements that respond to light, various hormones (such as ABA, auxin, etc.), and non-biological stresses, forming a complex transcriptional regulatory network. Transcriptomic and physiological analysis showed that candidate ClC4H1 and ClC4H2 genes exhibited elevated expression during early fruit rind development, which tended to coincide with higher endogenous lignin content. The predicted protein-protein interaction and molecular docking suggested that ClC4H1 might form an interaction network with ClPAL and ClCCR2-like to participate in lignin synthesis. The RT-qPCR-based relative expressions of the candidate genes also validated the differentiated lignin biosynthesis at different developmental stages of rind texture in contrasted watermelon materials; however, subcellular localization confirmed that ClC4H1 is located in the endoplasmic reticulum. These findings provide important candidate genes and a theoretical basis for using molecular breeding techniques to improve the texture of watermelon fruit.

The species degeneration caused by traditional potato cultivation methods is becoming increasingly evident, and it is particularly important to study new potato cultivation methods. Sprout planting technology has the advantages of large reproductive capacity, fast growth speed, and simplified maintenance of cultivated crops. In this study, four disease-free potato varieties (‘Fujin’, ‘Youjin’, ‘Zhongshu 4’, and ‘Feiwuruita’) were treated with different parts (top bud, middle bud, and tail bud) and different bud lengths (10 cm, 15 cm, and 20 cm), and then potato sprout planting was carried out. A nutrient pot experiment was performed following a randomized complete block design (RCBD) with various replicates and a natural control (CK) treatment. By comprehensively measuring the emergence, chlorophyll content, net photosynthetic rate, dry matter distribution during the bulking period of blocks, and effect of growth and quality with bud direct seeding under both treatments, it was found that potato block top bud direct seeding cultivation is significantly superior to other parts. In terms of early maturity and yield statistics, the advantage of top bud cultivation in ‘zhongshu 4’ is most obvious; it reaches maturity an average of 14 days earlier, and the yield can be increased by 38.05%. Therefore, top bud direct seeding is more suitable for potato sprout planting technology. On this basis, the 20 cm and 15 cm bud length treatments of top buds were used for direct cultivation, and all the above indicators performed well. Among them, in the zhongshu 4 variety, the yields of 15 cm and 20 cm bud length treatments increased by 41.78% and 38.05%, the growth rates of commercial potatoes increased by 6% and 6.9%, respectively, and the effects were the most obvious. In conclusion, the deep research and application of potato sprouting technology has high utilization value for improving potato yield and quality and has guiding significance for greenhouse potato cultivation in early spring.

Non-specific Lipid Transfer Proteins (nsLTPs) constitute a ubiquitous family of plant proteins that play a critical role in mediating plant adaptation and tolerance to abiotic stress. While their functions have been extensively characterized in model plants such as Arabidopsis thaliana and rice (Oryza sativa L.), they remain largely unexplored in Cucurbitaceae crops. We identified 31 CmnsLTP genes in the melon (Cucumis melo L.) genome, these genes were unevenly distributed across 11 chromosomes and classified into 8 subfamilies. Members of the same subfamily have similar gene structures and conserved domains, with all family members having motif 1 and motif 3. The promoter region contains cis elements that respond to light, hormones (ABA and MeJA response elements), and abiotic stress, suggesting that this gene is involved in melon growth, development, and stress response. Previous studies have identified copper resistant candidate MELO3C031073.2 through forward genetics, which belongs to the nsLTP family and was named CmnsLTPY.9 in this study. The RT qPCR results showed that the CmnsLTPY.9 exhibited specific expression in different tissues, The expression levels of CmnsLTPY.9 in leaves ranged from 0.3 to 3.2. Under copper stress, the ‘M625’ (copper-sensitive) showed a 3.2-fold increase, indicating marked upregulation. Additionally, CmnsLTPY.9 was localized to the endoplasmic reticulum, and the position remains unchanged after copper stress. This study provides the first systematic analysis of the CmnsLTP gene family in melon; these findings provide fundamental insights into their specific functions in plant development and stress response, as well as valuable genetic resources for future research on copper-tolerant molecular breeding.

Trans-species polymorphisms (TSPs) are fundamental to preserving ancient genetic diversity, yet the evolutionary forces driving their long-term maintenance remain largely unexplored. Here, we investigate genome-wide TSPs in two Cucumis species, cucumber and melon, using whole-genome sequencing data from over 1200 accessions. A total of 5149 TSPs were identified, which predominantly located in genic and promoter regions. Coalescent analysis indicated that both gene flow and balancing selection have contributed to the persistence of these ancestral alleles. Moreover, among the 99 genes with shared coding-region polymorphisms, two genes that cluster by alleles rather than by species provide evidence of long-term balancing selection. These genes are involved in the immune and stress response processes with pleiotropic effects. Our findings elucidate the complex evolutionary forces driving TSPs in Cucumis, providing mechanistic insights into the maintenance of intraspecific genetic diversity in plants across deep evolutionary timescales.