A domestication-associated gene, CsLH, encodes a phytochrome B protein that regulates hypocotyl elongation in cucumber

Plant height is an important agronomic trait; tall plants are prone to collapse (lodging) and are unsuitable for high-density planting (Li et al., 2020). During the Green Revolution, a multitude of genes acting as core or peripheral regulators of plant height were identified and used in breeding (Eshed and Lippman, 2019); however, most were reported in cereal crop plants (Eshed and Lippman, 2019) and few have been characterized in the Cucurbitaceae, which are economically important horticultural plants cultivated worldwide. Here, we describe LONG HYPOCOTYL (CsLH), encoding the photoreceptor phytochrome B (PHYB), which we show has been subjected to selection during cucumber (Cucumis sativus L.) domestication.info:eu-repo/semantics/publishedVersio

Root Morphological and Physiological Adaptations to Low Phosphate Enhance Phosphorus Efficiency at Melon (Cucumis melo L.) Seedling Stage

The high phosphorus (P) acquisition ability of crops can reduce their dependence on artificial inorganic phosphate (Pi) supplementation under Pi-limited conditions. Melon (Cucumis melo L.) is vulnerable to Pi deficiency. This study was carried out to explore the morphological and physiological responses of melon to low-Pi stress under a hydroponic system. The results show that low-Pi stress significantly disturbed nutrient homeostasis, reduced P content, and resulted in iron accumulation in melon seedlings and brown iron plaque formation on the root surface. A nutrient pool of P and Fe formed on the roots to forage for more Pi under low-Pi conditions. Severe long-term low-Pi stress promoted primary root elongation and inhibited lateral root growth, which increased the longitudinal absorption zone of the roots. The decrease in P content of the roots upregulated the expression of the acid phosphatase (APase) gene and increased APase activity. The high-affinity phosphate transporter (Pht1) genes were also upregulated significantly. These morphological and physiological responses significantly increased Pi uptake rate and P utilization efficiency at the melon seedling stage. These findings will be useful for screening low-Pi-tolerant varieties and sustaining melon production in P-limited environments

Characterization and stress-responsive regulation of CmPHT1 genes involved in phosphate uptake and transport in Melon (Cucumis melo L.)

Abstract Background Phosphorus (P) deficiency, a major nutrient stress, greatly hinders plant growth. Phosphate (Pi) uptake in plant roots relies on PHT1 family transporters. However, melon (Cucumis melo L.) lacks comprehensive identification and characterization of PHT1 genes, particularly their response patterns under diverse stresses. Results This study identified and analyzed seven putative CmPHT1 genes on chromosomes 3, 4, 5, 6, and 7 using the melon genome. Phylogenetic analysis revealed shared motifs, domain compositions, and evolutionary relationships among genes with close histories. Exon number varied from 1 to 3. Collinearity analysis suggested segmental and tandem duplications as the primary mechanisms for CmPHT1 gene family expansion. CmPHT1;4 and CmPHT1;5 emerged as a tandemly duplicated pair. Analysis of cis-elements in CmPHT1 promoters identified 14 functional categories, including putative PHR1-binding sites (P1BS) in CmPHT1;4, CmPHT1;6, and CmPHT1;7. We identified that three WRKY transcription factors regulated CmPHT1;5 expression by binding to its W-box element. Notably, CmPHT1 promoters harbored cis-elements responsive to hormones and abiotic factors. Different stresses regulated CmPHT1 expression differently, suggesting that the adjusted expression patterns might contribute to plant adaptation. Conclusions This study unveils the characteristics, evolutionary diversity, and stress responsiveness of CmPHT1 genes in melon. These findings lay the foundation for in-depth investigations into their functional mechanisms in Cucurbitaceae crops

A domestication-associated gene, CsLH, encodes a phytochrome B protein that regulates hypocotyl elongation in cucumber

This work was supported by the National Key Research and Development Program of China (2019YFD1000300), the Severo Ochoa Programme for Centers of Excellence in R&D 2016–2010 (SEV-2015-0533) Postdoctoral Program, and the International Postdoctoral Exchange Fellowship program from the China Postdoctoral Council (20170053).Peer reviewe

Green synthesized zinc oxide nanoparticles confer drought tolerance in melon (Cucumis melo L.)

Green synthesized nanoparticles present an eco-friendly and cost-effective solution for plant modulation against abiotic stress. The present research aims to explore the role of biogenically synthesized zinc oxide nanoparticles (ZnO.NPs) in mitigating drought-induced alterations in Cucumis melo L. For this experiment, plants were exposed to drought, elicited by polyethylene glycol (10%) and treatments of ZnO.NPs. Treatments were designed as non-stressed seedlings, drought-stressed (DS), and 4 doses of ZnO.NPs (75, 100, 125 and 150mgL-1 ZnO.NPs + DS). Results show that drought exposure caused oxidative damage in melon seedlings, which was reflected from incline in hydrogen peroxide, lipid peroxidation, electrolyte leakage and decline in pigments and osmolytes as well as chloroplast ultrastructural integrity. Furthermore, the photosynthetic functions, vegetative growth and nutrients uptake were significantly compromised. Alternatively, melon seedlings supplemented with ZnO.NPs manifested enhancement in tolerance against drought. ZnO.NPs dosage stimulated the drought tolerance associated genes (SOD, POD, CAT, APX, DREB2D, DREB3), antioxidant activities and improvement in nutrients acquisitions. Moreover, plant photosynthetic functions and pigments content, soluble sugar and protein, vegetative growth and chlorophyll fluorescence showed significant improvement with ZnO.NPs application. The upregulation of genes, antioxidant activities, osmolytes and nutrients acquisition synergistically improved the tolerance of melon seedlings against oxidative damage. Furthermore, the decrease in oxidative damage to melon seedlings was confirmed through chloroplast ultrastructural observation using a transmission electron microscope. Nevertheless, this remarkable change was more notable at optimum concentrations of ZnO.NPs (75 and 100mgL-1). The findings of the current study offer potential contribution in preserving melon crops from oxidative damage induced by drought stress and a step forward into sustainable agriculture

Exploring drought tolerance in melon germplasm through physiochemical and photosynthetic traits

Drought stress is a global concern that has a negative impact on the growth and production of melon (Cucumis melo L.). In this study, 58 melon accessions were subjected to drought stress induced by polyethylene glycol (PEG-6000). Comprehensive evaluations were performed to identify various morphological, biochemical, and physiological attributes of melon. Drought stress significantly reduced shoot length (SL), stem diameter (SD), leaf width (LW), and leaf length (LL) in the melon seedlings. Similarly, drought stress resulted in a significant reduction in photosynthetic pigments (Chl, Car), relative water content (RWC), chlorophyll fluorescence (Fv/Fm), transpiration rate (Tr), stomatal conductance (Gs), net photosynthetic rate (Pn) and intercellular CO2 concentration (Ci). On the other hand, biochemical indicators such as malondialdehyde content (MDA), soluble protein content (SP) and soluble sugar content (SS) were observed to be enhanced upon exposure to drought stress. Most indicators showed strong positive correlations based on Pearson correlation analysis. Furthermore, the modified membership function and D values for the drought tolerance indices were calculated to evaluate the drought tolerance level of melon accessions. In addition, melon accessions were classified into drought-resistant and drought-sensitive groups based on cluster analysis. As a result, mel-46, mel-58 and mel-15 were identified as drought-resistant genotypes among the assessed melon accessions. Taken together, these accessions provide potential genetic resources for further improvement and breeding of melon genotypes. Furthermore, the indicators responsible for the assessment of drought tolerance can provide a baseline for future studies

Underwater Organic Solar Cells via Selective Removal of Electron Acceptors near the Top Electrode

Electron acceptor degradation of organic solar cells is considered a main contributor to performance instability and a barrier for the commercialization of organic solar cells. Here, we selectively remove the electron acceptors on the surface of donor:acceptor blend films using a tape stripping technique. The near-edge X-ray absorption fine structure (NEXAFS) spectrum reveals that only 6% of the acceptor component is left on the blend film surface after the tape stripping, creating a polymer-rich surface. The optimized morphology avoids direct contact of electron acceptors with the oxygen and water molecules from the film surface. Moreover, the polymer-rich surface dramatically enhances the adhesion between the photoactive layer and the top metal electrode, which prevents delamination of the electrode. Our results finally demonstrate that the selective removal of electron acceptors near the top electrode facilitates the realization of highly durable organic solar cells that can even function under water without encapsulation