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The water droplets on the surface of the overhead line (OHL) conductors are subject to an intensive electric field, which induces electric force on the charged liquid surface. Under the combined action of the surface tension as well as the electric force, movement and deformation can be observed on those water droplets. These result in a re-distribution of charge density on the liquid surface and therefore a re-distribution of electric force. In this paper, in order to strengthen the understanding of this complex multi-physics problem of interaction and mutual coupling, the vibration characteristics of water droplets under alternating electric fields is studied using the finite element method (FEM). Parameters such as the volume size of the water droplet, static/dynamic contact angle between the water droplet and conductor surface and voltage level are studied in relation to the vibration characteristics. The reproducible correlation between the phase and amplitude of the water droplet vibration on the surface of the conductor and the applied voltage is established. According to the calculated instantaneous electric field strength, it is explained that protrusions such as water droplets are the starting point of corona discharge.

Resin-impregnated paper (RIP) bushing has gained significant interest due to its extended application in Extra High Voltage (EHV) and Ultra High Voltage (UHV) electricity transmission systems. However, the design criterion of its overall structure, the geometry parameters of the condenser layers, and stress release devices, etc., are still not fully understood. This article proposes a unique electric field optimization technique to integrate both the analytical and the numerical methods. The charge simulation method (CSM) is employed to create the overall equipotential surface, within which the finite element analysis (FEA) is adapted to study the localized field enhancement effects, taking into consideration the multi-physics coupled fields. A case study is performed on an actual UHV bushing. The results are compared to the traditional methods, to demonstrate the benefit of the hybrid method.

Two important traits of Chinese cabbage, internode length and budding time, destroy the maintenance of rosette leaves in the vegetative growth stage and affect flowering in the reproductive growth stage. Internodes have received much attention and research in rice due to their effect on lodging resistance, but they are rarely studied in Chinese cabbage. In Chinese cabbage, internode elongation affects not only the maintenance of rosette leaves but also bolting and yield. Budding is also an important characteristic of Chinese cabbage entering reproductive growth. Although many studies have reported on flowering and bolting, studies on bud emergence and the timing of budding are scarce. In this study, the mutant lcc induced by EMS (Ethyl Methane Sulfonate) was used to study internode elongation in the seedling stage and late budding in the budding stage. By comparing the gene expression patterns of mutant lcc and wild-type A03, 2280 differentially expressed genes were identified in the seedling stage, 714 differentially expressed genes were identified in the early budding stage, and 1052 differentially expressed genes were identified in the budding stage. Here, the transcript expression patterns of genes in the plant hormone signaling and clock rhythm pathways were investigated in relation to the regulation of internode elongation and budding in Chinese cabbage. In addition, an F2 population was constructed with the mutants lcc and R500. A high-density genetic map with 1602 marker loci was created, and QTLs for internode length and budding time were identified. Specifically, five QTLs for internode length and five QTLs for budding time were obtained. According to transcriptome data analysis, the internode length candidate gene BraA02g005840.3C (PIN8) and budding time candidate genes BraA02g003870.3C (HY5-1) and BraA02g005190.3C (CHS-1) were identified. These findings provide insight into the regulation of internode length and budding time in Chinese cabbage.

Virus-induced gene silencing (VIGS) is an RNA-mediated reverse genetics technology that has evolved into an indispensable approach for analyzing the function of genes. It downregulates endogenous genes by utilizing the posttranscriptional gene silencing (PTGS) machinery of plants to prevent systemic viral infections. Based on recent advances, VIGS can now be used as a high-throughput tool that induces heritable epigenetic modifications in plants through the viral genome by transiently knocking down targeted gene expression. As a result of the progression of DNA methylation induced by VIGS, new stable genotypes with desired traits are being developed in plants. In plants, RNA-directed DNA methylation (RdDM) is a mechanism where epigenetic modifiers are guided to target loci by small RNAs, which play a major role in the silencing of the target gene. In this review, we described the molecular mechanisms of DNA and RNA-based viral vectors and the knowledge obtained through altering the genes in the studied plants that are not usually accessible to transgenic techniques. We showed how VIGS-induced gene silencing can be used to characterize transgenerational gene function(s) and altered epigenetic marks, which can improve future plant breeding programs.

Cyclins are involved in cell division and proliferation by activating enzymes required for the cell cycle progression. Our genome-wide analysis identified 76 cyclin genes in Brassica rapa, which were divided into nine different types (A-, B-, C-, D-, H-, L-, P-, T-, and SDS-type). Cyclin genes were unevenly scattered on all chromosomes, with a maximum of 10 on A08 and a minimum of 2 on A04. The gene structure and conserved motif analysis showed that the cyclins which belonged to the same type or subgroup have a comparable intron/exon pattern or motif. A total of 14 collinear gene pairs suggested that the B. rapa cyclin genes experienced a mass of segmental duplication. The Ka/Ks analysis revealed that the Brcyclin gene family has undergone an extensive purifying pressure. By analyzing the cis-elements in the promoters, we identified 11 cis-elements and five of them are related to the hormone response. We observed 48 potential miRNAs targeting 44 Brcyclin genes, which highlighted the involvement of miRNAs in the regulation of cyclin genes. An association analysis between the leaf size and SNPs in mutants and a transcriptome analysis of two Chinese cabbage-cabbage translocation lines also showed that the Brcyclin gene family was involved in the development of the leaves. The functional characterization of the B. rapa cyclin gene family will provide the foundation for future physiological and genetic studies in the regulation of leaf growth.

Leaf size is a crucial trait in eggplant breeding, as it influences photosynthesis, plant biomass and management. However, little is known about the molecular mechanism regulating leaf size in eggplant. This study reports a small leaf mutant (slf) generated with the mutagen ethyl methane sulfonate (EMS). The slf mutant showed restricted cell proliferation and an increased content of auxin. Transcriptome analysis revealed that several genes involved in auxin signaling are upregulated in slf. Exogenous application of auxinole, an auxin antagonist of TIR1/AFB receptors, repressed the expression of these genes and restored leaf growth of slf, suggesting that the small leaf size of slf is likely associated with auxin signaling. This study provides essential clues to unveil the molecular mechanism of leaf size regulation in eggplant.

Purple eggplant fruits often turn brown during maturity stages, severely influencing their market value and shelf life. However, the metabolites and genes accounting for the fruit color changes are largely unknown. Here, metabolites and gene expression analyses were used to explore the candidates underlying the differences in fruit color changes between two eggplant genotypes, ‘14-345’ and ‘CGN23829’, with contrasting fruit color changes during fruit development. We found that flavonoids are the most differentially accumulated metabolites between ‘14-345’ and ‘CGN23829’. Higher contents of D3R and D3G are important for keeping the purple color at the maturity stage. Naringenin chalcone likely accounts for the color changes from purple to brown in ‘14-345’. Notably, at the physiological maturity stage, lower expression of early biosynthetic genes (EBGs) involved in the flavonoid biosynthesis pathway is important to keep lower contents of metabolites upstream of anthocyanins, thus leading to more purple coloring. Taken together, the results indicate that delphinidins and naringenin chalcone play important roles in determining eggplant fruit color changes at maturity stages, which is helpful for further dissecting the mechanisms underlying fruit color differences and changes in eggplants.

Eggplant is a vegetable crop with high economic value that is cultivated worldwide. The dwarf mutant is an important germplasm material that has been extensively used in crop breeding. However, no eggplant dwarf mutants have been reported, and little is known regarding the genes responsible for dwarfism in eggplant. In this study, we isolated an eggplant dwarf mutant (dwf) from an ethyl methyl sulfonate (EMS)-induced mutant library. Genetic analysis revealed that dwf was caused by a single recessive gene. A candidate gene SmCPR1, encoding cytochrome P450 reductases (CPR1), was identified by bulked segregant analysis (BSA). Mutation from G to A at 8216 bp of SmCPR1 resulted in mutation of the amino acid from valine to isoleucine. The results of KASP and Sanger sequencing further support the conclusion that SmCPR1 is a candidate gene responsible for the dwarfism of dwf. Moreover, the activity of SmCPR1 was significantly increased in dwf, which might be a response to dwarfism in dwf.

Dwarfism is a desirable trait in eggplant breeding, as it confers higher lodging resistance and allows simplified management and harvest. However, a few dwarf mutants have been reported, and the molecular mechanism underlying dwarfism in eggplant is completely unknown. Here, we report a dwarf mutant (dwf) isolated from an ethyl methyl sulfonate (EMS)-induced mutant library. The hypocotyl length, plant height, and length of internode cells of dwf were significantly decreased compared to those of the wild-type parent ‘14-345’ (WT). Differential gene expression analysis revealed that GA-related genes, including GA2ox and DELLA, were up-regulated whereas the gibberellin (GA3) content decreased in dwf. Moreover, exogenous GA3 treatment significantly increased the relative growth rate of dwf compared to WT, further indicating the important roles of GA in regulating the dwarf phenotype of dwf. Collectively, our findings shed light on GA-mediated dwarfism in dwf plants and offer a good germplasm that could be used for eggplant dwarfism breeding in the future.