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Bamboo is a nontimber woody plant featuring a long vegetative stage and uncertain flowering time. Therefore, the genes belonging to flowering repressors might be essential in regulating the transition from the vegetative to reproductive stage in bamboo. The Short Vegetative Phase ( SVP) gene plays a pivotal role in floral transition and development. However, little is known about the bamboo SVP homologues. In this study, Phyllostachys violascens PvSVP1 is isolated by analysis of the P. edulis transcriptome database. Phylogenetic analysis shows that PvSVP1 is closely related to OsMADS55 (rice SVP homolog). PvSVP1 is ubiquitously expressed in various tissues, predominantly in vegetative tissues. To investigate the function of PvSVP1, PvSVP1 is overexpressed in Arabidopsis and rice under the influence of the 35S promoter. Overexpression of PvSVP1 in Arabidopsis causes early flowering and produces abnormal petals and sepals. Quantitative real-time PCR reveals that overexpression in Arabidopsis produces an early flowering phenotype by downregulating FLC and upregulating FT and produces abnormal floral organs by upregulating AP1, AP3 and PI expressions. Simultaneously, overexpression of PvSVP1 in rice alters the expressions of flowering-related genes such as Hd3a, RFT1, OsMADS56 and Ghd7 and promotes flowering under field conditions. In addition, PvSVP1 may be a nuclear protein which interacts with PvVRN1 and PvMADS56 on the yeast two-hybrid and BiFC systems. Our study suggests that PvSVP1 may play a vital role in flowering time and development by interacting with PvVRN1 and PvMADS56 in the nucleus. Furthermore, this study paves the way toward understanding the complex flowering process of bamboo.

Developing CRISPR/Cas9-mediated non-transgenic mutants in asexually propagated perennial crop plants is challenging but highly desirable. Here, we report a highly useful method using an Agrobacterium-mediated transient CRISPR/Cas9 gene expression system to create non-transgenic mutant plants without the need for sexual segregation. We have also developed a rapid, cost-effective, and high-throughput mutant screening protocol based on Illumina sequencing followed by high-resolution melting (HRM) analysis. Using tetraploid tobacco as a model species and the phytoene desaturase (PDS) gene as a target, we successfully created and expediently identified mutant plants, which were verified as tetra-allelic mutants. We produced pds mutant shoots at a rate of 47.5% from tobacco leaf explants, without the use of antibiotic selection. Among these pds plants, 17.2% were confirmed to be non-transgenic, for an overall non-transgenic mutation rate of 8.2%. Our method is reliable and effective in creating non-transgenic mutant plants without the need to segregate out transgenes through sexual reproduction. This method should be applicable to many economically important, heterozygous, perennial crop species that are more difficult to regenerate.

Parasitic oscillations in the rectifier diode voltage of phase-shifted-full-bridge (PSFB) converters limit their application in high-voltage and high-power situations. The conventional analysis method for parasitic oscillation in rectifier diode voltage in PSFB converters treats the filter inductor as a constant current source and fails to consider the impact of changes in filter inductor current on the rectifier diode's parasitic oscillation. Consequently, this approach does not apply when analyzing the rectifier diode voltage's parasitic oscillations in high-power PSFB converters employing an input-parallel output-series (IPOS) configuration with interleaved drive. This research paper introduces an innovative equivalent circuit model for analyzing the parasitic oscillations of rectifier diode voltage in IPOS high-power PSFB converters. The model takes into account the mutual influence of rectifier diode voltage oscillations between submodules under interleaved control, considering the influence of changes in filter inductor current on rectifier diode parasitic oscillation. Based on the circuit model, we explain the mechanism of multiple oscillations of the rectifier diode voltage and the reason for the high peak of the first oscillation. Consequently, the interplay of rectifier diode voltage oscillations in IPOS high-power k-module PSFB converters under interleaved control is analyzed. To mitigate the adverse effects of rectifier diode voltage parasitic oscillation, a buffering strategy involving the connection of a resistor capacitor diode (RCD) circuit in parallel after the rectifier bridge is adopted, considering the structure of the IPOS high-power PSFB converter. The study provides a detailed analysis of the circuit's operation mechanism upon incorporating the RCD buffer circuit and establishes the relationship between buffer capacitance, resistance, and spike voltage. Furthermore, a design method for buffer capacitors and discharge resistors in buffer circuits is presented. Finally, a 100 kW prototype is tested to verify the rectifier diode voltage oscillation mechanism of the IPOS high-power PSFB converter and the rationality of the buffer capacitor and discharge resistor design method under the interleaved drive approach. [ABSTRACT FROM AUTHOR]

The standalone solar‐storage AC supply system is an efficient form of utilizing renewable energy. The solar‐storage supply system normally includes two types of converters, grid‐forming (GFM) and grid‐following (GFL) converters. Nevertheless, the incompatibility of the dynamic performance between the GFM and GFL converters due to different control schemes may introduce the transient instability risk to the solar‐storage supply system. To address this issue, it is extremely necessary to perform transient stability analysis and stability‐enhanced control for such a system. In this paper, a sixth‐order model of the dc‐link timescale for the solar‐storage supply system is developed, whose accuracy and applicability are verified by comparing with the detailed electromagnetic model. Based on the derived model, the analysis demonstrates that the solar‐storage supply system faces the potential risk of transient instability under large disturbances of sudden load variation, due to the mismatch of the transient response speeds between virtual excitation control of the GFM converter and dc voltage control of the GFL converter. The transient stability boundary of the system is quantitatively investigated, by depicting the basin of attraction of the post‐disturbance equilibrium point. Furthermore, from the perspective of improving the coordination of the transient behaviours between the GFM converter and the GFL converter, the parameters related to virtual excitation control and dc voltage control are designed to enhance the transient stability of the system. Time‐domain simulations and real‐time simulations are conducted to validate the theoretical analysis. DC–AC power convertors, microgrids, power system control, power system transient stability, renewable energy power conversion [ABSTRACT FROM AUTHOR]

Dendrocalamus farinosus is one of the essential bamboo species mainly used for food and timber in the southwestern region of China. In this study, the complete chloroplast (cp) genome of D. farinosus is sequenced, assembled, and the phylogenetic relationship analyzed. The cp genome has a circular and quadripartite structure, has a total length of 139,499 bp and contains 132 genes: 89 protein-coding genes, eight rRNAs and 35 tRNAs. The repeat analyses showed that three types of repeats (palindromic, forward and reverse) are present in the genome. A total of 51 simple sequence repeats are identified in the cp genome. The comparative analysis between different species belonging to Dendrocalamus revealed that although the cp genomes are conserved, many differences exist between the genomes. The analysis shows that the non-coding regions were more divergent than the coding regions, and the inverted repeat regions are more conserved than the single-copy regions. Moreover, these results also indicate that rpoC2 may be used to distinguish between different bamboo species. Phylogenetic analysis results supported that D. farinosus was closely related to D. latiflorus. Furthermore, these bamboo species' geographical distribution and rhizome types indicate two evolutionary pathways: one is from the tropics to the alpine zone, and the other is from the tropics to the warm temperate zone. Our study will be helpful in the determination of the cp genome sequences of D. farinosus, and provides new molecular data to understand the Bambusoideae evolution. [ABSTRACT FROM AUTHOR]