FLOURY ENDOSPERM8, encoding the UDP-glucose pyrophosphorylase 1, affects the synthesis and structure of starch in rice endosperm

Wuhua Long,Bangning Dong,Yihua Wang,Pengyi Pan,Yunlong Wang,Linglong Liu,Xiaoli Chen,Xi Liu,Shijia Liu,Yunlu Tian,Liangming Chen,Jianmin Wan 한국식물학회 2017 Journal of Plant Biology Vol.60 No.5

Cereal opaque-kernel mutants are ideal geneticmaterials for studying the mechanism of starch biosynthesisand amyloplast development. Here we isolated and identifiedtwo allelic floury endosperm 8 (flo8) mutants of rice, namedflo8-1 and flo8-2. In the flo8 mutant, the starch content wasdecreased and the normal physicochemical features ofstarch were altered. Map-based cloning and subsequentDNA sequencing analysis revealed a single nucleotidesubstitution and an 8-bp insertion occurred in UDP-glucosepyrophosphorylase 1 (Ugp1) gene in flo8-1 and flo8-2,respectively. Complementation of the flo8-1 mutant restorednormal seed appearance by expressing full length codingsequence of Ugp1. RT-qPCR analysis revealed that Ugp1was ubiquitously expressed. Mutation caused the decreasedUGPase activity and affected the expression of most of genesassociated with starch biosynthesis. Meanwhile, western blotand enzyme activity analyses showed the comparability ofprotein levels and enzyme activity of most tested starchbiosynthesis related genes. Our results demonstrate thatUgp1 plays an important role for starch biosynthesis in riceendosperm.

A rice White-stripe leaf3 (wsl3) mutant lacking an HD domain-containing protein affects chlorophyll biosynthesis and chloroplast development

Shaolu Zhao,Wuhua Long,Yihua Wang,Linglong Liu,Yunlong Wang,Mei Niu,Ming Zheng,Di Wang,Jianmin Wan 한국식물학회 2016 Journal of Plant Biology Vol.59 No.3

Leaf-color mutants are ideal genetic materials for understanding the mechanism of chloroplast development and chlorophyll (Chl) biosynthesis. Here we isolated and identified a new leaf-color mutant of rice, named white-stripe leaf3 (wsl3), from a 60Co-irradiated mutant pool. The wsl3 mutant displayed a visible white-stripe leaf in both young seedlings and flag leaves of mature plant. Chl content in homozygous wsl3 mutant was approximately 47% of that in the wild type. Besides, chloroplast development in the mutant was severely arrested. By a map-based cloning strategy, the wsl3 gene was finely confined to a 50.8 kb region on chromosome 1. Moreover, a 9-bp deletion was identified in the genomic region of LOC_Os01g01920, which encodes an HD (histidine and aspartic acid) domaincontaining protein. Genetic complementation confirmed that LOC_Os01g01920 could recover the lesion of wsl3 mutation. Real-time PCR analyses showed that the expression levels of WSL3 were the highest in young and flag leaves among various tissues, and most of the genes associated with Chl biosynthesis were significantly down-regulated in the wsl3 mutant. Meanwhile, in contrast to many nuclear gene-encoded phage-type RNA polymerase(s) (NEP) transcribed genes were up-regulated, most of plastid-encoded bacterialtype RNA polymerase (PEP) transcribed genes were downregulated. These results demonstrated that the WSL3 gene, as an HD domain-containing protein, is involved in chl biosynthesis and chloroplast development in rice.

Analysis of Pre-compensator for Disturbance Signal Elimination in Single-Phase Inverters with Virtual Vector Control

Yuxiang Wang,Yunjie Gu,Wuhua Li,Xiangning He 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

In virtual vector control schemes for singlephase current-regulated voltage source inverters, a transient disturbance may be induced due to the time-delay in the virtual orthogonal signal. This disturbance deteriorates the dynamic current-tracking capability and power quality. A unified scalar model is developed to analyze the phenomenon. Based on this model, an improved control scheme with a pre-compensator is proposed to solve the problem. The pre-compensator reshapes the current commands so that the transient disturbance signal is eliminated while the desired response is unaffected. Experimental results of the proposed strategy are compared with the conventional solution to substantiate enhanced dynamic performance.

Novel Rotor Winding Investigation for Reduction of Torque Pulsation and Electromagnetic Noise in Squirrel Cage Induction Motor

Yang Zhou,Xiaohua Bao,Wuhua Jiang,Jiwei Liu,Wei Xu 한국자기학회 2019 Journal of Magnetics Vol.24 No.1

In the design of squirrel-cage induction machines, torque pulsation and electromagnetic noise always exist. However, they cannot be minimized simultaneously with no matter which slot combination. Electromagnetic noise is aroused by the spatial harmonics in the air gap which are generated by stator magneto-motive force and rotor magneto-motive force. Generally, stator slot number cannot be changed while rotor slot number and slot size could be modified optionally. One set of uniform-bar rotor winding cannot solve this problem. To investigate this issue, this paper proposes a novel rotor winding connection topology for the simultaneous reduction of torque pulsation and electromagnetic noise. 2D finite element models with conventional rotor winding and novel rotor winding are simulated and compared.

Module Multilevel-Clamped Composited Multilevel Converter (M-MC²) with Dual T-Type Modules and One Diode Module

Haoze Luo,Yufei Dong,Wuhua Li,Xiangning He 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.6

A modular multilevel-clamped composited multilevel converter (M-MC²) is proposed. M-MC² enables topology reconfiguration, power device reuse, and composited clamping. An advanced five-level converter (5L-M-MC²) is derived from the concept of M-MC². 5L-M-MC² integrates dual three-level T-type modules and one three-level neutral point clamped module. This converter can also integrate dual three-level T-type modules and one passive diode module by utilizing the device reuse scheme. The operation principle and SPWM modulation are discussed to highlight converter performance. The proposed M-MC² is comprehensively compared with state-of-the-art five-level converters. Finally, simulations and experimental results are presented to validate the effectiveness of the main contributions of this study.

A Busbar Integrated SiC-based Converter with Embedded Heat-pipes

Yao Chang,Amir Sajjad Bahman,Haoze Luo,Wuhua Li,Xiangning He,Francesco Iannuzzo,Frede Blaabjerg 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

In this paper, a bus-bar integrated packaging technology for press-pack power modules is proposed. The proposed packaging technology features high power-density, even pressure distribution among chips, and low stray parameters. The structure design and fabrication flow process are analyzed and experiments are made to verify the feasibility of proposed solution. The critical challenge about the package is related to thermal management. To reduce the thermal stress of chips, a heat-pipe integrated heatsink is developed and finite-element-method (FEM) simulations are used to evaluate the cooling performance of the proposed heatsink. The results demonstrate that the proposed heatsink has a relatively low cost and works effectively. It paves the way to better packaging design and more efficient thermal management method for high power devices.

Module Multilevel-Clamped Composited Multilevel Converter (M-MC²) with Dual T-Type Modules and One Diode Module

Luo, Haoze,Dong, Yufei,Li, Wuhua,He, Xiangning The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.6

A modular multilevel-clamped composited multilevel converter ($M-MC^2$) is proposed. $M-MC^2$ enables topology reconfiguration, power device reuse, and composited clamping. An advanced five-level converter ($5L-M-MC^2$) is derived from the concept of $M-MC^2$. $5L-M-MC^2$ integrates dual three-level T-type modules and one three-level neutral point clamped module. This converter can also integrate dual three-level T-type modules and one passive diode module by utilizing the device reuse scheme. The operation principle and SPWM modulation are discussed to highlight converter performance. The proposed $M-MC^2$ is comprehensively compared with state-of-the-art five-level converters. Finally, simulations and experimental results are presented to validate the effectiveness of the main contributions of this study.

Synchronous Frequency Resonance of Virtual Synchronous Generators and Damping Control

Jinhua Wang,Yuxiang Wang,Yunjie Gu,Wuhua Li,Xiangning He 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

The Virtual Synchronous Generator (VSG) is an effective solution for high-penetration renewable energy sources integrated into the power system. Although the VSG has a similar behavior as the conventional synchronous generator, the fast and flexible control capability of converters may give rise to some specific characteristics. In this paper, it is explained that flux dynamics may induce synchronous frequency resonance in VSGs, which possibly leads to power-angle oscillations. A precise small-signal model is established to investigate the synchronous frequency resonance phenomenon. Based on this model, two damping control methods are proposed, which suppress the resonance through increasing the virtual mechanical inertia or adding virtual electrical resistance. The effectiveness of the theoretical conclusions is verified by simulation and experimental results.

Green-revertible Chlorina 1 (grc1) is Required for the Biosynthesis of Chlorophyll and the Early Development of Chloroplasts in Rice

Jieqin Li,Yihua Wang,Juntao Chai,Lihua Wang,Chunming Wang,Wuhua Long,Di Wang,Yunlong Wang,Ming Zheng,Cheng Peng,Mei Niu,Jianmin Wan 한국식물학회 2013 Journal of Plant Biology Vol.56 No.5

The nuclear genes involved in chloroplast developmentand chlorophyll biosynthesis must be investigated tounderstand their functions in plant growth and development. In this study, we isolated and identified a unique leaf-colormutant of rice with a green-yellow phenotype before thefour-leaf stage and named the mutation green-revertiblechlorina 1 (grc1). The mutants had significantly lower plantheight, number of tillers, and panicle length and headedsignificantly earlier than the wild type. The levels ofchlorophylls, carotenoids, and chlorophyll precursors werealso lower. The mutation in grc1 affected chloroplastultrastructure, particularly thylakoid development. Geneticanalysis indicated that the green-yellow phenotype wascontrolled by a single recessive gene. We mapped the grc1gene to a 32.4-kb region on the long arm of chromosome 6. Through map-based cloning, we identified a 45-bp insertionin the genomic region of LOC_Os06g40080, which encodeda heme oxygenase. Expression of LOC_Os06g40080 wassignificantly down-regulated in the grc1 mutant. Subcellularlocalization showed that this heme oxygenase was localizedin the chloroplast. In summary, we isolated and identified thegene for grc1, which plays an important role in chlorophyllbiosynthesis and chloroplast development in rice.

Transcriptomic profiling of the cold stress and recovery responsiveness of two contrasting Guizhou HE rice genotypes

Wang Zhongni,Wu Xian,Chen Yuxuan,Wu Chaoxin,Long Wuhua,Zhu Susong 한국유전학회 2023 Genes & Genomics Vol.45 No.4

Background At the seed germination stage, rice is sensitive to cold stress, which adversely affects its growth and development. Guizhou HE rice comprises several different landraces, most of which are cold tolerant. Objective To identify differentially expressed genes and molecular mechanism underlying the cold tolerance of Guizhou HE. Methods Two Guizhou HE genotypes, AC44 (cold-sensitive) and AC96 (cold-tolerant), which exhibit opposite phenotypes in response to cold treatment at the seed germination stage were used. Comprehensive gene expressions of AC44 and AC96 under 4 °C cold treatment and subsequent recovery conditions were comparatively analyzed by RNA sequencing. Results Overall, 11,082 and 7749 differentially expressed genes were detected in AC44 and AC96, respectively. Comparative transcriptome analysis demonstrated that, compared with AC44, AC96 presented fewer upregulated and downregulated genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses demonstrated that AC96 presented more upregulated GO terms, especially terms associated with biological processes. However, AC44 presented more terms related to cellular components, mainly chloroplasts. Moreover, DEGs related to the auxin signaling pathway (including ARF and IAA family members) and transcription factors (including members of the F-box, bZIP, basic helix-loop-helix [bHLH], and MYB-like transcription factor families) were found to be expressed specifically in AC96; thus, these DEGs may be responsible for the cold tolerance of AC96. Conclusions These findings present information about the cold tolerance mechanism of Guizhou HE rice at the germination stage, providing valuable resources and candidate genes for breeding cold-tolerant rice genotypes.