Basic helix-loop-helix(bHLH)transcription factors regulate diverse plant processes,particularly anthocyanin biosynthesis through the MYB-bHLH-WD40 complex.Despite snapdragon(Antirrhinum majus)serving as a classical mo...Basic helix-loop-helix(bHLH)transcription factors regulate diverse plant processes,particularly anthocyanin biosynthesis through the MYB-bHLH-WD40 complex.Despite snapdragon(Antirrhinum majus)serving as a classical model for studying flower pigmentation genetics,its bHLH gene family has rarely been comprehensively characterized.Here,we performed a genome-wide identification and systematic characterization of the bHLH gene family in A.majus,with a focus on candidates involved in anthocyanin biosynthesis.A total of 150 AmbHLH genes were identified and subjected to in-silico analyses,including phylogenetic classification,structural analysis,and promoter cis-element characterization.Comparative transcriptomic profiling between anthocyanin-poor(“SIPPE50”,Green)and anthocyanin-rich(“JI2R”,Red)snapdragon lines highlighted eight differentially expressed AmbHLHs.AmbHLH001,AmbHLH002,and AmbHLH042 showed significant upregulation in the anthocyanin-rich line and showed positive correlations with the expression of key anthocyanin biosynthetic genes.Among these,AmbHLH002 was prioritized as a candidate and was assessed via heterologous overexpression in tomatoes.Notably,AmbHLH002 is a newly identified regulator whose overexpression in tomato resulted in visible purple pigmentation and increased anthocyanin accumulation.These findings support the view that AmbHLH002 acts as a positive regulator,with phylogenetic evidence for conservation of anthocyanin biosynthesis,presenting valuable potential for engineering pigmentation traits in ornamental plants and serving as a candidate visible marker for plant genetic transformation.展开更多
The electro-hydrostatic actuator(EHA)pump is required to operate in a wide range of pressures and speeds to meet the variable output power demands.However,the reliable operation range of EHA pumps is restricted,and th...The electro-hydrostatic actuator(EHA)pump is required to operate in a wide range of pressures and speeds to meet the variable output power demands.However,the reliable operation range of EHA pumps is restricted,and the cylinder block tilting is considered a serious factor.This paper presents an analytical approach for evaluating the critical operation range of EHA pumps based on a criterion for cylinder tilting states.It explicitly reveals the fundamental principle of the cylinder block tilting limiting the operation range.The criterion is verified with the measured tilting angle and leakage flow.Results show that the calculated critical conditions accurately identify the inflection point of performance changes.Beyond the critical operation range,the severe cylinder block tilting leads to a sharp increase in leakage and may even result in a sudden failure.Furthermore,the impacts of the center spring force,the piston-slipper assembly mass,and the position of the spline reaction on the critical operation range are investigated.展开更多
基金funded by the USDANIFA grant 2019-67013-29236the USDA HATCH program FLA-MFC-006387,awarded to Heqiang Huo.
文摘Basic helix-loop-helix(bHLH)transcription factors regulate diverse plant processes,particularly anthocyanin biosynthesis through the MYB-bHLH-WD40 complex.Despite snapdragon(Antirrhinum majus)serving as a classical model for studying flower pigmentation genetics,its bHLH gene family has rarely been comprehensively characterized.Here,we performed a genome-wide identification and systematic characterization of the bHLH gene family in A.majus,with a focus on candidates involved in anthocyanin biosynthesis.A total of 150 AmbHLH genes were identified and subjected to in-silico analyses,including phylogenetic classification,structural analysis,and promoter cis-element characterization.Comparative transcriptomic profiling between anthocyanin-poor(“SIPPE50”,Green)and anthocyanin-rich(“JI2R”,Red)snapdragon lines highlighted eight differentially expressed AmbHLHs.AmbHLH001,AmbHLH002,and AmbHLH042 showed significant upregulation in the anthocyanin-rich line and showed positive correlations with the expression of key anthocyanin biosynthetic genes.Among these,AmbHLH002 was prioritized as a candidate and was assessed via heterologous overexpression in tomatoes.Notably,AmbHLH002 is a newly identified regulator whose overexpression in tomato resulted in visible purple pigmentation and increased anthocyanin accumulation.These findings support the view that AmbHLH002 acts as a positive regulator,with phylogenetic evidence for conservation of anthocyanin biosynthesis,presenting valuable potential for engineering pigmentation traits in ornamental plants and serving as a candidate visible marker for plant genetic transformation.
基金supported in part by the National Natural Science Foundation of China(No.51890882)the National Natural Science Foundation of China(No.52305075)+1 种基金the China Postdoctoral Science Foundation(No.2023M733065)the Aeronautical Science Foundation of China(No.20220028076003)。
文摘The electro-hydrostatic actuator(EHA)pump is required to operate in a wide range of pressures and speeds to meet the variable output power demands.However,the reliable operation range of EHA pumps is restricted,and the cylinder block tilting is considered a serious factor.This paper presents an analytical approach for evaluating the critical operation range of EHA pumps based on a criterion for cylinder tilting states.It explicitly reveals the fundamental principle of the cylinder block tilting limiting the operation range.The criterion is verified with the measured tilting angle and leakage flow.Results show that the calculated critical conditions accurately identify the inflection point of performance changes.Beyond the critical operation range,the severe cylinder block tilting leads to a sharp increase in leakage and may even result in a sudden failure.Furthermore,the impacts of the center spring force,the piston-slipper assembly mass,and the position of the spline reaction on the critical operation range are investigated.
