GOLDEN 2-LIKE transcription factors regulate chlorophyll biosynthesis and flavonoid accumulation in response to UV-B in tea plants

Flavonoids are critical secondary metabolites that determine the health benefits and flavor of tea,while chlorophylls are important contributors to the appearance of tea.However,transcription factors(TFs)that can integrate both chlorophyll biosynthesis and flavonoid accumulation in response to specific light signals are rarely identified.In this study,we report that the GOLDEN 2-LIKE TF pair,CsGLK1 and CsGLK2,orchestrate UV-B-induced responses in the chlorophyll biosynthesis and flavonoid accumulation of tea leaves.The absence of solar UV-B reduced the transcriptional expression of CsGLKs in the tea leaves and was highly correlated with a decrease in flavonoid levels(especially flavonol glycosides)and the expression of genes and TFs involved in chlorophyll biosynthesis and flavonoid accumulation.In vivo and in vitro molecular analyses showed that CsGLKs could be regulated by the UV-B signal mediator CsHY5,and could directly bind to the promoters of gene and TF involved in light-harvesting(CsLhcb),chlorophyll biosynthesis(CsCHLH,CsHEMA1,and CsPORA),and flavonoid accumulation(CsMYB12,CsFLSa,CsDFRa,and CsLARa),eventually leading to UV-B-induced responses in the chlorophylls and flavonoids of tea leaves.Furthermore,UV-B exposure increased the levels of total flavonoids,CsGLK1 protein,and expression of CsGLKs and target genes in the tea leaves.These results indicate that CsGLKs may modulate tea leaf characteristics by regulating chlorophyll biosynthesis and flavonoid accumulation in response to solar UV-B.As the first report on UV-B-induced changes in flavonoid and chlorophyll regulation mediated by CsGLKs,this study improves our understanding of the environmental regulations regarding tea quality and sheds new light on UV-B-induced flavonoid responses in higher plants.

Review of advanced road materials, structures, equipment, and detection technologies

As a vital and integral component of transportation infrastructure,pavement has a direct and tangible impact on socio-economic sustainability.In recent years,an influx of groundbreaking and state-of-the-art materials,structures,equipment,and detection technologies related to road engineering have continually and progressively emerged,reshaping the landscape of pavement systems.There is a pressing and growing need for a timely summarization of the current research status and a clear identification of future research directions in these advanced and evolving technologies.Therefore,Journal of Road Engineering has undertaken the significant initiative of introducing a comprehensive review paper with the overarching theme of“advanced road materials,structures,equipment,and detection technologies”.This extensive and insightful review meticulously gathers and synthesizes research findings from 39 distinguished scholars,all of whom are affiliated with 19 renowned universities or research institutions specializing in the diverse and multidimensional field of highway engineering.It covers the current state and anticipates future development directions in the four major and interconnected domains of road engineering:advanced road materials,advanced road structures and performance evaluation,advanced road construction equipment and technology,and advanced road detection and assessment technologies.

Shading effects revisited:Comparisons of spring and autumn shading treatments reveal a seasonal-dependent regulation on amino acids in tea leaves

Shading is an effective way to improve tea quality by modulating the accumulation of the flavor-related secondary metabolites of tea leaves.However,shading effects on amino acids have been conflicting for years as both shading-induced increases and decreases have been detected.This study aims to investigate the effects of shading levels on catechins and amino acids,in particular,a comparison was made in April and August to better understand the involvement of seasonal environmental parameters.Shading reduced major catechins(catechin,gallocatechin,epicatechin,epigallocatechin,epicatechin gallate,and epigallocatechin gallate)in both seasons.Heavy shading(80%−90%)increased total and individual amino acids(threonine,glutamic acid,and alanine)in April but decreased those in August.In both seasons,ᴏ-Phosphoethanolamine increased under heavy shading,butα-aminoadipic acid,ornithine and glutamine showed decreases.Theanine showed no shading response in April but decreased under heavy shading in August.These results indicate that shading-induced reduction of leaf catechins is mainly determined by shading level,but the shading effects on amino acids are seasonally-dependent.As our first report focuses on the synergistic effects of seasons,this study improves our understanding of shading regulation on secondary metabolites of tea leaves and guides shading treatments to improve tea quality.

The effects of circadian rhythm on catechin accumulation in tea leaves

As the major bitter-and astringent-tasting components in tea leaves,catechins play an essential role in determining flavor characteristics and health benefits of tea products.This study analyzed the circadian rhythm effects on the accumulation pattern of catechins in tender leaves of three tea cultivars,'Huangkui'(HK),'Longjing43'(LJ43)and'Fuding Dabaicha'(FD).There were two major factors involved in the catechin regulation in tea plants:genetic background of the cultivar-specific regulation,and temporal effects of the circadian rhythm.Etiolated leaves of'HK'contained lower levels of catechins than'LJ43'and'FD'.The composition of EGCG in total catechins was significantly higher in'LJ43'leaves(65%)when compared with that in'HK'and'FD'(45%).The accumulation of individual catechins increased during the daytime but decreased overnight,especially over the time period of 22:00−02:00.The correlation analysis between catechins and environmental factors indicated catechin accumulation in tea leaves potentially resulted from a combined regulation of light and temperature.These findings provide new insights into our understanding of circadian rhythm regulation on flavor-important secondary metabolites in tea leaves.

Numerical Quantification Model and Experiment of External Force on Roller Hemming of Curved Edge Aluminium Alloy with Adhesive

Accurate quantification of external force is the key to improve the high-precision hemming of autobody closure panels.However,the mechanism of external force on forming quality of complex contour sheet metal with adhesive is not clear subjected to geometric curvature and materials.In the present study,taking the curved edge aluminum sheet as the research object,SPH(smooth particle hydrodynamics)is introduced to simulate the viscous adhesive,and the SPH-FEM(Finite element method)coupling model of adhesive and panels considering the viscosity-pressure effect is established.The numerical simulation of the roller hemming process is carried out,then the validity and reliability of the proposed method are verified by measuring the external force in real time using triaxial force sensor.The multi-step forming process and the effect of external force on the roll in/out,surface wave and plastic strain of aluminum alloy sheet under the viscosity-pressure effect are studied,and the relationship between process parameters and external force is discussed.Results show that the coupling SPH-FEM model can well reflect the hemming process of curved edge structure.The normal force is about 2–3 times of the tangential force in the pre and final hemming process.Compared with the case without adhesive,the surface wave of flange part of the hemming with adhesive is slightly larger.The normal force and the tangential force increase about 90 N and 30 N respectively,when the height increases by 1 mm.It provides an important basis for the accurate control of hemming trajectory and the improvement of manufacturing quality of autobody closure panels.

Hippo(YAP)-autophagy axis protects against hepatic ischemia-reperfusion injury through JNK signaling

Background:Hepatic ischemia-reperfusion injury(HIRI)remains a common complication during liver transplantation(LT)in patients.As a key downstream effector of the Hippo pathway,Yes-associated protein(YAP)has been reported to be involved in various physiological and pathological processes.However,it remains elusive whether and how YAP may control autophagy activation during ischemia-reperfusion.Methods:Human liver tissues from patients who had undergone LT were obtained to evaluate the correlation between YAP and autophagy activation.Both an in vitro hepatocyte cell line and in vivo liver-specific YAP knockdown mice were used to establish the hepatic ischemia-reperfusion models to determine the role of YAP in the activation of autophagy and the mechanism of regulation.Results:Autophagy was activated in the post-perfusion liver grafts during LT in patients,and the expression of YAP positively correlated with the autophagic level of hepatocytes.Liver-specific knockdown of YAP inhibited hepatocytes autophagy upon hypoxia-reoxygenation and HIRI(P<0.05).YAP deficiency aggravated HIRI by promoting the apoptosis of hepatocytes both in the in vitro and in vivo models(P<0.05).Attenuated HIRI by overexpression of YAP was diminished after the inhibition of autophagy with 3-methyladenine.In addition,inhibiting autophagy activation by YAP knockdown exacerbated mitochondrial damage through increasing reactive oxygen species(P<0.05).Moreover,the regulation of autophagy by YAP during HIRI was mediated by AP1(c-Jun)N-terminal kinase(JNK)signaling through binding to the transcriptional enhanced associate domain(TEAD).Conclusions:YAP protects against HIRI by inducing autophagy via JNK signaling that suppresses the apoptosis of hepatocytes.Targeting Hippo(YAP)-JNK-autophagy axis may provide a novel strategy for the prevention and treatment of HIRI.

Dynamic Relationship Between Human Microbiota and Host Factors

There have been considerable investigations into the composition of the microbiota inhabiting various anatomical sites of the human body,including but not limited to the gut and skin.However,the distribution of the microbiota composition and functionality across anatomical sites within the same individual are not yetwell-established,in particular in relation with host health and disease.