A high-quality chromosome-scale assembly of the centipedegrass[Eremochloa ophiuroides(Munro)Hack.]genome provides in sights into chromosomal structural evolution and prostrate growth habit

Centipedegrass[Eremochloa ophiuroides(Munro)Hack.],a member of the Panicoideae subfamily,is one of the most important warm-season turfgrasses originating from China.This grass has an extremely developed prostrate growth habit and has been widely used in transitional and warm climatic regions.To better understand the genetic basis of important biological characteristics,such as prostrate growth and seed yield,in warm-season turfgrasses,we present a high-quality reference genome for centipedegrass and use PacBio,BioNano,and Hi-C technologies to anchor the 867.43 Mb genome assembly into nine pseudochromosomes,with a scaffold N50 of 86.05 Mb and 36,572 annotated genes.Centipedegrass was most closely related to sorghum and diverged from their common ancestor~16.8 Mya.We detected a novel chromosome reshuf fling event in centipedegrass,namely,the nest chromosome fusion event in which fusion of chromosomes 8 and 10 of sorghum into chromosome 3 of centipedegrass likely occurred after the divergence of centipedegrass from sorghum.The typical prostrate growth trait in centipedegrass may be linked to the expansion of candidate PROSTRATE GROWTH 1(PROG1)genes on chromosome 2.Two orthologous genes of OsPROGl,EoPROGl,and EoPROG2,were con firmed to increase the stem number and decrease the stem angle in Arabidopsis.Collectively,our assembled reference genome of centipedegrass offers new knowledge and resources to dissect the genome evolution of Panicoideae and accelerate genome-assisted breeding and improvement of plant architecture in turf plants.

Influence of low-vacuum helium cold plasma pre-treatment on the rooting and root growth of zoysiagrass(Zoysia Willd.) stolon cuttings

The influence of low-vacuum helium cold plasma treatment on the rooting percentage,root growth and physiochemical properties of zoysiagrass stolon cuttings was studied.Zoysiagrass stolon cuttings were pre-treated with 0,100,200,300 and 400 W of cold plasma for 15 s.The cold plasma positively stimulated rooting and improved the root growth of the zoysiagrass stolon cuttings,and the 300 W treatment produced the best effect.The rooting percentage and root growth parameters,including the root length,total root surface area,total root volume,average root diameter,and root dry weight,significantly improved in response to the cold plasma treatment.In addition,the water uptake and relative conductivity of the stolon cuttings increased significantly in response to the cold plasma treatment.The results revealed that cold plasma-stimulated rooting and root growth appear to be a consequence of the improvement in permeability and water absorbing capacity of zoysiagrass stolon cuttings.The results of the present study will provide inspiration and support for the application of cold plasma in the vegetative propagation of plants.

Genetic diversity in centipedegrass[Eremochloa ophiuroides(Munro)Hack.]

Genetic diversity is the heritable variation within and among populations,and in the context of this paper describes the heritable variation among the germplasm resources of centipedegrass.Centipedegrass is an important warmseason perennial C4 grass belonging to the Poaceae family in the subfamily Panicoideae and genus Eremochloa.It is the only species cultivated for turf among the eight species in Eremochloa.The center of origin for this species is southern to central China.Although centipedegrass is an excellent lawn grass and is most widely used in the southeastern United States,China has the largest reserve of centipedegrass germplasm in the world.Presently,the gene bank in China holds~200 centipedegrass accessions collected from geographical regions that are diverse in terms of climate and elevation.This collection appears to have broad variability with regard to morphological and physiological characteristics.To efficiently develop new centipedegrass varieties and improve cultivated species by fully utilizing this variability,multiple approaches have been implemented in recent years to detect the extent of variation and to unravel the patterns of genetic diversity among centipedegrass collections.In this review,we briefly summarize research progress in investigating the diversity of centipedegrass using morphological,physiological,cytological,and molecular biological approaches,and present the current status of genomic studies in centipedegrass.Perspectives on future research on genetics and genomics and modern breeding of centipedegrass are also discussed.

EoPHR2,a Phosphate Starvation Response Transcription Factor,Is Involved in Improving Low-Phosphorus Stress Resistance in Eremochloa ophiuroides

As a macronutrient,Phosphorus(P)takes many roles in plant growth and development.It should be significant to explore the molecular mechanism of low-phosphorus stress response of plants.Phosphate starvation response(PHR)transcription factors play important roles in response to phosphorus deficiency stress in plants.In this study,we isolated a gene related to the plant phosphorus signaling system from the acid-soil-resistant centipedegrass(Eremochloa ophiuroides[Munro]Hack.),termed EoPHR2.The subcellular localization of EoPHR2 protein was observed to be nuclear located.The expression patterns of EoPHR2 in different tissues and Al/Pi-stress conditions were analyzed by qRT-PCR,they suggested a potential role in response to the multiple-stress under acid soil adversity.Based on the functional identification through transgenic plants,we found that(1)EoPHR2 is involved in the Pi-signaling pathway,and(2)overexpression of EoPHR2 mimics Pi-starvation signalling resulting on enhanced roots whether under Pi-deficiency stress or not.In conclusion,EoPHR2 transcription factor plays a role in response to the multiple stresses under acid soil conditions,improving the low-phosphorus stress resistance of Eremochloa ophiuroides.

A Hybrid Simulation Test Platform for Verifying the Protection Settings of SPS

To verify the effectiveness and correctness of the protection settings in ring structure Shipboard Power System (SPS), a digital-physical hybrid simulation platform at China Ship Development and Design Center (CSDDC) has been built, which aims to give double verification effect of design scheme and physical device. The platform consists of eMEGAsim digital simulator, signal power amplifiers and digital-analog interface equipments. With this platform, the multiple protection device of ring structure grid can be accessed to form a close-loop test system. Since eMEGAsim model-simulated faults and actual protection device actions are on real time, the tripping settings of each device as well as their coordinate performance between multiple devices can be verified in this close-loop test.

Identification and characterization of two human immunodeficiency virus type 1 unique recombinant forms from Yunnan, China

Dear Editor,Recombination contributes greatly to the diversity of human immunodeficiency virus type 1（HIV-1）.A large number of recombinant strains have been found in China,particularly in Yunnan,which is considered the HIV-1 epicenter of China.Surveillance of unique recombinant forms is helpful for prediction of new circulating recombinant forms.

Long noncoding RNA XIST:Mechanisms for X chromosome inactivation,roles in sex-biased diseases,and therapeutic opportunities

Sexual dimorphism has been reported in various human diseases including autoimmune diseases,neurological diseases,pulmonary arterial hypertension,and some types of cancers,although the underlying mechanisms remain poorly understood.The long noncoding RNA(lncRNA)X-inactive specific transcript(XIST)is involved in X chromosome inactivation(XCI)in female placental mammals,a process that ensures the balanced expression dosage of X-linked genes between sexes.XIST is abnormally expressed in many sex-biased diseases.In addition,escape from XIST-mediated XCI and skewed XCI also contribute to sex-biased diseases.Therefore,its expression or modification can be regarded as a biomarker for the diagnosis and prognosis of many sex-biased diseases.Genetic manipulation of XIST expression can inhibit the progression of some of these diseases in animal models,and therefore XIST has been proposed as a potential therapeutic target.In this manuscript,we summarize the current knowledge about the mechanisms for XIST-mediated XCI and the roles of XIST in sex-biased diseases,and discuss potential therapeutic strategies targeting XIST.