An AGAMOUS-like factor is associated with the origin of two domesticated varieties in Cymbidium sinense (Orchidaceae)

Cymbidium has been artificially domesticated for centuries in Asia,which produced numerous cultivated varieties.Flowers with stamenoid tepals or those with multiple tepals have been found in different species of Cymbidium;however,the molecular basis controlling the formation of these phenotypes is still largely unknown.Previous work demonstrated that AGAMOUS/AG lineage MADS genes function in floral meristem determinacy as well as in reproductive organs development in both dicots and monocots,indicating a possible relationship with the origin of two flower varieties in Cymbidium.Here,we characterized and analyzed two AG lineage paralogues,CsAG1 and CsAG2,from Cymbidium sinense,both of which were highly expressed in the gynostemium column of a standard C.sinense.Interestingly,we detected ectopic expression of CsAG1 rather than CsAG2 in all floral organs of a stamenoid-tepal variety and significant down-regulation of CsAG1 in a variety with multiple tepals.Over-expression of CsAG1 in wild type Arabidopsis resulted in petal-to-stamen homeotic conversion,suggesting a conserved C-function of CsAG1 in the development of Cymbidium flower.Altogether,our results supported a hypothesis that disruption of a single AG-like factor would be associated with the formation of two domesticated varieties in C.sinense.

Salt-responsive genes in rice revealed by cDNA microarray analysis

We used cDNA microarrays containing ～9,000 unigenes to identify 486 salt responsive expressed sequence tags (ESTs) (representing ～450 unigenes) in shoots of the highly salt-tolerant rice variety, Nona Bokra (Oryza sativa L. Ssp.Indica pv. Nona). Some of the genes identified in this study had previously been associated with salt stress. Howeverthe majority were novel, indicating that there is a great number of genes that are induced by salt exposure. Analysis of the salt stress expression profile data of Nona provided clues regarding some putative cellular and molecular processes that are undertaken by this tolerant rice variety in response to salt stress. Namely, we found that multiple transcription factors were induced during the initial salt response of shoots. Many genes whose encoded proteins are implicated in detoxification, protectant and transport were rapidly induced. Genes supporting photosynthesis were repressed and those supporting carbohydrate metabolism were altered. Commonality among the genes induced by salt exposure with those induced during senescence and biotic stress responses suggests that there are shared signaling pathways among these processes. We further compared the transcriptome changes of the salt-sensitive cultivar, IR28, with that of Nona rice. Many genes that are salt responsive in Nona were found to be differentially regulated in IR28. This study identified a large number of candidate functional genes that appear to be involved in salt tolerance and further examination of these genes may enable the molecular basis of salt tolerance to be elucidated.

NECK LEAF 1, a GATA type transcription factor, modulates organogenesis by regulating the expression of multiple regulatory genes during reproductive development in rice

In the monocot rice species Oryza sativa L., one of the most striking morphological processes during reproductive development is the concurrence of panicle development with the sequential elongation of upper internodes （UPIs）. To elucidate the underlying molecular mechanisms, we cloned the rice gene NECK LEAF 1 （NL1）, which when mutated results in delays in flowering time, smaller panicles with overgrown bracts and abnormal UPI elongation patterns. The NL1 gene encodes a GATA-type transcription factor with a single zinc finger domain, and its transcripts are de- tected predominantly in the bract primordia, which normally degenerate in the wild-type plants. Overexpression of NL1 in transgenic plants often gives rise to severe growth retardation, less vegetative phytomers and smaller leaves, suggesting that NL1 plays an important role in organ differentiation. A novel mutant allele of PLASTOCHRON1 （PLAD, a gene known to play a key role in regulating leaf initiation, was identified in this study. Genetic analysis demonstrated an interaction between nil and plal, with NL1 acting upstream of PLA1. The expression level and spatial pattern of PLA1 were found to be altered in the nil mutant. Furthermore, the expression of two regulators of flowering, Hd3a and OsMADS1, was also affected in the nil mutant. On the basis of these findings, we propose that NL1 is an intrinsic factor that modulates and coordinates organogenesis through regulating the expression of PLA1 and other regulatory genes during reproductive development in rice.

Different expression patterns of duplicated PHANTASTICA-like genes in Lotus japonicus suggest their divergent functions during compound leaf development

Recent studies on leaf development demonstrate that the mechanism on the adaxial-abaxial polarity pattern formation could be well conserved among the far-related species, in which PHANTASTICA （PAHN）-Iike genes play important roles. In this study, we explored the conservation and diversity on functions of PHAN-Iike genes during the compound leaf development in Lotusjaponicus, a papilionoid legume. Two PHAN-Iike genes in L. japonicus, LjPHANa and LjPHANb, were found to originate from a gene duplication event and displayed different expression patterns during compound leaf development. Two mutants, reduced leafletsl （rell） and reduced leaflets3 （rel3）, which exhibited decreased adaxial identity of leaflets and reduced leaflet initiation, were identified and investigated. The expression patterns of both LjPHANs in rel mutants were altered and correlated with abnormalities of compound leaves. Our data suggest that LjPHANa and LjPHANb play important but divergent roles in regulating adaxial-abaxial polarity of compound leaves in L. japonicus.

Wrinkled petals and stamens 1,is required for the morphogenesis of petals and stamens in Lotus japonicus

Although much progress has been made in understanding how floral organ identity is determined during the floral development, less is known about how floral organ is elaborated in the late floral developmental stages. Here we describe a novel floral mutant, wrinkled petals and stamens1 （wps1）, which shows defects in the development of petals and stamens. Genetic analysis indicates that wpsl mutant is corresponding to a single recessive locus at the long arm of chromosome 3. The early development of floral organs in wpsl mutant is similar to that in wild type, and the malfunction of the mutant commences in late developmental stages, displaying a defect on the appearance of petals and stamens. In the mature flower, petals and stamen filaments in the mutant are wrinkled or folded, and the cellular morphology under L1 layer of petals and stamen filaments is abnormal. It is found that the expression patterns of floral organ identity genes are not affected in wpsl mutants compared with that of wild type, consistent with the unaltered development of all floral organs. Furthermore, the identities of epidermal cells in different type of petals are maintained. The histological analysis shows that in wpsl flowers all petals are irregularly folded, and there are knotted structures in the petals, while the shape and arrangement of inner cells are malformed and unorganized. Based on these results, we propose that Wpsl acts downstream to the class B floral organ identity genes, and functions to modulate the cellular differentiation during the late flower developmental stages.

Genetic control of compound leaf development in the mungbean(Vigna radiata L.)

Many studies suggest that there are distinct regulatory processes controlling compound leaf development in different clades of legumes.Loss of function of the LEAFY(LFY)orthologs results in a reduction of leaf complexity to different degrees in inverted repeat-lacking clade(IRLC)and non-IRLC species.To further understand the role of LFY orthologs and the molecular mechanism in compound leaf development in non-IRLC plants,we studied leaf development in unifoliate leaf(un)mutant,a classical mutant of mungbean(Vigna radiata L.),which showed a complete conversion of compound leaves into simple leaves.Our analysis revealed that UN encoded the mungbean LFY ortholog(VrLFY)and played a significant role in leaf development.In situ RNA hybridization results showed that STM-like KNOXI genes were expressed in compound leaf primordia in mungbean.Furthermore,increased leaflet number in heptafoliate leaflets1(hel1)mutants was demonstrated to depend on the function of VrLFY and KNOXI genes in mungbean.Our results suggested that HEL1 is a key factor coordinating distinct processes in the control of compound leaf development in mungbean and its related non-IRLC legumes.

Study on Thermal Deformation Measurement of Optical RemoteSensing Satellite Platform Based on Machine Vision

To solve the special requirements of the high orbit optical remote sensing satellite for the thermal deformation of the platform the thermal deformation test and measurement scheme of the satellite platform is designed. Through the comparative analysis of test results the rationality of the thermal deformation design of the platform structure is verified. The results of thermal deformation measurement show that the maximum deformation of A camera mounting surface is 57.5〃 and the maximum deformation of B camera mounting surface points to 79.3〃 which can be used as the basis for thermal deformation prediction of satellite during the orbit operation.

Functional Diversity of CYCLOIDEA-like TCP Genes in the Control of Zygomorphic Flower Development in Lotus japonicus

CYCLOIDEA （CYC）-like TCP genes play key roles in dorsoventral differentiation of zygomorphic flowers in Papilionoideae legumes. In this study, we analyzed the kew mutants whose flowers lost lateral identity, and investigated the diverse functions of three LjCYC genes during zygomorphic flower development in the model legume Lotus japonicus. We showed that kew1 and kew3 are allelic mutants of LjCYC3, a CYC-like TCP gene. Through transgenic experiments, it was shown that LjCYC1 possesses dorsal activity similar to LjCYC2, and that LjCYC3 alone is sufficient to confer lateral activity, and an epistatic effect between dorsal and lateral activities was identified. Sequence analysis revealed a striking alteration at the 3 end of the LjCYC3 open reading frame （ORF） in comparison with those of LjCYC1 and LjCYC2 ORFs. Furthermore, it was found that LjCYC proteins could interact with each other and possess different activities by means of a transcriptional activity assay. Our data demonstrate that the sequence variation and the subsequent alteration of protein property play important roles in the functional diversity of different LjCYC genes in controlling zygomorphic flower development in Lotus japonicus.

LATHYROIDES, Encoding a WUSCHEL-Related Homeoboxl Transcription Factor, Controls Organ Lateral Growth, and Regulates Tendril and Dorsal Petal Identities in Garden Pea （Pisum sativum L.）

During organ development, many key regulators have been identified in plant genomes, which play a conserved role among plant species to control the organ identities and/or determine the organ size and shape. It is intriguing whether these key regulators can acquire diverse function and be integrated into different molecular pathways among different species, giving rise to the immense diversity of organ forms in nature. In this study, we have characterized and cloned LATHYROIDES （LATH）, a classical locus in pea, whose mutation displays pleiotropic alteration of lateral growth of organs and predominant effects on tendril and dorsal petal development. LATH encodes a WUSCHEL-related home- oboxl （WOX1） transcription factor, which has a conserved function in determining organ lateral growth among different plant species. Furthermore, we showed that LATH regulated the expression level of TENDRIL-LESS （TL）, a key factor in the control of tendril development in compound leaf, and LATH genetically interacted with LOBED STANDARD （LST）, a floral dorsal factor, to affect the dorsal petal identity. Thus, LATH plays multiple roles during organ development in pea： it maintains a conserved function controlling organ lateral outgrowth, and modulates organ identities in compound leaf and zygomorphic flower development, respectively. Our data indicated that a key regulator can play important roles in different aspects of organ development and dedicate to the complexity of the molecular mechanism in the control of organ development so as to create distinct organ forms in different species.

Multiple Components are Integrated to Determine Leaf Complexity in Lotus japonicus

Transcription factors and phytohormones have been reported to play crucial roles to regulate leaf complexity among plant species. Using the compound-leafed species Lotus japonicus, a model legume plant with five visible leaflets, we characterized four independent mutants with reduced leaf complexity, proliferating floral meristem （pfm）, proliferating floral organ-2 （pfo-2）, fused leaflets1 （ful1） and umbrella leaflets （uml）, which were further identified as loss-of-function mutants of Arabidopsis orthologs LEAFY （LFY ）, UNUSUAL FLORAL ORGANS （UFO）, CUP-SHAPED COTYLEDON 2 （CUC2） and PIN-FORMED 1 （PIN1）, respectively. Comparing the leaf development of wild-type and mutants by a scanning electron microscopy approach, leaflet initiation and/or dissection were found to be affected in these mutants. Expression and phenotype analysis indicated that PFM/LjLFY and PFO/LjUFO determined the basipetal leaflet initiation manner in L. japonicus. Genetic analysis of ful1 and uml mutants and their double mutants revealed that the CUC2-like gene and auxin pathway also participated in leaflet dissection in L. japonicus, and their functions might influence cytokinin biogenesis directly or indirectly. Our results here suggest that multiple genes were interplayed and played conserved functions in controlling leaf complexity during compound leaf development in L. japonicus.

Preparation of horizontally aligned single-walled carbon nanotubes with floating catalyst

A strategy to prepare horizontally aligned single-walled carbon nanotubes(SWNTs) at moderate temperatures(≤600 ℃) were developed.Using ferocene as the catalyst precursor,Fe nanoparticles are formed in the gaseous phase and catalyze the nucleation and growth of SWNTs in situ.Then the resultant SWNTs are deposited onto the substrates downstream and aligned by the surface lattice of the ST-cut single crystal quartz.The preparation of SWNT arrays at moderate temperatures is important for combining the tube growth with device fabrication.

Transcriptional and Post-transcriptional Modulation of SQU and KEW Activities in the Control of Dorsal-Ventral Asymmetric Flower Development in Lotus japonicus

In Papilionoideae legume, Lotusjaponicus, the development of dorsal-ventral （DV） asymmetric flowers is mainly controlled by two TB1/CYCLOIDEA/PCF （TCP） genes, SQUARED STANDARD （SQU） and KEELED WINGS IN LOTUS （KEW）, which determine dorsal and lateral identities, respectively. However, the molecular basis of how these two highly homologous genes orchestrate their diverse functions remains unclear. Here, we analyzed their expression levels, and investigated the transcriptional activities of SQUand KEW. We demonstrated that SQU possesses both activation and repression activities, while KEW acts only as an activator. They form homo- and heterodimers, and then collaboraUvely regulate their expression at the transcription level. Furthermore, we identified two types of post-transcriptional modifications, phosphor- ylation and ATP/GTP binding, both of which could affect their transcriptional activities. Mutations in ATP/ GTP binding motifs of SQU and KEW lead to failure of phosphorylation, and transgenic plants bearing the mutant proteins display defective DV asymmetric flower development, indicating that the two conjugate modifications are essential for their diverse functions. Altogether, SQU and KEW activities are precisely modulated at both transcription and post-transcription levels, which might link DV asymmetric flower development to different physiological status and/or signaling pathways.

PHOSPHATIDYLSERINE SYNTHASE1 is Required for Inflorescence Meristem and Organ Development in Arabidopsis

Phosphatidylserine （PS）, a quantitatively minor membrane phospholipid, is involved in many biological processes besides its role in membrane structure. One PS synthesis gene, PHOSPHATIDYLSERINE SYNTHASE1 （PSSl）, has been discovered to be required for microspore development in Arabidopsis thaliana L. but how PSS1 affects postembryonic development is still largely unknown. Here, we show that PSSl is also required for inflorescence meristem and organ development in Arabidopsis. Disruption of PSSI causes severe dwarfism, smaller lateral organs and reduced size of inflorescence meristem. Morphological and molecular studies suggest that both cell division and cell elongation are affected in the pssl-1 mutant. RNA in situ hybridization and promoter GUS analysis show that expression of both WUSCHEL （WUS） and CLA VA TA3 （CL V3） depend on PSS1. Moreover, the defect in meristem maintenance is recovered and the expression of WUS and CLV3 are restored in the pssl-1 clvl-1 double mutant. Both SHOOTSTEMLESS （STM） and BREVIPEDICELLUS （BP） are upregulated, and auxin distribution is disrupted in rosette leaves of pssl-1. However, expression of BP, which is also a regulator of internode development, is lost in the pssl-1 inflorescence stem. Our data suggest that PSS1 plays essential roles in inflorescence meristem maintenance through the WUS-CLV pathway, and in leaf and internode development by differentially regulating the class I KNOX genes.

Petal Development in Lotus japonicus

Previous studies have demonstrated that petal shape and size in legume flowers are determined by two separate mechanisms, dorsoventral （DV） and organ internal （IN） asymmetric mechanisms, respectively. However, little is known about the molecular mechanisms controlling petal development in legumes. To address this question, we investigated petal development along the floral DV axis in Lotus japonicus with respect to cell and developmental biology by comparing wild-type legumes to mutants. Based on morphological markers, the entire course of petal development, from initiation to maturity, was grouped to define 3 phases or 13 stages. In terms of epidermal micromorphology from adaxial surface, mature petals were divided into several distinct domains, and characteristic epidermal cells of each petal differentiated at stage 9, while epidermal cells of all domains were observed until stage 12. TCP and MIXTA-like genes were found to be differentially expressed in various domains of petals at stages 9 and 12. Our results suggest that DV and IN mechanisms interplay at different stages of petal development, and their interaction at the cellular and molecular level guides the elaboration of domains within petals to achieve their ideal shape, and further suggest that TCP genes determine petal identity along the DV axis by regulatincl MIXTA-like clene expression.

LjCYC Genes Constitute Floral Dorsoventral Asymmetry in Lotus japonicus

Previous study shows that LjCYC2,a CYC-like TCP （TB1,CYC and PCFs） gene in the model legume,Lotus japonicus,is involved in dorsal petal development,which together with the other two homologous genes,LjCYC1 and LjCYC3,belongs to an LjCYC gene cluster.In this report,we modified the transformation system in L.japonicus,and constructed different RNAi transgenes to target different LjCYC genes.The expression of three endogenous LjCYC genes was specifically suppressed by different specific RNAi transgenes,and a chimerical RNAi transgene that contains the specific sequences from LjCYC1 and LjCYC2 was found to downregulate the expression of both endogenous genes simultaneously.Effects of silencing three LjCYC genes were mainly restricted on either dorsal or lateral petals,demonstrating their dorsalizing and lateralizing activities during the development of zygomorphic flower.Furthermore,abolishing the expression of three LjCYC genes could give rise to complete loss of dorsoventral （DV） differentiation in the flower whose petals all resembled the ventral one in the wild type and displayed intact organ internal （IN） asymmetry.Our data demonstrate that during zygomorphic flower development,the DV asymmetry is constituted by the LjCYC genes,while the floral organ IN asymmetry is independently determined by other genetic factors.

Genetic Analysis of ele Mutants and Comparative Mapping of ele1 Locus in the Control of Organ Internal Asymmetry in Garden Pea

Previous study has shown that during zygomorphic development in garden pea （Pisum sativum L.）, the organ internal （IN） asymmetry of lateral and ventral petals was regulated by a genetic locus, SYMMETRIC PETAL 1 （SYP1）, while the dorsoventral （DV） asymmetry was determined by two CYC-like TCP genes or the PsCYC genes, KEELED WINGS （K） and LOBED STANDARD 1 （LST1）. In this study, two novel loci, ELEPHANT EAR-LIKE LEAF 1 （ELE1） and ELE2 were characterized. These mutants exhibit a similar defect of IN asymmetry as syp1 in lateral and ventral petals, but also display pleiotropic effects of enlarged organ size. Genetic analysis showed that ELE1 and ELE2 were involved in same genetic pathway and the enlarged size of petals but not compound leaves in e/e2 was suppressed by introducing k and Ist1, indicating that the enlargement of dorsal petal in e/e2 requires the activities of K and LST1. An experimental framework of comparative genomic mapping approach was set up to map and clone LjELE1 locus in Lotus japonicus. Cloning the ELE1 gene will shed light on the underlying molecular mechanism during zygomorphic development and further provide the molecular basis for genetic improvement on legume crops.

A member of the ALOG gene family has a novel role in regulating nodulation in Lotus japonicus

Legumes can control the number of symbiotic nodules that form on their roots, thus balancing nitrogen assimilation and energy consumption. Two major pathways participate in nodulation: the Nod factor(NF)signaling pathway which involves recognition of rhizobial bacteria by root cells and promotion of nodulation, and the autoregulation of nodulation(AON) pathway which involves long-distance negative feedback between roots and shoots. Although a handful of genes have a clear role in the maintenance of nodule number, additional unknown factors may also be involved in this process. Here, we identify a novel function for a Lotus japonicus ALOG(Arabidopsis LSH1 and Oryza G1) family member, LjALOG1,involved in positively regulating nodulation. LjALOG1 expression increased substantially after inoculation with rhizobia, with high levels of expression in whole nodule primordia and in the base of developing nodules. The ljalog1 mutants, which have an insertion of the LORE1 retroelement in LjALOG1, had significantly fewer nodules compared with wild type, along with increased expression of LjCLE-RS1(L. japonicus CLE Root Signal 1), which encodes a nodulation suppressor in the AON pathway. In summary,our findings identified a novel factor that participates in controlling nodulation, possibly by suppressing the AON pathway.

Universal Image Steganalysis Based on Convolutional Neural Network with Global Covariance Pooling

Recently,steganalytic methods based on deep learning have achieved much better performance than traditional methods based on handcrafted features.However,most existing methods based on deep learning are specially designed for one image domain(i.e.,spatial or JPEG),and they often take long time to train.To make a balance between the detection performance and the training time,in this paper,we propose an effective and relatively fast steganalytic network called US-CovNet(Universal Steganalytic Covariance Network)for both{the}spatial and JPEG domains.To this end,we carefully design several important components of{US-CovNet}that will significantly affect the detection performance,including the high-pass filter set,the shortcut connection and the pooling{layer}.Extensive experimental results show that compared with the current best steganalytic networks(i.e.,SRNet and J-YeNet),{US-CovNet}can achieve the state-of-the-art results for detecting spatial steganography and have competitive performance for detecting JPEG steganography.For example,the detection accuracy of US-CovNet is at least 0.56%higher than that of SRNet in the spatial domain.In the JPEG domain,US-CovNet performs slightly worse than J-YeNet in some cases with the degradation of less than 0.78%.However,the training time of US-CovNet is significantly reduced,which is less than 1/4 and 1/2 of SRNet and J-YeNet respectively.

Review of Low Carrier Ratio Converter System

With the rapid development of new energy power generation and high-power traction technology,the voltage and power levels of converter devices have been continuously improved,and the application of high-power converters is becoming increasingly widespread.However,high-power converters are affected by switching losses and heat dissipation,meaning they are not suitable for high carrier conditions.Therefore,research of low carrier ratio converter systems has received increased attention.Based on existing research,the problems of large current harmonics,low observation accuracy,and poor stability that may occur at low carrier ratios are explained.In addition,the topologies,modulation strategies,and control methods of the low carrier ratio converter system are analyzed and classified.Finally,future research directions of low carrier ratio converter systems are proposed.