Characterization of increased cuticular wax mutant and analysis of genes involved in wax biosynthesis in Dianthus spiculifolius

Cuticular wax formation on the surface of plant leaves is associated with drought-stress tolerance.The identification of wax biosynthesis-related genes will contribute to the genetic improvement of drought resistance in plants.In this study,we characterize a novel Dianthus spiculifolius mutant with increased cuticular wax.The mutant exhibited stronger drought resistance as indicated by less leaf wilting and death,higher leaf relative water content and water retention capacity,and slower water loss and chlorophyll extraction than did the wild type during drought treatment.In the mutant leaves,2730 upregulated and 2151 downregulated differentially expressed genes(DEGs)were identified by transcriptome sequencing.A wax biosynthesis pathway of the identified DEGs was significantly enriched.Finally,three key genes(DsCER1,DsMAH1,and DsWSD1)involved in wax biosynthesis were identified and verified by qPCR.These results suggest that differential expression of DEGs involved in wax biosynthesis may be associated with the increase in cuticular wax in the mutant.Taken together,our results help elucidate wax formation patterns in D.spiculifolius.Furthermore,the DEGs involved in wax biosynthesis identified here may be valuable genetic resources for improving plant stress tolerance through increased accumulation of cuticular wax.

Reliable and Efficient Agrobacterium tumefaciens-Mediated Genetic Transformation of Dianthus spiculifolius

Dianthus spiculifolius is a perennial herbaceous flower with strong environmental adaptability and is an important ornamental ground cover plant.In this study,seeds of D.spiculifolius were used as explants for callus induction,adventitious bud differentiation,and rooting by adding different concentrations of 2,4-dichlorophenoxyacetic acid(2,4-D),6-benzyl aminopurine(6-BA),and naphthaleneacetic acid(NAA)to Murashige and Skoog medium.The calli generated were co-cultured with Agrobacterium tumefaciens EHA105 containing pBI121-GUS or pBI121-GFP plasmids for 30 min,and transgenic regenerated plants were obtained by kanamycin(30mg·L^−1)screening.RT-PCR confirmed the stable expression of the exogenous GUS and GFP genes in the D.spiculifolius.Theβ-glucuronidase(GUS)histochemical staining confirmed GUS gene expression in transgenic calli,adventitious buds,and regenerated plants of D.spiculifolius.The green fluorescent protein(GFP)visual analysis showed GFP gene expression in transgenic calli.Furthermore,subcellular localization analysis showed that the three organelle marker proteins were not only successfully expressed but also accurately localized to their corresponding organelles in D.spiculifolius callus cells.These results indicated a successful establishment of a reliable and efficient A.tumefaciens-mediated genetic transformation system,which will contribute to functional gene research and genetic improvement of D.spiculifolius.

Tubular epicuticular wax is an important trait for limiting nonstomatal water loss from leaves in several Dianthus species

Cuticular wax plays an important role in plant drought tolerance by limiting non-stomatal water loss and has a diverse micromorphology and composition.However,the contribution of different wax components to limiting non-stomatal water loss remains unclear.We investigated and compared the micromorphology of cuticular wax on the leaves of five Dianthus plants and its role in limiting non-stomatal water loss.Furthermore,we further analyzed the chemical components of the cuticular waxes.Our results showed that cuticular wax crystals on the leaves of five Dianthus plants were mainly composed of irregular platelets or tubular epicuticular wax.The deposition of tubular wax may be related to better limiting non-stomatal water loss than platelets wax in the leaves of five Dianthus plants.Chemical component analysis revealed that the tubular wax was mainly composed of tricosane-2,4-dione.Our study suggests that tubular wax composition is an important trait for limiting nonstomatal water loss in several Dianthus species and contributes to the improvement of drought tolerance in other Dianthus plants.

Bi-objective evolutionary Bayesian network structure learning via skeleton constraint

Bayesian network is a popular approach to uncertainty knowledge representation and reasoning. Structure learning is the first step to learn a Bayesian network. Score-based methods are one of the most popular ways of learning the structure. In most cases, the score of Bayesian network is defined as adding the log-likelihood score and complexity score by using the penalty function. If the penalty function is set unreasonably, it may hurt the performance of structure search. Thus, Bayesian network structure learning is essentially a bi-objective optimization problem. However, the existing bi-objective structure learning algorithms can only be applied to small-scale networks. To this end, this paper proposes a bi-objective evolutionary Bayesian network structure learning algorithm via skeleton constraint (BBS) for the medium-scale networks. To boost the performance of searching, BBS introduces the random order prior (ROP) initial operator. ROP generates a skeleton to constrain the searching space, which is the key to expanding the scale of structure learning problems. Then, the acyclic structures are guaranteed by adding the orders of variables in the initial skeleton. After that, BBS designs the Pareto rank based crossover and skeleton guided mutation operators. The operators operate on the skeleton obtained in ROP to make the search more targeted. Finally, BBS provides a strategy to choose the final solution. The experimental results show that BBS can always find the structure which is closer to the ground truth compared with the single-objective structure learning methods. Furthermore, compared with the existing bi-objective structure learning methods, BBS is scalable and can be applied to medium-scale Bayesian network datasets. On the educational problem of discovering the influencing factors of students’ academic performance, BBS provides higher quality solutions and is featured with the flexibility of solution selection compared with the widely-used Bayesian network structure learning methods.

Effect of economic policies on the stock and bond market under the impact of COVID-19

The global epidemic of COVID-19 has made a huge impact on global health and financial markets.And the spread of the virus has stalled economic development in many parts of the world.As stocks and bonds are two important financial assets,how to take appropriate economic policies to restore the stock and bond markets is the focus of governments as they are seeking for quick recovery.Based on the Event Study method and the GARCH model,data from 1 October 2019 to 1 April 2020 were collected from 26 countries or regions as analytic samples.The results show:1)COVID-19 has made greater impacts on the stock market than the bond market;2)the economic policy responses after the COVID-19 has brought impacts on both of the stock and the bond markets;3)the monetary policy responses has brought greater volatility to the stock market than the fiscal policy responses,while the fiscal policy responses has brought greater volatility to the bond market than the monetary policy;4)the fiscal policy has brought more positive effects on the stock market,and monetary policy has brought more positive effects on the bond market.This research is helpful to understand the mechanism of COVID-19’s impacts on the stock and bond market.And it is of great practical significance to the governments’decisions to make economic policy responses after an epidemic.

OPTIMAL RISK CONTROL POLICIES FOR DIFFUSION MODELS WITH NON-CHEAP PROPORTIONAL REINSURANCE AND BANKRUPTCY VALUE

这份报纸在散开模型的背景关于比例的再保险的优化考虑这个问题。作者同时考虑非便宜的比例的再保险和破产价值。目的是发现最大化总数的风险控制政策打折保守和破产值。结果表演，最佳的风险控制政策和函数改变的相应最佳的回来，两个都取决于在保险和再保险的高级的率之间的破产价值和关系的范围。

2D/2D atomic double-layer WS_(2)/Nb_(2)O_(5)shell/core nanosheets with ultrafast interfacial charge transfer for boosting photocatalytic H_(2)evolution

Low-efficiency charge transfer is a critical factor to limit the photocatalytic H_(2)evolution activity of semiconductor photocatalysts.The interface design is a promising approach to achieve high chargetransfer efficiency for photocatalysts.Herein,a new 2 D/2 D atomic double-layer WS_(2)/Nb_(2)O_(5)shell/core photocatalyst(DLWS/Nb_(2)O_(5))is designed.The atom-resolved HAADF-STEM results unravel the presence of an unusual 2 D/2 D shell/core interface in DLWS/Nb_(2)O_(5).Taking advantage of the advanced femtosecond-resolved ultrafast TAS spectra,the average lifetime of charge carriers for DLWS/Nb_(2)O_(5)(180.97 ps)is considerably shortened as compared to that of Nb_(2)O_(5)(230.50 ps),strongly indicating that the 2 D/2 D shell/core interface enables DLWS/Nb_(2)O_(5)to achieve ultrafast charge transfer from Nb_(2)O_(5)to atomic double-layer WS_(2),thus yielding a high photocatalytic H_(2)evolution rate of 237.6 mmol/h,up to10.8 times higher than that of pure Nb_(2)O_(5)nanosheet.This study will open a new window for the development of high-efficient photocatalytic systems through the interface design.

Pandemic Bonds Issued by the Chinese Government Supported Post-Disaster Recovery from COVID-19 Pandemic

During the SARS-CoV-2(COIVD-19)outbreak,China repeatedly stressed that the response to the pandemic required action at all levels of government,including the issuance of Pandemic Bonds to help the country return to work and production.However,studies on the effectiveness of Pandemic Bonds during that period are rare.Starting with China’s national financial bond market data after COVID-19 in 2020,this paper focuses on the correlation between the Credit Spreads of the relevant bonds and the corresponding bond market rate of return,based on the Copula model.The empirical analysis is also carried out for multiple dimensional groupings such as enterprises,industries,provinces,and bond maturities.The results show that there is a significant positive correlation between the Credit Spreads of Pandemic Bonds and market returns.In addition,the market correlation is higher for Pandemic Bonds issued in Hubei Province,which is at the center of the 2020 pandemic,and the shorter the maturity of the Pandemic Bond issued,the stronger the relationship with market returns.Finally,this paper provides recommendations for financial regulators and policy makers to consider in their decisions on how to build a more resilient financial system under heavy economic,fiscal,and social pressures.