Search

Salt-tolerant breeding of maize has great significance to the development and utilization of saline–alkaline soil and the maintenance of grain security. Genome-wide association study (GWAS) has been widely used in maize genetics and breeding. To discover new salt-tolerant genes in maize by association analysis, which can provide technical supports for the innovation and genetic improvement of salt-tolerant germplasm resources in maize. Totally 150 maize inbred lines were genotyped with a high-density chip. GWAS was carried out to identify the significant single nucleotide polymorphisms (SNPs) which were associated with maize salt tolerance. Totally 34,972 SNPs with high quality and diversity were selected from 56,110 SNP markers, which were distributed on 10 chromosomes of maize. The GLM algorithm in TASSEL5.2 was used to analyze the five traits related to salt tolerance. Using a strict LOD threshold of 4.5, totally 7 SNP loci were identified, which were significantly correlated with plant height change rate and fresh weight change rate. The high density fingerprints of 150 inbred lines were clustered by TASSEL5.2 software to construct genetic clustering map to estimate the genetic distance and the subgroups. The 150 maize inbred lines were divided into two groups: SS group and NSS group, and the SNP loci of the salt-tolerant index showed difference in chromosome distribution. Based on previous studies, we screened 8 candidate genes for salt tolerance in maize and four of them were further validated by real-time quantitative PCR. Totally 7 SNP loci and 8 candidate genes related to salt tolerance in maize were identified, which will be of special value in molecular breeding of salt-tolerant maize.

Non-additive (synergistic or antagonistic) effect, a common phenomenon for the decomposition of mixed litter in nature, is usually regulated by litter quality and environmental factors. In this study, we investigated decomposition rates and nutrient (C, N, and P) dynamics in response to water availability in six litter treatments using plant material from Dongting Lake, China. Three single-litter treatments (leaves of Carex brevicuspis, leaves of Miscanthus sacchariflorus, and stems of M. sacchariflorus) and three mixed-litter treatments (1:1 mixtures of single litters) were incubated at three levels of water availability (20%, 46%, and 100% saturation) for 120 days in a mesocosm experiment. Decomposition rates for single-litter treatments were ranked: M. sacchariflorus leaves > C. brevicuspis leaves > M. sacchariflorus stems. Decomposition rates generally increased with increasing water availability. Antagonistic or additive interactions occurred in the M. sacchariflorus leaves + M. sacchariflorus stems ...

The size,composition,vertical distribution and species diversity of seed bank as well as its relationship with aboveground vegetation were studied in three dominant plant communities(Miscanthus sacchariflorus,Carex sp.,and Phalaris arundinacea) distributing with different water levels in Lake Dongting.The density of seed bank was highest in M.sacchariflorus(44656 seeds/m2),followed by P.arundinacea(31725 seeds/m2) and lowest in Carex sp.(15146 seeds/m2).Seeds in the seed bank distributed mainly within 0～5cm soil layer and decreased rapidly along with the soil depth.The seed banks of the three communities were composed of 53 species belonging to 18 families,39 genera.Among them,20 species were perennial while 33 were annual or biannual.The proportions of perennial species were 29.9%,35.2% and 38.0% in the soil seed bank of M.sacchariflorus,C.sp.and P.arundinacea communities,respectively.The diversity indexes of seed bank and aboveground vegetation were 0.76 and 0.53 in M.sacchariflorus,0.70 and 0.17 in C.sp.,0.72 and 0.45 in P.arundinacea,respectively.The similarity indexes between seed bank and aboveground vegetation were 0.28 in C.sp.,0.40 in M.sacchariflorus and 0.52 in P.arundinacea,respectively.The diversity index of seed bank was higher than that of aboveground vegetation and the similarity was relatively low.Therefore,perennial aboveground vegetation has limited contribution to the soil seed bank in large Yangtze-connected lake wetlands,where seeds might be mainly imported into seed bank through other pathways,such as water flow.

The characteristics of wetland vegetations in three different restoration modes of "returning farmland to lake"(natural restoration,reed plantation and poplar plantation) were studied based on the field investigation of 2006 in the Lake Dongting area.The results showed that the highest and lowest species richness was found in the modes of natural restoration and reed plantation,respectively.Moreover,the highest richness of wetland plants was also found in the mode of natural restoration,which took 81.0% of the total number of species,while in the other two restoration modes,the ratios of wetland plants were 78.7%(poplar plantation) and 69.4%(reed plantation),respectively.11 community types were found in the mode of natural restoration,including 3 communities of aquatic plants,while there were 8 and 1 community types in the modes of poplar plantation and reed plantation,respectively;the productivity changed significantly among different plant community types and the highest productivity was found in the mode of poplar plantation,while the lowest biodiversity was found in the mode of reed plantation.Based on the above results,we concluded that natural restoration was the best modes among the three different restoration modes for the restoration of the Lake Dongting area.

The accuracy of thickness is an important standard to measure the strip quality. Therefore, it is crucial to accurately obtain a high precision thickness. The ELM (extreme learning machine) based on clustering forecast method is presented for hot rolled strip thickness prediction. Firstly, strong correlation properties of thickness are obtained by data pretreatment, in order to ensure the effectiveness of the thickness model. Then, a clustering analysis is made about the strong correlation attribute data. Finally, ELM network is performed respectively for each type of prediction. This paper uses filed production data for training and testing, and takes the BP network prediction model as comparison. The simulation results show that this method can predict the thickness more quickly and accurately, and better meet the needs of actual production.

Macrophages and CD4(+) T-cells are the major reservoirs for HIV-1 infection. CD63 is a tetraspanin transmembrane protein, which has been shown to play an essential role during HIV-1 replication in macrophages. In this study, we further confirm the requirement of CD63 in HIV-1 replication events in primary human CD4(+) T-cells, dendritic cells, and a CD4(+) cell line. Most interestingly, we also show the evidences for the co-localization and internalization of CD63 and HIV-1 major receptor CD4 in primary human macrophages and CD4(+) cell line by confocal microscopy and Co-Immunoprecipitation assay. Analysis revealed that CD63-depleted CD4(+) T-cells, dendritic cells, and a cell line showed significant decrease in HIV-1 production. Further analysis showed that CD63 down regulation reduced production of the early HIV protein Tat, and affected HIV protein Gag by CD63-Gag interaction. In agreement, CD63 silencing also inhibited production of the late protein p24. Furthermore, we revealed that CD63 silencing has no effect on HIV-1 replication with extensive viral challenge (MOI0.2). These findings suggest that CD63 plays a dual-role both in early and late HIV-1 life cycle with a range of HIV-1 infection (MOI0.2).