The Naturally Occurring Amino Acid Substitution in the VPg α1-α2 Loop Breaks eIF4E-Mediated Resistance to PRSV by Enabling VPg to Re-Hijack Another eIF4E Isoform eIF(iso)4E in Watermelon.

Plant resistance, which acts as a selective pressure that affects viral population fitness, leads to the emergence of resistance-breaking virus strains. Most recessive resistance to potyviruses is related to the mutation of eukaryotic translation initiation factor 4E (eIF4E) or its isoforms that break their interactions with the viral genome-linked protein (VPg). In this study, we found that the VPg α1-α2 loop, which is essential for binding eIF4E, is the most variable domain of papaya ringspot virus (PRSV) VPg.

A natural substitution of a conserved amino acid in eIF4E confers resistance against multiple potyviruses.

Eukaryotic translation initiation factor 4E (eIF4E), which plays a pivotal role in initiating translation in eukaryotic organisms, is often hijacked by the viral genome-linked protein to facilitate the infection of potyviruses. In this study, we found that the naturally occurring amino acid substitution D71G in eIF4E is widely present in potyvirus-resistant watermelon accessions and disrupts the interaction between watermelon eIF4E and viral genome-linked protein of papaya ringspot virus-watermelon strain, zucchini yellow mosaic virus or watermelon mosaic virus. Multiple sequence alignment and protein modelling showed that the amino acid residue D located in the cap-binding pocket of eIF4E is strictly conserved in many plant species.

A tobacco ringspot virus-based vector system for gene and microRNA function studies in cucurbits.

Cucurbits are economically important crops worldwide. The genomic data of many cucurbits are now available. However, functional analyses of cucurbit genes and noncoding RNAs have been impeded because genetic transformation is difficult for many cucurbitaceous plants.

[Monitoring Atmospheric CO2 and delta(13)C (CO2) Background Levels at Shangdianzi Station in Beijing, China].

The study presented time series of atmospheric CO2 concentrations from flask sampling at SDZ regional station in Beijing during 2007 and 2013, together with delta(13)CO2) values during 2009 and 2013. The "representative data" of CO2 and delta(13)C (CO2) were selected from the complete data for further analysis. Annual CO2 concentrations increased from 385.

[Evaluation on the Impacts of Different Background Determination Methods on CO2 Sources and Sinks Estimation and Seasonal Variations].

To accurately determine background conditions or extract sources and sinks information from the observed atmospheric carbon dioxide (CO2) concentration is crucial for quantitative estimation of regional and global carbon budget and future trends of atmospheric CO2. In this study, the synchronized observed surface winds and carbon monoxide (CO) concentration have been examined to test their effectiveness as filter factors to determine CO2 background conditions at Waliguan site. The results show that the surface winds and CO concentrations can be used as filter factor in winter, but they are not very effective in summer.

[Gas chromatography with a Pulsed discharge helium ionization detector for measurement of molecular hydrogen(H2) in the atmosphere].

A high precision GC system with a pulsed discharge helium ionization detector was set up based on the commercial Agilent 7890A gas chromatography. The gas is identified by retention time and the concentration is calculated through the peak height. Detection limit of the system is about 1 x 10(-9) (mole fraction, the same as below).

[Establishment and assessment of QA/QC method for sampling and analysis of atmosphere background CO2].

To strengthen scientific management and sharing of greenhouse gas data obtained from atmospheric background stations in China, it is important to ensure the standardization of quality assurance and quality control method for background CO2 sampling and analysis. Based on the greenhouse gas sampling and observation experience of CMA, using portable sampling observation and WS-CRDS analysis technique as an example, the quality assurance measures for atmospheric CO,sampling and observation in the Waliguan station (Qinghai), the glass bottle quality assurance measures and the systematic quality control method during sample analysis, the correction method during data processing, as well as the data grading quality markers and data fitting interpolation method were systematically introduced. Finally, using this research method, the CO2 sampling and observation data at the atmospheric background stations in 3 typical regions were processed and the concentration variation characteristics were analyzed, indicating that this research method could well catch the influences of the regional and local environmental factors on the observation results, and reflect the characteristics of natural and human activities in an objective and accurate way.

[Atmospheric CO2 data filtering method and characteristics of the molar fractions at the Longfengshan WMO/GAW regional station in China].

Based on the in-situ observation results of atmospheric CO2 molar fractions at two levels (10 m and 80 m above the ground) at Longfengshan (LFS) regional background station in Heilongjiang Province during January 2009 to December 2011, this study mainly focused on the results from 10 m above the ground level (a. g. l.

[Distribution of CO at Lin'an station in Zhejiang Province].

Background CO mole fractions were continuously measured at Lian'an background station in Zhejiang province from September, 2010 to February, 2012 using Cavity Ring Down Spectroscopy (CRDS) system. The diurnal variation of CO was strongly influenced by anthropogenic activities with two peaks occurring at 07:00-10:00 and 19:00-20:00 (local time). The average daily mole fraction and amplitude in summer were the lowest among four seasons with values of 314.

[In-situ measurement of atmospheric methyl chloroform at the Shangdianzi GAW regional background station].

An in-situ GC-ECD monitoring system was established at the Shangdianzi GAW regional background station (SDZ) for a 2-year atmospheric methyl chloroform (CH3CCl3) measurement experiment. Robust extraction of baseline signal filter was applied to the CH3CCl3 time series to separate the background and pollution data. The yearly averaged background mixing ratios of atmospheric CH3CCl3 were (9.

[Study on the in-situ measurement of greenhouse gas by an improved FTIR].

The real-time, automatic, highly accurate and efficient system for measuring the mixing ratios of CO2, CH4, CO and N2O has been developed by combining the commercial FTIR system (Wollongong University) with an auto-sampling system and a working standard module. Based on the tests conducted, the FTIR showed the high precision and a relatively low accuracy associated with its poor determination of correction factors. The absolute error of the mixing ratio of CO was above 38.

[In-situ measurement of background atmospheric HCFC-142b using GC-MS and GC-ECD method].

Custom-made GC-MS and GC-ECD in-situ measurement systems were established at the Shangdianzi GAW Regional station. From May 2010 to May 2011, the precisions for GC-MS and GC-ECD systems were 0.23% and 0.

[Impacts of meteorological factors on atmospheric methane mole fractions in the background area of Yangtze River delta].

Impacts of surface wind direction, surface wind speed, surface air temperature and sunshine hours on the CH4 concentration at Lin'an regional atmospheric background station were studied based on the results from Jan. 2009 to Dec. 2011.

[CH4 concentrations and the variation characteristics at the four WMO/GAW background stations in China].

Background CH4 concentrations were continuously measured at the 4 WMO/GAW stations [Waliguan in Qinghai (WLG), Lin'an in Zhejiang (LAN), Shangdianzi in Beijing (SDZ), and Longfengshan in Heilongjiang (LFS)] by Cavity Ring Down Spectroscopy system. From 2009 to 2010, the diurnal cycle of hourly average CH4 concentration at LAN was found to be similar in all four seasons, with the highest level detected at 05:00 (Beijing Time) and the lowest at about 14:00. Similar CH4 diurnal cycles were observed at LFS in the summer time.

[Study on the in-situ measurement of atmospheric CH4 and CO by GC-FID method at the Shangdianzi GAW regional station].

In-situ GC-FID system for atmospheric CH4 and CO mixing ratio measurements at the Shangdianzi (SDZ) GAW regional station in Beijing was designed and optimized in 2009 based on a comparable system at the Waliguan GAW global station in Qinhai. Results from this study indicate that the system's precisions for CH4 and CO are higher than 0.03% and 0.

[Data processing and QA/QC of atmosphere CO2 and CH4 concentrations by a method of GC-FID in-situ measurement at Waliguan station].

To strengthen scientific management and sharing of greenhouse gas data obtained from atmospheric background stations in China, it is important to ensure the standardization of observations and establish the data treatment and quality control procedure so as to maintain consistency in atmospheric carbon dioxide (CO2) and methane (CH4) measurements from different background stations. An automated gas chromatographic system (Hewlett Packard 5890GC employing flame ionization detection) for in situ measurements of atmospheric CO2 and CH4 has been developed since 1994 at the China Global Atmosphere Watch Baseline Observatory at Mt. Waliguan, in Qinhai.

[In situ measurement of atmospheric HCFC-22 at the Shangdianzi GAW regional station].

An in situ GC-ECD monitoring system was established at the Shangdianzi GAW Regional station from April 2007 to March 2008, and the mixing ratio of atmospheric HCFC-22 was (278.1 +/- 113.6) x 10(-12) (mol/mol).

[Study of distinguish root respiration from total soil respiration by root exclusion method in the temperate semi-arid grassland in Inner Mongolia, China].

In order to determine the possibility of measuring the root respiration by using root exclusion method, we conducted field experiments to measured total soil respiration and net soil respiration in three temperate grassland communities including Leymus chinensis free-grazed steppe, stipa grandis free-grazed steppe and Leymus chinensis degenerated free-grazed steppe in the growing season, 2005. At the same time, the proportion of the root respiration to the total soil respiration was estimated in different steppes by this method separately. The results indicated that the root exclusion method was very operable in estimating the proportion of the root respiration to the total soil respiration in temperate grassland communities, and the proportion varied from 25% - 45% with the mean value of 35.