Delays in sowing have significant effects on the grain yield, yield components, and grain protein concentrations of winter wheat.  However, little is known about how delayed sowing affects these characteristics at different positions in the wheat spikes.  In this study, the effects of sowing date were investigated in a winter wheat cultivar, Shannong 30, which was sown in 2019 and 2020 on October 8 (normal sowing) and October 22 (late sowing) under field conditions.  Delayed sowing increased the partitioning of ¹³C-assimilates to spikes, particularly to florets at the apical section of a spike and those occupying distal positions on the same spikelet.  Consequently, the increase in grain number was the greatest for the apical sections, followed by the basal and central sections.  No significant differences were observed between sowing dates in the superior grain number in the basal and central sections, while the number in apical sections was significantly different.  The number of inferior grains in each section also increased substantially in response to delayed sowing.  The average grain weights in all sections remained unchanged under delayed sowing because there were parallel increases in grain number and ¹³C-assimilate partitioning to grains at specific positions in the spikes.  Increases in grain number m^–2 resulted in reduced grain protein concentrations as the limited nitrogen supply was diluted into more grains.  Delayed sowing caused the greatest reduction in grain protein concentration in the basal sections, followed by the central and apical sections.  No significant differences in the reduction of the grain protein concentration were observed between the inferior and superior grains under delayed sowing.  In conclusion, a 2-week delay in sowing improved grain yield through increased grain number per spike, which originated principally from an increased grain number in the apical sections of spikes and in distal positions on the same spikelet.  However, grain protein concentrations declined in each section because of the increased grain number and reduced N uptake.

The nonstructural protein 10 (nsp10) of porcine reproductive and respiratory syndrome virus (PRRSV) encodes for helicase which plays a vital role in viral replication.  In the present study, a truncated form of nsp10, termed nsp10a, was found in PRRSV-infected cells and the production of nsp10a was strain-specific.  Mass spectrometric analysis and deletion mutagenesis indicated that nsp10a may be short of about 70 amino acids in the N terminus of nsp10.  Further studies by rescuing recombinant viruses showed that the Glu-69 in nsp10 was the key amino acid for nsp10a production.  Finally, we demonstrated that nsp10a exerted little influence on the growth kinetics of PRRSV in vitro. 

Maize rough dwarf disease (MRDD) is a viral disease caused by brown planthopper infestation, and leads to great yield loss, especially in China.  Comparative proteomics was performed using maize inbred line Zheng 58 and LN 287.  MRDD pathogen was detected as rice black-streaked dwarf virus (RBSDV) by quantitative real time PCR (qRT-PCR) in Shandong Province, China.  The modified trichloroacetic acid (TCA)/acetone method was used for soluble protein extraction from leaves.  Two-dimensional electrophoresis (2-DE) analysis was performed on 24-cm long, pH 4-7 linear immobilized pH gradient (IPG) strips, and gels were stained with silver and coomassie brilliant blue.  We identified 944 proteins expressed in RBSDV infected maize leaves by proteomics approaches.  Among these, 44 protein spots that revealed a 1.5-fold difference in intensity were identified  by mass spectrometry between mock-inoculated and RBSDV infected samples.  Among these, 17 and 26 spots were up-regulated, and 27 and 18 spots were down-regulated in the virus infected samples of Zheng 58 and LN 287, respectively.  Differential protein spots were analyzed by mass spectrometry identification, which could be divided into six categories.  Furthermore, the expression of stress-related proteins was detected and confirmed by qRT-PCR.  This study lays the foundation for further investigations, enabling the enhancement of MRDD resistance in maize.

    Porcine reproductive and respiratory syndrome virus (PRRSV) actively induces cell apoptosis both in vitro and in vivo, which can contribute critically to viral pathogenesis.  Previous studies have shown that the PRRSV nonstructural protein 4 (nsp4) is an important mediator of this process, but the underlying molecular details remain poorly understood.  In this study, we found that the PRRSV nsp4 interacted with the mitochondrial inner membrane protein cytochrome c1 (cyto.c1) and induced its proteolytic cleavage.  Interestingly, the cleaved N-terminal fragment of cyto.c1 was found to exert apoptotic activity, which could cause mitochondrial fragmentation, resulting in apoptotic cell death.  And RNA interference (RNAi) silencing experiments further confirmed the crucial role which cyto.c1 played in nsp4- and PRRSV-induced cell apoptosis.  Thus, our data provide an important piece of mechanistic clues for PRRSV-induced cell apoptosis and also elucidate a novel mechanism for the 3C-like proteases in this finding. 

   The glycoprotein 5 (GP5) of porcine reproductive and respiratory syndrome virus (PRRSV) is a multi-functional protein that plays important roles in virus assembly, entry and viral anti-host responses. In the present study, we investigated the cellular binding partners of GP5 by using lentivirus transduction coupled with immunoprecipitation and mass spectrometry. There were about 40 cellular proteins identified with high Confidence Icons by MS/MS. Ingenuity Pathway Analysis (IPA) indicated that these proteins could be assigned to different functional classes and networks. Furthermore, we validated some of the interactions by co-immunoprecipitation (Co-IP) and confocal microscopy, including those with mitofilin, a mitochondrial inner membrane protein that might be involved in PRRSV or GP5-induced apoptosis, and calnexin, a protein chaperone that might facilitate the folding and maturation of GP5. The interactome data contribute to understand the role and molecular mechanisms of GP5 in PRRSV pathogenesis.

Construction of a food-grade expression vector for application to lactic acid bacteria (LAB) is of importance for dairy fermentation system. An α-galactosidase (aga) gene encoding an enzyme degrading melibiose was amplified by PCR from the plasmid pRAF800 of Lactococcus lactis NZ9000. The aga gene was introduced into pMG36e to substitute the primary antibiotic selectable marker of pMG36e, resulting in construction of a new food-grade expression vector pMG36-aga. To testify the expression efficiency of exogenous gene in pMG36-aga, a 1.5 kb long α-amylase (amy) gene from Bacillus licheniformis was cloned by PCR and introduced into the plasmid pMG36-aga. The resultant plasimd pMG36-aga-amy was transformed into L. lactis ML23 by electroporation. The positive clones were selected with the medium containing melibiose as the sole carbon source. The selection efficiency of aga was 8.71×103 CFU with a standard deviation of 9.1×102 CFU mg-1 DNA of pMG36-aga. Furthermore, the SDS-PAGE analysis showed that the pMG36-aga-amy expressed a 56.4 kDa protein which was the same as the putative molecular weight of α-amylase. The starch plate assay also indicated that L. lactis ML23 displayed high activity of α-amylase by expressing of amy gene of pMG36-aga-amy.

Detailed analysis of canopy structural heterogeneity is an essential step in conducting parameters for a canopy structural model. This paper aims to analyze the structural heterogeneity of a cucumber (Cucumis sativus L.) canopy by means of analyzing leaf distribution in a greenhouse environment with natural sunlight and also to assess the effect of structural canopy heterogeneity on light interception and photosynthesis. Two experiments and four measurements were carried out in autumn 2011 and spring 2012. A static virtual three-dimensional (3D) canopy structure was reconstructed using a 3D digitizing method. The diurnal variation of photosynthesis rate was measured using CIRAS-2 photosynthesis system. The results showed that, leaf azimuth as tested with the Rayleigh-test was homogeneous at vine tip over stage but turned heterogeneous at fruit harvest stage. After eliminating the influence of the environment on the azimuth using the von Mises-Fisher method, the angle between two successive leaves was 144°; at the same time, a rule for the azimuth distribution in the canopy was established, stating that the azimuth distribution in cucumber followed a law which was positive spin and anti-spin. Leaf elevation angle of south-oriented leaves was on average 13.8° higher than that of north-oriented leaves. The horizontal distribution of light interception and photosynthesis differed significantly between differently oriented leaves. East- and west-oriented leaves exhibited the highest photosynthetic rate. In conclusion, detailed analysis of canopy structural heterogeneity in this study indicated that leaf azimuth and elevation angle were heterogeneous in cucumber canopy and they should be explicitly described as they have a great impact both on light distribution and photosynthesis.