Gossypium raimondii (2n=2x=26, D₅), an untapped wild species, is the putative progenitor of the D-subgenome of G. hirsutum (2n=4x=52, AD₁), an extensively cultivated species.  Here, we developed a G. hirsutum (recipient)–G. raimondii (donor) introgression population to exploit the favorable QTLs/genes and mapped potential quantitative trait loci (QTLs) from wild cotton species.  The introgression population consisted of 256 lines with an introgression rate of 52.33% for the G. raimondii genome.  The introgression segment length range was 0.03–19.12 Mb, with an average of 1.22 Mb.  The coverage of total introgression fragments from G. raimondii was 386.98 Mb.  Further genome-wide association analysis (Q+K+MLM) and QTL mapping (RSTEP-LRT) identified 59 common QTLs, including 14 stable QTLs and six common QTL (co-QTL) clusters, and one hotspot of micronaire (MIC).  The common QTLs for seed index all showed positive additive effects, while the common QTLs for boll weight all had negative additive effects, indicating that the linkage between seed index and boll weight could be broken.  QTLs for lint percentage showed positive effects and could be beneficial for improving cotton yield.  Most QTLs for fiber quality had negative additive effects, implying these QTLs were domesticated/improved in G. hirsutum.  A few fiber quality QTLs showed positive additive effects, so they could be used to improve cotton fiber quality.  The introgression lines developed could be useful for molecular marker-assisted breeding and mapping QTLs precisely for mining desirable genes from the wild species G. raimondii.  Such genes can improve cultivated cotton in the future through a design-breeding approach. 

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.

Delayed sowing mitigates lodging in wheat.  However, the mechanism underlying the enhanced lodging resistance in wheat has yet to be fully elucidated.  Field experiments were conducted to investigate the effects of sowing date on lignin and cellulose metabolism, stem morphological characteristics, lodging resistance, and grain yield.  Seeds of Tainong 18, a winter wheat variety, were sown on October 8 (normal sowing) and October 22 (late sowing) during both of the 2015–2016 and 2016–2017 growing seasons.  The results showed that late sowing enhanced the lodging resistance of wheat by improving the biosynthesis and accumulation of lignin and cellulose.  Under late sowing, the expression levels of key genes (TaPAL, TaCCR, TaCOMT, TaCAD, and TaCesA1, 3, 4, 7, and 8) and enzyme activities (TaPAL and  TaCAD) related to lignin and cellulose biosynthesis peaked 4–12 days earlier, and except for the TaPAL, TaCCR, and TaCesA1 genes and TaPAL, in most cases they were significantly higher than under normal sowing.  As a result, lignin and cellulose accumulated quickly during the stem elongation stage.  The mean and maximum accumulation rates of lignin and cellulose increased, the maximum accumulation contents of lignin and cellulose were higher, and the cellulose accumulation duration was prolonged.  Consequently, the lignin/cellulose ratio and lignin content were increased from 0 day and the cellulose content was increased from 11 days after jointing onward.  Our main finding is that the improved biosynthesis and accumulation of lignin and cellulose were responsible for increasing the stem-filling degree, breaking strength, and lodging resistance.  The major functional genes enhancing lodging resistance in wheat that are induced by delayed sowing need to be determined.

The quality of oranges is grounded on their appearance and diameter.  Appearance refers to the skin’s smoothness and surface cleanliness; diameter refers to the transverse diameter size.  They are visual attributes that visual perception technologies can automatically identify.  Nonetheless, the current orange quality assessment needs to address two issues: 1) There are no image datasets for orange quality grading; 2) It is challenging to effectively learn the fine-grained and distinct visual semantics of oranges from diverse angles.  This study collected 12 522 images from 2 087 oranges for multi-grained grading tasks.  In addition, it presented a visual learning graph convolution approach for multi-grained orange quality grading, including a backbone network and a graph convolutional network (GCN).  The backbone network’s object detection, data augmentation, and feature extraction can remove extraneous visual information.  GCN was utilized to learn the topological semantics of orange feature maps.  Finally, evaluation results proved that the recognition accuracy of diameter size, appearance, and fine-grained orange quality were 99.50, 97.27, and 97.99%, respectively, indicating that the proposed approach is superior to others.

Transcription factors (TFs) regulate diverse stress defensive-associated physiological processes and plant stress responses.  We characterized TaNF-YB11, a gene of the NF-YB TF family in Triticum aestivum, in mediating plant drought tolerance.  TaNF-YB11 harbors the conserved domains specified by its NF-YB partners and targets the nucleus after the endoplasmic reticulum (ER) assortment.  Yeast two-hybrid assay indicated the interactions of TaNF-YB11 with TaNF-YA2 and TaNF-YC3, two proteins encoded by genes in the NF-YA and NF-YC families, respectively.  These results suggested that the heterotrimer established among them further regulated downstream genes at the transcriptional level.  The transcripts of TaNF-YB11 were promoted in roots and leaves under a 27-h drought regime.  Moreover, its upregulated expression levels under drought were gradually restored following a recovery treatment, suggesting its involvement in plant drought response.  TaNF-YB11 conferred improved drought tolerance on plants; the lines overexpressing target gene displayed improved phenotype and biomass compared with wild type (WT) under drought treatments due to enhancement of stomata closing, osmolyte accumulation, and cellular reactive oxygen species (ROS) homeostasis.  Knockdown expression of TaP5CS2, a P5CS family gene modulating proline biosynthesis that showed upregulated expression in drought-challenged TaNF-YB11 lines, alleviated proline accumulation of plants treated by drought.  Likewise, TaSOD2 and TaCAT3, two genes encoding superoxide dismutase (SOD) and catalase (CAT) that were upregulated underlying TaNF-YB11 regulation, played critical roles in ROS homeostasis via regulating SOD and CAT activities.  RNA-seq analysis revealed that numerous genes associated with processes of ‘cellular processes’, ‘environmental information processing’, ‘genetic information processing’, ‘metabolism’, and ‘organismal systems’ modified transcription under drought underlying control of TaNF-YB11.  These results suggested that the TaNF-YB11-mediated drought response is possibly accomplished through the target gene in modifying gene transcription at the global level, which modulates complicated biological processes related to drought response.  TaNF-YB11 is essential in plant drought adaptation and a valuable target for molecular breeding of drought-tolerant cultivars in T. aestivum.

Understanding of how combinations of agronomic options can be used to improve the grain yield and nitrogen use efficiency (NUE) of winter wheat is limited.  A three-year experiment involving four integrated management strategies was conducted from 2013 to 2015 in Tai’an, Shandong Province, China, to evaluate changes in grain yield and NUE.  The integrated management treatments were as follows: current practice (T1); improvement of current practice (T2); high-yield management (T3), which aimed to maximize grain yield regardless of the cost of resource inputs; and integrated soil and crop system management (T4) with a higher seeding rate, delayed sowing date, and optimized nutrient management.  Seeding rates increased by 75 seeds m^–2 with each treatment from T1 (225 seeds m^–2) to T4 (450 seeds m^–2).  The sowing dates were delayed from T1 (5th Oct.) to T2 and T3 (8th Oct.), and to T4 treatment (12th Oct.).  T1, T2, T3, and T4 received 315, 210, 315, and 240 kg N ha^–1, 120, 90, 210 and 120 kg P₂O₅ ha^–1, 30, 75, 90, and 45 kg K₂O ha^–1, respectively.  The ratio of basal application to topdressing for T1, T2, T3, and T4 was 6:4, 5:5, 4:6, and 4:6, respectively, with the N topdressing applied at regreening for T1 and at jointing stage for T2, T3, and T4.  The P fertilizers in all treatments were applied as basal fertilizer.  The K fertilizer for T1 and T2 was applied as basal fertilizer while the ratio of basal application to topdressing (at jointing stage) of K fertilizer for both T3 and T4 was 6:4.  T1, T2, T3, and T4 were irrigated five, four, four and three times, respectively.  Treatment T3 produced the highest grain yield among all treatments over three years and the average yield was 9 277.96 kg ha^–1.  Grain yield averaged across three years with the T4 treatment (8 892.93 kg ha^–1) was 95.85% of that with T3 and was 21.72 and 6.10% higher than that with T1 (7 305.95 kg ha^–1) and T2 (8 381.41 kg ha^–1), respectively.  Treatment T2 produced the highest NUE of all the integrated treatments.  The NUE with T4 was 95.36% of that with T2 and was 51.91 and 25.62% higher than that with T1 and T3, respectively.  The N uptake efficiency (UPE) averaged across three years with T4 was 50.75 and 16.62% higher than that with T1 and T3, respectively.  The N utilization efficiency (UTE) averaged across three years with T4 was 7.74% higher than that with T3.  The increased UPE with T4 compared with T3 could be attributed mostly to the lower available N in T4, while the increased UTE with T4 was mainly due to the highest N harvest index and low grain N concentration, which consequently led to improved NUE.  The net profit for T4 was the highest among four treatments and was 174.94, 22.27, and 28.10% higher than that for T1, T2, and T3, respectively.  Therefore, the T4 treatment should be a recommendable management strategy to obtain high grain yield, high NUE, and high economic benefits in the target region, although further improvements of NUE are required.

Phenazines are secondary metabolites with broad spectrum antibiotic activity and thus show high potential in biological control of pathogens. In this study, we identified phenazine biosynthesis (phz) genes in two genome-completed plant pathogenic bacteria Pseudomonas syringae pv. tomato (Pst) DC3000 and Xanthomonas oryzae pv. oryzae (Xoo) PXO99^A. Unlike the phz genes in typical phenazine-producing pseudomonads, phz homologs in Pst DC3000 and Xoo PXO99^A consisted of phzC/D/E/F/G and phzC/E1/E2/F/G, respectively, and the both were not organized into an operon. Detection experiments demonstrated that phenazine-1-carboxylic acid (PCA) of Pst DC3000 accumulated to 13.4 μg L^–1, while that of Xoo PXO99^A was almost undetectable. Moreover, Pst DC3000 was resistant to 1 mg mL^–1 PCA, while Xoo PXO99^A was sensitive to 50 μg mL^–1 PCA. Furthermore, mutation of phzF blocked the PCA production and significantly reduced the pathogenicity of Pst DC3000 in tomato, while the complementary strains restored these phenotypes. These results revealed that Pst DC3000 produces low level of and is resistant to phenazines and thus is unable to be biologically controlled by phenazines. Additionally, phz-mediated PCA production is required for full pathogenicity of Pst DC3000. To our knowledge, this is the first report of PCA production and its function in pathogenicity of a plant pathogenic P. syringae strain.

Sclerotinia sclerotiorum is one of the most devastating necrotrophic phytopathogens.  Virulence of the hyphae of this fungus at different ages varies significantly.  Molecular mechanisms underlying this functional distinction are largely unknown.  In this study, we confirmed the effect of mycelial culture time/age on virulence in two host plants and elucidated its molecular and morphological basis.  The virulence of the S. sclerotiorum mycelia in plants dramatically decreases along with the increase of the mycelial age.  Three-day-old mycelia lost the virulence in plants.  Comparative proteomics analyses revealed that metabolism pathways were comprehensively reprogrammed to suppress the oxalic acid (OA) accumulation in old mycelia.  The oxaloacetate acetylhydrolase (OAH), which catalyzes OA biosynthesis, was identified in the S. sclerotiorum genome.  Both gene expression and protein accumulation of OAH in old mycelia were strongly repressed.  Moreover, in planta OA accumulation was strikingly reduced in old mycelia-inoculated plants compared with young vegetative mycelia-inoculated plants.  Furthermore, supply with 10 mmol L^–1 OA enabled the old mycelia infect the host plants, demonstrating that loss of virulence of old mycelia is mainly caused by being unable to accumulate OA.  Additionally, aerial mycelia started to develop from 0.5-day-old vegetative mycelia and dominated over 1-day-old mycelia grown on potato dextrose agar plates.  They were much smaller in hypha diameter and grew significantly slower than young vegetative mycelia when subcultured, which did not maintain to progenies.  Collectively, our results reveal that S. sclerotiorum aerial hyphae-dominant old mycelia fail to accumulate OA and thereby lose the virulence in host plants.

This study was aimed to evaluate the potential effects of rest grazing on organic carbon storage in Stipa grandis steppe of Inner Mongolia, China. Using potassium dichromate heating method, we analyzed the organic carbon storage of plant and soil in Stipa grandis steppe after rest grazing for 3, 6, and 9 yr. The results indicated that as the rest grazing ages prolonged, the biomass of aboveground parts, litter and belowground plant parts (roots) of the plant communities all increased, meanwhile the C content of the biomass increased with the rest grazing ages prolonging. For RG0, RG3a, RG6a, and RG9a, C storage in aboveground vegetation were 60.7, 76.9, 82.8 and 122.2 g C m-2, respectively; C storage of litter were 5.1, 5.8, 20.4 and 25.5 g C m-2, respectively; C storage of belowground roots (0-100 cm) were 475.2, 663.0, 1 115.0 and 1 867.3 g C m-2, respectively; C storage in 0-100 cm soil were 13.97, 15.76, 18.60 and 32.41 kg C m-2, respectively. As the rest grazing ages prolonged, the organic C storage in plant communities and soil increased. The C storage of belowground roots and soil organic C was mainly concentrated in 0-40 cm soil body. The increased soil organic C for RG3a accounted for 89.8% of the increased carbon in vegetation-soil system, 87.2% for RG6a, and 92.6% for RG9a. From the perspective of C sequestration cost, total cost for RG3a, RG6a, and RG9a were 2 903.4, 5 806.8 and 8 710.2 CNY ha-1, respectively. The cost reduced with the extension of rest grazing ages, 0.15 CNY kg-1 C for RG3a, 0.11 CNY kg-1 C for RG6a and 0.04 CNY kg-1 C for RG9a. From the growth characteristics of grassland plants, the spring was one of the two avoided grazing periods, timely rest grazing could effectively restore and update grassland vegetation, and was beneficial to the sustainable use of grassland. Organic C storage for RG9a was the highest, while the cost of C sequestration was the lowest. Therefore, spring rest grazing should be encouraged because it was proved to be a very efficient grassland use pattern.

Visfatin, like insulin, induces phosphorylation of signal transduction proteins that operatate downstream of the insulin receptor. The present study is focused on detecting deletion of visfatin gene and analyzing its effect on growth traits in six Chinese cattle breeds (Nangyang, Luxi, Qinchuan, Jiaxian Red, Grassland Red, and Chinese Holstein) using DNA sequencing, PCR-SSCP and PCR-RFLP methods. For the first time, a 6-bp deletion of visfatin was described and two alleles were revealed: W and D. The χ2-test analysis demonstrated that all breeds were in agreement with Hardy-Weinberg equilibrium (P>0.05). The associations of the novel 6-bp deletion of visfatin gene with growth traits of Nanyang cattle at 6-, 12-, 18-, and 24-mon-old were analyzed. Birth weight, 12- and 24-mon-old cattle with genotype WW had greater birth weight and average daily gain than genotype WD (P<0.01 or P<0.05). These results suggest that the deletion may influence the birth weight and bodyweight in 12 mon-old cattle.

Nonhost resistance is a phenomenon that enables plants to protect themselves against the majority of potential pathogens, and thus has a great potential for application in plant protection. We recently found that CfHNNI1 (for Cladosporium fulvum host and nonhost plant necrosis inducer 1) is an inducer of plant hypersensitive response (HR) and nonhost resistance. In this study, its functional mechanism was analyzed. CfHNNI1 was a single copy gene in C. fulvum genome. The functional ORF of the CfHNNI1 cDNA was ATG3-TAG780, which showed homology with genes encoding bZIP transcription factors. The functional ORF included in frame an inner one ATG273-TAG780, which was sufficient to induce HR in plants. CfHNNI1 induced plant HR in a dose-dependent manner. CfHNNI1-induced necrosis in NahG transgenic tomato plants was significantly stronger than that in their wild type controls. However, the necrosis in Nr and def1 tomato mutants was similar to that in their corresponding wild type plants. These data demonstrate that induction of HR and nonhost resistance by CfHNNI1 is negatively regulated by salicylic acid signalling pathway but independent of ethylene and jasmonic acid signalling pathways.

Brucella spp., an intracellular bacterium, uses its type IV secretion system (T4SS) to regulate host signaling pathways and promote intracellular survival, but the molecular mechanism of this process remains largely unknown. Here we found that increasing the abundance of acetylated protein in host cells promotes the intracellular survival of Brucella. Moreover, our results demonstrated that the Brucella effector protein BspF can impact protein acetylation modification in host cells by interacting with other intracellular proteases. We conducted LC-MS/MS to characterize the protein acetylation mediated by BspF. We identified that SNAP29 K103 was acetylated, and that acetylated SNAP29 inhibited its interaction with STX17, thereby regulating the autophagy and providing an environment for the intracellular survival of Brucella. Furthermore, our results provide the first report of a bacterial effector using acetylation to affect the SNAP29-STX17-VAMP8 complex, and inhibit the host's defense system. Our results suggest a vital role of SNAP29 acetylation in autophagy of host cells under intracellular infection, by specifically regulating the assemble of SNARE.