The wheat above-ground biomass (AGB) is an important index that shows the life activity of vegetation, which is of great significance for wheat growth monitoring and yield prediction.  Traditional biomass estimation methods specifically include sample surveys and harvesting statistics.  Although these methods have high estimation accuracy, they are time-consuming, destructive, and difficult to implement to monitor the biomass at a large scale.  The main objective of this study is to optimize the traditional remote sensing methods to estimate the wheat AGB based on improved convolutional features (CFs).  Low-cost unmanned aerial vehicles (UAV) were used as the main data acquisition equipment.  This study acquired RGB and multi-spectral (MS) image data of the wheat population canopy for two wheat varieties and five key growth stages.  Then, field measurements were conducted to obtain the actual wheat biomass data for validation.  Based on the remote sensing indices (RSIs), structural features (SFs), and convolutional features (CFs), this study proposed a new feature named AUR-50 (Multi-source combination based on convolutional feature optimization) to estimate the wheat AGB.  The results show that AUR-50 could more accurately estimate the wheat AGB than RSIs and SFs, and the average R² exceeded 0.77.  AUR-50_MS had the highest estimation accuracy (R² of 0.88) in the overwintering period.  In addition, AUR-50 reduced the effect of the vegetation index saturation on the biomass estimation accuracy by adding CFs, where the highest R² was 0.69 at the flowering stage.  The results of this study provide an effective method to evaluate the AGB in wheat with high throughput and a research reference for the phenotypic parameters of other crops.

Avian infectious bronchitis (IB) is a highly contagious infectious disease caused by infectious bronchitis virus (IBV), which is prevalent in many countries worldwide and causes serious harm to the poultry industry.  At present, many commercial IBV vaccines have been used for the prevention and control of IB; however, IB outbreaks occur frequently.  In this study, two new strains of IBV, SX/2106 and SX/2204, were isolated from two flocks which were immunized with IBV H120 vaccine in central China.  Phylogenetic and recombination analysis indicated that SX/2106, which was clustered into the GI-19 lineage, may be derived from recombination events of the GI-19 and GI-7 strains and the LDT3-A vaccine.  Genetic analysis showed that SX/2204 belongs to the GVI-1 lineage, which may have originated from the recombination of the GI-13 and GVI-1 strains and the H120 vaccine.  The virus cross-neutralization test showed that the antigenicity of SX/2106 and SX/2204 was different from H120.  Animal experiments found that both SX/2106 and SX/2204 could replicate effectively in the lungs and kidneys of chickens and cause disease and death, and H120 immunization could not provide effective protection against the two IBV isolates.  It is noteworthy that the pathogenicity of SX/2204 has significantly increased compared to the GVI-1 strains isolated previously, with a mortality rate up to 60%.  Considering the continuous mutation and recombination of the IBV genome to produce new variant strains, it is important to continuously monitor epidemic strains and develop new vaccines for the prevention and control of IBV epidemics.

Citrus yellow vein clearing virus (CYVCV) is a new citrus virus that has become an important factor restricting the development of China’s citrus industry, and the CYVCV coat protein (CP) is associated with viral pathogenicity.  In this study, the Eureka lemon zinc finger protein (ZFP) ClDOF3.4 was shown to interact with CYVCV CP in vivo and in vitro.  Transient expression of ClDOF3.4 in Eureka lemon induced the expression of salicylic acid (SA)-related and hypersensitive response marker genes, and triggered a reactive oxygen species burst, ion leakage necrosis, and the accumulation of free SA.  Furthermore, the CYVCV titer in ClDOF3.4 transgenic Eureka lemon plants was approximately 69.4% that in control plants 6 mon after inoculation, with only mild leaf chlorotic spots observed in those transgenic plants.  Taken together, the results indicate that ClDOF3.4 not only interacts with CP but also induces an immune response in Eureka lemon by inducing the SA pathways.  This is the first report that ZFP is involved in the immune response of a citrus viral disease, which provides a basis for further study of the molecular mechanism of CYVCV infection.

Maize (Zea mays L.)–soybean (Glycine max L. Merr.) relay intercropping provides a way to enhance land productivity.  However, the late-planted soybean suffers from shading by the maize.  After maize harvest, how the recovery growth influences the leaf and nodule traits remains unclear.  A three-year field experiment was conducted to evaluate the effects of genotypes, i.e., supernodulating (nts1007), Nandou 12 (ND12), and Guixia 3 (GX3), and crop configurations, i.e., the interspecific row spacing of 45 (I45), 60 (I60), 75 cm (I75), and sole soybean (SS), on soybean recovery growth and N fixation.  The results showed that intercropping reduced the soybean total leaf area (LA) by reducing both the leaf number (LN) and unit leaflet area (LUA), and it reduced the nodule dry weight (NW) by reducing both the nodule number (NN) and nodule diameter (ND) compared with the SS.  The correlation and principal component analysis (PCA) indicated a co-variability of the leaf and nodule traits in response to the genotype and crop configuration interactions.  During the recovery growth stages, the compensatory growth promoted soybean growth to reduce the gaps of leaf and nodule traits between intercropping and SS.  The relative growth rates of ureide (RGR_U) and nitrogen (RGR_N) accumulation were higher in intercropping than in SS.  Intercropping achieved more significant sucrose and starch contents compared with SS.  ND12 and GX3 showed more robust compensatory growth than nts1007 in intercropping.  Although the recovery growth of relay intercropping soybean improved biomass and nitrogen accumulation, ND12 gained a more significant partial land equivalent ratio (pLER) than GX3.  The I60 treatment achieved more robust compensation effects on biomass and N accumulation than the other configurations.  Meanwhile, I60 showed a higher nodule sucrose content and greater shoot ureide and N accumulation than SS.  Finally, intercropping ND12 with maize using an interspecific row spacing of 60 cm was optimal for both yield advantage and N accumulation.

Maize (Zea mays L.) is an economically vital grain crop that is cultivated worldwide.  In 2011, a maize foliar disease was detected in Lingtai and Lintao counties in Gansu Province, China.  The characteristic signs and symptoms of this disease include irregular chlorotic lesions on the tips and edges of infected leaves and black punctate fruiting bodies in dead leaf tissues.  Given favourable environmental conditions, this disease spread to areas surrounding Gansu.  In this study, infected leaves were collected from Gansu and Ningxia Hui Autonomous Region between 2018 and 2020 to identify the disease-causing pathogen.  Based on morphological features, pathogenicity tests, and multi-locus phylogenetic analysis involving internal transcribed spacer (ITS), 18S small subunit rDNA (SSU), 28S large subunit rDNA (LSU), translation elongation factor 1-alpha (TEF), and β-tubulin (TUB) sequences, Eutiarosporella dactylidis was identified as the causative pathogen of this newly discovered leaf blight.  Furthermore, an in vitro bioassay was conducted on representative strains using six fungicides, and both fludioxonil and carbendazim were found to significantly inhibit the mycelial growth of E. dactylidis.  The results of this study provide a reference for the detection and management of Eutiarosporella leaf blight.

Food security is a strategic priority for a country’s economic development.  In China, high-standard farmland construction (HSFC) is an important initiative to stabilize grain production and increase grain production capacity.  Based on panel data from 31 sample provinces, autonomous regions, and municipalities in China from 2005–2017, this study explored the impact of HSFC on grain yield using the difference-in-differences (DID) method.  The results showed that HSFC significantly increased total grain production, which is robust to various checks.  HSFC increased grain yield through three potential mechanisms.  First, it could increase the grain replanting index.  Second, it could effectively reduce yield loss due to droughts and floods.  Last, HSFC could strengthen the cultivated land by renovating the low- and medium-yielding fields.  Heterogeneity analysis found that the HSFC farmland showed a significant increase in grain yield only in the main grain-producing areas and balanced areas.  In addition, HSFC significantly increased the yields of rice, wheat, and maize while leading to a reduction in soybean yields.  The findings suggest the government should continue to promote HSFC, improve construction standards, and strictly control the “non-agriculturalization” and “non-coordination” of farmland to increase grain production further.  At the same time, market mechanisms should be used to incentivize soybean farming, improve returns and stabilize soybean yields.

Adjustment of the sowing date is a widely used measure in rice production to adapt to high-temperature conditions.  However, the impact of delayed sowing date (DS) on rice quality may vary by variety and ecological conditions.  In this study, we conducted experiments using different sowing dates, that is, conventional sowing date 1 (CS1), CS2 (10 d later than CS1), DS1 (30 d later than CS1), and DS2 (30 d later than CS2), and three rice varieties, i.e., “Yixiangyou 2115,” “Fyou 498,” and “Chuanyou 6203.”  This experiment was conducted at four sites in the Sichuan basin in 2018 and 2019 to evaluate the influence of DS on the pasting properties of rice, which are a proxy for eating and cooking quality (ECQ).  In DS1 and DS2, rice had a significantly greater amylose content (AC) but a lower protein content (PC), peak viscosity (PKV), cool paste viscosity (CPV), and hot paste viscosity (HPV) than in CS1 and CS2.  Moreover, with the exception of CS2 and DS1 in 2018, DS1 and DS2 led to a 2.15–11.19% reduction in breakdown viscosity (BDV) and a 23.46–108.47% increase in setback viscosity (SBV).  However, the influence of DS on rice pasting properties varied by study site and rice variety.  In 2019, DS1 and DS2 led to a BDV reduction of 2.35–9.33, 2.61–8.61, 10.03–17.78, and 2.06–8.93%, and a SBV increase of 2.32–60.93, 63.74–144.24, 55.46–91.63, and -8.28–65.37% at the Dayi, Anzhou, Nanbu, and Shehong, respectively. DS resulted in a greater decrease in PKV, HPV, CPV, and BDV and a greater increase in the AC and SBV for Yixiangyou 2115 than for Chuanyou 6203 and Fyou 498.  Correlation analysis indicated that PKV and HPV were significantly and positively related to the mean, maximum, and minimum temperatures after heading.  These temperatures have to be greater than 25.9, 31.2, and 22.3℃ to increase the relative BDV and decrease the relative SBV of rice, thereby enhancing ECQ.  In conclusion, DS might contribute to a significant deterioration in ECQ in machine-transplanted rice in the Sichuan basin.  A mean temperature above 25.9℃ after heading is required to improve the ECQ of rice.

Waterlogging stress has been found to have adverse impacts on plant growth, subsequently reducing crop yields.  Spermidine (Spd), a second messenger, positively affects the growth of plants under waterlogging stress.  However, the molecular mechanisms of exogenous Spd application alleviating waterlogging stress remained unclear.  In this study, we performed physiological analysis and multi-omics to underlying the effect of Spd application on waterlogging stress.  Spd application increased genes expression level of light-harvesting complex (LHC) and photosynthesis-related and starch-related pathway, inhibited chlorophyll degradation and maintained higher photosynthetic rate, thus increased biomass accumulation under waterlogging stress.  The activation of genes related trehalose and Spd biosynthesis would result in high accumulation of trehalose and endogenous Spd.  Inhibiting 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase (ACO,) expression contributed to reduced ethylene emission.  All those changes increased maize resistance to waterlogging.  After Spd sparying, auxin-related genes up-regulated and IAA content was increased, those favor cell elongation in maize and thus keep normal growth after Spd application under waterlogging stress.  Most of genes involved in lipids were up-regulated and thus increased lipids content and protected cell membranes in maize after Spd application under waterlogging conditions.  All those changes contributed to increasing the resistance to waterlogging stress.  These findings broaden our understanding of the regulatory roles of Spd in alleviating waterlogging damage and will provide evidence for breeding waterlogging-tolerant maize varieties.

Femoral head necrosis (FHN) is a common leg disorder in the poultry industry often leads to significant cartilage damage. The mechanism behind abnormal apoptosis in FHN broilers, leading to cartilage damage, remains unclear; although endoplasmic reticulum stress (ERS) has been found to play a role in glucocorticoid-induced FHN broilers. In this study, we collected samples from broilers with femoral head separation (FHS) and femoral head separation accompanied with growth plate lacerations (FHSL) in a broiler farm. The aim was to investigate the potential association between the severity of FHN, bone remodeling and cartilage damage. Additionally, primary chondrocytes were treated with methylprednisolone (MP) to construct an in vitro FHN model, followed by inhibition or activation of ERS or hypoxia inducible factor-1α (HIF-1α) to further investigate the mechanism of apoptosis in cartilage. The results suggested that cartilage appeared to be the appropriate tissue to investigate the potential mechanisms of FHN, as the degree of cartilage damage was found to be closely related to the severity of the disease. Bone quality was only affected in FHSL broilers, although factors related to bone metabolism were significantly altered among FHN-affected broilers. In addition, cartilage in FHN-affected broilers exhibited high levels of apoptosis and upregulated expression of ERS-related and HIF-1α, which was consistent with both in vivo and in vitro findings after MP treatment. The results were further supported by treatment with HIF-1α or ERS inhibition or activation. In conclusion, bone remodeling and cartilage homeostasis were affected in FHN broilers, but only cartilage damage was significantly exacerbated with FHN development. Moreover, activation of ERS or HIF-1α resulted in apoptosis in cartilage, thus exhibiting a significant correlation with FHN severity.

The flavonoids produced by legume roots are signal molecules that induce nod genes for symbiotic rhizobium.  Nevertheless, the promoting effects of flavonoids in root exudates in intercropping system on soybean nodulation are still unknown.  A two years of field experiments was carried with maize soybean strip intercropping, i.e., the interspecific row spacing of 30 cm (MS30), 45 cm (MS45), 60 cm (MS60), and sole soybean/maize:SS/MM, and root interaction, i.e., root no barrier (NB) and root polythene-plastic barrier (PB), to evaluate relationships between flavonoids in root exudates and nodulation.  We found that root-root interaction between soybean and maize enhances the nodules number and fresh weight in intercropped soybean.  This enhancement increase gradually with expansion of interspecific distance.  Proportion of nodules with diameter greater than 0.4cm was higher in intercropped soybean with NB than with PB.  The expressions of nodules-related genes (GmENOD40, GmNIN2b and GmEXPB2) were up-regulated.  Furthermore, compared with monocropping, isoflavones secretion of soybean roots reduced, flavonoids and flavonols secretion of maize and soybean roots increased under intercropping.  The secretion of differential metabolites of flavonoids in the rhizosphere of maize and soybean declined with root barrier.  The expressions of GmCHS8 and GmIFS1 in soybean roots were up-regulated and GmICHG was down-regulated under root interaction.  The most of the flavonoids and flavonol compounds were positively correlated with nodule diameter.  The nodules number, the nodules fresh weight and the proportion of nodules with a diameter greater than 0.2 cm increased in different genotypes of soybean treated with maize root exudate, which promoted the improvement of nitrogen fixation capacity.  Therefore, maize-soybean strip intercropping combined with reasonable spacing to enhance the positive effect of underground root interaction, and improve the nodulation and nitrogen fixation capacity of intercropping soybean.

Streptococcus suis has garnered increasing attention due to its implication in severe infections in both swine and humans, as well as its development of multidrug resistance. The phenomenon of collateral sensitivity, whereby resistance to one antibiotic leads to increased sensitivity to another, provides new opportunities for mitigating the evolution of resistance. In this study, we evolved resistance in S. suis to 11 clinically used antibiotics and characterized the resulting collateral sensitivity profiles, revealing a complex network of interactions. Based on our findings, we identified dozens of such drug pairs and demonstrated collateral sensitivity to gamithromycin in ciprofloxacin-resistant S. suis both in vitro and in vivo. Gamithromycin effectively limits the evolution of resistance and reduces the mutant selection window for ciprofloxacin-resistant S. suis strains. Mechanistic studies indicated that the heightened sensitivity of ciprofloxacin-resistant S. suis to gamithromycin was associated with increased intracellular gamithromycin accumulation due to membrane potential alterations and reduced functions of proton motive force (PMF)-dependent efflux pumps. Furthermore, collateral sensitivity-based treatments significantly resensitized ciprofloxacin-resistant S. suis strains to gamithromycin, resulting in superior efficacy, lower pharmacodynamic targets, and higher treatment success rates in a murine thigh infection model. Our results indicate that gamithromycin sensitivity in S. suis is a collateral consequence of resistance to ciprofloxacin, providing valuable insight for the strategic design of collateral sensitivity-based antibiotic therapies for S. suis infections.

Wheat (Triticum aestivum L.) quality is a major focus of wheat breeding, which is influenced by multiple factors. The Huang-Huai wheat region, one of the main wheat-producing areas in China, provides favourable conditions for cultivating wheat cultivars with strong-gluten and medium-strong-gluten. In this study, a systematic assessment of seven crucial quality traits and important genetic loci (Glu-1 and Sec-1) in 436 wheat cultivars in the Huang-Huai wheat region of China by principal component analysis (PCA) and fuzzy comprehensive evaluation (FCE) methods showed that the stability time (ST), stretch area (SA), and maximum resistance (MAXR) were identified as three key factors, which significantly influenced wheat quality. Glu-1 and Sec-1 primarily impacted these three traits and subsequently influenced wheat quality. Compared to Glu-A1 and Glu-B1, Glu-D1 has a more significant impact on the comprehensive evaluation value D, principal components PC1-PC3, and the main traits ST, SA and MAXR of PC1. Wheat cultivars carrying the high-molecular-weight glutenin subunit (HMW-GS) Dx5+Dy10 exhibited a notable improvement in ST, SA, and MAXR traits compared with those carrying HMW-GS Dx2+Dy12, suggesting that Dx5+Dy10 may enhance wheat quality by improving ST, SA, and MAXR. By combining the results of D value, GYT (genotype by yield×trait) index, and HMW-GS score, 20 high-quality and high yield wheat cultivars were identified, which can be used as elite parents for wheat quality breeding.

Stone fruits, also known as drupes, have evolved an extremely hard wood-like shell called a stone to protect seeds. Currently, the market value of stoneless cultivars has risen dramatically, which highlights the need to cultivate stoneless fruit. Therefore, the underlying mechanism of fruit stones is urgently needed. By employing the stone-containing jujube cultivar ‘Youhe’ and two stoneless Chinese jujube cultivars, ‘Wuhefeng’ and ‘Jinsixiaozao’, we carried out a comprehensive study on the mechanism of fruit stone development in jujube. Anatomical analysis and lignin staining revealed that the stone cultivar ‘Youhe’ jujube exhibited much greater lignin accumulation in the endocarp than did the other two stoneless cultivars. Lignin accumulation may be the key reason for the formation of fruit stone. By analysing the transcriptome data and identifying differentially expressed genes (DEGs), 49 overlapping DEGs between ‘Youhe’ jujube vs ‘Wuhefeng’ jujube and ‘Youhe’ jujube vs ‘Daguowuhe’ jujube were identified. Among these DEGs, ZjF6H1-3 and ZjPOD, which are involved in lignin synthesis, were identified. Overexpression and silencing of ZjF6H1-3 and ZjPOD in wild jujube seedlings further confirmed their role in lignin synthesis. In addition, two bHLH transcription factors were also included in these 49 overlapping DEGs, and bHLH transcription factor motifs were found in the promoters of ZjF6H1-3 and ZjPOD, indicating that bHLH transcription factors are also involved in lignin synthesis and stone formation in Chinese jujube. This study provides new insight into the molecular networks underlying fruit stone formation and provides an important reference for the molecular design and breeding of stoneless fruit cultivars for jujube and fruit trees.

Sustainable increase in maize yield is severely constrained by the continuing reduction in topsoil depth due to irrational farming practices and the effects of climate change. However, the mechanisms by which topsoil depth affects crop physiology and biochemistry remain unclear, particularly with respect to photosynthesis and carbon assimilation.  To investigate the effects of topsoil depth on maize photosynthetic processes, carbon assimilation, and yield in the field, we used a two-factor random block design with five topsoil depths of 10 cm (S1), 20 cm (S2), 30 cm (S3), 40 cm (S4), and 50 cm (S5) at two planting densities of 60,000 plants ha⁻¹ (conventional density, D1) and 90,000 plants ha⁻¹ (high density, D2).  Increasing topsoil depth significantly increased maize grain yield, with maximum increases of 61.7% in D1 and 72.1% in D2.  Increasing topsoil depth also increased chlorophyll content, maximum photochemical efficiency (F_v/F_m), actual photochemical efficiency (ΦPSII), and photosynthetic enzyme activities, including ribulose-1,5-bisphosphate carboxylase (Rubisco), phosphoenolpyruvate carboxylase (PEPC), and pyruvate orthophosphate dikinase (PPDK).  With the increases in those parameters, plants maintained the highest net photosynthetic rate (P_nmax) when reaching the light saturation point, with maximum increases of 68.0% in D1 and 75.7% in D2, thereby increasing dry matter production at physiological maturity.  The accumulation of ¹³C-photosynthates in maize stem, leaf, and grain increased with the increase in topsoil depth, indicating increases in carbon assimilation capacity, distribution efficiency, and photosynthetic capacity.  In summary, increasing topsoil depth is an important factor in ensuring high and stable maize yields, and the increase in yield is closely related to the physiological differences caused by changes in topsoil depth.