Global warming is primarily characterized by asymmetric temperature increases, with greater temperature rises in winter/spring and at night compared to summer/autumn and the daytime.  We investigated the impact of winter night warming on the top expanded leaves of the spring wheat cultivar Yangmai 18 and the semi-winter wheat cultivar Yannong 19 during the 2020–2021 growing season.  Results showed that the night-time mean temperature in the treatment group was 1.27°C higher than the ambient temperature, and winter night warming increased the yields of both wheat cultivars, the activities of sucrose synthase and sucrose phosphate synthase after anthesis, and the biosynthesis of sucrose and soluble sugars.  Differentially expressed genes (DEGs) were identified using criteria of P-value<0.05 and fold change>2, and they were subjected to Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses.  Genes differentially expressed in wheat leaves treated with night warming were primarily associated with starch and sucrose metabolism, amino acid biosynthesis, carbon metabolism, plant hormone signal transduction, and amino sugar and nucleotide sugar metabolism.  Comparisons between the groups identified 14 DEGs related to temperature.  These results highlight the effects of winter night warming on wheat development from various perspectives.  Our results provide new insights into the molecular mechanisms of the response of wheat to winter night warming and the candidate genes involved in this process.

Global climate change is characterized by asymmetric warming, i.e., greater temperature increases in winter, spring, and nighttime than in summer, autumn, and daytime.  Field experiments were conducted using four wheat cultivars, namely ‘Yangmai 18’ (YM18), ‘Sumai 188’ (SM188), ‘Yannong 19’ (YN19), and ‘Annong 0711’ (AN0711), in the two growing seasons of 2019–2020 and 2020–2021, with passive night warming during different periods in the early growth stage.  The treatments were night warming during the tillering–jointing (NW_T–J), jointing–booting (NW_J–B), and booting–anthesis (NW_B–A) stages, with ambient temperature (NN) as the control.  The effects of night warming during different stages on wheat yield formation were investigated by determining the characteristics of dry matter accumulation and translocation, as well as sucrose and starch accumulation in wheat grains.  The wheat yields of all four cultivars were significantly higher in NW_T–J than in NN in the 2-year experiment.  The yield increases of semi-winter cultivars YN19 and AN0711 were greater than those of spring cultivars YM18 and SM188.  Treatment NW_T–J increased wheat yield mainly by increasing the 1,000-grain weight and the number of fertile spikelets, and it increased dry matter accumulation in various organs of wheat at the anthesis and maturity stages by increasing the growth rate at the vegetative growth stage.  The flag leaf and spike showed the largest increases in dry matter accumulation.  NW_T–J also increased the grain sucrose and starch contents in the early and middle grain-filling stages, promoting yield formation.  Overall, night warming between the tillering and jointing stages increased the pre-anthesis growth rate, and thus, wheat dry matter production, which contributed to an increase in wheat yield.

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.

The sweet potato weevil (Cylas formicarius (Fab.) (Coleoptera: Brentidae)) is a pest that feeds on sweet potato (Ipomoea batatas (L.) Lam. (Solanales: Convolvulaceae)), causing substantial economic losses annually.  However, no safe and effective methods have been found to protect sweet potato from this pest.  Herbivore-induced plant volatiles (HIPVs) promote various defensive bioactivities, but their formation and the defense mechanisms in sweet potato have not been investigated.  To identify the defensive HIPVs in sweet potato, the release dynamics of volatiles was monitored.  The biosynthetic pathways and regulatory factors of the candidate HIPVs were revealed via stable isotope tracing and analyses at the transcriptional and metabolic levels.  Finally, the anti-insect activities and the defense mechanisms of the gaseous candidates were evaluated.  The production of (Z)-3-hexenyl acetate (z3HAC) and allo-ocimene was induced by sweet potato weevil feeding, with a distinct circadian rhythm.  Ipomoea batatas ocimene synthase (IbOS) is first reported here as a key gene in allo-ocimene synthesis.  Insect-induced wounding promoted the production of the substrate, (Z)-3-hexenol, and upregulated the expression of IbOS, which resulted in higher contents of z3HAC and allo-ocimene, respectively.  Gaseous z3HAC and allo-ocimene primed nearby plants to defend themselves against sweet potato weevils.  These results provide important data regarding the formation, regulation, and signal transduction mechanisms of defensive volatiles in sweet potato, with potential implications for improving sweet potato weevil management strategies.

Excessive application of nitrogen (N) fertilizer is the main cause of N loss and poor use efficiency in winter wheat (Triticum aestivum L.) production in the North China Plain (NCP).  Drip fertigation is considered to be an effective method for improving N use efficiency and reducing losses, while the performance of drip fertigation in winter wheat is limited by poor N scheduling.  A two-year field experiment was conducted to evaluate the growth, development and yield of drip-fertigated winter wheat under different split urea (46% N, 240 kg ha^–1) applications.  The six treatments consisted of five fertigation N application scheduling programs and one slow-release fertilizer (SRF) application.  The five N scheduling treatments were N0–100 (0% at sowing and 100% at jointing/booting), N25–75 (25% at sowing and 75% at jointing and booting), N50–50 (50% at sowing and 50% at jointing/booting), N75–25 (75% at sowing and 25 at jointing/booting), and N100–0 (100% at sowing and 0% at jointing/booting).  The SRF (43% N, 240 kg ha^–1) was only used as fertilizer at sowing.  Split N application significantly (P<0.05) affected wheat grain yield, yield components, aboveground biomass (ABM), water use efficiency (WUE) and nitrogen partial factor productivity (NPFP).  The N50–50 and SRF treatments respectively had the highest yield (8.84 and 8.85 t ha^–1), ABM (20.67 and 20.83 t ha^–1), WUE (2.28 and 2.17 kg m^–3) and NPFP (36.82 and 36.88 kg kg^–1).  This work provided substantial evidence that urea-N applied in equal splits between basal and topdressing doses compete economically with the highly expensive SRF for fertilization of winter wheat crops.  Although the single-dose SRF could reduce labor costs involved with the traditional method of manual spreading, the drip fertigation system used in this study with the N50–50 treatment provides an option for farmers to maintain wheat production in the NCP.

Chinese cabbage is an economically important Brassica vegetable worldwide, and clubroot, which is caused by the soil-borne protist plant pathogen Plasmodiophora brassicae is regarded as a destructive disease to Brassica crops.  Previous studies on the gene transcripts related to Chinese cabbage resistance to clubroot mainly employed RNA-seq technology, although it cannot provide accurate transcript assembly and structural information.  In this study, PacBio RS II SMRT sequencing was used to generate full-length transcriptomes of mixed roots at 0, 2, 5, 8, 13, and 22 days after P. brassicae infection in the clubroot-resistant line DH40R.  Overall, 39 376 high-quality isoforms and 26 270 open reading frames (ORFs) were identified from the SMRT sequencing data.  Additionally, 426 annotated long noncoding RNAs (lncRNAs), 56 transcription factor (TF) families, 1 883 genes with poly(A) sites and 1 691 alternative splicing (AS) events were identified.  Furthermore, 1 201 of the genes had at least one AS event in DH40R.  A comparison with RNA-seq data revealed six differentially expressed AS genes (one for disease resistance and five for defensive response) that are potentially involved in P. brassicae resistance.  The results of this study provide valuable resources for basic research on clubroot resistance in Chinese cabbage.

This study investigated the effects of grape seed extract (GSE) on fresh and cooked meat color and premature browning (PMB) in ground meat patties (85% beef and 15% pork back fat) packaged under high-oxygen modified atmospheres (HiOx-MAP).  The GSE was added to patties at concentrations of 0, 0.10, 0.25, 0.50 and 0.75 g kg^–1.  This study evaluated the surface color, pH, lipid oxidation, and total viable counts (TVC) of raw patties, and the internal color and pH of patties cooked to a temperature of 66 or 71°C over 10-day storage at 4°C.  Compared with the control (0 g kg^–1 GSE), GSE improved the color stability (P<0.05) and significantly inhibited the lipid and myoglobin oxidation of raw patties from day 5 to 10, but GSE had no effect (P>0.05) on TVC.  Patties containing 0.50 and 0.75 g kg^–1 GSE cooked to 66°C exhibited greater (P<0.05) interior redness than the control and reduced the PMB of cooked patties in the late storage stage.  These results suggested that 0.50 and 0.75 g kg^–1 GSE can improve fresh meat color and minimize PMB of HiOx-MAP patties.

In maize, two root epidermis-expressed ammonium transporters ZmAMT1;1a and ZmAMT1;3 play major roles in high-affinity ammonium uptake.  However, the transcriptional regulation of ZmAMT1s in roots for ensuring optimal ammonium acquisition remains largely unknown.  Here, using a split root system we showed that ZmAMT1;1a and ZmAMT1;3 transcript levels were induced by localized ammonium supply to nitrogen-deficient roots.  This enhanced expression of ZmAMT1s correlated with increases in ¹⁵NH₄⁺ influx rates and tissue glutamine concentrations in roots.  When ammonium was supplied together with methionine sulfoximine, an inhibitor of glutamine synthase, ammonium-induced expression of ZmAMT1s disappeared, suggesting that glutamine rather than ammonium itself regulated ZmAMT1s expression.  When glutamine was supplied to nitrogen-deficient roots, expression levels of ZmAMT1s were enhanced, and negative feedback regulation could subsequently occur by supply of glutamine at a high level.  Thus, our results indicated an ammonium-dependent regulation of ZmAMT1s at transcript levels, and a dual role of glutamine was suggested in the regulation of ammonium uptake in maize roots.