Compared with sole nitrate (NO₃^–) or sole ammonium (NH₄⁺) supply, mixed nitrogen (N) supply may promote growth of maize seedlings.  Previous study suggested that mixed N supply not only increased photosynthesis rate, but also enhanced leaf growth by increasing auxin synthesis to build a large sink for C and N utilization.  However, whether this process depends on N absorption is unknown.  Here, maize seedlings were grown hydroponically with three N forms (NO₃^– only, 75/25 NO₃^–/NH₄⁺ and NH₄⁺ only).  The study results suggested that maize growth rate and N content of shoots under mixed N supply was little different to that under sole NO₃^– supply at 0–3 d, but was higher than under sole NO₃^– supply at 6–9 d.  ¹⁵N influx rate under mixed N supply was greater than under sole NO₃^– or NH₄⁺ supply at 6–9 d, although NO₃^– and NH₄⁺ influx under mixed N supply were reduced compared to sole NO₃^– and NH₄⁺ supply, respectively.  qRT-PCR determination suggested that the increased N absorption under mixed N supply may be related to the higher expression of NO₃^– transporters in roots, such as ZmNRT1.1A, ZmNRT1.1B, ZmNRT1.1C, ZmNRT1.2 and ZmNRT1.3, or NH₄⁺ absorption transporters, such as ZmAMT1.1A, especially the latter.  Furthermore, plants had higher nitrate reductase (NR) glutamine synthase (GS) activity and amino acid content under mixed N supply than when under sole NO₃^– supply.  The experiments with inhibitors of NR reductase and GS synthase further confirmed that N assimilation ability under mixed N supply was necessary to promote maize growth, especially for the reduction of NO₃^– by NR reductase.  This research suggested that the increased processes of NO₃^– and NH₄⁺ assimilation by improving N-absorption ability of roots under mixed N supply may be the main driving force to increase maize growth.

Various genetic and biochemical characteristics exist in tea plant cultivars, and they largely determine production suitability and tea quality.  Here, we performed transcriptomic and metabolomic analyses of young shoots of seven tea cultivars and identified major regulatory transcription factors (TFs) for the characteristic metabolites in different cultivars based on weighted gene co-expression network analysis (WGCNA).  Phenotypically, we found that ‘Tieguanyin’ (TGY) and ‘Fujian Shuixian’ (FJSX), which are suitable for oolong tea, had higher catechin contents.  The metabolites of ‘Jinxuan’ (JX) were more prominent, especially the contents of phenolic acids, flavonoids, terpenes, and tannins, which were higher than those of the other six cultivars.  Moreover, ‘Fudingdabai’ (FDDB), which is suitable for white tea, was rich in amino acids, linolenic acid, and saccharides.  At the molecular level, hydroxycinnamoyl CoA quinate hydroxycinnamoyl transferase (HCT) (CsTGY12G0001876, and CsTGY06G0003042) led to the accumulation of chlorogenic acid in TGY.  The main reason for the higher l-ascorbic acid content in FJSX was the high expression levels of L-galactono-1,4-lactone hydrogenase (GalLDH) (CsTGY13G0000389) and Myo-inositol oxygenase (MIOX) (CsTGY14G0001769, and CsTGY14G0001770), which were regulated by WRKY (CsTGY11G0001197).  Furthermore, FDDB, ‘Longjing 43’ (LJ43), ‘Shuchazao’ (SCZ)  and ‘Baihaozao’ (BHZ) had higher free fatty acid contents, among which MYB (CsTGY14G0002344) may be a hub gene for the regulation of palmitoleic acid accumulation.  More importantly, we found that the shoots of TGY were green with purple, mainly due to the accumulation of anthocyanins and the downregulation of the Mg-protoporphyrin IX nonomethyl ester cyclase (MPEC) (CsTGY10G0001989) gene that affects chlorophyll synthesis.  These results will provide a theoretical reference for tea cultivar breeding and suitability.

African swine fever (ASF), caused by the African swine fever virus (ASFV), is a devastating disease of domestic and wild pigs.  There is no effective vaccine, and the control of the disease relies mainly on surveillance and early detection of infected pigs.  Previously, serological assays, such as ELISA, have been developed mainly based on recombinant structural viral proteins of ASFV, including p72, p54, and p30.  However, the antibodies against these proteins do not provide efficient protection against ASFV infection in pigs.  Therefore, new serological assays that can be applied for clinical diagnosis and evaluating serological immune response in vaccinated pigs are still required.  In this study, we expressed and purified a recombinant pB602L protein.  The purified pB602L protein was then used as an antigen to develop an indirect ELISA assay.  This assay has no cross-reaction with the anti-sera against the 15 most common pig pathogens in China, such as classical swine fever virus, pseudorabies virus, and porcine parvovirus.  This assay and a commercial ELISA kit were then used to detect 60 field pig serum samples, including an unknown number of anti-ASFV sera.  The coincidence of the two assays was 95%.  Furthermore, the pB602L-based ELISA was employed to test the antibody responses to the seven-gene-deleted ASFV strain HLJ/18-7GD in pigs.  The results showed that the antibody levels in all vaccinated pigs, starting from the 10th day post-inoculation, have increased continuously during the observation period of 45 days.  Our results indicate that this pB602L-based indirect ELISA assay can be employed potentially in the field of ASFV diagnosis.

Effects of continuous negative pressure water supply on water consumption, growth and development, as well as physiological mechanism and quality of Capsicum annuum L. were investigated in this paper.  Meanwhile, the optimal negative pressure water supply conditions for growth of C. annuum L. were screened out to achieve the goals of water conservation, high yield and high quality, thus providing theoretical foundation for its field production.  The pot experiment within the greenhouse was utilized; the continuous negative pressure water supply was adopted; the four treatments, artificial watering (CK), –5 kPa (T1), –10 kPa (T2), and –15 kPa (T3) were set; and the daily water consumption, yield, as well as the biomass, nitrate reductase, root activity, vitamin C, capsaicin, and nutrient uptakes of nitrogen (N), phosphorus (P) and potassium (K) during various stages of its growth were determined.  Compared with CK, when the water supply pressure was controlled at –5 to –15 kPa in the experiment, the total water consumption of C. annuum L. reduced by 53.42 to 67.75%, the total water consumption intensity reduced by 54.29 to 67.14%, and the water use efficiency increased by 12.66 to 124.67%.  The N accumulation in a single strain of C. annuum L. from the color turning stage to the red ripe stage increased by 15.99 to 100.55%, respectively, compared with that of CK; the P accumulation increased by 20.47 to 154.00% relative to that of CK, and the K accumulation increased by 64.92 to 144.9% compared with that of CK.  Compared with CK, C. annuum L. yield was remarkably improved by 13.79% at T1, and contents of vitamin C, capsaicin as well as carotenoids at all growth stages were enhanced by 13.42–147.01%, 11.54–71.01%, and 41.1–568.06%, respectively.  Nitrate reductase activity, root activity and chlorophyll (a+b) were markedly increased by 335.78–500%, 79.6–140.68% and 114.95–676.19%, respectively, from immature stage to full ripe stage.  Adopting the continuous negative pressure water supply for C. annuum L. has a significant water-saving effect, and the water supply pressure being stable at –5 kPa contributes to its growth and development, improves yield, enhances root activity, promotes nutrient uptake, and improves its quality, thus achieving the effects of water conservation, high yield, high quality and high efficiency.

The study comparatively examined the leaf photosynthetic capacities of different adzuki bean cultivars, high-yield 2000-75 and Jihong 9218, and low-yield Hongbao 1 and Wanxuan 1 from flowering to ripening. It showed that after flowering, the leaves of the cultivars gradually aged, the leaf chlorophyll (Chl.), soluble protein (SP) contents, net photosynthetic rates (Pn), transpiration rates (Tr) and stomatal conductance (Gs) of the cultivars tended to decline, but the leaf intercellular CO2 concentration (Ci) of the cultivars tended to rise. The leaf photosynthetic capacities of the cultivars decreased gradually from the lower to the upper nodes. The dry seed yields of the cultivars were positively correlated with their leaf Chl., SP, Pn, and Tr and Gs, and negatively associated with their leaf Ci. At the late growth stages, the high-yield cultivars maintained higher leaf Chl. contents, SP contents, Pn, Tr, and Gs than the low-yield cultivars, indicating that leaf photosynthetic capacity was one of important yield-affecting factors of adzuki bean. Therefore, it was important for a crop at the crucial stage of yield formation to maintain a high leaf chlorophyll content and a high leaf photosynthetic capacity and delay leaf aging.