3´,5´-Cyclic adenosine monophosphate (cAMP) is an important metabolite that is specifically enriched in jujube. However, the effect of cAMP on jujube cellular responses has not been comprehensively studied. Here, we established jujube cell suspension cultures and investigated the calcium influx in response to cAMP treatment through protoplast isolation and fluorescence intensity. Firstly, cAMP treatment could promote jujube growth and increase the content of endogenous cAMP. Using transcriptome analysis with transgenic Arabidopsis plants overexpressing adenylate cyclase (ZjAC) as a positive control, we identified 60 calcium-related differential expressed genes (DEGs) that contributed to the calcium signaling and inter- or intra-cellular responses. Pharmacological treatments such as cAMP and the calcium ionophore A23187 could induce ZjAC expression, the accumulation of cAMP and calcium influx in jujube cells, while ethylene glycol tetraacetic acid (EGTA) or bithionol treatment inhibited these changes. Moreover, the calcium channels and transporters in calcium influx, such as the ZjCNGC2 channel and the mitogen activated protein (MAP) kinase pathway, could be activated by cAMP treatment. In summary, our findings demonstrated that cAMP biosynthesis is dependent on calcium influx and the amplifying effect between calcium and cAMP may be involved in intracellular signal induction, which might contribute to the growth and development of jujube.

H9N2 avian influenza virus (AIV) has widely circulated in poultry worldwide and sporadic infections in humans and mammals.  During our surveillance of chicken from 2019 to 2021 in Shandong Province, China, we isolated 11 H9N2 AIVs.  Phylogenetic analyses showed that the eight gene segments of the 11 isolates were closely related to several sublineages of Eurasian lineage: BJ/94-like clades (HA and NA genes), G1-like clades (PB2 and M genes), and SH/F/98-like clades (PB1, PA, NP and NS genes).  The isolates showed mutation sites that preferentially bind to human-like receptors (HA) and mammalian fitness sites (PB2, PB1 and PA), as well as mutations in antigen and drug resistance sites.  Moreover, studies with mice revealed four isolates with varying levels of pathogenicity.  The average antibody titer of the H9N2 AIVs was 8.60 log2.  Based on our results, the epidemiological surveillance of H9N2 AIVs should be strengthened.

Soft rot caused by Pectobacterium carotovorum (Pc) is a devastating disease of Brassica rapa, causing substantial reductions in crop yield and quality.  Identifying genes related to soft rot resistance is the key to solving this problem.  To characterize soft rot resistance, we screened a soft rot-susceptible Chinese cabbage (A03), a resistant pakchoi (‘Huaguan’), and a resistant mutant (sr).  An F₂ population was generated by crossing susceptible Chinese cabbage A03 and resistant pakchoi ‘Huaguan’ to identify quantitative trait loci (QTLs) that confer soft rot resistance.  A high-density genetic map was constructed and the three QTLs identified contain 166 genes.  Based on available transcriptome data, we analyzed the expression of the 166 genes during an important defense regulatory period in Pc infection in both A03 and the resistant mutant sr.  Among the 166 genes, six candidate genes were related to the soft rot defense response in B. rapa.  TIFY10B (JAZ2, BraA07g038660.3C) was located in the major soft rot resistance QTL, DRQTL-3 on A07, and we speculate that this gene may play an important role in the defense mechanism against soft rot in B. rapa.  This study lays the foundation for further investigations on the mechanism of soft rot resistance in B. rapa crops.

Plants glycerol-3-phosphate dehydrogenase (GPDH) catalyzes the formation of glycerol-3-phosphate, and plays an essential role in glycerolipid metabolism and stress responses. In the present study, the knock-out mutants of cytosolic GPDH (AtGPDHc2) and wild-type Arabidopsis plants were treated with 0, 50, 100, and 150 mmol L^–1 NaCl to reveal the effects of AtGPDHc2 deficiency on salinity stress responses. The fluctuation in redox status, reactive oxygen species (ROS) and antioxidant enzymes as well as the transcripts of genes involved in the relevant processes were measured. In the presence of 100 and 150 mmol L^–1 NaCl treatments, AtGPDHc2-deficient plants exhibited a pronounced reduction in germination rate, fresh weight, root length, and overall biomass. Furthermore, loss of AtGPDHc2 resulted in a significant perturbation in cellular redox state (NADH/NAD+ and AsA/DHA) and consequent elevation of ROS and thiobarbituric acid-reactive substances (TBARS) content. The elevated ROS level triggered substantial increases in ROS-scavenging enzymes activities, and the up-regulated transcripts of the genes (CSD1, sAPX and PER33) encoding the antioxidant enzymes were also observed. In addition, the transcript levels of COX15, AOX1A and GLDH in gpdhc2 mutants decreased in comparison to wild-type plants, which demonstrated that the deficiency of AtGPDHc2 might also has impact on mitochondrial respiration under salt stress. Together, this work provides some new evidences on illustrating the roles of AtGPDHc2 playing in response to salinity stress by regulating cellular redox homeostasis, ROS metabolism and mitochondrial respiration.

With increasing water shortage resources and extravagant nitrogen application, there is an urgent need to optimize irrigation regimes and nitrogen management for winter wheat (Triticum aestivum L.) in the North China Plain (NCP).  A 4-year field experiment was conducted to evaluate the effect of three irrigation levels (W1, irrigation once at jointing stage; W2, irrigation once at jointing and once at heading stage; W3, irrigation once at jointing, once at heading, and once at filling stage; 60 mm each irrigation) and four N fertilizer rates (N0, 0; N1, 100 kg N ha⁻¹; N2, 200 kg N ha⁻¹; N3, 300 kg N ha⁻¹) on wheat yield, water use efficiency, fertilizer agronomic efficiency, and economic benefits.  The results showed that wheat yield under W2 condition was similar to that under W3, and greater than that under W1 at the same nitrogen level.  Yield with the N1 treatment was higher than that with the N0 treatment, but not significantly different from that obtained with the N2 and N3 treatments.  The W2N1 treatment resulted in the highest water use and fertilizer agronomic efficiencies.  Compared with local traditional practice (W3N3), the net income and output-input ratio of W2N1 were greater by 12.3 and 19.5%, respectively.  These findings suggest that two irrigation events of 60 mm each coupled with application of 100 kg N ha⁻¹ is sufficient to provide a high wheat yield during drought growing seasons in the NCP. 

A novel nodulin gene, GmN479 genomic clone composing of 3 630 nucleotides was isolated from mature soybean nodules using GmN479 cDNA as a probe by subtractive hybridization procedure. GmN479 encodes 170 amino acids with 2.09 kb nucleotides promoter region, and contains two important upstream promoter elements, one is a conserved cis-acting sequence motif 5´-AAAGAT-3´ controlling nodulin gene expression, and the other is typical CAAT boxes. GmN479 gene has a single zinc-finger C2H2 domain YSCAFCQRGFSNAQALLGGHMNIH and a conserved motif, QALGGHMN in the zinc-finger with a short leucine repeat in the LDLELRLGL motif closed to C-terminal. These two conserved motifs share respectively higher identity with those in the floral regulator SUPERMAN gene, indicating that GmN479 may function as a transcriptional regulator, and is a likely candidate for playing a role in nodule-morphogenesis. Blotting data showed that GmN479 is a single copy presenting in the genome of soybean nodule, and its expression profile is similar to that of Lba, but it is different from that of ENOD2. GUS staining showed that GmN479 promoter just functions in the infected cells of nodules, indicating that the GmN479 is one of the truly symbiotically induced host genes, and belongs to a late nodulin gene. The expression pattern of GmN479 gene seems to imply that it may be closely related to the development of the nodule. In a sense, it may be a useful marker for identifying the development of the infected cell system in the nodules of soybean.