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Harpin proteins produced by plant-pathogenic Gram-negative bacteria are the venerable player in regulating bacterial virulence and inducing plant growth and defenses. A major gap in these effects is plant sensing linked to cellular responses, and plant sensor for harpin Hpa1 from rice bacterial blight pathogen points to plasma membrane intrinsic protein (PIP). Here we show that Arabidopsis AtPIP1;4 is a plasma membrane sensor of Hpa1 and plays a dual role in plasma membrane permeability of CO2 and H2O. In particular, AtPIP1;4 mediates CO2 transport with a substantial contribute to photosynthesis and further increases this function upon interacting with Hpa1 at the plasma membrane. As a result, leaf photosynthesis rates are increased and the plant growth is enhanced in contrast to the normal process without Hpa1-AtPIP1;4 interaction. Our findings demonstrate the first case that plant sensing of a bacterial harpin protein is connected with photosynthetic physiology to regulate plant growth.

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Previous studies have demonstrated that Lactobacillus has anti-inflammatory properties, but the protective functions of Lactobacillus and mechanisms of inhibition of necrotic enteritis (NE) in the intestines of chickens have not been fully clarified. In the present study, we selected a probiotic strain, Lactobacillus fermentum 1.2029, which has good adhesive ability and a high survival rate in low pH and bile salts. The objective of this study was to examine the anti-inflammatory properties of L. fermentum 1.2029 against NE in chickens. Two hundred forty 1-d-old male Arbor Acres broilers were blocked into 3 experimental groups as follows: (I) nonchallenge control group, (II) Clostridium perfringens challenge group, and (III) C. perfringens challenge + L. fermentum 1.2029 group. Lactobacillus fermentum 1.2029 (1.0 mL/d, 10(8) cfu/mL) was orally administered daily to group III during the course of the experiment, and all uninfected control chickens were inoculated accordingly with the same volume of PBS. Clostridium perfringens (0.5 mL on d 1 and 1.0 mL on d 14 to 21, 10(8) cfu/mL) was administered to chickens in group II. At 28 d, scoring of gross NE lesions was performed. Ileal segments of approximately 2 cm from 24 chickens in each experimental group were collected and fixed in 4% (wt/vol) neutral-buffered formalin solution for histological scoring. Ileal mucosa samples were also collected for mRNA analysis by real-time PCR. The results showed that L. fermentum 1.2029 reduced the severity of NE lesions in chickens. Histological scores revealed that L. fermentum 1.2029 also reduced the inflammation damage of NE in chickens. Changes in cytokines and Toll-like receptors (TLR) were determined, and L. fermentum 1.2029 was found to increase interleukin-10 levels and reduce interferon-γ and TLR2 levels in NE-infected chickens. The results showed that L. fermentum 1.2029 was able to regulate the intestinal mucosal immune response and ameliorate inflammation by changing expression levels of cytokines and TLR.

BackgroundDuring oviposition many parasitoid wasps inject various factors, such as polydnaviruses (PDVs), along with eggs that manipulate the physiology and development of their hosts. These manipulations are thought to benefit the parasites. However, the detailed mechanisms of insect host-parasitoid interactions are not fully understood at the molecular level. Based on recent findings that some parasitoids influence gene expression in their hosts, we posed the hypothesis that parasitization by a braconid wasp, Cotesia chilonis, influences the expression of genes responsible for development, metabolism and immune functions in the fatbody and hemocytes of its host, Chilo suppressalis.Methodology/Principal FindingsWe obtained 39,344,452 reads, which were assembled into 146,770 scaffolds, and 76,016 unigenes. Parasitization impacted gene expression in fatbody and hemocytes. Of these, 8096 fatbody or 5743 hemocyte unigenes were down-regulated, and 2572 fatbody or 1452 hemocyte unigenes were up-regulated. Gene ontology data showed that the majority of the differentially expressed genes are involved in enzyme-regulated activity, binding, transcription regulator activity and catalytic activity. qPCR results show that most anti-microbial peptide transcription levels were up-regulated after parasitization. Expression of bracovirus genes was detected in parasitized larvae with 19 unique sequences identified from six PDV gene families including ankyrin, CrV1 protein, cystatin, early-expressed (EP) proteins, lectin, and protein tyrosine phosphatase.ConclusionsThe current study supports our hypothesis that parasitization influences the expression of fatbody and hemocyte genes in the host, C. suppressalis. The general view is that manipulation of host metabolism and immunity benefits the development and emergence of the parasitoid offsprings. The accepted beneficial mechanisms include the direct impact of parasitoid-associated virulence factors such as venom and polydnavirus on host tissues (such as cell damage) and, more deeply, the ability of these factors to influence gene expression. We infer that insect parasitoids generally manipulate their environments, the internal milieu of their hosts.

Forty one Bacillus thuringiensis (Bt) standard reference strains and 118 Bt local isolates were screened for vip1/vip2 genes by PCR amplification, with only three strains (HD201, HD109 and HD12) producing the desired bands. Southern blot showed that vip1/vip2 genes were located on a 10 Kb EcoRV fragment of their total DNAs. Furthermore, the vip1-Ca/vip2Ac genes were cloned from a partial genomic library of HD201. Sequence homologous analysis revealed that vip2Ac gene was highly conserved and encoded a protein possibly having ADP-ribosyltransferase activity, and that vip1Ca gene was of low homology, especially at its 3-terminus. Western blot showed that Vip1Ca and Vip2Ac proteins could be detected from middle logarithmic phase to the stationary phase in Bt HD201. However, bioassays of HD201 supernatants exhibited no activity against Culex quinquefasciatus, Spodoptera exigua, S. litura, Helicoverpa amigera and Tenebrio molitor larvae. Whether Vip1Ca and Vip2Ac proteins have any toxicity to other susceptible targets still needs to be investigated.

BackgroundLong non-coding RNAs (lncRNAs) play important roles in plant growth and stress responses. Studies of lncRNAs in non-model plants are quite limited, especially those investigating multiple dehydration stresses. In this study, we identified novel lncRNAs and analyzed their functions in dehydration stress memory in switchgrass, an excellent biofuel feedstock and soil-conserving plant in the Gramineae family.ResultsWe analyzed genome-wide transcriptional profiles of leaves of 5-week-old switchgrass plantlets grown via tissue culture after primary and secondary dehydration stresses (D1 and D2) and identified 16,551 novel lncRNAs, including 4554 annotated lncRNAs (targeting 3574 genes), and 11,997 unknown lncRNAs. Gene ontology and pathway enrichment analysis of annotated genes showed that the differentially expressed lncRNAs were related to abscisic acid (ABA) and ethylene (ETH) biosynthesis and signal transduction, and to starch and sucrose metabolism. The upregulated lncRNAs and genes were related to ABA synthesis and its signal transduction, and to trehalose synthesis. Meanwhile, lncRNAs and genes related to ETH biosynthesis and signal transduction were suppressed. LncRNAs and genes involved in ABA metabolism were verified using quantitative real-time PCR, and the endogenous ABA content was determined via high performance liquid chromatography mass spectrometry (HPLC-MS). These results showed that ABA accumulated significantly during dehydration stress, especially in D2. Furthermore, we identified 307 dehydration stress memory lncRNAs, and the ratios of different memory types in switchgrass were similar to those in Arabidopsis and maize.ConclusionsThe molecular responses of switchgrass lncRNAs to multiple dehydration stresses were researched systematically, revealing novel information about their transcriptional regulatory behavior. This study provides new insights into the response mechanism to dehydration stress in plants. The lncRNAs and pathways identified in this study provide valuable information for genetic modification of switchgrass and other crops.Electronic supplementary materialThe online version of this article (10.1186/s12870-018-1288-3) contains supplementary material, which is available to authorized users.

A lysogenic phage, MZTP02, was produced via induction by mitomycin C from Bacillus thuringiensis (B. thuringiensis) strain MZ1. Plaques were about 3 mm in diameter with a small inner zone consisting of new B. thuringiensis colonies. Electron microscopic analysis showed that MZTP02 had a long tail (220 nm x 18 nm) and an icosahedral head (82 nm x 85 nm). MZTP02 was insensitive to organic solvents such as chloroform, and infected six B. thuringiensis strains. Its complete genome contained 15,717 base pairs (bp) with 37.55% G + C content. Two inverted terminal repeats consisting of 40 bp were 65% identical. Twenty putative open reading frames (ORFs) were found in the MZTP02 genome, and nine predicted proteins, including two terminase subunits, portal protein, minor head protein, scaffold protein, two putative membrane proteins, tail component, and minor structural protein, showed similarity to other phage proteins. But six ORFs were unique. The presence of a terminal protein at the 5'-terminus was demonstrated using proteinase K, lambda exonuclease and E. coli exonuclease III to digest the genome DNA. A TMP phylogenetic tree was constructed based on amino acid sequences from ten phages.