The OsmiR396–OsGRF8–OsF3H‐flavonoid pathway mediates resistance to the brown planthopper in rice (Oryza sativa)

Multi‐functional microRNAs (miRNAs) are emerging as key modulators of plant–pathogen interactions. Although the involvement of some miRNAs in plant–insect interactions has been revealed, the underlying mechanisms are still elusive. The brown planthopper (BPH) is the most notorious rice (Oryza sativa)‐specific insect that causes severe yield losses each year and requires urgent biological control. To reveal the miRNAs involved in rice–BPH interactions, we performed miRNA sequencing and identified BPH‐responsive OsmiR396. Sequestering OsmiR396 by overexpressing target mimicry (MIM396) in three genetic backgrounds indicated that OsmiR396 negatively regulated BPH resistance. Overexpression of one BPH‐responsive target gene of OsmiR396, growth regulating factor 8 (OsGRF8), showed resistance to BPH. Furthermore, the flavonoid contents increased in both the OsmiR396‐sequestered and the OsGRF8 overexpressing plants. By analysing 39 natural rice varieties, the elevated flavonoid contents were found to correlate with enhanced BPH resistance. Artificial applications of flavonoids to wild type (WT) plants also increased resistance to BPH. A BPH‐responsive flavanone 3‐hydroxylase (OsF3H) gene in the flavonoid biosynthetic pathway was proved to be directly regulated by OsGRF8. A genetic functional analysis of OsF3H revealed its positive role in mediating both the flavonoid contents and BPH resistance. And analysis of the genetic correlation between OsmiR396 and OsF3H showed that down‐regulation of OsF3H complemented the BPH resistance characteristic and simultaneously decreased the flavonoid contents of the MIM396 plants. Thus, we revealed a new BPH resistance mechanism mediated by the OsmiR396–OsGRF8–OsF3H–flavonoid pathway. Our study suggests potential applications of miRNAs in BPH resistance breeding.     

Nucleotide polymorphism and molecular evolution of the LRR region in potato late blight resistance gene Rpi-blb2

Rpi-blb2, which is originally derived from Solanum bulbocastanum, is a broad-spectrum potato late blight resistance gene and belongs to the NBS-LRR family. Here, the LRR homologues of Rpi-blb2 were cloned with PCR method from 40 potato cultivars (including 20 resistant potato cultivars and 20 susceptible ones) and 7 wild potato populations. Then, the similarities of the sequences, polymorphic (segregating) sites, and nucleotide diversities were estimated by bioinformatic methods. The results showed that high nucleotide polymorphism and some hot-spot mutations existed in the LRR region of Rpi-blb2. The test of Ka/Ks ratio showed that the function of LRR was conserved because of the purifying selection, although different positions of the Rpi-blb2 LRR region were under different selection pressures. Moreover, the LRR region of Rpi-blb2 had no clear differentiation between the cultivated and wild potatoes.     

Enhanced secreting expression and improved properties of a recombinant alkaline endoglucanase cloned in <Emphasis Type="Italic">Escherichia coli</Emphasis>

An alkaline endoglucanase from Bacillus akibai III-3A was successfully expressed in Escherichia coli in active form, and secretion was greatly enhanced by addition of 5 g/l ethylenediamine tetraacetic acid (EDTA) to the culture medium at the induction time of 12 h. Under the optimal culture conditions, extracellular and total endoglucanase activities were 18.5 and 31.2 U/ml, respectively. Both the recombinant and native enzymes exhibited similar properties with respect to broad pH stability, good thermostability, and resistibility to various metal ions and reagents examined. However, unlike the native endoglucanase that was partly inhibited by sodium dodecyl sulfate (SDS), the recombinant enzyme had good resistibility to SDS, being very stable in the commercial detergents, and no decrease in residual activity was observed in 0.2% (w/v) laundry detergent, indicating that it was suitable for application in detergents industry.     

Altered Gut Microbiota Composition Associated with Eczema in Infants

Eczema is frequently the first manifestation of an atopic diathesis and alteration in the diversity of gut microbiota has been reported in infants with eczema. To identify specific bacterial communities associated with eczema, we conducted a case-control study of 50 infants with eczema (cases) and 51 healthy infants (controls). We performed high-throughput sequencing for V3–V4 hypervariable regions of the 16S rRNA genes from the gut fecal material. A total of 12,386 OTUs (operational taxonomic units) at a 97% similarity level were obtained from the two groups, and we observed a difference in taxa abundance, but not the taxonomic composition, of gut microbiota between the two groups. We identified four genera enriched in healthy infants: Bifidobacterium, Megasphaera, Haemophilus and Streptococcus; and five genera enriched in infants with eczema: Escherichia/Shigella, Veillonella, Faecalibacterium, Lachnospiraceae incertae sedis and Clostridium XlVa. Several species, such as Faecalibacterium prausnitzii and Ruminococcus gnavus, that are known to be associated with atopy or inflammation, were found to be significantly enriched in infants with eczema. Higher abundance of Akkermansia muciniphila in eczematous infants might reduce the integrity of intestinal barrier function and therefore increase the risk of developing eczema. On the other hand, Bacteroides fragilis and Streptococcus salivarius, which are known for their anti-inflammatory properties, were less abundant in infants with eczema. The observed differences in genera and species between cases and controls in this study may provide insight into the link between the microbiome and eczema risk.     

High-Density Genetic Linkage Map Construction and QTL Mapping of Grain Shape and Size in the Wheat Population Yanda1817 × Beinong6

High-density genetic linkage maps are necessary for precisely mapping quantitative trait loci (QTLs) controlling grain shape and size in wheat. By applying the Infinium iSelect 9K SNP assay, we have constructed a high-density genetic linkage map with 269 F ₈ recombinant inbred lines (RILs) developed between a Chinese cornerstone wheat breeding parental line Yanda1817 and a high-yielding line Beinong6. The map contains 2431 SNPs and 128 SSR & EST-SSR markers in a total coverage of 3213.2 cM with an average interval of 1.26 cM per marker. Eighty-eight QTLs for thousand-grain weight (TGW), grain length (GL), grain width (GW) and grain thickness (GT) were detected in nine ecological environments (Beijing, Shijiazhuang and Kaifeng) during five years between 2010–2014 by inclusive composite interval mapping (ICIM) (LOD≥2.5). Among which, 17 QTLs for TGW were mapped on chromosomes 1A, 1B, 2A, 2B, 3A, 3B, 3D, 4A, 4D, 5A, 5B and 6B with phenotypic variations ranging from 2.62% to 12.08%. Four stable QTLs for TGW could be detected in five and seven environments, respectively. Thirty-two QTLs for GL were mapped on chromosomes 1B, 1D, 2A, 2B, 2D, 3B, 3D, 4A, 4B, 4D, 5A, 5B, 6B, 7A and 7B, with phenotypic variations ranging from 2.62% to 44.39%. QGl.cau-2A.2 can be detected in all the environments with the largest phenotypic variations, indicating that it is a major and stable QTL. For GW, 12 QTLs were identified with phenotypic variations range from 3.69% to 12.30%. We found 27 QTLs for GT with phenotypic variations ranged from 2.55% to 36.42%. In particular, QTL QGt.cau-5A.1 with phenotypic variations of 6.82–23.59% was detected in all the nine environments. Moreover, pleiotropic effects were detected for several QTL loci responsible for grain shape and size that could serve as target regions for fine mapping and marker assisted selection in wheat breeding programs.     

Acute activation of acid ceramidase affects cytokine-induced cytotoxicity in rat islet β-cells

Ceramidase hydrolyzes ceramide and produces sphingosine as a substrate of sphingosine kinase (SPHK), which transforms sphingosine to sphingosine-1-phosphate. It has been reported that cytokines elicit SPHK activation in rat β-cells. As a sphingosine provider, ceramidase should also be activated. In our previous work, we showed that the increase in mRNA and protein levels in cytokine-treated INS-1 rat β-cells resulted in chronic activation of neutral ceramidase. Here we found that acid ceramidase (AC) is activated by cytokines at an early stage via tyrosine phosphorylation. In addition, basal AC activity was first detected in INS-1 cells and isolated rat islets, and cytokine-induced cell growth was significantly repressed when AC was pharmacologically inhibited.     

Morphology,ontogeny and molecular phylogeny of a new brackish water ciliate Bakuella subtropica sp. n. (Ciliophora,Hypotricha) from southern China

This paper investigates the morphology, ontogenesis and small subunit (SSU) rRNA gene-based phylogeny of a new urostylid ciliate, Bakuella subtropica sp. n., discovered from the estuary of the Pearl River in Guangzhou, southern China. The new species is diagnosed by its elongate body, one buccal and one parabuccal cirrus, midventral complex comprised of 9–23 midventral pairs and one or two midventral rows extending to four fifths of body length, yellow-brown to yellow-greenish cortical granules and an estuary habitat. Its main ontogenetic features are: (1) in the proter, the parental adoral zone of membranelles is completely renewed by new structures and old midventral pairs join the formation of frontal-midventral-transverse cirral anlagen (FVT-anlagen); (2) in the opisthe, the oral primordium originates apokinetally, FVT-anlagen are formed besides and some old midventral cirri join the formation; (3) the anlagen for marginal rows and dorsal kineties develop intrakinetally; and (4) the numerous macronuclear nodules fuse into a single mass before dividing. Based on the SSU rDNA sequences, phylogenetic analyses show a close relationship between Bakuella subtropica sp. n., Apobakuella and Neobakuella, forming a clade separated from the other genera in the family Bakuellidae. Available morphological and ontogenetic data challenge the monophyly of Bakuellidae.     

Tetranor PGDM, an abundant urinary metabolite reflects biosynthesis of prostaglandin D2 in mice and humans

Prostaglandin D(2) (PGD(2)) is a cyclooxygenase (COX) product of arachidonic acid that activates D prostanoid receptors to modulate vascular, platelet, and leukocyte function in vitro. However, little is known about its enzymatic origin or its formation in vivo in cardiovascular or inflammatory disease. 11,15-dioxo-9alpha-hydroxy-2,3,4,5-tetranorprostan-1,20-dioic acid (tetranor PGDM) was identified by mass spectrometry as a metabolite of infused PGD(2) that is detectable in mouse and human urine. Using liquid chromatography-tandem mass spectrometry, tetranor PGDM was much more abundant than the PGD(2) metabolites, 11beta-PGF(2alpha) and 2,3-dinor-11beta-PGF(2alpha), in human urine and was the only endogenous metabolite detectable in mouse urine. Infusion of PGD(2) dose dependently increased urinary tetranor PGDM > 2,3-dinor-11beta-PGF(2alpha) > 11beta-PGF(2alpha) in mice. Deletion of either lipocalin-type or hemopoietic PGD synthase enzymes decreased urinary tetranor PGDM. Deletion or knockdown of COX-1, but not deletion of COX-2, decreased urinary tetranor PGDM in mice. Correspondingly, both PGDM and 2,3-dinor-11beta-PGF(2alpha) were suppressed by inhibition of COX-1 and COX-2, but not by selective inhibition of COX-2 in humans. PGD(2) has been implicated in both the development and resolution of inflammation. Administration of bacterial lipopolysaccharide coordinately elevated tetranor PGDM and 2,3-dinor-11beta-PGF(2alpha) in volunteers, coincident with a pyrexial and systemic inflammatory response, but both metabolites fell during the resolution phase. Niacin increased tetranor PGDM and 2,3-dinor-11beta-PGF(2alpha) in humans coincident with facial flushing. Tetranor PGDM is an abundant metabolite in urine that reflects modulated biosynthesis of PGD(2) in humans and mice.