AIMS AND SCOPE FEMS Microbiology Letters aims to publish articles that merit urgent publication by virtue of their originality. MiniReviews cover all aspects of microbiology. Research Letters cover the following subject categories:  Biotechnology  Environmental microbiology; plant-microbe interactions  Eukaryotic cells  Evolution, taxonomy and typing  Genetics and molecular biology  Genomics and bioinformatics  Pathogenicity including veterinary microbiology  Physiology and biochemistry MiniReviews  Commissioned by six MiniReviews Editors, who cover wide specialist areas, which refl ect the various subject categories covered in the journal.

A new type of sulfobetaine with double alkyl polyoxyethylene (n) ether chains, dicoconut oil alcohol polyoxethylene (n) ether methylhydroxylpropyl sulfobetaine (diC12–14EnHSB) was synthesized using a commercial nonionic surfactant, coconut oil alcohol polyoxethylene (n) ether, as raw material and its properties as a surfactant for enhanced oil recovery (EOR) in the absence of alkali was studied. The purified product is a mixture of homologues with mainly C12/C12, C12/C14 and C14/C14 alkyl chains and widely distributed EO chains (n = 2.2 on average) with an average molar mass of 742.6 g/mol. The diC12–14E2.2HSB has an improved aqueous solubility at 25 °C compared with didodecylmethylhydroxylpropyl sulfobetaine (diC12HSB), a homologue without an EO chain, and is highly surface active as reflected by its low CMC (4.6 × 10−6 mol/L), high saturated adsorption (6.8 × 10−10 mol/cm2) and small cross sectional area (0.24 nm2/molec.) at the air/water interface. With a hydrophile–lipophile balance well matched with Daqing crude oil/connate water system, the sulfobetaine can reduce Daqing crude oil/connate water interfacial tension to ultra‐low values at 45 °C in the absence of alkali, and displays a low saturated adsorption at the sandstone/water interface (0.0024 mmol/g), reduced by 69 and 92 % respectively in comparison with that of the corresponding carboxyl betaine, diC12–14E2.2B and its homologue without an EO chain, didodecylmethylcarboxyl betaine (diC12B). With these excellent properties diC12–14E2.2HSB gives a high tertiary recovery, 18.4 % original oil in place, when mixed with other hydrophobic and hydrophilic sulfobetaines in surfactant‐polymer (SP) flooding free of alkali. The insertion of EO chains in combination with the replacement of carboxyl betaine by sulfobetaine is therefore very efficient for improving the properties of the double chain hydrophobic carboxyl betaines as surfactants for SP flooding free of alkali.

A defence response can be induced by nonpathogenic Fusarium oxysporum CS-20 in several crops, but the molecular mechanism has not been clearly demonstrated. In the present study, we analysed the defence mechanism of a susceptible cucumber cultivar (Cucumis sativus L. 9930) against a pathogen (F. oxysporum f. sp. cucumerinum) through the root precolonization of CS-20. A challenge inoculation assay indicated that the disease severity index (DSI) was reduced, ranging from 18.83 to 61.67 in comparison with the pathogen control. Root colonization analysis indicated that CS-20 clearly did not appear to influence the growth of cucumber seedlings. Quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) revealed that CS-20-mediated defence response was activated by PR3, LOX1 and PAL1 and the pathogenmediated resistance response was regulated by PR1 and PR3. Moreover, both nonpathogenic and pathogenic F. oxysporum were able to upregulate NPR1 expression. In contrast to a pathogen, CS-20 can activate the Ca 2+ /CaM signal transduction pathway, and the gene expression of both CsCam7 and CsCam12 increased significantly. The gene expression analysis indicated that CS-20 strongly enhanced the expression of PR3, LOX1, PAL1, NPR1, CsCam7 and CsCam12 after inoculation. Overall, the defence response induced by CS-20 can be controlled by multiple genes in the cucumber plant.

Velvet genes play critical roles in the regulation of diverse cellular processes. In current study, we identified the gene FocVel1, a homolog of Fusarium graminearum VelA, in the plant pathogenic fungus F. oxysporum f. sp. cucumerinum. This pathogen causes the destructive disease called cucumber Fusarium wilt (CFW), which severely affects the production and marketing of this vegetable worldwide. Transcript analyses revealed high expression of FocVel1 during conidiophore development. Disruption of the FocVel1 gene led to several phenotypic defects, including reduction in aerial hyphal formation and conidial production. The deletion mutant ΔFocVel1 showed increased resistance to both osmotic stress and cell wall-damaging agents, but increased sensitivity to iprodione and prochloraz fungicides, which may be related to changes in cell wall components. In the process of biofilm formation in vitro, the mutant strain ΔFocVel1 displayed not only a reduction in spore aggregation but also a delay in conidial germination on the polystyrene surface, which may result in defects in biofilm formation. Moreover, pathogenicity assays showed that the mutant ΔFocVel1 exhibited impaired virulence in cucumber seedlings. And the genetic complementation of the mutant with the wild-type FocVel1 gene restored all the defects of the ΔFocVel1. Taken together, the results of this study indicated that FocVel1 played a critical role in the regulation of various cellular processes and pathogenicity in F. oxysporum f. sp. cucumerinum.

Laccases are blue copper oxidases (E.C. 1.10.3.2) that catalyze the one-electron oxidation of phenolics, aromatic amines, and other electron-rich substrates with the concomitant reduction of O2 to H2O. A novel laccase gene pclac2 and its corresponding full-length cDNA were cloned and characterized from Phytophthora capsici for the first time. The 1683 bp full-length cDNA of pclac2 encoded a mature laccase protein containing 560 amino acids preceded by a signal peptide of 23 amino acids. The deduced protein sequence of PCLAC2 showed high similarity with other known fungal laccases and contained four copper-binding conserved domains of typical laccase protein. In order to achieve a high level secretion and full activity expression of PCLAC2, expression vector pPIC9K with the Pichia pastoris expression system was used. The recombinant PCLAC2 protein was purified and showed on SDS-PAGE as a single band with an apparent molecular weight ca. 68 kDa. The high activity of purified PCLAC2, 84 U/mL, at the seventh day induced with methanol, was observed with 2,2′-azino-di-(3-ethylbenzothialozin-6-sulfonic acid) (ABTS) as substrate. The optimum pH and temperature for ABTS were 4.0 and 30 °C, respectively. The reported data add a new piece to the knowledge about P. Capsici laccase multigene family and shed light on potential function about biotechnological and industrial applications of the individual laccase isoforms in oomycetes.