No abstract

Brown root rot (BRR), caused by the white rot fungus Phellinus noxius, is an epidemic disease of diverse broadleaved and coniferous tree species in many tropical and subtropical regions. Flooding and trenching control measures are difficult to implement, and chemical controls can have an adverse impact on ecosystems. Previous studies have provided in vitro evidence for the potential use of Trichoderma spp. for biocontrol of BRR. Here, we analyzed the in vitro antagonistic and mycoparasitic abilities of four Trichoderma spp. isolates against four P. noxius isolates in dual culture and Ficus microcarpa wood blocks. A convenient inoculation system based on root inoculation of a highly susceptible loquat (Eriobotrya japonica) with P. noxius-colonized wheat-oat grains was developed to examine the effect of Trichoderma treatment in planta. Preventive application of Trichoderma asperellum TA, the isolate showing high antagonistic activity in vitro, was effective in preventing and delaying the wilting of P. noxius-inoculated loquat cuttings in greenhouse trials. To understand the specific niche in which T. asperellum TA interacts with P. noxius, KOH-aniline blue fluorescence microscopy was used to investigate the colonization of loquat roots by P. noxius and/or T. asperellum TA. Dilution plating assays were also conducted to quantify Trichoderma populations in the rhizosphere and potting mix. T. asperellum TA was able to robustly establish in the rhizosphere and potting mix but with scarce root penetration limited to the superficial layer. We discuss the timing and strategy for applying antagonistic Trichodema sp. on living trees or in BRR-infested areas for BRR management.

Near-field scanning optical microscopy (NSOM) enables observation of light-matter interaction with a spatial resolution far below the diffraction limit without the need for a vacuum environment. However, modern NSOM techniques remain subject to a few fundamental restrictions. For example, concerning the aperture tip (a-tip), the throughput is extremely low, and the lateral resolution is poor; both are limited by the aperture size. Meanwhile, with regard to the scattering tip (s-tip), the signal-to-noise ratio (SNR) appears to be almost zero; consequently, one cannot directly use the measured data. In this work, we present a plasmonic tip (p-tip) developed by tailoring subwavelength annuli so as to couple internal radial illumination to surface plasmon polaritons (SPPs), resulting in an ultrastrong, superfocused spot. Our p-tip supports both a radial symmetric SPP excitation and a Fabry-Pérot resonance, and experimental results indicate an optical resolution of 10 nm, a topographic resolution of 10 nm, a throughput of 3.28%, and an outstanding SNR of up to 18.2 (nearly free of background). The demonstrated p-tip outperforms state-of-the-art NSOM tips and can be readily employed in near-field optics, nanolithography, tip-enhanced Raman spectroscopy, and other applications.

[structure: see text] A push-pull conjugated molecule, 2,7-bis(1H-pyrrol-2-yl)ethynyl-1,8-naphthyridine (BPN), has been designed to bind selectively with octyl glucopyranoside (OGU). The BPN/OGU quadruple hydrogen-bonding complex adopts a rigid BPN conformation in which the proton donor (d) and acceptor (a) relays (daad) are resonantly conjugated through the ethynyl bridge, inducing pi-electron delocalization, i.e., a charge transfer effect. The excellent photophysical properties make BPN a highly sensitive probe for monitoring glucopyranoside to a detection limit of approximately 100 pM.