Possible roles and functions of LPL1 gene encoding lysophospholipase during early infection by Magnaporthe grisea

The rice blast fungus Magnaporthe grisea differentiates appressoria, which are required to attack its rice plant host. Clone A26, tentatively named LPL1, was previously found to be homologous to the known lysophospholipase genes from our subtractive cDNA library. The LPL1 protein had a consensus motif (GxSxG) and a catalytic triad (S, D, H) of esterases in the deduced amino acid sequence, and the protein expressed in Escherichia coli had lysophospholipase activity. To clarify the functions and possible roles of LPL1, the gene was disrupted by targeted gene replacement. The ΔLPL1 mutants formed fewer appressoria on the hydrophobic surface of GelBond film, and the appressoria had reduced turgor pressure and penetration into cells of the leaf sheath. The ΔLPL1 mutants and wild-type differentiated normal appressoria on other artificial substrata such as polycarbonate plate and on rice leaf sheath. Cytological analysis of the appressoria indicated that ΔLPL1 mutants had a delay in the disappearance of lipid droplets. These findings imply that LPL1, phospholipid metabolism, or both are involved in glycerol biosynthesis and accumulation to generate turgor pressure in the appressorium. LPL1 was, however, dispensable for full pathogenicity, suggesting that other complementary pathways or similar genes related to phospholipid metabolism probably function in M. grisea.     

Panama disease of banana occurred in Miyakojima Island,Okinawa, Japan

In 2016, in Miyakojima, Okinawa, Japan, banana plants (Musa?×?paradisiaca) ‘Shima-banana’ developed yellowing and wilt associated with vascular discoloration of the pseudostems. Fusarium oxysporum, identified based on morphological characters, was frequently isolated from the vascular tissue of the infected plant and reproduced the original symptoms on ‘Shima-banana’ after drench inoculation with a spore suspension. Thereby, we determined that the disease is Panama disease caused by F. oxysporum. This is the first official report of Panama disease (Panama-byo in Japanese) of banana in Japan.     

Control of clubroot of crucifers by Phoma glomerata and its product epoxydon

Phoma glomerata strain JCM9972 controls clubroot of cruciferous crops caused by Plasmodiophora brassicae and the activity depends upon epoxydon (5-hydroxy-3-(hydroxymethyl)-7-oxabicyclo [4.1.0]hept-3-en-2-one) produced by the strain.     

Low diversity in the native populations of Croton tetradenius Baill. when using SNP markers: a future crop with an insecticidal activity

Genetic Resources and Crop Evolution - Croton tetradenius Baill. is an aromatic plant species whose essential oils have high economic importance. Its incorporation into Active Germplasm Banks is...     

Use of fluorescent proteins to visualize interactions between the Bakanae disease pathogen <Emphasis Type="Italic">Gibberella fujikuroi</Emphasis> and the biocontrol agent <Emphasis Type="Italic">Talaromyces</Emphasis> sp. KNB-422

Talaromyces sp. isolate KNB-422, isolated from a rice seedling, is a biofungicidal agent effective against several seedborne pathogens of rice including Gibberella fujikuroi, which causes Bakanae disease. Because the fungal mode of action (MOA) has not yet been clarified, we used the fluorescent protein markers GFP and RFP to visualize cell–cell interactions between the biocontrol agent and the pathogen G. fujikuroi. In slide culture, the hyphal cell wall of G. fujikuroi collapsed, and fluorescence of its cytoplasm disappeared 3 days after contact with hyphae of Talaromyces sp. On inoculated rice plants, both fungi occupied the same regions of coleoptiles and roots, where the biocontrol effect of Talaromyces sp. must be exerted. Our observations suggest that the MOA of Talaromyces sp. is mycoparasitic.     

Controlled-release systems for the delivery of cyromazine into water surface

Controlled-release systems (CRSs) for the insect growth regulator cyromazine (Neporex), as a larvicide against Culex pipiens (Culicidae) mosquitoes, are under development. Despite promising results obtained previously for both in vitro (dissolution tests) and in vivo systems (mosquito larvae floating on water surfaces), it was evident that the CRSs did not remain afloat for sufficiently long times. The present study was thus conducted to determine the relationship between the process parameters and the potential contact time of the active ingredient with the mosquito larvae. A series of CRSs were prepared by an extrusion process, alone or in combination with a supplementary coating. The active ingredient was incorporated into the matrix or the coating. The matrix comprised low-density polyethylene 600 and perlite, and the coating, a polyurea with or without the addition of paraffin wax. The study showed that the cumulative release of the active ingredient into water could be controlled by manipulating the preparation techniques, the types and concentrations of inert materials, and the concentration of the active ingredient.     

Postharvest heat treatment as a possible means of reducing superficial scald of apples

A pre-storage heat treatment of 38°C for four days applied to apples (Malus domestica cv. ‘Granny Smith’) before standard storage in air at 0°C was found to inhibit the development of superficial scald. Apples stored for three months after heat treatment had superficial scald levels similar to those of apples dipped in diphenylamine (DPA), while all control apples had scald. This inhibitory effect was no longer apparent after five months of storage. The heat treatment inhibited the accumulation of α-farnesene and conjugated trienes in apple cuticle while DPA inhibited only a-farnesene oxidation. Heat treated apples also had lower polyphenoloxidase activity in the peel than untreated apples. This treatment may be a substitute for chemical treatments for short-term storage of scald- susceptible apple varieties.     

The degradation of diflubenzuron and its chief metabolites in soils. Part II: Fate of 4-chlorophenylurea

The fate of 4-chlorophenylurea in soils was studied with two preparations: one labelled with ¹⁴C in the phenyl ring and the other in the carbonyl group. The initial dose of 1 mg kg^?1 decreased to 50% in about 5 weeks in aerobic sandy clay and in about 16 weeks in anaerobic hydrosoil. Soil treatment with each of the preparations resulted in the release of [¹⁴C]carbon dioxide, pointing to decarbonylation and ring opening. The fraction of non-extractable (soil-bound) radioactivity increased during incubation. Quantities of ring-¹⁴C-labelled and carbonyl-¹⁴C-labelled bound residues differed strongly in the aerobic soil but only slightly in the anaerobic hydrosoil. It is assumed that two sorts of bound residues are formed from 4-chlorophenylurea: one is fairly stable and might consist of bound 4-chloroaniline or its transformation products, whereas the other is presumed to be a degradable derivative of 4-chlorophenylurea.