Fusarium fungi, including F. culmorum, cause seedling blight, foot rot, and head blight diseases of cereals, resulting in yield loss. In a screen for potential disease control organisms and agents, Pseudomonas fluorescens strains MKB 100 and MKB 249, P. frederiksbergensis strain 202, Pseudomonas sp. strain MKB 158, and chitosan all significantly reduced the extent of both wheat coleoptile growth retardation and wheat and barley seedling blight caused by F. culmorum (by 53 to 91%). Trichodiene synthase is a Fusarium enzyme necessary for trichothecene mycotoxin biosynthesis; expression of the gene encoding this enzyme in wheat was 33% lower in stem base tissue coinoculated with Pseudomonas sp. strain MKB 158 and F. culmorum than in wheat treated with bacterial culture medium and F. culmorum. When wheat and barley were grown in soil amended with either chitosan, P. fluorescens strain MKB 249, Pseudomonas sp. strain MKB 158, or culture filtrates of these bacteria, the level of disease symptoms on F. culmorum-inoculated stem base tissue (at 12 days post- F. culmorum inoculation) was >/=31% less than the level on F. culmorum-inoculated plants grown in culture medium-amended soil. It seems likely that at least part of the biocontrol activity of these bacteria and chitosan may be due to the induction of systemic disease resistance in host plants. Also, in coinoculation studies, Pseudomonas sp. strain MKB 158 induced the expression of a wheat class III plant peroxidase gene (a pathogenesis-related gene).

. Can. J. Chem. 54, 2706Chem. 54, (1976.The syntheses of P-N bonded pyrrolyl-and 2,5-dimethylpyrrolylphosphines +,P(py),-, and +ZP(Mezpy)3-z (x = 0-2) and the oxy derivatives py3PO and (Mezpy)2P(O)Cl by the reaction of potassium pyrrolide or 2,5-dimethylpyrrolide with an appropriate chlorophosphine or with POC13 are described. Molecular structures were inferred from spectroscopic data. The P-N bonded phosphines are stable to solvolytic attack by water or alcohols and do not undergo insertion reactions with CS2, but they are oxidised by oxygen and suffer nucleophilic displacement of the azole moiety by strong base. The Lewis acid BC13 cleaves the P-N bond and CH31 reacts with only one member, +2P(py), to form a phosphonium salt. Hindered rotation about the P-N bond was detected in the (2,5-dimethylpyrroly1)phosphine series, but not among the corresponding oxy derivatives. The nature of the P-N bond and trends in the basicity of the phosphorus atom are discussed. On d k r i t les syntheses de pyrrolyl et de dimethyl-2,5 pyrrolyl phosphines +,P(P~)~-, et +,P(Me2py)3-, (x = 0-2) contenant des liens P-N et des derives oxy py3P0 et (Me2py)2P(0)C1 par la rhction du pyrrolure de potassium ou du dimethyl-2,5 pyrrolure de potassium avec une chlorophosphine approprike ou avec POC13. On a propose les structures molCculaires ii partir des donn6es spectroscopiques. Les phosphines contenant un lien P-N sont stables aux attaques solvolytiques de I'eau ou des alcools et ne subissent pas de reactions d'insertion avec le CS2; ils sont toutefois oxydees par l'oxygkne et subissent des ddplacements nuclCophiles de la portion azole sous I'influence de bases fortes. L'acide de Lewis BC13 coupe le lien P-N et le CH31 r h g i t uniquement avec le +2P(py) conduisent ii un sel de phosphonium. On a detect6 un empechement ii la rotation autours du lien P-N dans la serie dimethyl-2,5 pyrrolyl phosphine; ce n'est toutefois pas le cas dans les derives oxy correspondants. On discute de la nature du lien P-N et des tendances dans la basicit6 de I'atome de phosphore.[Traduit par le journal] Introduction The N-pyrrolylphosphines and phosphine oxides are members of the azole phosphine class of compounds, where a heteroaromatic system is bonded via nitrogen to phosphorus (1). Modifications of the chemistry of the P-N bond and of the coordination properties of the phosphorus centre, as compared to dialkylaminophosphine and tris(ary1)phosphine systems, may be expected. In this paper the syntheses and reactions of pyrrolylphosphines are described. A study of metal coordination complexes will be reported later.

Most animals orient themselves in their environment through the perception of olfactory cues. In order to gain insight into the principles of olfactory processing in Drosophila, we misexpressed olfactory receptor Or43a in additional olfactory receptor neurons of the third antennal segment using enhancer trap line GH320. The behavioral response of GH320/UAS-or43a flies was changed upon benzaldehyde application. Using the T-maze assay, misexpressing flies performed a reduced avoidance reaction to benzaldehyde as compared with wild type. This reduction of avoidance could be mimicked in wild type flies by exposing them to a mixture of benzaldehyde and ethyl acetate. We therefore conclude that the application of benzaldehyde, an identified ligand of Or43a, resulted in activation of a number of glomeruli in transformed flies in addition to glomerulus DA4, which is the regular target of Or43a expressing neurons. Our results demonstrate the relevance of specific olfactory sensory input and subsequent processing in the antennal lobe for Drosophila behavior.

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