Transformation of Stylosanthes spp. using Agrobacterium tumefaciens

Tumours were incited on leaf sections of Stylosanthes humilis, S. hamata, S. guianensis and S. scalra following infection by Agrobacterium tumefaciens. The suitability of 2 binary vectors (pGA472, BIN6) for gene transfer in S. humilis was tested and kanamycin-resistant tumour tissue was obtained from infected leaf pieces. The presence and expression of the neomycin phosphotransferase (NPT II) gene in the plant cells was demonstrated by hybridization of the coding region of the NPT II gene of the transposon Tn5 to DNA and RNA of kanamycin resistant tumours and by detection of significant NPT II activity in tissue extracts. Tumours also produced teratomatous shoots expressing the NPT II gene, but these could not be rooted

Human hypervariable minisatellite probes detect DNA polymorphisms in the fungus Colletotrichum gloeosporioides

The human minisatellite probes for hypervariable regions within the genome are able to detect restriction fragment length polymorphisms between subgroups of the filamentous fungus Colletotrichum gloeosporioides. The two types of this pathogen that cause anthracnose on Stylosanthes spp. in Australia were distinguishable using the polycore probes 33.6 and 33.15. This is the first report of the use of these versatile probes for detecting polymorphic DNA regions in fungi

The effect of infection by erysiphe graminis f.sp. hordei on protein synthesis in vivo in leaves of barley

The effect of infection by Erysiphe graminis f.sp. hordei on protein synthesis in a susceptible cultivar of Hordeum vulgare has been studied using in vivo labelling. Results have indicated a decline in protein synthesis in the chloroplasts at 1, 3 and 5 days after inoculation and in the cytoplasm at 3 and 5 days after inoculation. The most extensive effect of the pathogen was on the synthesis of a 32 Kd protein synthesised in the chloroplasts

Accumulation of systemic fungicides and other solutes by haustorial complexes isolated from Pisum sativum infected with Erysiphe pisi

Haustorial complexes, isolated from pea leaves infected with powdery mildew, were incubated with individual C‐labelled systemic fungicides or other solutes, and the accumulation of these compounds by the complexes was assessed following filter centrifugation of the products through silicone oil. Inulincarboxylic acid and butyric acid were not absorbed; glucose, sucrose, acetic acid and glycerol were absorbed very slowly by the complexes. All the systemic fungicides, which included nuarimol, fenarimol, dimethirimol, ethirimol, and other pyrimidine‐based analogues, were accumulated against large concentration gradients (30‐1500 fold). The fatty acids, linoleic and lauric, were also readily accumulated. The accumulation of the fatty acids and fungicides was usually complete within 5–15 min. The degree of accumulation of all the solutes was significantly correlated with their lipophilicity, indicating that partitioning of compounds into sub‐cellular lipids was the major mechanism determining accumulation by the complexes. The cations 2‐hydroxyethylarnmonium and 1‐methylpyridinium were also accumulated against large concentration gradients (18‐and 46‐fold, respectively) but less rapidly than the fungicides. The significance of these findings for the systemic distribution and mode of action of fungicides is discussed

Efficient transformation with regeneration of the tropical pasture legume Stylosanthes humilis using Agrobacterium rhizogenes and a Ti plasmid-binary vector system

Agrobacterium rhizogenes carrying the binary Ti plasmid vector pGA492 was used to transform leaf and stem explants of the tropical pasture legume Stylosanthes humilis. Conditions which yielded kanamycin resistant roots at a frequency of up to 86% and subsequent plant regeneration at a frequency of 23% were defined. Transgenic plants were fertile and either grew normally or had stunted growth but otherwise showed only minor morphological abnormalities. Transgenic plants with normal phenotypes were obtained in the progeny of the primary regenerants. The presence of active neomycin phosphotransferase enzyme activity and binary vector DNA and TL-DNA was demonstrated in the regenerated plants. Evidence for the independent transfer of binary vector and TL-DNA was also obtained. This high frequency production of transgenic plants of S. humilis is a major improvement over previous methods using disarmed strains of A. tumefaciens as helper

Genome sequences of six Wheat-infecting fusarium species isolates

Fusarium pathogens represent a major constraint to wheat and barley production worldwide. To facilitate future comparative studies of Fusarium species that are pathogenic to wheat, the genome sequences of four Fusarium pseudograminearum isolates, a single Fusarium acuminatum isolate, and an organism from the Fusarium incarnatum-F. equiseti species complex are reported

Hexitols as major intermediates of glucose assimilation by mycelium of Puccinia graminis

Mycelium of Puccinia graminis was grown for 4 d on 200 mM D-[U-14C]glucose followed by a cold chase for 30 h. Analysis of cellular metabolites during the chase indicated significant turnover only in carbohydrates soluble in 80% (w/v) ethanol. A kinetic analysis of the depletion of [14C] in pools of free sugars and sugar alcohols indicated that the trehalose pools and a small proportion (12-16%) of the mannitol and glucitol pools did not turn over, whilst pools of glucose, fructose, and the remainder of the hexitols became totally,depleted of label during the chase. Because the [14C] was totally lost from the pools of glucose and fructose prior to the hexitols, it was deduced that both of these hexoses were precursors of the hexitols. Estimation of the carbon fluxes through pools indicated that 52, 36 and 16% of the carbon from glucose was assimilated via glucitol, fructose and mannitol respectively, demonstrating that glucitol could not have originated from fructose as sole precursor. After offering D-[U-14C]glucitol, [14C] was assimilated into trehalose phosphate, glucans and amino acids, but not into free glucose or fructose. These data indicate that hexitols are quantitatively important intermediates during the assimilation of glucose by Puccinia graminis