Legume seed protein extraction,processing, and end product characteristics

Because of the difficulties in growing soybean in many parts of the world, other leguminosae crops (fababean, pea, lentil, lupine, bean chickpea, cow pea, etc.) are now being studied as new protein sources. They generally have a high protein content and a satisfactory amino acid composition. The studies which have led to the development of industrial flow sheets for protein extraction have mainly been carried out on pea (Pisum sativum), fababean (Vicia faba), and lupine (Lupinus albus). The processes generally used are (1) pin-milling plus air-classification which when applied to starch-rich legume seeds (pea, fababean), results in concentrates (defined as having protein contents of 60–75%), and (2) wet processes which produce isolates (defined as having protein contents of 90% to 95%). By air-classification, concentrates having 68% and 65% protein can be obtained, respectively, from fababean (31% protein) and pea (21% protein). Isolates, prepared by extraction of the flour proteins with alkaline solution followed by acid precipitation, have a protein content (N × 6.25) generally between 90% and 96% and a protein recovery yield varying between 60% and 65%. As a rule, isolates resulting from ultrafiltered extracts have a higher protein content. From the nutritional evaluation of these two types of products, concentrates and isolates, it appears that wet processes are more efficient for eliminating antinutritional factors. α-galactosides and glycosides are present in isolates only in traces. As for trypsin inhibitors and haemagglutinins, only one third of the activities in the flour remained in the isolates (in dry processes, the residual levels of these antinutritional factors were higher). From the studies of their functional properties, it appears that isolates and concentrates from sources such as fababean and peas, produced by the new processes described, are to some extent complementary or equivalent in their functional properties to those of the soybean, particularly for emulsifying and foaming purposes. These observations should encourage the development of these new processes.     

Composition and nutritional quality of pea (Pisum sativum L.), faba bean (Vicia faba L. spp. minor) and lentil (Lens culinaris Medik.) meals,protein concentrates and isolates

Pea (Pisum sativum L.), faba bean (Vicia faba L. spp. minor), and lentil (Lens culinaris Medik.) meals, protein concentrates and isolates were analyzed for proximate composition, oligosaccharides, and amino acid composition. Protein quality was evaluated using a mouse bio-assay. The concentrates contained 59.2 to 70.6% and the isolates 86.7 to 90.8% protein (N × 6.25) on moisture-free basis. Glucose, sucrose, raffinose, stachyose and verbascose were present in the highest concentrations in the protein concentrates (7.1 to 11.1%), the pea protein concentrate contained 8.7% sugars and faba bean and lentil protein concentrates 7.1% and 6.6% respectively. The protein isolates were almost free (containing less than 0.79%) of the sugars. Amino acid composition of the meals, concentrates and isolates showed, as expected, sulfur-amino acid deficiency (about two thirds of the rat requirement), which was probably largely responsible for the low protein efficiency ratios (0.75 to 1.18), and net protein ratios (0.25 to 0.73) of the three products, compared to values of 2.56 and 2.18 respectively obtained for casein. The protein digestibilities of the meals, concentrates and isolates (81 to 90%) were similar to that of casein (87%). The poor growth-promoting abilities of the meals, concentrates and isolates were possibly also due to growth-depressing factors such as tannins, trypsin inhibitors and hemagglutinins present, particularly in faba bean and lentil.     

The influence of the system of silage harvesting and feeding and the use of protected protein on milk production

The study compared two systems of silage harvesting, direct-cutting flail harvesting (flail-direct) or pre-cutting, followed by wilting and collection by a meter-chop harvester (precision-wilted). Each silage was self or easy fed to dairy cows. In addition, the response to protected soya bean meal included in the supplementary concentrate was also examined. Approximately 400 t of each of the two silages were produced from the same swards under good weather conditions with formic acid applied as an additive. The resulting silages were well preserved and had mean particle lengths of 43 and 29-mm, and D-values of 0-74 and 0-71 for the flail-direct and precision-wilted silages, respectively. During a 159-d feeding period commencing on 5 November, the silages were offered to 88 British Friesian cows in a 2³ factorial design, continuous feeding experiment. The cows calved during the experiment and had a mean calving date of 18 January. The feeding treatments involved both silage types, two systems of silage feeding (self and easy) and two sources of protein in the supplementary concentrate given after calving (soya bean or 100 g kg^-1 protected soya bean). No concentrates were offered pre-calving and all animals were given 7.6 kg d^-1 concentrates post-calving. There were no significant interactions between the system of silage harvesting and feeding. Animals on the precision-wilted silage consumed 14% more silage dry matter (10.9 vs. 9.6 kg DM d^-1) over the total period and by the end of the experiment were producing 7% less milk per day (25.4 vs. 27.2 kg). However, the responses in the output of total milk constituents (fat and protein) were lower than those obtained in milk yield. Animals offered silage by self feeding had similar dry matter intakes, but produced marginally less milk than those easy-fed. Ration digestibility and nitrogen utilization data, obtained from a concurrent change-over design experiment, suggested that the energy from the precision-wilted silage was less efficiently utilized for milk production. There was no significant response in either milk yield or composition to the inclusion of protected soya bean in the supplement.     

Hazard from reliance on cruciferous hosts as sources of major gene-based resistance for managing blackleg (Leptosphaeria maculans) disease

The host range of eighty isolates of Leptosphaeria maculans obtained from various cruciferous hosts in Western Australia was tested by inoculating onto cotyledons of 13 cruciferous hosts, including six Brassica species and one interspecific line of Brassica. These field isolates produced highly variable responses across the hosts tested. One or more isolates overcame the resistance in each of the tested Brassica species with the B-genome, such as B. juncea, B. nigra and B. carinata and of other species tested, including Raphanus raphanistrum, Crambe abyssinica, Sinapis alba, Eruca vesicaria and Raphanus sativus. None of the isolates tested to date were virulent on Camelina sativa. Of all isolates, 48.8% (and 75% of isolates taken from cultivars containing single dominant gene-based resistance derived from B. rapa ssp. sylvestris) showed high virulence against canola cultivars containing this single dominant gene-based resistance. There was a relationship between host source of isolates with virulence. Results clearly illustrated that extensive levels of variation exist within L. maculans populations in Western Australia such that major gene-based resistance in a range of these hosts could be rapidly overcome by one or more field populations of the pathogen. It is noteworthy that this ability to overcome such resistance in various cruciferous hosts was found to be present in certain isolates in the L. maculans population even prior to exposure of the pathogen to such major gene-based resistance sources in commercial crops. Our results indicated that seeking major gene-based resistance from within cruciferae for B. napus canola breeding, including from taxa which to date have shown resistance to L. maculans when used in the field as rotation, industrial oil or green manure crops, may lead to both breakdown and wastage of these valuable sources of resistance to blackleg disease.     

Improvement of the functionality of vegetable proteins by controlled enzymatic hydrolysis

Vegetable proteins are available to the food industry in various forms, such as flours, concentrates, isolates, and TVP (textured vegetable protein). However, the functional properties of these products are not always optimal and need improvement for certain applications. In recent years it has been demonstrated that a limited enzymatic hydrolysis offers a convenient and specific means of improving certain functional properties of vegetable proteins. The hydrolysis reaction is controlled by the degree of hydrolysis (DH) which is defined as the percentage of peptide bonds cleaved. Under neutral or slightly alkaline conditions, DH can be monitored continuously by the pH-stat technique, since the amount of base necessary to maintain a constant pH is proportional to DH. The reaction is terminated at a preset DH-value to obtain the desired properties of the hydrolysate.Protein products from soya bean, faba bean, and potato were hydrolysed to DH 0%, 3% and 5%, and certain functional properties (iso-electric solubility, emulsification capacity, whipping expansion, and foam stability) were evaluated. The general picture observed is an increase, often pronounced, in these four properties with increasing DH — however, there are also distinct differences between the protein sources as well as between the different forms of a particular protein. This work demonstrates that protein sources indigenous to Europe are fully comparable to soya protein with respect to potential functional uses.     

Silage fermentation profile,chemical composition and economic evaluation of millet and soya bean grown in monocultures and as intercrops

In recent years, dairy farmers in semi‐arid regions have shifted from maize (Zea mays L.) as their primary source of feed to drought‐tolerant crops, such as millet (Pennisetum glaucum L.), due to lack of water for irrigation. However, millet alone may not provide feed of sufficient quality and crude protein content for dairy cows. A field experiment was conducted in 2 years to evaluate (i) whether intercropping millet with a relatively drought‐tolerant soya bean cultivar (Glycine max Merr, cv. Williams) could improve silage quality with minimum yield penalty, and (ii) if the application of molasses could further enhance the nutritive value of silage of millet–soya bean intercrops. There were three intercropping ratios (60% millet with 40% soya bean, 50% millet with 50% soya bean, 40% millet with 60% soya bean) and monocultures of millet and soya bean. Mixed forages were treated with three levels of molasses: M₀ (without molasses), M₁, and M₂ (2·5 and 5% fresh matter respectively). Inclusion of soya bean in millet crops resulted in decreased silage yield compared with millet alone. The highest yield was obtained from the ratio of 60% millet with 40% soya bean. Molasses‐treated silage had higher lactic acid, lower pH, and lower acid detergent fibre (ADF) and neutral detergent fibre (NDF). Silage produced from millet–soya bean intercrops exhibited enhanced fermentation, indicated by lower pH (3·64) and higher lactic acid (16·63 g kg^?1 DM) than silage from monocultures. Intercropping ratios had lower water‐soluble carbohydrate, ADF and NDF than millet monoculture. Overall, an intercropping ratio of 60% millet with 40% soya bean was advantageous over other ratios in terms of higher yield, nutritive value and economic value.     

Cultivar discrimination of Portuguese Lupinus albus by seed protein electrophoresis: the importance of considering “glutelins” and glycoproteins

The Osborne protein fractions of seeds of 17 Lupinus albus cultivars from different regions in Portugal (obtained from plants grown at the same location) were analysed. The objective of this work was to examine the variability in the seed protein fractions of such a L. albus germplasm sample in order to disclose existing genetic relationships and to obtain information useful for a breeding program. Globulins and, interestingly, the fraction extracted with NaOH (“glutelins”) were the major seed protein constituents. The several protein fractions were separated by electrophoresis (reducing SDS polyacrylamide gel electrophoresis) and the patterns examined by multivariate analysis. Bands of “glutelins” together with those of glycosylated polypeptides were found to have the highest discriminating capacity. Lupin populations were grouped according to their clinal geographical distribution from north (small-seeded, higher plant architecture and later flowering type) to south (large-seeded, shorter and early flowering type). It is also possible that polypeptide patterns could reflect microclimatic specificities related with altitude and temperature. In fact, one cultivar from the south but from high altitude was grouped with the north plant types adapted to colder and wetter weather, whereas two cultivars from a warmer north region were grouped with the southern types. The results show, in addition, that a general correlation exists between cultivar early flowering characteristics and higher amounts of both total seed protein and glutelins, and lower glutelin glycosylation. Since high seed protein content and early flowering are important aims of lupin breeding programs, these findings on the seed protein fractions could stimulate and direct future research in lupin improvement.     

Cloning,Expression, and Purification of a GDSL-like Lipase/Acylhydrolase from a Native Lipase-Producing Bacterium,Lactobacillus fermentum

Background: Lipase enzymes are of great importance in various industries. Currently, extensive efforts have been focused on exploring new lipase producer microorganism as well as genetic and protein engineering of available lipases to improve their functional features. Methods: For screening lipase-producing lactobacilli, isolated strains were inoculated onto tributyrin agar plates. Molecular identification of lipase-producing Lactobacilli was performed by sequencing the 16Sr DNA gene, and a phylogenetic tree was constructed. The LAF_RS05195 gene, encoding lipase protein in L. fermentum isolates, was identified using specific primers, amplified by PCR (918 bp) and cloned into the pET28a (+) vector. The recombinant proteins were expressed 2, 4, 6, and 12 hours after induction with IPTG and assessed using the SDS-PAGE. Enzymatic activity of the purified recombinant protein was measured at 410 nm in the presence of ρ-NPA and ρ-NPP. Results:Among five identified native lipase-producing isolates, one isolate showed 98% similarity with Enterococcus species. The other four isolates indicated 98% similarity to L. fermentum. After purification steps with Ni-NTA column, a single protein band of about 34 kDa was detected on SDS- PAGE gel. The enzymatic activity of purified recombinant protein alongside ρ-NPA and ρ-NPP was measured to be 0.6 U/ml and 0.2 U/ml, respectively. Conclusion:In the present research, a novel lipase/esterase from L. fermentum was cloned and expressed. The novel lipase/esterase has the merit to be further studied due to its substrate specificity. Key Words: Escherichia coli, Gene expression, Lactobacillus, Lipase, Phylogeny     

Comparison of Antimicrobial Susceptibility of Campylobacter Strains Isolated from Food Samples and Patients with Diarrhea

Background:

Campylobacter infections may lead to serious conditions, including septicemia or other invasive forms of the disease, which require rapid and accurate laboratory diagnosis and subsequently appropriate antimicrobial therapy. The aim of this study was to compare the species distribution and antimicrobial susceptibility pattern of Campylobacter spp. strains isolated from patients and food samples.

Methods:

Biochemical identification was performed on 15 clinical and 30 food isolates of Campylobacter recovered onto Brucella agar containing 5% sheep blood. PCR was carried out to confirm the identity of Campylobacter spp. using primers for cadF, hipO, and asp genes of Campylobacter. To determine antibiotic sensitivity of isolates, Kirby-Bauer assay was carried out using 16 different antibiotic discs.

Results:

PCR assay and biochemical tests confirmed all 45 isolates as Campylobacter: 20 (44.44%) as C. jujeni, 10 (22.22%) as C. coli, and 15 (33.34%) as other Campylobacter strains. The maximum resistance was observed to cefotaxime and imipenem (each 86.49%) and the maximum sensitivity to erythromycin (48.65%).

Conclusion:

C. jujeni is dominant among isolates from clinical and food samples. In addition, tetracycline remains the first-line therapeutic agent against Campylobacter infections in Iran. Key Words: Campylobacter, Genetic diversity, Drug resistance     

The nutritional quality of Lupinseed

Mature seeds of four Lupinus species,L. albus, L. angustifolius, L. luteus andL. mutabilis, have been analysed comprehensively to evaluate their potential for nutrition. Particular interest attaches to the comparison betweenlupinus species and soyabeans. All species are rich in high-quality protein, as judged from amino-acid profiles,In vitro studies indicate high levels of digestibility and imply the presence of few interfering factors. In contrast to many other legumes, lupinseeds are free of both protease inhibitors and haemagglutinins. Only one factor, a C-glycosyl poly-hydroxy flavone, which could conceivably interfere with protein absorption, has been identified. Lupinseed could possibly be developed as an oilseed crop, though oil contents are currently somewhat lower than those of soyabeans. The composition of lupinseed oil is similar to that of soyabean oil, both being limited in quality by the presence of linolenic acid. The bright yellow colour of the partially refined oil is due to the presence of the two carotenoids, β-carotene and zeaxanthin. Lupinseed is well-known to contain toxic alkaloids of the quinolizidine group. However, intensive breeding programmes involving all four named species have been in progress for many years. At least in the cases of the first three species, cultivars have been developed that are virtually alkaloid-free. Alkaloid profiles are of interest in being decisive chemotaxonomic indicators of species. The pyrimidine bases responsible for inducing favism through the consumption ofVicia faba are absent from lupinseed. Like soyabeans, lupinseed invariably contains a range of chemically complex saponins. Concentrations in the seed are of a similar order, but it is doubtful whether these should be considered significant anti-nutritional factors for Man. Lupinseeds contain a range of oligosaccharides—raffinose, stachyose and verbascose —which correspond with the flatus factors present in soyabeans and many other legumes. Levels, however, are no higher than those found in soyabeans.     

Host range,symptomology, and serology of isolates of potato virus Y (PVY) that share properties with both the PVYN and PVYO strain groups

In surveys for the tobacco veinal necrosis strain of potato virus Y (PVY^N) in potato, two isolates (I-136 and I-L56) were obtained that shared properties with both the PVY^N and the common (PVY^O) strain groups. The isolates produced veinal necrosis on tobacco (Nicotiana tabacum L.) and mild symptoms on potato (Solanum tuberosum L.) cv. Jemseg, typical of PVY^N but their symptoms on some other indicator species such asCapsicum frutescens L.,Chenopodium amaranticolor Coste & Reyn.),Physalis angulata L.,P. floridana Rybd. were more typical of PVY^O. Their serological properties were also more typical of PVY^O in that they reacted with a PVY^O-specific monoclonal antibody (MAb) in ELISA and they failed to react with four PVY^N-specific MAbs. The possible taxonomic position of these isolates is discussed.     

Ukrainian Dietary Bread with Selenium-Enriched Soya Malt

The production of bread with addition of selenium-enriched soya malt was studied. Processing of this soya malt included soaking of the soya beans in the solution of hydroselenite with concentration 1.5 mg Se/L (20 μg of Se per 1 g of soya beans), then 4 days of beans germination at 20 °C, drying at 50 °C until moisture content 8%, separation from the sprouts and grinding. The soya malt was a powder containing 15–18 μg of Se in 1 g. The accumulated selenium was mainly in the protein fraction of soya malt. Addition of selenium-enriched soya malt to leaven intensified activity of yeasts and lactic acid bacteria. The quality of the wheat bread with selenium-enriched soya malt was better than that of the bread in control. The enriched bread had specific pleasant smell and soft texture. The daily intake of 277 g of bread with the selenium-enriched soya malt, which is added in quantity of 1.0–1.75% to mass of plain flour, ensures the consumption of 30–50% of selenium recommended daily allowance for 17 million population of the northern and northwestern Ukraine.

     

Diversity and phylogeny of basidiomycetous yeasts from plant leaves and soil: Proposal of two new orders,three new families,eight new genera and one hundred and seven new species

Nearly 500 basidiomycetous yeast species were accepted in the latest edition of The Yeasts: A Taxonomic Study published in 2011. However, this number presents only the tip of the iceberg of yeast species diversity in nature. Possibly more than 99 % of yeast species, as is true for many groups of fungi, are yet unknown and await discovery. Over the past two decades nearly 200 unidentified isolates were obtained during a series of environmental surveys of yeasts in phyllosphere and soils, mainly from China. Among these isolates, 107 new species were identified based on the phylogenetic analyses of nuclear ribosomal DNA (rDNA) [D1/D2 domains of the large subunit (LSU), the small subunit (SSU), and the internal transcribed spacer region including the 5.8S rDNA (ITS)] and protein-coding genes [both subunits of DNA polymerase II (RPB1 and RPB2), the translation elongation factor 1-α (TEF1) and the mitochondrial gene cytochrome b (CYTB)], and physiological comparisons. Forty-six of these belong to 16 genera in the Tremellomycetes (Agaricomycotina). The other 61 are distributed in 26 genera in the Pucciniomycotina. Here we circumscribe eight new genera, three new families and two new orders based on the multi-locus phylogenetic analyses combined with the clustering optimisation analysis and the predicted similarity thresholds for yeasts and filamentous fungal delimitation at genus and higher ranks. Additionally, as a result of these analyses, three new combinations are proposed and 66 taxa are validated.     

Recovery ofVerticillium dahliae from North American certified seed potatoes and characterization of strains by vegetative compatibility and aggressiveness

Samples of tubers collected from commercial potato seed lots produced across North America were assayed forVerticillium dahliae. V. dahliae was successfully isolated from 65 of 224 seed lots tested, a successful isolation rate of nearly 30%. Vegetative compatibility of the isolates was assessed through complementation tests using nitrate non-utilizing mutants. AllV. dahliae isolates belonged to vegetative compatibility group (VCG) 4. Of the 162 isolates recovered, 64% belonged to VCG 4A, 33% to VCG 4B, and 3% to VCG 4AB. All 39 of the isolates tested in the greenhouse on potato cv. Superior were pathogenic to potato. Disease symptoms developed earlier, were more severe, and plants died earlier when inoculated with VCG 4A compared to 4B isolates. As a group, AUSPC values were significantly higher (p=0.05) for VCG 4A than for 4B isolates. These data suggest that (1) commercial certified seed tubers from diverse locations are commonly infected withV. dahliae and thus may serve as primary sources of the pathogen; (2) potato isolates ofV. dahliae in North America belong to VCG 4A and 4B and these strains are widely distributed via seed tubers; and (3) VCG 4A and 4B are distinct pathotypes ofV. dahliae that vary in their aggressiveness to potato.     

Investigation of diacylglycerol acyltransferase (DGAT) activity of microsomes from the seeds of three euphorbs

Unusual fatty acids such as ricinoleate (12-hydroxyoleic acid) occurring in Ricinus communis L. or vernoleate (12,13-epoxyoleic acid) occurring in Euphorbia lagascae L. are suitable for industrial uses. Euphorbia lathyris L. is also a potential new oilseed crop on account of its high content of oleic acid in the seeds. The objective of this work was to test in vitro the preferences of E. lathyris microsomes for its native substrates (oleoyl-CoA and diolein) and to compare with R. communis and E. lagascae systems.The diacylglycerol acyltransferase (DGAT) catalyses the final step in transferring a fatty acid moiety to a diacylglycerol (DAG) into a triacylglycerol (TAG). To study the DGAT activity in microsomes of the three euphorbs: (1) plants of the three species were grown in a glasshouse at Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (Murcia, Spain), (2) endosperms were removed from developing seeds and the tissue was extracted, (3) in vitro DGAT assays using [¹⁴C]-oleoyl-CoA with or without 1,2-diolein were carried out and 4) labelled TAG were recorded using a molecular imager and a scintillation counter.Incorporation of [¹⁴C]-oleoyl into TAG was greater in R. communis and E. lathyris (72–89% of total TAG) than in E. lagascae. Adding exogenous 1,2-diolein (1 mM) to E. lagascae microsomes increased the amount of labelled TAG to 39%, suggesting that other acyl groups were being incorporated as well. R. communis and E. lagascae microsomes gave more-polar radiolabelled TAGs than E. lathyris possibly because endogenous DAGs (not 1,2-diolein) were being used in the reaction. Although E. lathyris microsomes showed specificity towards 1,2-diolein as a substrate, the preparations from R. communis, E. lagascae and E. lathyris were able to use the acyl donor and acyl receptor, possibly suggesting that DGAT enzymes would not be a limiting factor to engineer Euphorbiaceae crops with functionalized fatty acids.     

Edible oil and protein concentrate fromLupinus mutabilis

The seeds ofLupinus mutabilis show on average a protein content of 42.6% and a fat content of 18.7%. Unfortunately they contain up to 4.5% of bitter alkaloids which must be removed before consumption. Edible oil and protein concentrate were produced from the seeds at an industrial level. The oil is of good quality and is recommended for human nutrition. The main fatty acid is oleic while the main tocopherol is γ-tocopherol. During the refining process, which includes a washing process with aqueous acids for debittering, the alkaloid content of the oil is reduced to 5 ppm. During the extraction of the oil the alkaloids are concentrated in the oil cake, from which they can be removed by washing with an ethanol-water mixture. A protein concentrate containing 72.3% protein and 0.06% residual alkaloids is obtained. The analysis of alkaloid pattern by gas-chromatography showed that the alkaloid composition of the crude oil differs totally from that of the seed. The relative percentage of the alkaloid esters and that of the Tetrahydrorhombifoline are very much higher in the oil than in the seed. During the debittering process of the oil cake the relative percentage of the hydroxylupanines increases.     

Effect of legume flours on baking characteristics of gluten-free bread

The objective of this work was to study the characteristics of four gluten-free bread formulations and the possibility of substituting soya protein with other legume proteins. Four bread recipes were prepared with chickpea flour, pea isolate, carob germ flour or soya flour. Carob germ flour batter structure was thicker compared with the other batters, probably due to the different protein behaviour and the residual gums present in carob germ flour. However, carob germ flour bread obtained the lowest specific volume values (2.51 cm³/g), while chickpea bread obtained the highest (3.26 cm³/g). Chickpea bread also showed the softest crumb. Confocal scanning-laser microscopy results showed a more compact microstructure in carob germ flour bread compared with soya and chickpea formulations. Chickpea bread exhibited the best physico-chemical characteristics and, in general, good sensory behaviour, indicating that it could be a promising alternative to soya protein.     

Screening of endophytic bacteria and evaluation of selected isolates for suppression of burrowing nematode (Radopholus similis Thorne) using three varieties of black pepper (Piper nigrum L.)

Radopholus similis is a serious threat to black pepper (Piper nigrum L.) cultivation being the main causal organism of slow decline disease. Because of its migratory nature most fungal and bacterial antagonists are ineffective in suppressing R. similis. The presence of a number of endophytic bacteria in black pepper tissues has been proved in earlier studies. This study was undertaken to evaluate the bacteria isolated from black pepper for suppressing R. similis. In vitro and in vivo screenings were used initially to identify the efficient strains of endophytic bacteria that suppress R. similis. Seventy four isolates of endophytic bacteria obtained from black pepper were screened against R. similis by various bioassays. Results of the in vitro experiments were inconclusive and did not match the rest of the studies. However, six isolates were short-listed based on the preliminary in vivo screening and further tested in an evaluation trial using three varieties of black pepper. Irrespective of the varieties, significantly higher nematode suppression was observed with one isolate (TC 10) followed by another (BP 17). These isolates were identified to the species level by sequence analysis of the 16S rRNA gene. The results showed that these isolates shared 99% identity with Bacillus megaterium and Curtobacterium luteum, respectively. More studies are required to understand their mode of action as well as the dose–response relationship with nematodes.     

Inheritance of the resistance toMeloidogyne incognita,M. javanica,andM. arenaria in potatoes

The objectives of this research were: 1) to try to determine the inheritance of the resistance toMeloidogyne incognita, M. javanica, andM. arenaria and 2) to study genetic relationships among the three species of root-knot nematodes in potatoes. The source of resistance used wasSolanum sparsipilum. The progenies analyzed in this study may be grouped into a few discrete segregation patterns, three forM. incognita andM. javanica and two forM. arenaria. More than one dominant locus, but not many loci are needed to explain the segregation obtained in the three species. Susceptible clones ofS. sparsipilum possess recessive or epistatic genes which affect the pattern of segregation for resistance, when these clones are crossed to resistant clones. Maternal effects were expressed in reciprocal crosses between susceptible and resistant clones when they were tested for resistance toM. arenaria. Clones in this study which are resistant toM. arenaria are also resistant toM. incognita andM. javanica     

Resistance to thiabendazole and thiophanate-methyl in canadian isolates ofFusarium sambucinum andHelminthosporium solani

Resistance to both thiabendazole (TBZ) and thiophanate-methyl (TPM) was observed in Canadian isolates ofFusarium sambucinum andHelminthosporium solani recovered from diseased potato tubers. Resistance was not found in isolates ofFusarium avenaceum, Fusarium culmorum, Fusarium equiseti andFusarium solani. A high level of resistance to both TBZ (EC₅₀ 180 to ?500 mg/l) and TPM (EC₅₀ ?500 mg/l) was observed forH. solani isolates, whereasF. sambucinum exhibited a relatively low level of resistance to TBZ (EC₅₀ 34 to 71 mg/l) and a high level of resistance to TPM (growth uninhibited by 2,500 mg/l). The incidence ofF. sambucinum resistant to the benzimidazoles was lower (60%) than that observed forH. solani (95%)