Dependence of vertical distribution of cyst-forming nematodes from cultivated host plants and ways of principal tilling of soil

Anatoly G. BABICH

National Agricultural University, Kiev 03041, Ukraine,

Subsurface tillage of soil in Ukraine earlier was being implemented in the regions of insufficient moistening of steppe area. However, last time less energy-consuming technologies are applied also in the regions of non-stable and sufficient moistening of forest-steppe area and Polesya zone. The aim of research is investigation of influence of principal tilling of soil on vertical distribution of cyst-forming nematodes. It is found that localisation of cysts in the soil depends on cultivated host plants, kinds of nematodes, types of soil and ways of its tilling. Thus, on humus-scarce black soils the prevailing number of beet nematode cysts after growing up oil radish and rape was found in plow layer up to 20 cm, sugar beet -15-30 cm, and oats nematode after cultivating crops in the range of 5-15cm. On the turf and podzol soils with shallow lying of fertile layers the range of 10-20 cm was the most invaded by the beet nematode and the range 0-10 cm by oats nematode. Thus, the distribution of nematode cysts across the soil depends on depth of prevailing lying of root system of host plants. That is why their maximum number on black soils is usually situated 5-10 cm deeper than in turf-and-podzol soil. The disc tillage and flat-cut plowing cause minimal influence on vertical distribution of cysts. Plowing with soil layer turning leads to more even distribution of cysts in the soil range of 0-20 cm in case of usual plowing, and 0-30 cm in case of deep plowing for sugar beet plantation. Therefore, applying only subsurface soil tillage would promote accumulation of cyst-forming nematodes in the area of maximum location of root system of host plants. So it is advisable to apply plowing with the soil layer turning in case of technical and vegetable crops, and to apply flat-cut plowing in case of grain crops.

Soil nematodes as bioindicators for territories along main oil pipelines

Alexander S. EROSHENKO

Institute of Biology and Soil Sciences FEB RAS, Vladivostok, 690022, Russia,

Investigations of natural biocenoses for soil nematode determination were carried out in the North Sakhalin from the north-east Piltun Bay to the north-west Pogibi Cape on the territory near to the main oil pipe in 2001. There were selected 4 ecological-faunistic complexes (EFC): i) coast-seal, ii) forestry, iii) riverside, iv) meadow-marshal. Specimens from 25 families of different groups were determined. Dominant bacterial feeders were represented by Cephalobidae and Plectidae; fungal feeders were represented by Tylenchidae. These families were main groups both frequently and domineering. Bacterial feeders with families Plectidae, Cephalobidae, Prismatolaimidae, plant feeders with Tylenchidae and root-ectoparasite with the genus Hemicycliophora (which was collected from rhizosphere of Pinus pumila) were dominant in the coast-seal EFC. The number of nematodes was limited from 2680 thousand specimens per 1 m2 of soil. Bacterial feeders with Plectidae, Cephalobidae, Prismatolaimidae, plant and fungal feeders with Tylenchidae and Diphterophoridae were dominant in the forestry EFC. The omnivorous Dorylaimida were dominant in the forestry EFC too. The nematode number was limited average 1360 thousand specimens in deciduous forests, 8035 thousand specimens in fir forests. The number of nematodes in burnt-over forests was noted as 620 thousand specimens. The same groups were dominant in the riverside EFC, and the number of nematodes registered was from 1886 to 3680 thousands specimens per 1 m2 of soil for different biotopes. The lowest density (584 thousands) was noted in the meadow-marshal EFC. The bacterial feeders Alaimidae, Prismatolaimidae, Plectidae and Teratocephalobidae were registered in this complex as dominants. Most nematode taxa had Maturity Indexes c-p 2 and c-p 3. They relate to constant inhabitants of investigative biotopes and reflex nondisturbed natural ecosystems. (Financial support - Ecological Company "Sakhalin").

Distribution of plant-nematodes in the Russian Far East

Alexander S. EROSHENKO, Tamara V.VOLKOVA

Institute of Biology and Soil Sciences FEB RAS, Vladivostok, 690022, Russia,

The order Tylenchida includes 160, Aphelenchida - 67, and Dorylaimida - 15 species of 242 species of plant-nematodes found in plants or rhizosphere of roots in the Russian Far East. On the coniferous the main parasites from 163 species, found in rhizosphere and vegetative organs of wood, brushes and lianas plants in natural forests of Far East of Russia are species of the family Tylenchidae, genera Rotylenchus, Hemicriconemoides, Ogma, Pratylenchoides, the species Criconema varicaudata, Mesocriconema curvatum,Criconemoides sabulosus, Helicotylenchus clarkei, Hemicycliophora montana, Xiphinema thornei, Bursaphelenchus mucronatus. The root parasites Meloidodera sikhotealiniensis, Meloinema maritima, Sphaeronema salicis are widespread in broadleaves trees in valley forests. 109 species of nematodes are parasites on grass plants. Group of spiral nematodes of genera Helicotylenchus and Scutellonema and criconematids (Criconema, Mesocriconema and Ogma) have a wide spectrum of host-plants and may be considered as dominant species. Cyst-forming nematode Globodera artemisiae (sibling species of potato globoder) is widely distributed in the Far East of Russia and prefers Artemisia spp. Other species of cyst-forming nematodes: Heterodera graminis, H riparia, Afenestrata orientale parasitize on Poaceae in Primorye Territory, Heterodera humuli - on Urtica sp. in Kamchatka Region. Anguina agrostis is widespread in all regions and forms galls on the different species of Poaceae. Subanguina graminophila and S.radicicola inhabit small-reed (Calamagrostis langsdorffii) in Primorye, Khabarovsk and Sakhalin Regions and form leaf and root galls respectively. Anguina moxai forms leaf galls on Artemisia spp. and is widespread in the south of Primorye Territory. 10 species from 20 plant-nematodes are known as parasites of soybean roots. Cyst-forming nematode Heterodera glycines (common species in Primorye and Amur Regions) is most serious parasite of soybean. 3 pathogenic nematodes species are registered on the potato: cyst-forming nematode Heterodera rostochiensis (localy spreading in personal plots of citizens in all regions of Far East of Russia), Ditylenchus destructor and D dipsaci. Two species of gall-gorming nematodes: stem nematode Ditylenchus dipsaci and root endoparasite Pratylenchus vulnus (parasitizing on different vegetable and floral cultures in greenhouses) are the most dangerous for vegetable cultures. Aphelenchoides fragaria and Ditylenchus dipsaci damage strawberry in all Regions. Aphelenchoides besseyi is parasite of rice, and Heterodera graminis is parasite of maize in Primorye Region.

The role of culture medium in the tolerance of soil nematode Cephalobus persegnis to lead acetate effect

Anatoly I. GRUZDEV, Ludmila I. GRUZDEVA, Tatiana E. KOVALENKO, Elizaveta M. MATVEEVA

Institute of Biology, Karelian Research Centre, RAS, Petrozavodsk, 185610, Karelia, Russia,

Cephalobus persegnis was grown on the 2 % standard bactoagar "Difco" (BA) and potato dextrose agar (PDA) with fungus Althernaria tenuis. Activities of cytochrome C oxidase, aldolase and NAD-linked malate dehydrogenase (MDH) isozymes were measured to determine the physiological state of C. persegnis exposed to lead acetate at concentrations from 0.75 to 25 mg/l for three days. It was displayed that in the C. persegnis cultured on BA without lead acetate the activities of the aldolase and the MDH-A2 isozyme (gluconeogenic enzymes) were significantly lower than those of C. persegnis cultured on PDA. It gave an indication of the gluconeogenesis weakening, admittedly associated with glucose synthesis from galactose which is the major constituent of BA. Experimentally, in C. persegnis cultured on BA, the aldolase activity grew progressively up twofold whereas the lead acetate dosage increased. It could be indicative of that storage carbohydrates in C. persegnis broke down by glycolysis. This assumption was confirmed by the correlation analysis applied to the data received. Using the method of probabilistic estimation of the toxic effect (Kopanev et al., 1988), we have found that the minimal toxic concentrations of lead acetate for C. persegnis cultured on PDA and BA were 0.141 ± 0.025 and 0.045 ± 0.019 mg/l, accordingly, and differed significantly (p = 0.025). Thus, C. persegnis cultured on BA differed from that cultured on PDA in fermentative status and this could be the reason why they had a reduced vitality observed on exposure to lead acetate.

The nematodes of family Tylenchidae Orley, 1880 in the Russian Far East


Institute of Biology and Soil Sciences FEB RAS, Vladivostok 690022, Russia,

Representatives of 5 subfamilies, 9 genera and 21 species of family Tylenchidae were registered in the Russian Far East. Specimens from genera Filenchus (F. retusus, F. thornei, F. vulgaris, F. hamatus, F. ditissimus), Coslenchus (C. costatus), Malenchus (M. bryophilus, M.pressulus), Cephalenchus (C.hexalineatus, C. leptus) are widely distributed. Filenchus helenae and Tylenchus elegans are registered very seldom. Tylenchus davainei and Aglenchus ainakamure are revealed on Sakhalin only. Coslenhus bisexualis is noted in the Russian Far East at first. It was known earlier for Indian nematode fauna. Basiria paraobliqua is widely distributed in Primorye Region. Basiria graminophila and B. tumida are found seldom. Malenchus bryanti is collected from forest trees as single specimen. Lelenchus leptosoma is noted on Sakhalin and Primorye Regions.

Local and Systemic induced resistance to the root-knot nematodes (Meloidogyne incognita) in tomato by different doses of chemicals and its comparison with biological control agent (Paenibacillus polymyxa)

Hafeez U. KHAN1, Young Ho KIM2

1Pakistan Science Foundation, Islamabad, Pakistan

2School of Agricultural Biotechnology, Seoul National University, Suwon 441-744, Korea

A 60 days glasshouse experiment was conducted to assess the influence of two doses of BABA (DL-B-aminobutyric acid) and BTH (Benzo-(1.2.3)-thiadiazole-7-carbothioic acid S-methylester) with 20 mM and 40 mM and one dose of GBR-I (Paenibacillus polymyxa) on the multiplication of Meloidogyne incognita and growth of tomato (Lycopersicon esculentum). GBR-I was better at improving tomato growth and reducing number of galls formed on each tomato seedlings as compared to BABA and BTH. Study revealed that GBR-I gave minimum number of galls (9.2) on each tomato seedlings which was 91.8 percent less as compared with the control. BABA with 40 mM dose ranked second in performance as it gave 17.6 galls per plant which was 84.3 percent less as compared to control. The minimum reduction in gall formation on each tomato seedling was observed with BTH at 20mM dose and it was only 62 percent less than control. Thus biological control treatment with GBR-I (Paenibacillus polymyxa) proved best in reducing the number of galls formed on each tomato seedlings and improving the plant growth as compared to chemical treatments with BABA and BTH.

Discovery of the nematode Sheraphelenchus sp. in dead-wood of the pine Pinus koraiensis from Primorski territory, Far East Russia


Institute of Biology and Soil Sciences FEB RAS, Vladivostok, 690022, Russia,

The genus Sheraphelenchus Nickle, 1970 includes only two species. They have a phoretic relationship with the nitidulid beetles; the free-living generations were collected from split and decaying oranges in USA (Texas, California, Hawaii, Colorado and New Mexico) and in Italy. Females of the genus Sheraphelenchus were collected from the dead-wood of the pine Pinus koraiensis in Primorsky Territory, Far East of Russia. The species from Primorye differs from both known species by morphological characters. It is characterized by long body (1,27-1,8 mm against 0,48-1,19 mm), long stylet (16-17 μm & 12 μm), location of nerve ring, long oesophageal glands. The Primorye females differ from one of the type species, S. entomophagus Nickle, 1960, by length and shape of tale.

Distribution of nematodes inside trunk and branches of the dead 200 years old pine Pinus koraiensis


Institute of Biology and Soil Sciences FEB RAS, Vladivostok, 690022, Russia,

Primary location of different nematodes in separate parts of the stem and branches was found during investigation of the nematodefauna of dead-wood of the pine Pinus koraiensis. Most nematodes collected were mycophagous and saprobiont forms. Content of the nematodes in the bark was approximately: 50% - Cryptaphelenchus ipinius; 30% - Parasitorhabditis acanthocini, 22% - Bursaphelenchus mucronatus and 8% - Ektaphelenchoides pini. Specimens of Diastolaimus grossus were more than half of all nematodes in the branches; Panagrobelus phloesini, Aphelenchoides saprophilus, Bursaphelenchus sp. and Deladenus sp. were collected in uniform proportions. The species B. mucronatus occupies a core of the middle part of the stem where a funous lesion was not visualized. Its quantity in this sample was estimated as 97,2%. Considerable fungous infection was found in the external layer of the middle part of the stem. The dominant species in this habitat were Bealius pissodi - 55%, P.acanthocini - 19%, Rhabditis cucumeris - 12%, Neoditylenchus corniculatus - 10 % and B. mucronatus - 4 %. Areas with considerable fungous infection were not observed in the upper part of the stem while fungi were scattered in sawcut almost evenly. Here the estimated quantity of B.mucronatus was 71%. C. ipinius dominated (52%) in the lower part of the stem with strong fungous infection. The species Bursaphelenchus silvestris, Neodiplogaster wacheki, Parasitorhabditis acanthocini, Neoditylenchus corniculatus and Parasitaphelenchus sp. were also registered here.

Fauna of xylobiont nematodes of the pine Pinus densiflora from Primorye


Institute of Biology and Soil Sciences FEB RAS, Vladivostok, 690022, Russia,

Fauna of xylobiont nematodes of the pine Pinus densiflora is characterized by much less number of species compared with other pine species growing in Primorye. Quantity of nematodes is also much less. Nematodes were not found almost in half of trees investigated. 18 species of nematodes were found in stems and branches of a pine Pinus densiflora: Plectus rhizophilus, Macrolaimus arboreus, Diastolaimus grossus, Heterocephalobus elongatus, H. cf. pauciannulatus, Panagrolaimus rigidus, Panagrobelus phloesini, Protodiplogasteroides saperda, Ditylenchus cf. tenuidens, D. uniformis, Deladenus durus, Aphelenchoides hamatus. A.paramonovi, A.rhytium, A.saprophilus, Ektaphelenchus prolobus, Bursaphelenchus mucronatus. Only two of them (H. elongatus and E. prolobus) were not found in other pine species. Most of nematodes collected are mycophagous and saprophagous forms. More abundant saprophags were P. phloesini, M. arboreus and D. grossus. A. saprophilus was more abundant mycophag. B. mucronatus, always accompanied by other species of nematodes, was found in 12,5% of the investigated trees. Such frequent occurrence is much more higher than in the forest P.koraiensis but less than in P.koraiensis and P.silvestris from the forest nurseries. Quantity of B. mucronatus in wood of P. densiflora is very low. This fact testifies against the pathogenicity of B. mucronatus for P. densiflora.

Review of nematode order Aphelenchida Siddiqi, 1980 from stems and branches of pines from Primorye


Institute of Biology and Soil Sciences FEB RAS, Vladivostok, 690022, Russia,

Nematodes belonging to the order Aphelenchida are very numerous in dead-wood of pines in Primorye. 28 species of aphelenchids belonging to 10 genera of five families (Paraphelenchidae, Aphelenchoididae, Seinuridae, Ektaphelenchidae, Parasitaphelenchidae) were registered. The family Aphelenchoididae is represented by three genera (Aphelenchoides, Laimaphelenchus, Sheraphelenchus) with 11 species. Genus Sheraphelenchus was found in Russia for the first time. Most of the nematodes found belong to the genus Aphelenchoides - 9 species. One of these species is new for science; five species were found in the Russian Far East for the first time. Family Parasitaphelenchidae is represented by two genera (Bursaphelenchus, Parasitaphelenchus) with 10 species. Seven species belong to the genus Bursaphelenchus. Three of them are new for science; two species are registered in the Russian Far East for the first time. Three species from the genus Parasitaphelenchus also were found in the Russian Far East for the first time. Three genera (Ektaphelenchus with 3 species, Cryptaphelenchus with 1 species and Ektaphelenchoides with 1 species) belong to the family Ektaphelenchidae. All five species were registered in the Far East for the first time. Species from the families Paraphelenchidae and Seinuridae were found in the dead-wood of pines only as sporadic specimens. One species was registered for each family. Thus, four of 28 species of aphelenchids found in the Russian Far East are new for science; 16 species were found for the first time, eight species have been registered previously.

Description of Meloidogyne zhanjiangensis n.sp. from China

Jinling LIAO*, Zhixin FENG

Lab of Plant Nematology, College of Environmental and Natrual Resource, South China Agricultural University, Guangzhou 510642, P.R.China, *

A new species Meloidogyne zhanjiangensis on pea from Guangdong province, China was observed and described. For female: stylet 12-13.3 μm length; perineal pattern changed much, near round, sometimes regular; arch low to middle high; fine striae, smooth to waved; tail terminus covered with irregular circles. In compare with M. arenaria, M. zhanjiangensis has irregular pattern, perineal pattern with higher arch, smooth striae in lateral field, irregular former lip, whereas M. arenaria has typical dumbbell lips. Lower esterase migrating rate belongs to VS1-S1 type. Nal type of malic dehydrogenase. For the second stage juvenile: body length 320-475μm; stylet 13.5-15 μm length; tail has 1-4 indentations, small rounded terminus. Smaller mtDNA fragment compared with M.arenaria (0.7 kb for M. zhanjiangensis, 1 kb for M. arenaria). The host reaction of Meloidogyne zhanjiangensis on some crops also was discussed (Natural Science Foundation of China, grant No. 30170611).

Structure of soil nematode communities in potato fields infested with potato cyst nematode (PCN)

Elizaveta M. MATVEEVA, Ludmila I. GRUZDEVA, Tatiana E. KOVALENKO

Institute of Biology, Karelian Research Centre, RAS, Petrozavodsk, 185610, Karelia, Russia,

Plant parasitic nematode complexes are usually formed from natural communities existing in local areas. Agroecosystems are characterized with monoculture that enhances a distribution of specialized plant parasitic nematodes, once occurred in the soil (e.g. potato - PCN as example). Diversity of soil nematode fauna, eco-trophic structure of the nematode communities in the infested potato fields were compared with those of health fields and after the applying of control measures against PCN. Nematode fauna diversity was decreased in the highly infested potato fields (over 200 viable PCN juveniles per 100 g of soil): 17 genera are observed while from 22 up to 30 nematode genera were found in the slightly infested fields. Maturity index (MI) of the nematodes communities was low (2.4 - 2.5); plant parasite index (PPI) was high (3.0 -3.2). Nematodes - bacteriotrophs were the most numerous among eco-trophic groups. Plant parasites were observed as a subdominant group, and genus Globodera was the most abundant in the plant parasite complex. Polytrophs and predacious nematodes were scanty. PCN population showed the 3-fold decline after the growing of potato cultivars resistant to the nematode and a 5-fold decline under fallow for 2 years. Simultaneously, changes in the trophic structure of the nematode communities were established. Bacteriotrophs were still dominant; polytrophs and predacious nematodes occurred as subdominants instead of plant parasites. Changes in the plant parasite complex were also found: representatives of Tylenchorhynchus, Pratylenchus, Paratylenchus were increased in numbers. This was mainly due to a succession of plants growing on the former fields and, consequently, occurrence of new relations in agrosystem. (Grant from Department of General Biology Programme "Biological resources").

Response of a Root-Knot Nematode, Meloidogyne incognita, to Homobrassinolide and Epibrassinolide

Puja OHRI1, Satwinder K. SOHAL1, Renu BHARDWAJ2

1Department of Zoology, Guru Nanak Dev University, Amritsar, India,

2Department of Botanical and Environmental Sciences, Guru Nanak Dev University, Amritsar, India,

The regulatory effects of Brassinosteroids (BS) have been extensively demonstrated in plants and have been documented on animal systems too. Since plant-parasitic nematodes are intimately associated with plants for their nutritional requirement for sterol, therefore the present study was a preliminary step in this regard to see the effect of two most potent brassinosteroids - Epibrassinolide (EBl) and Homobrassinolide (HBl) on a root - knot nematode, Meloidogyne incognita. Six concentrations of both the steroids were prepared in distilled water (10-5,10-6, 10-7,10-8,10-9and10-10 M). The egg masses of M. incognita were exposed in vitro to the above six concentrations for 7 days. Observations recorded after 24, 48, 72, 96h and 7 days of hatching revealed much higher percentage of hatching in treated egg masses (except in 10-10 M HBl) as compared to control. Some higher concentrations resulted into almost double percentage of egg hatching. The second stage juveniles were also tested with the same concentrations of HBl and EBl for their vigour. Juveniles apparently were as active as in controls. The juvenile mortality in treatments was not significantly different from control.

Soil nematodes of broad-leaved wood in southern Primorye Region


Institute of Biology and Soil Sciences FEB RAS, Vladivostok, 690022, Russia,

The samples were collected in broad-leaved wood where the oak Quercus mongolica is a dominant. Representatives of 26 families of soil nematodes were determined. Ecological-taxonomic analysis of nematode species showed that fauna of plant and soil nematodes is typical for natural forest cenosis. Plant nematodes are represented by seven families, where Rotylenchus feroxis and Xenocriconemella macrodora are dominant. Fungal feeders are represented by genera Filenchus, Aphelenchus and Aphelenchoides. Bacterial feeders are represented by rhabditids, cephalobids and plectids. Significant percent of fauna is formed by predators from the family Mononchidae, with the dominant genus Coomansus, and omnivores from the order Dorylaimida. The highest density of soil nematodes is noted in oak woods in the region of the lake Lotos and in Popov Island, the lowest - near the dust-heap of Vladivostok City. The highest diversity of nematode species is noted in oak woods in Popov Island, settlement Rybachii and Shamora bay, the lowest - in the region of the City’s dust-heap. Dynamics of development of nematofauna is wave-like during the vegetation season. Bacterial feeders and predators have stable dynamics type. Plant nematodes have more sharp seasonal fluctuations of the number. Main peak of the number of criconematids was accounted in June and September, for spiral hoplolaimids - at July and October. Sharp reduction of abundance of these groups was observed at August. It seems, this is connected with aridity of this month. The omnivorous form of Dorylaimida had practically constant, relatively high number from May to July, sharp reduction in August and September and an increasing number in October.

The influence of the soil acidity (pH) on nematode density

Tamara V. VOLKOVA, Alexander S. EROSHENKO, Serafima V. TEPLYAKOVA

Institute of Biology and Soil Sciences FEB RAS, Vladivostok, 690022, Russia,

The soil samples were collected from rhizosphere of oak Quercus mongolica for studing the influence of the soil acidity on nematode density in August-September, 2001. Sampling sites were disposed along the highway Vladivostok-Artem nearby the Ussuriisky Bay at the distance 2 km each from other including ash disposal area and cities’ dust-heaps - technogenic and urban pollution zones. The highest acidity was revealed in the region of dust-heap and neighbouring sites (pH 3.1-3.8). There was marked the reduction of nematode density compared with other sites (N=245 per 1000 ml soil). The bacterial feeders were most abundant from the trophic groups. This group was represented by rhabditids, cephalobids and plectids. The lowest acidity, near to neutral, was revealed in the region of ash disposal and neighbouring sites (pH 5.5-7.0). The highest nematode density (N = 807 per 1000 ml soil) were recorded here. Main peak of the number was accounted among the fungal feeders. This group was represented by the genus Filenchus. The soil acidity within the limits of pH 4.0-6.5 was noted for other sites. The optimal soil acidity (pH 5.1-5.5) was recorded for the plant feeders with the dominant species Rotylenchus feroxcis and Xenocriconemella macrodora. Other nematode groups responded to pH insignificantly.

The dependence of nematode density from heavy metal content

Tamara V. VOLKOVA, Alexander S. EROSHENKO, Serafima V. TEPLYAKOVA

Institute of Biology and Soil Sciences FEB RAS, Vladivostok, 690022, Russia,

The 35 soil samples were collected from rhizosphere of oak Quercus mongolica for study the dependence of nematode density on heavy metal content in August-September, 2001. Sampling sites were disposed along the highway Vladivostok-Artem nearby the Ussuriisky Bay at distance 2-km each from other. Heavy metals were represented by Fe, Mn, Zn, Cu, Co, Ni, Cd, Pb. Content of general and mobile forms of heavy metals was revealed in the collected samples. General form of heavy metal content showed stability of these elements. Dependence of nematode density from general form of heavy metal content has not found. This form reflects only the general pollution level. Changing of nematode density was evaluated by mobile form of heavy metal content. The constant nematode density of all groups depended from pollution stability. Small nematode density deflections were recorded during sharp overranging of admissible concentration limit (ACL). The high ACL was noted in 6 samples only. The decrease nematode density except predators was noted during overranging of the lead (Pb) content. Decrease of density of all nematode groups was noted during the overranging of cadmium (Cd) content. Combinations of overranging lead + copper (Cu) and lead + zink content were revealed the regularity of plant and fungal feeders density increase. Probably, zinc and copper smooth out negative activity of lead and cadmium, but to certain degree.

Research of intensity of Globodera rostochiensis infection in potatoes with endotoxine-gene Bacillus thuringiensis


1Institute of Parasitology RAS, Moscow 119071, Russia,,

2Bach Institute of Biochemistry RAS, Moscow 119071, Russia,

Transgenic plants with expressed modified genes of entomocide proteins, encoding only their toxic domens, are known to exhibit unexpected resistance spectrum to other pathogens. The greatest progress in this field was achieved with transfer to plants of endotoxine gene Bacillus thuringiensis which could inhibit not only insects but other invertebrates, including nematodes. Effect of cyst-forming nematode Globodera rostochiensis (race 3) on potatoes with endotoxine-gene B. thurigiensis var. tenebrionis (Bt) developed on Superior ("Monsanto" USA) cv., resistant to Colorado potato beetle, was studied. Plants with unchanged genotype susceptible to G.rostochiensis were used as controls. The experiments were conducted in greenhouses. Potatoes were infected at germination with 10 000 larvae/plant. Fifteen replicates were completed for each variant. G.rostochiensis cyst counts were made in 2 months in roots and soil after germination. The results showed that cyst number in roots of transgenic potatoes was 2.3 times as low as in control. The number of larvae presented in cysts did not differ in both variants. Transgenic potatoes with endotoxine-gene Bt were more resistant to phytopathogenes in treatment with biogenic elicitors.

© Russian Society of Nematologists, Institute of Marine Biology FEB RAS, 2002