Neuropeptides of root-knot nematodes: functional significance in parasite locomotions (short review)

The purpose of the research is to analyze the literature devoted to the study of the physiological role and functional significance of biologically active substances: FMRFamide-like neuropeptides in the locomotion of root-knot nematodes Meloidogyne incognita, M. minor, M. hapla and M. graminicola using immunological, phylogenetic, molecular and bioinformatic research methods.Results and discussion. The present work shows the importance of endogenous FMRFamide-like neuropeptides (FLPs) in such behavioral reactions of plant nematodes as locomotion, which ensures the vital activity of plant parasites; the functional significance of flp genes in the neurobiology of root-knot nematodes is discussed. It was especially noted that the main physiological and functional characteristics of endogenous FLP in root-knot nematodes were obtained as a result of studies of the functional role of the flp genes encoding these neuropeptides. In the nematodes M. incognita and M. graminicola, components of the peptidergic nervous system were identified in the nervous structures: FMRFamide-like positive immunoreactivity, FLP, flp genes encoding neuropeptides, and G-protein-coupled receptors (GPCR) activated by these neuropeptides. It was shown that the main functional characteristics of endogenous FLPs in nematodes were obtained using one of the methods of reverse genetics, i.e., flp genes knockdown in shadow by means of RNA-interference. It has been established that FLP cause two types of physiological effects on the somatic muscles of root-knot nematodes – stimulation of the locomotor activity of the muscles and its inhibition. In most works, the data obtained on the physiological effects of neuropeptides on the locomotor activity of phytonematodes are considered with a view to their possible use in the development of new targeted anthelmintic drugs

РОЛЬ СТЕРОИДНЫХ СОЕДИНЕНИЙ ВО ВЗАИМООТНОШЕНИЯХ РАСТЕНИЙ И ПАРАЗИТИЧЕСКИХ НЕМАТОД

Literature data on steroid metabolism of plant-parasitic nematodes and own research on the feasibility of regulating the number of pathogenic nematodes using plant steroids are presented. Steroidal compounds are essential components of cell membranes, play a significant role in the regulatory process and are signaling mo- lecules. On one side it was shown possibility to affect the steroid metabolism of nematodes depressing their development, depriving necessary sterols; on other side to impact the mevalonate pathway in plants enhancing their immune properties. Analysis of a number of steroid compounds: glycoalkaloids, saponins and ecdy- sones extracted from plants of the Solanaceae, Labiatae and Dioscoreaceae, shows that all tested compounds to a greater or lesser degree can affect the development of the nematode. In examined tomato plant system Solanum esculentum Mill, root- knot nematode Meloidogyne incognita (Kofoid et White) Chitwood, the highest activity among steroidal glycoalkaloids had ɑ-tomatin and ɑ-chaconine, among saponins - tomatozide. While observing the direct impact of steroids on nematodes, we can point out the nematostatic effect of compounds in applied concentrations. On the example of tomato plants treated with ɑ-tomatin the activity of protease inhibitors, agents interrupting digestion of insects and nematodes, is analyzed. Treatment of plants with ɑ-tomatin increases the activity of trypsin inhibitors in the tomato tissues that allows expecting the relation between the plant treatment with ɑ-tomatin and degree of resistance of tomato to nematodesПриведены литературные данные о стероидном метаболизме фитонематод и собственные исследова- ния, касающиеся возможности регулирования чис- ленности патогенных нематод с помощью раститель- ных стероидов. Показана возможность влияния, с од- ной стороны, на стероидный метаболизм нематоды, угнетая еѐ развитие, лишая необходимых стеринов; с другой, - на мевалонатный путь в растениях, повы- шая его иммунные свойства. Анализ ряда стероидных соединений, выделенных из растений семейств пасле- новых, диоскорейных и губоцветных, показал, что все исследованные соединения могут оказывать воздейст- вие на развитие нематоды. В исследуемой системе то- мат Solanum esculentum Mill. - галловая нематода Me- loidogyne incognita (Kofoid et White) Chitwood наи- большей активностью среди стероидных гликоалка- лоидов обладали ɑ-томатин и ɑ-чаконин, среди сапо- нинов - томатозид. При непосредственном воздейст- вии стероидов на нематоду соединения в используемой концентрации обладали нематостатическим действи- ем. На примере обработки растений томата ɑ- томатином проведен анализ активности ингибиторов протеиназ - соединений, нарушающих процесс пище- варения у насекомых и нематод. Обработка растений томатином повышает активность ингибиторов трип- сина в тканях томата, что позволяет предполагать на- личие связи между обработкой растений ɑ-томатином и степенью устойчивости томатов к нематодам

Нейропептиды галловых нематод: функциональное значение в локомоциях паразитов (краткий обзор)

The purpose of the research is to analyze the literature devoted to the study of the physiological role and functional significance of biologically active substances: FMRFamide-like neuropeptides in the locomotion of root-knot nematodes Meloidogyne incognita, M. minor, M. hapla and M. graminicola using immunological, phylogenetic, molecular and bioinformatic research methods.Results and discussion. The present work shows the importance of endogenous FMRFamide-like neuropeptides (FLPs) in such behavioral reactions of plant nematodes as locomotion, which ensures the vital activity of plant parasites; the functional significance of flp genes in the neurobiology of root-knot nematodes is discussed. It was especially noted that the main physiological and functional characteristics of endogenous FLP in root-knot nematodes were obtained as a result of studies of the functional role of the flp genes encoding these neuropeptides. In the nematodes M. incognita and M. graminicola, components of the peptidergic nervous system were identified in the nervous structures: FMRFamide-like positive immunoreactivity, FLP, flp genes encoding neuropeptides, and G-protein-coupled receptors (GPCR) activated by these neuropeptides. It was shown that the main functional characteristics of endogenous FLPs in nematodes were obtained using one of the methods of reverse genetics, i.e., flp genes knockdown in shadow by means of RNA-interference. It has been established that FLP cause two types of physiological effects on the somatic muscles of root-knot nematodes – stimulation of the locomotor activity of the muscles and its inhibition. In most works, the data obtained on the physiological effects of neuropeptides on the locomotor activity of phytonematodes are considered with a view to their possible use in the development of new targeted anthelmintic drugs.Цель исследований – анализ литературы, посвященной изучению физиологической роли и функциональному значению биологически активных веществ: FMRFамид-подобных нейропептидов в локомоциях галловых нематод Meloidogyne incognita, M. minor, M. hapla и M. graminicоla с помощью иммунологических, филогенетических, молекулярных и биоинформатических методов исследования.Результаты и обсуждение. Показано важное значение эндогенных FMRFамид-подобных нейропептидов (FLP) в таких поведенческих реакциях фитонематод, как локомоции, которые обеспечивают жизнедеятельность растительных паразитов; обсуждается функциональное значение flp генов в нейробиологии галловых нематод. Основные физиологические и функциональные характеристики эндогенных FLP у галловых нематод получены в результате исследований функциональной роли flp генов, кодирующих эти нейропептиды. У нематод M. incognita и M. graminicоla в нервных структурах идентифицированы компоненты пептидергической нервной системы: FMRFамид-подобная положительная иммунореактивность, FLP, flp гены, кодирующие нейропептиды, и G-протеин связанные рецепторы (GPCR), активируемые этими нейропептидами. Основные функциональные характеристики эндогенных FLP у нематод получены с помощью одного из методов обратной генетики – временного выключения flp генов посредством РНК-интерференции. Установлено, что FLP вызывают на соматической мускулатуре галловых нематод два вида физиологических эффектов – стимуляцию локомоторной активности мускулатуры и ее угнетение. В большинстве работ полученные данные, о физиологических эффектах нейропептидов на двигательную активность фитонематод рассматриваются с целью возможного использования при разработке новых антигельминтных препаратов направленного действия

Influence of insectocompost obtained by cultivation of the during beetle <i>Ulomoides dermestoides</i> on the ecological-trophic composition and development of soil and phytoparasitic nematodes

The purpose of the research is to study the effect of insect compost obtained as a result of the vital activity of insects of the Coleoptera order Ulomoides dermestoides on the quantitative and qualitative composition of soil nematodes of various ecological and trophic groups, as well as on the morphological and physiological state of plants and infection of tomato plants with root-knot nematodes.Materials and methods. Under laboratory conditions, soil containing a diverse fauna of nematodes was treated with 1% dry and 0.5; 0.75 and 1% aqueous solutions of biocompost. Insect compost was obtained by keeping the U. dermestoides on a dry nutrient mixture. Then a mixture of lawn grasses was sown in the ground. After 30 days, the composition of nematodes was analyzed. The ability of insect compost to suppress parasitic nematode species was studied using the tomato-knot nematode model system. Tomatoes were infected with Meloidogyne incognita at a rate of 500 larvae (J2) per plant and simultaneously treated with a 0.5% aqueous biocompost solution.Results and discussion. The insect compost U. dermestoides has an effect on quantitative and qualitative indicators in the community of soil nematodes, increasing the number of predatory and saprobiotic nematodes and displacing parasitic ones. And due to the content of various biologically active compounds, it affects the development of rootknot nematodes in tomato roots. When tomatoes are treated with an aqueous solution of insect compost, the infection score and the number of nematodes that penetrate the roots are reduced. The introduction of compost when growing a mixture of lawn grasses and tomatoes can improve the condition of the plants

Effect of <i>Meloidogyne incognita</i> infection on the accumulation of phenolic compounds in plants of the genus Mint (Mentha L.)

The purpose of the research is to compare the accumulation of phenolic compounds of different species and varieties of mint, zoned in Central Russia against the background of plant infection by Meloidogyne incognita.Materials and methods. Plants were grown from cuttings in a growing experiment in open ground. Mentha × piperita L. (varieties: Tik-Tak, Orange, Minneola, Mojito, Mitchum, Chocolate), M. spicata L. (varieties Morocco, Crispa) and M. longifolia L. (Longifolia) were taken for the study. A month later, the rooted plants were infected at the rate of 1000 sp. infective larvae of M. incognita per plant. After 8 weeks leaves were fixed in ethanol. The total content of phenolic compounds (PC), phenylpropanoids, flavonoids and catechins was studied using a spectrophotometer. The determination of the total content of PС was carried out using the Folin-Cecolte reagent with measurement at 725 nm, phenylpropanoids – by direct measurement of optical density at 330 nm, flavonoids – by reaction with aluminum chloride at 415 nm, the total content of flavans (catechins - flavan-3-ols), their oligomeric forms – proanthocyanidins, as well as leukoanthocyanidins were assessed by reaction with vanillin at 500 nm.Results and discussion. It has been shown that the accumulation of phenols is related to the species of plants. The varieties Mentha × piperita L. in most cases contained more phenols than M. spicata L. and M. longifolia L. A significant number of PC was noted in the violet-colored varieties Mitchum, Chocolate and Orange. The total content of PC almost completely correlates with the content of their precursors – phenylpropanoids. In terms of the content of flavonoids, the Mitchum variety stands out noticeably, and in terms of the content of catechins, the Orange variety stands out. Nematode infection in most varieties causes a noticeable increase in the total accumulation of soluble PC, phenylpropanoids and flavans, but leads to a decrease in the content of flavonoids

Role of steroid compounds in relationship of plants and parasitic nematodes

Literature data on steroid metabolism of plant-parasitic nematodes and own research on the feasibility of regulating the number of pathogenic nematodes using plant steroids are presented. Steroidal compounds are essential components of cell membranes, play a significant role in the regulatory process and are signaling mo- lecules. On one side it was shown possibility to affect the steroid metabolism of nematodes depressing their development, depriving necessary sterols; on other side to impact the mevalonate pathway in plants enhancing their immune properties. Analysis of a number of steroid compounds: glycoalkaloids, saponins and ecdy- sones extracted from plants of the Solanaceae, Labiatae and Dioscoreaceae, shows that all tested compounds to a greater or lesser degree can affect the development of the nematode. In examined tomato plant system Solanum esculentum Mill, root- knot nematode Meloidogyne incognita (Kofoid et White) Chitwood, the highest activity among steroidal glycoalkaloids had ɑ-tomatin and ɑ-chaconine, among saponins - tomatozide. While observing the direct impact of steroids on nematodes, we can point out the nematostatic effect of compounds in applied concentrations. On the example of tomato plants treated with ɑ-tomatin the activity of protease inhibitors, agents interrupting digestion of insects and nematodes, is analyzed. Treatment of plants with ɑ-tomatin increases the activity of trypsin inhibitors in the tomato tissues that allows expecting the relation between the plant treatment with ɑ-tomatin and degree of resistance of tomato to nematode

INDUCTION OF PLANT RESISTANCE TO NEMATODES SEDENTARY BIOGENIC ELICITORS

Objective of research: to study the mechanisms of induced tomato plant resistance to rootknot nematode Meloidogyne incognita and potato to cyst nematode Globodera rostochiensis.Materials and methods: The biogenic elicitors — chitosan and signal molecules — SA, JA for the modulation of immune plant responses were used. In experiment 1, tubers of potato cultivars Istrinskii (PCN-susceptibility) and Krinitsa (PCN-resistant), were treated with aqueous solutions of the immunomodulators at the specified concentrations. A low molecular weight soluble chitosan and acetylation degree of 15% and signal molecule — SA was used as an elicitor. In experiment 2, system tomato M. incognia was studied. Water solutions of chitosan, signal molecules: SA, JA were used for treatment of tomato seeds for 2 h and then the seeds were planted in sterile soil. The control plants were treated with water. Cultivation of plants was carried out by the standard technique. Plants were maintained in a greenhouse long enough for the nematodes to complete their life cycle. Development of nematodes in the processed plants estimated on morphophysiological and population characteristics. Biochemical indicators of roots and leaves of tomatoes estimated for 14 days after infection of plants. Previously identified major biochemical indicators of the plants in the genome that contain genes that determine the resistance of plants. The effects of biogenic elicitors on plant resistance were also evaluated by some metabolic changes related to natural plant resistance to tomato and potato to plant nematodes. These indicators were studied in clarifying mechanisms of induced resistance.Results and discussion: Biogenic elicitors induce systemic resistance of plants to plant parasitic nematodes — Meloidogyne incognita and Globodera rostochiensis (decrease in the parasitic invasion of the roots; an inhibition of the vital activity of the parasite; a decrease in fertility and the amount of agents sources (larvae and eggs) capable of infecting the plants). The addition of signal molecules (salicylic and jasmonic acid) to elicitors increased their activity as immunomodulators. In present investigation, the mechanisms of induced plant resistance nematode were studied. The data obtained suggest that the mechanisms natural and induced by biogenic elicitors tomato resistance to the nematode have the same origin. These features meet all requirements of the new generation of methods of plant protection and the use of biogenic elicitors to raise plant resistance to parasitic nematodes may be promising

ИНДУЦИРОВАННАЯ УСТОЙЧИВОСТЬ РАСТЕНИЙ КАК АЛЬТЕРНАТИВА ХИМИЧЕСКИМ СРЕДСТВАМ ЗАЩИТЫ РАСТЕНИЙ

Objective of research: to study the mechanisms of induced tomato plant resistance to rootknot nematode Meloidogyne incognita and potato to cyst nematode Globodera rostochiensis.Materials and methods: The biogenic elicitors — chitosan and signal molecules — SA, JA for the modulation of immune plant responses were used. In experiment 1, tubers of potato cultivars Istrinskii (PCN-susceptibility) and Krinitsa (PCN-resistant), were treated with aqueous solutions of the immunomodulators at the specified concentrations. A low molecular weight soluble chitosan and acetylation degree of 15% and signal molecule — SA was used as an elicitor. In experiment 2, system tomato M. incognia was studied. Water solutions of chitosan, signal molecules: SA, JA were used for treatment of tomato seeds for 2 h and then the seeds were planted in sterile soil. The control plants were treated with water. Cultivation of plants was carried out by the standard technique. Plants were maintained in a greenhouse long enough for the nematodes to complete their life cycle. Development of nematodes in the processed plants estimated on morphophysiological and population characteristics. Biochemical indicators of roots and leaves of tomatoes estimated for 14 days after infection of plants. Previously identified major biochemical indicators of the plants in the genome that contain genes that determine the resistance of plants. The effects of biogenic elicitors on plant resistance were also evaluated by some metabolic changes related to natural plant resistance to tomato and potato to plant nematodes. These indicators were studied in clarifying mechanisms of induced resistance.Results and discussion: Biogenic elicitors induce systemic resistance of plants to plant parasitic nematodes — Meloidogyne incognita and Globodera rostochiensis (decrease in the parasitic invasion of the roots; an inhibition of the vital activity of the parasite; a decrease in fertility and the amount of agents sources (larvae and eggs) capable of infecting the plants). The addition of signal molecules (salicylic and jasmonic acid) to elicitors increased their activity as immunomodulators. In present investigation, the mechanisms of induced plant resistance nematode were studied. The data obtained suggest that the mechanisms natural and induced by biogenic elicitors tomato resistance to the nematode have the same origin. These features meet all requirements of the new generation of methods of plant protection and the use of biogenic elicitors to raise plant resistance to parasitic nematodes may be promising.На системах картофель — Globodera rostochiensis и томаты — Meloidogyne incognita показано, что обработка семян томатов и клубней картофеля перед посадкой биогенными индукторами (хитозаном, жасмоновой и салициловой кислотами по отдельности и в сочетании с хитозаном) индуцирует системную устойчивость (СИУ) восприимчивых растений и популяция нематод на растениях, обработанных этими препаратами в определенных концентрациях, проявляла признаки морфо-физиологического угнетения. Показано, что механизм действия СИУ связан с изменением тех же защитных механизмов, которые отмечены при естественном иммунитете растений к нематодам. Применение для повышения устойчивости растений исследованных биогенных индукторов удовлетворяет требованиям нового поколения препаратов для защиты растений и их использование может быть перспективны

THE EFFECT OF RADIATION ON DEVELOPMENT OF ROOT-KNOT NEMATODES

Root-knot nematodes (Meloidogyne spp.) are one of the most important plant parasitic nematodes of great economic importance which reduce the quantity and the quality of the yields of many cultivated and wild plants everywhere (in tropical, subtropical and temperate regions). The objectives of the study were to investigate the changes in the Meloidogyne arenaria and its host Tiny Tim tomato plant under radiation influence The influence of various doses of γ-irradiation (90, 700 and 1800 mGy) on cv. Tiny Tim tomato plants and developing eggs sacs of root-knot nematode Meloidogyne arenaria were investigated. Ionizing radiations of tomato seeds by low dose (90 mGy) stimulate development of plants. High doses of γ-irradiation (700 and 1800 mGy) suppress development (height, root and shoot weight) of tomato plants. High irradiation doses (700 and 1800 mGy) retarded the growth of nematodes. Metric characteristics of M. arenaria females, mainly body size, were smaller. The highest experimental dose (1800 mGy) prevented the development of females of M. arenaria (J4) to mature forms. A change of female to male ratio under the influence of γ- ionizing radiation has been observed, resulting in a decrease in males. These results show aspects for future research into the application of γ-irradiation in management of root-knot nematode

THE INFLUENCE OF RESISTANCE OF TOMATOES ON THE MORPHO-PHYSIOLOGICAL DIVERSITY AND POPULATION CHARACTERISTICS OF ROOT-KNOT NEMATODES MELOIDOGYNE INCOGNITA (KOFOID, WHITE, 1919), CHITWOOD, 1949

Objective of research:  to provide data on the effect of tomato plants with different varietal resistance and immuno-chemical characteristics on the morpho-physiological and population features of root-knot nematode Meloidogyne incognita (Kofoid, White, 1919), Chitwood, 1949.Materials and methods: Tomato plants were infected and cultivated by standard methods.Parameters of nematodes (size, fertility, duration of life cycle, age and sex structure) of 156 lines in hybrids and cultivars of tomato Lycopersicon esculentum (Mill.) with different degrees of resistance to that nematode (resistance index  20% to 90%), as well the tomato cultivar (F1Karlson) which immune status was corrected with the use of immunomodulators.Results and discussion: The increased resistance of plants has a significant effect on total morpho-physiological and some population parameters (size, fertility, time to reach sexual maturity, terms of development, the number of males, etc.). This fact may indicate the modifying effect of immunity factors on parasites. Morpho-physiological features express a regular association between the level of immunity and standard features of parasitic invasions, which is required to ensure a relative stability of host-parasite systems in each particular case