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The state of Santa Catarina is the second-largest producer of rice seeds in Brazil. Research on phytopathogenicbacterias in this crop is scarce and the high frequency of panicle diseases leads to the hypothesis that seeds may be infected by bacteria. This research quantified the incidence of bacteria in the seeds, verified the bacteria viability during the storage period and characterized the associated bacteria. Seeds from the 2018/19 and 2019/20 seasons were analyzed. To check the incidence, the seeds were disinfected, plated on a nutrient agar + fungicide culture medium, and incubated for seven days at 27 °C. To assess viability, every 45 days, three cultivars stored in a processing unit were subjected to the same detection methodology. To characterize, prevalent colonies were isolated on semi-selective culture medium Pantoea genus-specific agar (PGSA), where the ones that showed growth were subjected to deoxyribonucleic acid (DNA) extraction and Polymerase Chain Reaction (PCR), DNA sequencing, and sequence comparison on GenBank. The hypersensitivity reaction (HR) in tobacco was performed using a bacterial suspension of each isolate. All seed samples had an average incidence of 83%. During storage, the seeds maintained stable bacterial viability, with an average incidence of 95% at the beginning of storage and 99% at the end of it. All isolates that grew in PGSA culture medium were identified by molecular characterization with 100% identity with two specimens of Pantoeaananatis and one of them induced RH in tobacco.

O estado de Santa Catarina é o segundo maior produtor de sementes de arroz do Brasil. As pesquisas com bactérias fitopatogênicas nesta cultura são escassas e a alta frequência de doenças da panícula leva à hipótese de que sementes podem estar infectadas por bactérias. O objetivo desta pesquisa foi quantificar a incidência de bactérias nas sementes, verificar a viabilidade das bactérias durante o período de armazenamento e caracterizar as bactérias associadas. Foram analisadas sementes das safras 2018/19 e 2019/20. Para verificar a incidência, as sementes foram desinfestadas, plaqueadas em meio de cultura ágar nutriente + fungicida e incubadas por sete dias a 27 °C. Para avaliar a viabilidade, a cada 45 dias, três cultivares armazenadas em uma unidade de beneficiamento foram submetidas à mesma metodologia de detecção. Para caracterizar, colônias prevalentes foram isoladas em meio de cultura semisseletivo Pantoea genus-specific ágar (PGSA), onde as que apresentaram crescimento foram submetidas à extração do ácido desoxirribonucléico (DNA) e Reação em Cadeia da Polimerase (PCR), sequenciamento do DNA e comparação de sequências no GenBank. A reação de hipersensibilidade (HR) em tabaco foi realizada utilizando uma suspensão bacteriana de cada isolado. Todas as amostras de sementes apresentaram incidência média de 83%. Durante o armazenamento, as sementes mantiveram viabilidade bacteriana estável, com incidência média de 95% no início do armazenamento e 99% ao fim. Todos os isolados que cresceram no meio de cultura PGSA, foram identificados por caracterização molecular com 100% de identidade com dois espécimes de Pantoea ananatis e um deles induziu HR em tabaco.

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En Guatemala, la producción del cultivo de papa se ve afectada por los nematodos Globodera rostochiensis y Globo-dera pallida. La capacidad de ambas especies para formar quistes complica su control y provoca el aumento de sus poblaciones. En Guatemala se reporta la presencia de ambas especies de nematodos por identificación morfológica, sin embargo, no se ha realizado una confirmación molecular. Este es el primer estudio para validar la presencia de ambas especies de nematodos por PCR múltiple y la determinación de la diversidad y estructura genética de las poblaciones utilizando marcadores moleculares. Se realizaron muestreos en cuatro departamentos productores de papa del país. La identificación por PCR se realizó con el cebador común ITS5 y los cebadores PITSr3 específico para G. rostochiensisy PITSp4 para G. pallida. La caracterización molecular se realizó con el marcador AFLP. Se confirmó la presencia de las dos especies de nematodos en los cuatro departamentos. Los índices de diversidad Shannon y heterocigosidad esperada revelaron mayor diversidad genética en G. rostochiensis (H = 0.311, He = 0.301) que en G. pallida (H = 0.035, He = 0.223). Los métodos NJ, DAPC y PCA exhibieron una débil estructura entre las poblaciones de ambas especies de nematodos. Los resultados sugieren un patrón de dispersión desde Quetzaltenango hacia el resto del país, atribuido a la comercialización de semilla contaminada con nematodos. Se sugiere promover programas de socialización sobre los beneficios del uso de semilla certificada, además de constantes monitoreos moleculares para un diagnóstico certero de ambas especies de nematodos.

In Guatemala, potato crop production is affected by the nematodes Globodera rostochiensis and Globodera pallida. The ability of both species to form cysts complicates their control and causes an increase in their populations. In Guatemala, both species of nematodes have been reported by morphological identification; however, molecular confirmation has not been carried out. It is the first study to validate the presence of both nematode species by multiplex PCR and determine the diversity and genetic structure of the populations using molecular markers. Sampling was carried out in four pota-to-producing departments of the country. PCR identification was performed with the common primer ITS5 and the primers PITSr3 specific for G. rostochiensis and PITSp4 for G. pallida. We performed molecular characterization with the AFLP marker. We confirmed the presence of the two nematode species in the four departments. Shannon diversity and expected heterozygosity indices revealed higher genetic diversity in G. rostochiensis (H = 0.311, He = 0.301) than in G. pallida (H = 0.035, He = 0.223). The NJ, DAPC, and PCA methods exhibited weak structure among populations of both nematode species. The results suggest a dispersal pattern from Quetzaltenango to the rest of the country, attributed to the commer-cialization of seed contaminated with nematodes. We suggest promoting socialization programs on the benefits of using certified seeds and constant molecular monitoring for an accurate diagnosis of both species of nematodes.

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Body size is commonly associated with biological features such as reproductive capacity, competition, and resource acquisition. Many studies have tried to understand how these isolated factors can affect the body pattern of individuals. However, little is known about how interactions among species in multitrophic communities determine the body shape of individuals exploiting the same resource. Here, we evaluate the effect of fruit infestation, parasitism rate, and seed biomass on size, allometric and asymmetric patterns of morphological structures of insects that exploit the same resource. To test it, we measured 750 individuals associated with the plant Senegalia tenuifolia (Fabaceae), previously collected over three consecutive years. Negative allometry was maintained for all species, suggesting that with increasing body size the body structure did not grow proportionally. Despite this, some variations in allometric slopes suggest that interactions in a multitrophic food web can shape the development of these species. Also, we observed a higher confidence interval at higher categories of infestation and parasitism rate, suggesting a great variability in the allometric scaling. We did not observe fluctuating asymmetry for any category or species, but we found some changes in morphological structures, depending on the variables tested. These findings show that both allometry and morphological trait measurements are the most indicated in studies focused on interactions and morphometry. Finally, we show that, except for the fluctuating asymmetry, each species and morphological structure respond differently to interactions, even if the individuals play the same functional role within the food web.

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The stink bug Nezara viridula is one of the most threatening pests for agriculture in North and South America, and its oral secretion may be responsible for the damage it causes in soybean (Glycine max) crop. The high level of injury to seeds caused by pentatomids is related to their feeding behavior, morphology of mouth parts, and saliva, though information on the specific composition of the oral secretion is scarce. Field studies were conducted to evaluate the biochemical damage produced by herbivory to developing soybean seeds. We measured metabolites and proteins to profile the insect saliva in order to understand the dynamics of soybean-herbivore interactions. We describe the mouth parts of N. viridula and the presence of metabolites, proteins and active enzymes in the watery saliva that could be involved in seed cell wall modification, thus triggering plant defenses against herbivory. We did not detect proteins from bacteria, yeasts, or soybean in the oral secretion after feeding. These results suggest that the digestive activity and organic compounds of watery saliva may elicit a plant self-protection response. This study adds to our understanding of stink bug saliva plasticity and its role in the struggle against soybean defenses.

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The coffee berry borer (CBB) is one of the main coffee pests in the world including Colombia. This pest is difficult to manage because of its cryptic habits and the continuous availability of coffee fruits. Among the new management strategies being tested is the use of volatile compounds as insect repellents. In this work, the behavioral response of female adult CBBs to terpenes previously identified in the CBB-repellent plant species Lantana camara was evaluated. α-Terpinene, (R)-limonene, farnesene and ß-caryophyllene terpenes were tested via a Y-tube olfactometer in which ripe coffee fruits were accompanied by terpenes at concentrations between 25 and 200 ppm. Only ß-caryophyllene induced a significant and consistent CBB repellent effect at all tested doses. The protective effect of microencapsulated ß-caryophyllene was then determined under laboratory conditions by incorporating the terpene in a colloidosome-gel system at 2.8 × 105 ng/h in the middle of coffee fruits with adult CBBs. The coffee fruits in turn presented a decrease in fruit infestation. Furthermore, the protection of coffee fruits when ß-caryophyllene gels were hung in coffee trees was evaluated in the field; infestations were artificially induced by the use of raisins (CBB-infested old coffee fruits) placed on the ground. Compared with unprotected trees, the trees treated with caryophyllene gels exhibited a 33 to 45% lower degree of infestation. Taken together, the results show that ß-caryophyllene is a promising compound for an integrated pest management (IPM) program in commercial coffee plantations.

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The aim of this research was to identify and quantify fungi infecting irrigated rice seeds produced in the 2015/16, 2016/17 and 2017/18 harvests in the pre-germinated system in the Alto Vale do Itajaí Region, Santa Catarina State, Brazil. A total of 479 lots of eight cultivars were analyzed. Seeds were disinfected and sown in potato-sucrose-agar culture medium with incubation for seven days at 25ºC ± 2ºC and photoperiod of 12 hours. The main fungus detected in the three crops season was Microdochium albescens with 54.9% of average incidence, followed by Alternaria padwikii (7.7%) and Bipolaris oryzae (3.3%).(AU)

O objetivo deste trabalho foi identificar e quantificar fungos infectando sementes de arroz irrigado, produzidas nas safras 2015/16, 2016/17 e 2017/18, no sistema pré-germinado na região do Alto Vale do Itajaí, estado de Santa Catarina. Foram analisados 479 lotes de oito cultivares, sendo as sementes desinfestadas e semeadas em meio de cultura de batata-sacarose-ágar com incubação por sete dias a 25ºC ± 2 ºC e fotoperíodo de 12 horas. O principal fungo detectado nas três safras foi Microdochium albescens com 54,9% de incidência média, seguido de Alternaria padwikii (7,7%) e Bipolaris oryzae (3,3%).(AU)

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We studied seeds from a set of plant species from the Convolvulaceae family. Seeds collected from natural populations and infested with beetles of genus Megacerus were monitored until the beetle emergence. We analyze the relationship between body weight of beetles and seed weight of host plants, and its connection with between-species differences and sexual dimorphism. The results show that differences in the scaling of body weight of beetles are associated with sexual dimorphism. For the same species of beetle, the females tend to have heavier bodies than the males. Differences between host plants species in the weight of seeds are related to differences in the body weight Megacerus species, resulting in a distinctive pattern of seed infestation across hosts. Small-sized (lighter) species of beetles tended to infest small-sized (lighter) seed species and, correspondingly, heavier beetles species tended to do it in heavier seed species. Mechanisms of female oviposition preferences may be involved to generate that pattern. In general, the beetle weight showed an asymptotic relation with the host seed weight. The greater the weight of the seed, the greater the weight of adult beetle was. However, the proportion in weights reaches an asymptotic value probably because beetles reached the maximum possible weight for their species. We conclude that the process of specialization in the seed-beetle assemblage studied is influenced by intrinsic traits of the species involved in the interaction (beetles and seeds) and by differences between sexes in their sexual-allocation paths.

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Aphelenchoides besseyi and A. fujianensis have been frequently found in mixed populations associated with forage grass seed in Brazil. The morphological similarity between both species has previously led A. fujianensis to be erroneously identified as A. besseyi. A. besseyi is a quarantine pest in many countries that import Brazilian forage seed; however, there is no current evidence suggesting that A. fujianensis is a plant-parasitic species. Two real-time polymerase chain reaction (qPCR) diagnostics were developed to detect each species and an operational envelope was established. A set of primers and hydrolysis probes for each species was designed targeting the large subunit (LSU) region. To assess their specificity, primers and probes sets were tested with samples of nontarget Aphelenchoides and Paraphelenchus sp. also frequently associated with forage seed. Experiments using dilutions of purified plasmid standards underpinned the sensitivity of the qPCR assays, which detected as few as 10 copies of target nematode ribosomal DNA. Thus, the developed diagnostics were sufficiently sensitive to detect DNA extracted from a fragment of a single target nematode. There was a positive correlation between copy number of the target species and nematode abundance, suggesting the potential of this method for quantification. Evidence of intra-individual variability among cloned sequences of the LSU region in a single A. besseyi population is also reported.

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The objective of this study was to evaluate the efficacy of the active ingredient abamectin, either in isolation or in combination with fungicides and insecticides formulated for the industrial seed treatment, on the population of Meloidogyne javanica, tested under greenhouse and in vitro conditions. In both tests, the combination of the following treatments was assessed: abamectin; thiamethoxam; fludioxonil + metalaxyl-M + thiabendazole. Water was used as control for the in vitro assay, whereas under greenhouse conditions, controls were inoculated and not inoculated with M. javanica. The tests were conducted in a completely randomized design with six (in vitro) and ten (greenhouse) replicates. For in vitro studies the effect on hatching, motility, and mortality of juveniles of M. javanica was evaluated. Under greenhouse conditions, the soybean BRS 133 seeds were treated, and at 15, 30, and 60 days after inoculation (DAI) with M. javanica, plant measurements were recorded. The penetration of second stage juveniles (J2) was also evaluated at 15 DAI. At 30 DAI, galls, egg masses, nematodes/g of root, and final population were evaluated. At 60 DAI, the final population of nematodes in the roots was quantified. The treatments containing abamectin were the most effective in diminishing the hatching of juveniles. All treatments had an effect on nematode motility when compared to the control, and in thetreatment containing only abamectin, total juvenile mortality was observed. In greenhouse conditions,at 15 DAI, the treated soybean plants had the highest root mass and shoot length, differing statisticallyfrom the inoculated control. All treatments reduced the number of nematodes per gram of root, differingfrom the control. At 30 DAI, treatment efficiency was observed in reducing the final population of M.javanica, particularly the treatments using abamectin, and abamectin + thiamethoxam + fludioxonil +metalaxyl-M + thiabendazole. However, at 60 DAI...(AU)

O objetivo do trabalho foi avaliar a eficiência do ingrediente ativo abamectina, isolado ou em combinação com fungicidas e inseticidas formulados para o tratamento industrial de sementes, sobre a população de Meloidogyne javanica, in vitro e em casa de vegetação. Em ambos os ensaios, avaliou-se a combinação dos tratamentos: abamectina; thiamethoxam; fludioxonil + metalaxil-m + tiabendazol. Como controle utilizou-se água para o ensaio in vitro, e testemunhas inoculada e não inoculada com M. javanica, em casa de vegetação. Os ensaios foram realizados em delineamento inteiramente casualizado com seis (in vitro) e 10 (casa de vegetação) repetições. In vitro, avaliou-se o efeito sobre a eclosão, motilidade e mortalidade dos juvenis de M. javanica. Em casa de vegetação, as sementes da cultivar de soja BRS 133 foram tratadas e aos 15, 30 e 60 dias após a inoculação (DAI) com M. javanica foram realizadas mensurações fitométricas das plantas. Avaliaram-se, também, aos 15 DAI a penetração de juvenis de segundo estádio (J2); aos 30 DAI avaliou-se galhas, massas de ovos, nematoides/g de raiz e população final; e aos 60 DAI quantificou-se a população final de nematoides nas raízes. Os tratamentos contendo abamectina foram os mais eficientes em diminuir a eclosão dos juvenis. Todos os tratamentos apresentaram efeito na motilidade dos nematoides com relação à testemunha, sendo que no tratamento contendo apenas abamectina foi observada, também, a total mortalidade dos juvenis. Emcasa de vegetação, aos 15 DAI, as plantas de soja tratadas apresentaram maior massa fresca de raiz ecomprimento da parte aérea, diferindo estatisticamente da testemunha inoculada. Todos os tratamentosreduziram o número de nematoides por grama de raiz, diferindo da testemunha. Aos 30 DAI, observouseeficiência dos tratamentos em reduzir a população final de M. javanica, destacando-se os tratamentosabamectina e abamectina + thiamethoxam + fludioxonil + metalaxil-m + tiabendazole. No entanto...(AU)

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Root-knot nematodes (Meloidogyne spp) are destructive agricultural pests that reduce the productivity of cultivated vegetables worldwide, especially when vegetables are cropped continuously in greenhouses. Cucumbers (Cucumis sativus L.), in particular, suffer extensive damage due to root-knot nematodes, and only a few wild species are known to be resistant. Grafting of cultivated plants to rootstocks of known resistant germplasms could be an effective method to resolve this problem. In this study, 21 cucumber germplasms and seven rootstocks were evaluated for resistance based on the growth of cucumber seedlings and resistance indexes to Meloidogyne incognita, which were surveyed 25 days after inoculation with M. incognita. Cluster analysis and principal component analysis (PCA) were used to investigate the resistance of 21 cucumber germplasms and seven rootstocks based on their growth and resistance indexes after inoculation with M. incognita. These analyses showed that the 21 germplasms and seven rootstocks could be divided into three groups based upon their resistance levels: moderately resistant, susceptible, and highly susceptible to M. incognita. All 21 cucumber germplasms exhibited susceptibility or high susceptibility to M. incognita and most rootstocks exhibited moderate resistance. The PCA results were consistent with those of the clustering analysis. The Jinyou No.1 cultivar had the highest resistance to M. incognita among the 21 cucumber germplasms, and Huangzhen No.1 cultivar had the highest resistance among the seven rootstock cultivars.

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The availability of common bean cultivars tolerant to Meloidogyne javanica is limited in Brazil. Thus, the present study aimed to evaluate the reactions of 33 common bean genotypes (23 landrace, 8 commercial, 1 susceptible standard and 1 resistant standard) to M. javanica, employing multivariate statistics to discriminate the reaction of the genotypes. The experiment was conducted in a greenhouse using a completely randomized design with seven replicates. The seeds were sown in 1-L pots containing autoclaved soil and sand in a 1:1 ratio (v:v). On day 19, after emergence of the seedlings, the plants were treated with inoculum containing 4000 eggs + second-stage juveniles (J2). At 60 days after inoculation, the seedlings were evaluated based on biometric and parasitism-related traits, such as number of galls, final nematode population per root system, reproduction factor, and percent reduction in the reproduction factor of the nematode (%RRF). The data were subjected to analysis of variance using the F-test. The Mahalanobis generalized distance was used to obtain the dissimilarity matrix, and the average linkage between groups was used for clustering. The use of multivariate statistics allowed groups to be separated according to the resistance levels of genotypes, as observed in the %RRF. The landrace genotypes FORT-09, FORT-17, FORT-31, FORT-32, FORT-34 and FORT-36 presented resistance to M. javanica; thus, these genotypes can be considered potential sources of resistance.

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PREMISE OF STUDY: The factors driving variation in species interactions are often unknown, and few studies have made a link between changes in interactions and the strength of selection. METHODS: We report on spatial variation in functional responses by a seed predator (SP) and its parasitic wasps associated with the herb Ruellia nudiflora. We assessed the influence of plant density on consumer responses and determined whether density effects and spatial variation in functional responses altered natural selection by these consumers on the plant. We established common gardens at two sites in Yucatan, Mexico, and planted R. nudiflora at two densities in each garden. We recorded fruit output and SP and parasitoid attack; calculated relative fitness (seed number) under scenarios of three trophic levels (accounting for SP and parasitoid effects), two trophic levels (accounting for SP but not parasitoid effects), and one trophic level (no consumer effects); and compared selection strength on fruit number under these scenarios across sites and densities. KEY RESULTS: There was spatial variation in SP recruitment, whereby the SP functional response was negatively density-dependent at one site but density-independent at the other; parasitoid responses were density-independent and invariant across sites. Site variation in SP attack led, in turn, to differences in SP selection on fruit output, and parasitoids did not alter SP selection. There were no significant effects of density at either site. CONCLUSIONS: Our results provide a link between consumer functional responses and consumer selection on plants, which deepens our understanding of geographic variation in the evolutionary outcomes of multitrophic interactions.

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The objective of this study was to evaluate the efficacy of the active ingredient abamectin, either in isolation or in combination with fungicides and insecticides formulated for the industrial seed treatment, on the population of Meloidogyne javanica, tested under greenhouse and in vitro conditions. In both tests, the combination of the following treatments was assessed: abamectin; thiamethoxam; fludioxonil + metalaxyl-M + thiabendazole. Water was used as control for the in vitro assay, whereas under greenhouse conditions, controls were inoculated and not inoculated with M. javanica. The tests were conducted in a completely randomized design with six (in vitro) and ten (greenhouse) replicates. For in vitro studies the effect on hatching, motility, and mortality of juveniles of M. javanica was evaluated. Under greenhouse conditions, the soybean BRS 133 seeds were treated, and at 15, 30, and 60 days after inoculation (DAI) with M. javanica, plant measurements were recorded. The penetration of second stage juveniles (J2) was also evaluated at 15 DAI. At 30 DAI, galls, egg masses, nematodes/g of root, and final population were evaluated. At 60 DAI, the final population of nematodes in the roots was quantified. The treatments containing abamectin were the most effective in diminishing the hatching of juveniles. All treatments had an effect on nematode motility when compared to the control, and in thetreatment containing only abamectin, total juvenile mortality was observed. In greenhouse conditions,at 15 DAI, the treated soybean plants had the highest root mass and shoot length, differing statisticallyfrom the inoculated control. All treatments reduced the number of nematodes per gram of root, differingfrom the control. At 30 DAI, treatment efficiency was observed in reducing the final population of M.javanica, particularly the treatments using abamectin, and abamectin + thiamethoxam + fludioxonil +metalaxyl-M + thiabendazole. However, at 60 DAI...

O objetivo do trabalho foi avaliar a eficiência do ingrediente ativo abamectina, isolado ou em combinação com fungicidas e inseticidas formulados para o tratamento industrial de sementes, sobre a população de Meloidogyne javanica, in vitro e em casa de vegetação. Em ambos os ensaios, avaliou-se a combinação dos tratamentos: abamectina; thiamethoxam; fludioxonil + metalaxil-m + tiabendazol. Como controle utilizou-se água para o ensaio in vitro, e testemunhas inoculada e não inoculada com M. javanica, em casa de vegetação. Os ensaios foram realizados em delineamento inteiramente casualizado com seis (in vitro) e 10 (casa de vegetação) repetições. In vitro, avaliou-se o efeito sobre a eclosão, motilidade e mortalidade dos juvenis de M. javanica. Em casa de vegetação, as sementes da cultivar de soja BRS 133 foram tratadas e aos 15, 30 e 60 dias após a inoculação (DAI) com M. javanica foram realizadas mensurações fitométricas das plantas. Avaliaram-se, também, aos 15 DAI a penetração de juvenis de segundo estádio (J2); aos 30 DAI avaliou-se galhas, massas de ovos, nematoides/g de raiz e população final; e aos 60 DAI quantificou-se a população final de nematoides nas raízes. Os tratamentos contendo abamectina foram os mais eficientes em diminuir a eclosão dos juvenis. Todos os tratamentos apresentaram efeito na motilidade dos nematoides com relação à testemunha, sendo que no tratamento contendo apenas abamectina foi observada, também, a total mortalidade dos juvenis. Emcasa de vegetação, aos 15 DAI, as plantas de soja tratadas apresentaram maior massa fresca de raiz ecomprimento da parte aérea, diferindo estatisticamente da testemunha inoculada. Todos os tratamentosreduziram o número de nematoides por grama de raiz, diferindo da testemunha. Aos 30 DAI, observouseeficiência dos tratamentos em reduzir a população final de M. javanica, destacando-se os tratamentosabamectina e abamectina + thiamethoxam + fludioxonil + metalaxil-m + tiabendazole. No entanto...

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Malpighia emarginata is cultivated in almost all Brazil and is considered an important agricultural crop. The root-knot nematode Meloidogyne enterolobii has been described as a major threat to this crop, causing great production losses. Due to the scarcity of information about the severity of this parasite in M. emarginata plants in Brazil, this study investigated M. enterolobii resistance of ten M. emarginata genotypes from the active germplasm bank of Universidade Federal Rural de Pernambuco. The experiment was conducted adopting a completely randomized design in a factorial arrangement of 11 x 2 x 5, where M. emarginata cuttings were inoculated with 10,000 eggs in a greenhouse. After 150 days, plants were evaluated for the following parameters: gall index, egg mass index, number of eggs per root system, number of eggs per gram of root, and reproduction factor. The accessions showed different responses depending on host x pathogen interaction, from susceptibility to moderate tolerance. Accessions 027-CMF and 031-CMF were considered tolerant to the nematode and could be of great value in new breeding programs for resistance to M. enterolobii infection.

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Gall inducers use these structures as shelters and sources of nutrition. Consequently, they cause multiple physiological changes in host plants. We studied the impact caused by seed coat galls of a braconid wasp on the performance of fruits, seeds and seedlings of tree Inga laurina. We tested whether these seed galls are 'nutrient sinks' with respect to the fruit/seed of host plant, and so constrain the reproductive ability and reduce seedling longevity. We measured the influence of such galls on the secondary compounds, fruit and seed parameters, seed viability and germination and seedling performance. Inga laurina has indehiscent legumes with polyembryonic seeds surrounded by a fleshy sarcotesta rich in sugars. The galls formed inside the seed coat and galled tissues presented higher phenol concentrations, around 7-fold that of ungalled tissues. Galls caused a significant reduction in parameters such as fruit and seed size, seed weight and the number of embryos. Fluctuating asymmetry (a stress indicator) was 31% higher in leaves of galled seed plants in comparison to ungalled seed plants. However, the negative effects on fruit and seed parameters were not sufficient to reduce seed germination (except the synchronization index) or seedling performance (except leaf area and chlorophyll content). We attributed these results to the ability of I. laurina to tolerate gall attack on seeds without a marked influence on seedling performance. Moreover, because of the intensity of seed galling on host plant, we suggest that polyembryony may play a role in I. laurina reproduction increasing tolerance to seed damage.

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The seed coat is an external tissue that participates in defense against insects. In some nonhost seeds, including Albizia lebbeck, the insect Callosobruchus maculatus dies during seed coat penetration. We investigated the toxicity of A. lebbeck seed coat proteins to C. maculatus. A chitin-binding protein fraction was isolated from seed coat, and mass spectrometry showed similarity to a C1 cysteine protease. By ELM program an N-glycosylation interaction motif was identified in this protein, and by molecular docking the potential to interact with N-acetylglucosamine (NAG) was shown. The chitin-binding protein fraction was toxic to C. maculatus and was present in larval midgut and feces but not able to hydrolyze larval gut proteins. It did not interfere, though, with the intestinal cell permeability. These results indicate that the toxicity mechanism of this seed coat fraction may be related to its binding to chitin, present in the larvae gut, disturbing nutrient absorption.

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BACKGROUND: Southern green stink bugs (Nezara viridula L.) invade field-grown soybean crops, where they feed on developing seeds and inject phytotoxic saliva, which causes yield reduction. Although leaf responses to herbivory are well studied, no information is available about the regulation of defences in seeds. RESULTS: This study demonstrated that mitogen-activated protein kinases MPK3, MPK4 and MPK6 are expressed and activated in developing seeds of field-grown soybean and regulate a defensive response after stink bug damage. Although 10-20 min after stink bug feeding on seeds induced the expression of MPK3, MPK6 and MPK4, only MPK6 was phosphorylated after damage. Herbivory induced an early peak of jasmonic acid (JA) accumulation and ethylene (ET) emission after 3 h in developing seeds, whereas salicylic acid (SA) was also induced early, and at increasing levels up to 72 h after damage. Damaged seeds upregulated defensive genes typically modulated by JA/ET or SA, which in turn reduced the activity of digestive enzymes in the gut of stink bugs. Induced seeds were less preferred by stink bugs. CONCLUSION: This study shows that stink bug damage induces seed defences, which is perceived early by MPKs that may activate defence metabolic pathways in developing seeds of field-grown soybean. © 2015 Society of Chemical Industry.

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Horismenus abnormicaulis sp. nov., H. patensis sp. nov. and H. zuleidae sp. nov. (Hymenoptera: Eulophidae), all authored by Pikart, Costa & Hansson, are described from material obtained from seed pods of Pithecellobium dulce (Roxb.) Benth. (Fabaceae) collected in Northeastern Brazil. The seed pods were infested with larvae of Coleoptera (Chrysomelidae (Bruchinae) and Curculionidae). The associations of the Horismenus species and the beetle larvae have not been established. Morphological similarities between these new species and previously described species with host known suggest that H. patensis and H. zuleidae are primary parasitoids of Bruchinae, whereas H. abnormicaulis may act as a hyperparasitoid on other Horismenus species. The three species are compared with similar species of Horismenus.

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RESUMO

The objective of this research was to develop a methodology to describe the movement of the coffee berry borer Hypothenemus hampei (Coleoptera: Curculionidae) in the field through: (i) the evaluation of allele variation of a microsatellite marker on polymorphic Colombian H. hampei populations; (ii) the invention of a device for releasing H. hampei adults; (iii) the standardization of a release-recapture technique for H. hampei populations; (iv) the estimation of the flight distance of the insect; and (v) the calculation of a mathematical expression that describes the movement of H. hampei in space over time. The results indicated that: (i) the microsatellite molecular marker HHK.1.6 was exclusively present in a population from Guapotá-Santander, was dominant and allows the evaluation of H. hampei movement for several generations; (ii) a device that released 88.8% of H. hampei adults in 2 s was designed; (iii) this device was used as H. hampei populations containing HHK.1.6 marker release strategy, and coffee seeds as recapture strategy; (iv) it was estimated that H. hampei adults flew as far as 65 m, however, 90% were recovered in a radius of <40 m. Finally, (v) the mathematical expression that described the movement of H. hampei in space over time was [Formula: see text], being [Formula: see text] the average number of borer beetles recaptured per tree, and x the distance in meters. This method will allow to determine the movement of H. hampei from different environmental and ecological scenarios.

Assuntos

RESUMO

Scatter hoarding of seeds by animals contributes significantly to forest-level processes, including plant recruitment and forest community composition. However, the potential positive and negative effects of caching on seed survival, germination success, and seedling survival have rarely been assessed through experimental studies. Here, I tested the hypothesis that seed burial mimicking caches made by scatter hoarding Central American agoutis (Dasyprocta punctate) enhances seed survival, germination, and growth by protecting seeds from seed predators and providing favorable microhabitats for germination. In a series of experiments, I used simulated agouti seed caches to assess how hoarding affects seed predation by ground-dwelling invertebrates and vertebrates for four plant species. I tracked germination and seedling growth of intact and beetle-infested seeds and, using exclosures, monitored the effects of mammals on seedling survival through time. All experiments were conducted over three years in a lowland wet forest in Costa Rica. The majority of hoarded palm seeds escaped predation by both invertebrates and vertebrates while exposed seeds suffered high levels of infestation and removal. Hoarding had no effect on infestation rates of D. panamensis, but burial negatively affected germination success by preventing endocarp dehiscence. Non-infested palm seeds had higher germination success and produced larger seedlings than infested seeds. Seedlings of A. alatum and I. deltoidea suffered high mortality by seed-eating mammals. Hoarding protected most seeds from predators and enhanced germination success (except for D. panamensis) and seedling growth, although mammals killed many seedlings of two plant species; all seedling deaths were due to seed removal from the plant base. Using experimental caches, this study shows that scatter hoarding is beneficial to most seeds and may positively affect plant propagation in tropical forests, although tradeoffs in seed survival do exist.

Assuntos