The liquid-liquid extraction with low-temperature partitioning technique (LLE/LTP) was miniaturized to determine the pesticides chlorpyrifos, bifenthrin, λ-cyhalothrin, and deltamethrin in a biological matrix, by gas chromatography. The method was proposed for fetal-bovine serum samples (500 μL), by using a full factorial design (23) with one center point. The evaluated factors included the volume of water added to the sample (1000 μL), volume of extraction solvent (500 μL) and stirring time (60 s) – a cleanup step was not necessary. The method was validated for the main figures of merit. The results indicated that the LLE/LTP/GC/ECD miniaturized method was efficient in extracting pesticides from blood-serum samples (75 to 115%). It showed both selectivity and sensitiveness, with limits of quantification (LOQ) ranging from 8 at 17 μg L-1;. Once validated, the method was applied to blood-serum samples of rural workers from a city in the Brazilian state of Minas Gerais. In that case, the presence of chlorpyrifos was detected in two of the samples.

Abstract The spittlebugs Mahanarva spectabilis economically challenges cattle production of neotropical regions, due to its voracious feeding on tropical grasses. Here, we evaluated biochemical responses of the interaction between M. spectabilis and the widely cultivated tropical grasses Brachiaria spp. (i.e., brizantha and decumbens) and elephant grasses (cvs. Roxo de Botucatu and Pioneiro), regarding lipoxygenases, protease inhibitors, phytohormones, and proteolytic activities in the midgut of M. spectabilis. The M. spectabilis-infested grasses increased lipoxygenases activity, except for cv. Pioneiro. The levels of the phytohormones jasmonic and abscisic acids were similarly low in all genotypes and increased under herbivory. Furthermore, salicylic acid concentration was constitutively higher in Brachiaria sp., increasing only in spittlebug-infested B. decumbens. M. spectabilis infestations did not induce increases of protease inhibitors in any forage grass type. The trypsin activity remained unaltered, and the total proteolytic activity increased only in B. decumbens-fed insects. Our findings revealed that most forage grasses exposed to spittlebugs activate the lipoxygenases pathway, resulting in increased abscisic and jasmonic acids. However, greater amounts of these hormones do not induce protease inhibitory activity in response to spittlebug attack. This knowledge certainly helps to guide future projects aiming at reducing the impact of spittlebugs on forage production.

Abstract Anticarsia gemmatalis Hübner, 1818 (Lepidoptera) is a major pest of soybean in the Brazil. It is known that the reduction of proteolytic activity by the ingestion of protease inhibitors reduces digestion and larval development of the insects. Control via inhibition of the digestive enzymes necessitates deeper knowledge of the enzyme kinetics and the characterization of the inhibition kinetics of these proteases, for better understanding of the active centers and action mechanisms of this enzyme. Trypsin-like proteases found in the gut of Anticarsia gemmatalis were purified in a p-aminobenzamidine agarose column. Kinetic characterization showed KM 0.503 mM for the L-BApNA substrate; Vmax= 46.650 nM s-1; Vmax/[E]= 9.256 nM s-1 mg L-1 and Vmax/[E]/KM= 18.402 nM s-1 mg L-1 mM. The Ki values for the inhibitors benzamidine, berenil, SKTI and SBBI were 11.2 µM, 32.4 µM, 0.25 nM and 1.4 nM, respectively, and all revealed linear competitive inhibition. The SKTI showed the greatest inhibition, which makes it a promising subject for future research to manufacture peptide mimetic inhibitors.

Abstract The recognition of protease inhibitors with insecticidal activity is important as a basis for the development of mimetic peptides with potential use as biorational insecticides. We sprayed benzamidine on soybean plants and assessed whether this potent synthetic trypsin-inhibitor has protease inhibitory, insecticidal and deterrent effects on the velvetbean caterpillar Anticarsia gemmatalis Hübner (Lepidoptera: Erebidae). Activity of trypsin inhibition in soybean leaves was increased and total proteolytic activity in the midgut extract from larvae fed on these leaves was reduced by benzamidine. Different concentrations of benzamidine sprayed on the plant caused approximately 50 % of larval mortality, and larval choice and moth preference and oviposition were all negatively affected. Low concentrations of benzamidine increased mortality and hindered insect choice and oviposition as well as higher doses. Since many synthetic protease inhibitors are usually expensive, small doses of benzamidine may be effective to protect soybean against A. gemmatalis attack. Our results highlight the potential of synthetic protease inhibitors for insecticidal and deterrent purposes in insect pest management.

Endogenous mechanisms of plant resistance to herbivorous insects could be adapted to enable the development of alternative strategies for pest control. Activation of the lipoxygenase (LOX) pathway by jasmonic acid, the hormone responsible for activating genes encoding protease inhibitors (PI), is one of the main direct defenses of plants against insects. In this study, soybean cultivars at the V3 stage that were either susceptible or resistant to herbivorous insects were used to investigate changes in the activity of LOX and concentration of PIs in response to 24- or 48-h feeding by fourth and fifth instar Anticarsia gemmatalis (Lepidoptera: Noctuidae) larvae. LOX activity (0.0-0.007 nm s-1/mg) and the PI concentration (60 to 125 mg of trypsin inhibitor / mg of protein and 90 to 120 mg of trypsin inhibitor / mg protein after 24 and 48 h after attack, respectively) both increased in response to damage caused by A. gemmatalis. Proteolytic activity decreased by approximately 50% in cultivars with different degrees of resistance. Raised enzyme profiles in the midgut of A. gemmatalis may be related to tryptic enzymes that increased, compensating for the inhibition of proteases by entomotoxic substances of the soybean cultivars.

Los mecanismos de resistencia endógenos de las plantas contra insectos herbívoros pueden permitir el desarrollo de estrategias alternativas para el control de plagas. La activación de la vía de las lipoxigenasas con la producción de ácido jasmónico, hormona responsable por la activación de los genes inhibidores de proteasa, es una de las principales formas de defensa directa de las plantas contra los insectos. En el presente estudio, cultivares de soya en estadio V3, susceptibles y resistentes a insectos herbívoros fueron utilizadas para investigar las alteraciones en la actividad de LOX y la concentración de PIs, en respuesta al ataque de orugas en cuarto y quinto instar de Anticarsia gemmatalis (Lepidóptera: Noctuidae) por 24 y 48 horas. La actividad de LOX (0,00 a 0,007 nm s-1/mg) y la concentración de inhibidores de proteasa (60 a 125 mg de inhibidor de tripsina/ mg de proteína y 90 a 120 mg de inhibidor de tripsina/mg de proteína después de 24 y 48 horas del ataque respectivamente) aumenta en respuesta a los daños ocasionados por A. gemmatalis. La actividad proteolítica disminuyó aproximadamente en 50% en los cultivares con diferentes grados de resistencia. El aumento del perfil enzimático del intestino medio de A. gemmatalis puede estar relacionado al aumento de las enzimas trípticas para compensar la inhibición de proteasas por sustancias entomotóxicas de los cultivares de soya.

O estudo investigou o efeito do silício (Si) e de doses de manganês (Mn) na atividade das enzimas peroxidases (POX), polifenoloxidases (PFO) e fenilalanina amônia-liases (FAL) em plantas não inoculadas e inoculadas com Bipolaris oryzae. Plantas de arroz (cultivar Metica 1) foram cultivadas em solução nutritiva com 0 (-Si) e 2 mmol Si L-1 (+Si) e com as doses de 0,5; 2,5 e 10 µmol Mn L-1. As plantas foram inoculadas com B. oryzae e amostras de folhas foram coletadas às 6, 12, 18, 24, 36 e 48 h após inoculação (hai). Amostras de folhas de plantas não-inoculadas, nestes mesmos tempos, também foram coletadas. Para as doses de 0,5 e 2,5 µmol Mn L-1, a atividade da POX aumentou para as plantas -Si com um pico às 48 hai na dose de 10 mmol Mn L-1. Para as plantas +Si, a atividade da POX também aumentou, mas foi baixa para as doses de 2,5 e 10 mmol Mn L-1. A atividade da POX não foi afetada pelas doses de Mn na presença de Si. No entanto, na ausência de Si a atividade da POX aumentou. Para a dose de 0,5 mmol Mn L-1, a atividade da PFO nas plantas -Si aumentou, mas não foi afetada pelas outras duas doses de Mn, exceto um pico às 18 hai na dose de 10 mmol Mn L-1. Na presença de Si, a atividade PFO aumentou nas plantas que receberam 2,5 mmol Mn L-1 em contraste com as outras duas doses de Mn para as quais a atividade da PFO decresceu. Ao comparar os tratamentos -Si e +Si na dose de 2,5 mmol Mn L-1, atividade da PFO aumentou das 18 às 36 hai para as plantas supridas com Si. A atividade da FAL nas plantas -Si decresceu independentemente das doses de Mn. Nas plantas +Si e inoculadas com B. oryzae, houve menor atividade da FAL tanto na maior quanto na menor dose de Mn e também nas plantas não-inoculadas. A atividade da FAL não aumentou na presença de Si, mas na ausência desse elemento, houve aumento em atividade. Os resultados deste estudo mostram que as atividades da POX, PFO e FAL não aumentaram devido ao suprimento de Si independente da dose de Mn.

This study investigated the role of silicon (Si) and manganese (Mn) rates on the activity of peroxidases (POX), polyphenoloxidases (PPO) and phenylalanine ammonia-lyases (PAL) on rice plants non-inoculated and inoculated with Bipolaris orzyae. Rice plants (cultivar Metica 1) were grown in nutrient solution with 0 (-Si) or 2 mmol Si L-1 (+Si) and with 0.5, 2.5 and 10 μmol Mn L-1. Plants were inoculated with B. oryzae and leaf samples were collected at 6, 12, 18, 24, 36 and 48 h after inoculation (hai). Leaf samples were also collected from non-inoculated plants at these same time-points. POX activity increased for -Si plants inoculated with B. oryzae at both rates of 0.5 and 2.5 µmol Mn L-1 with one peak at 48 hai at 10 µmol Mn L-1. For plants supplied with Si, POX activity also increased, but seemed to be low at the rates of 2.5 and 10 µmol Mn L-1. POX activity did not show to be greatly influenced by the Mn rates in the presence of Si. However, in the absence of Si, POX activity increased. PPO activity on -Si plants increased at the rate of 0.5 µmol Mn L-1 and was not affected by the other two Mn rates, except a peak at 18 hai at the rate of 10 µmol Mn L-1. In the presence of Si, PPO activity increased on plants supplied with 2.5 µmol Mn L-1 in contrast to the other two Mn rates for which the PPO activity decreased. By comparing the -Si and +Si treatments at the rate of 2.5 µmol Mn L-1, PPO activity increased from 18 to 36 hai in the presence of Si than on its absence. PAL activity on -Si plants decreased regardless of the Mn rates. On plants supplied with Si and inoculated with B. oryzae, PAL showed low activity at the highest Mn rate and also at the rate of 0.5 µmol Mn L-1, besides its activity been very low compared to the non-inoculated plants. PAL did not increase in activity in the presence of Si, but on its absence, high levels of activity were achieved. Results from this study showed that the activities of POX, PPO and PAL were not boosted by Si at any Mn rate.

Isoformas de cisteíno protease obtidas do intestino médio de lagartas de 5° instar de Anticarsia gemmatalis (Hübner, 1818) foram caracterizadas. A isoforma solúvel foi chamada de Fração Solúvel enquanto a isoforma ligada à membrana celular, de Fração Insolúvel. As maiores atividades foram observadas em pH 3,6 a 45° C para a Fração Solúvel e pH 4,6 a 50° C para a Fração Insolúvel. Ao analisar o efeito de modificadores químicos, a Fração Solúvel mostrou-se insensível à aprotinina e E-64, porém teve sua atividade aumentada pela adição de EDTA e levemente inibida pela adição de íons Ca2+, mostrando se tratar de enzimas independentes de íons metálicos para sua atividade. A Fração Insolúvel também se mostrou insensível à aprotinina, porém teve sua atividade parcialmente inibida por E-64. A adição de EDTA levou a uma redução nos valores de atividade, demonstrando a necessidade de íons metálicos para a atividade dessas enzimas, porém não se trata de enzimas cálcio-dependentes, uma vez que sua atividade foi reduzida com a adição desse íon. Os valores de K M app e Vmáx app foram, respectivamente, 0,6398 mM e 42,556 nM s-1 para Fração Solúvel e 0,0413 mM e 10,854 nM s-1 para Fração Insolúvel. Esses resultados fornecem evidências da presença de cisteíno protease solúvel e ligada à membrana celular do intestino de lagartas de A. gemmatalis. O conhecimento e a caracterização das principais classes de proteases presentes no trato digestivo da lagarta da soja, bem como a interação dessas enzimas com inibidores de protease têm uma importante consequência aos programas de melhoramento de soja.

Cysteine protease isoforms obtained from the midgut of 5th instar Anticarsia gemmatalis (Hübner, 1818) larvae were characterized. The soluble enzyme isoform was called Soluble Fraction and cell membrane-bound enzyme isoform, the Insoluble Fraction. The highest activities were observed at pH 3.6 and 45° C for the Soluble Fraction and pH 4.6 and 50° C for the Insoluble Fraction. Analyzing the effect of chemical modifiers, the Soluble Fraction was shown to be insensitive to aprotinin and E-64, although its activity was increased by the addition of EDTA and slightly inhibited by the addition of Ca2+, showing to be enzymes independent of metal ions to its activity. The Insoluble Fraction was also insensitive to aprotinin, but its activity was partially inhibited by E-64. The addition of EDTA reduced the activity values, demonstrating the need for metal ions for the activity of these enzymes, but they are not calcium-dependent enzymes, since their activity was reduced with the addition of this ion. The values of K M app and Vmax app were, respectively, 0.6398 mM and 42.556 nM s-1 for Soluble Fraction and 0.0413 mM and 10.854 nM s-1 for Insoluble Fraction. These results provide evidence for the presence of soluble and cell membrane-bound cysteine proteases in the gut of A. gemmatalis larvae. The knowledge and characterization of the major classes of proteases produced by the digestive tract of the soybean caterpillar, as well as the interaction of these enzymes with protease inhibitors, have a major implication for soybeans breeding programs.

A ferrugem, causada por Hemileia vastatrix, é a principal doença do cafeeiro. Este trabalho avaliou o efeito do silício (Si) em alguns componentes de resistência do cafeeiro à ferrugem e o possível aumento na atividade de quitinases (QUI), β-1,3-glucanases (GLU) e peroxidases (POX). Mudas de cafeeiro (cv. Catuaí vermelho 44) foram crescidas em solução nutritiva de Clarck modificada, aerada, contendo 0 (-Si) ou 2 mmol L-1 Si (+Si) por 45 dias e inoculadas com H. vastatrix.Não houve diferença significativa entre os tratamentos -Si e +Si para o teor foliar de Si, mas o teor desse elemento nas raízes foi significativamente maior para o tratamento +Si. Os tratamentos -Si e +Si não foram estatisticamente diferentes para o período de incubação, período latente, número de pústulas por folha, área pustular, expansão de pústulas e área abaixo da curva do progresso da ferrugem. A atividade de QUI, GLU e POX aumentou após a inoculação com H. vastatrix, embora com aumentos e decréscimos durante as épocas de coletas. O Si não teve efeito pronunciado em maximizar a atividade dessas enzimas, salvo incrementos em épocas de coletas específicas. Os resultados deste estudo indicaram que o cafeeiro foi ineficiente em translocar o Si das raízes para a parte aérea, restringindo-o exclusivamente ao sistema radicular o que não garantiu o aumento da resistência do cafeeiro à ferrugem.

Coffee leaf rust, caused by Hemileia vastatrix, is the most important disease on coffee. This study aimed to evaluate the effect of silicon (Si) on some components of coffee resistance to rust and to determine if it could increase the activity of chitinases (CHI), β-1,3-glucanases (GLU), and peroxidases (POX). Coffee plants (cultivar "Catuaí vermelho 44") were grown on aerated Clarck’s nutrient solution containing 0 (-Si) or 2 mmol L-1 Si (+Si) for 45 days and inoculated with H. vastatrix. There was no significant difference between the -Si and +Si treatments for Si content in leaf tissue, but Si content in root tissue was significantly higher for the +Si treatment. The -Si and +Si treatments were not significantly different for incubation period, latent period, number of pustules per leaf, pustule size, pustule expansion, and area under rust progress curve. The activity of CHI, GLU, and POX increased after inoculation with H. vastatrix, even with increase or decrease in activities during the sampling times. There was not a pronounced effect of Si in increasing the activity of these enzymes, except for rare increases in specific sampling times. Results from this study indicated that coffee plants were inefficient in uptaking Si from the nutrient solution and translocating it to the shoot. Silicon was exclusively restricted to the root system, which did not guarantee an increase in coffee resistance to rust.

A principal medida de controle da ferrugem do cafeeiro, causada por Hemileia vastatrix, é o uso de fungicidas. O fornecimento de silício (Si) às plantas é uma estratégia de controle interessante considerando o potencial desse elemento em aumentar a resistência de várias espécies de plantas à patógenos. Este trabalho avaliou o efeito da aplicação foliar do Si na redução da severidade da ferrugem e na possível potencialização da atividade de seis enzimas relacionadas com a resistência de plantas à patógenos. Mudas de café (cultivar Catuaí Vermelho 44) foram pulverizadas com água destilada, solução de silicato de potássio (KSi) (35 g/L, pH 10,5), KSi (35 g/L, pH 5,5) e solução de acibenzolar-S-metil (ASM) (200 µg/L) 24 horas antes da inoculação. Não houve diferença significativa entre os tratamentos para os teores foliares de Si e potássio. A severidade foi significativamente maior em mudas pulverizadas com água em relação aos demais tratamentos. O ASM reduziu significativamente a severidade em 70% em relação à aplicação de água. A aplicação de soluções de KSi, independente do pH, também reduziu a severidade. O ASM foi eficiente em aumentar a atividade de quitinases e β-1,3-glucanases, porém a aplicação de KSi, independente do pH da solução, foi ineficiente em potencializar a atividade das seis enzimas estudadas, embora tenha reduzido a severidade.

The major method for control of coffee leaf rust, caused by Hemileia vastatrix, is the use of fungicides. The supply of silicon (Si) to plants is an interesting control strategy because this element can increase the resistance of many plant species to pathogens. This study aimed to evaluate the effect of foliar application of Si on reducing rust severity as well as to determine if it can potentiate the activity of enzymes related to host resistance to pathogens. Coffee plants (cultivar Catuaí Vermelho 44) were sprayed with distilled water, potassium silicate (KSi) solution (35 g/L, pH 10.5), KSi (35 g/L, pH 5.5), and acibenzolar-S-methyl (ASM) solution (200 µg/L) 24 hours before inoculation. There was no significant difference among the treatments regarding the content of Si and potassium in the leaf tissue. Rust severity was significantly higher on plants sprayed with water as compared to the other treatments. The ASM significantly decreased rust severity by 70% in comparison to the water spray treatment. Foliar application of KSi, regardless of the pH, was efficient in decreasing rust severity. The ASM was efficient in increasing the activity of chitinases and β-1,3-glucanases. On the other hand, the application of KSi, regardless of the pH, was inefficient to potentiate the activity of these six enzymes studied, even though it had a great impact on reducing rust severity.

A ferrugem da soja, causada por Phakopsora pachyrhizi, tem sido controlada pela aplicação de fungicidas devido a indisponibilidade de cultivares resistentes. O silício (Si) tem aumentado a resistência de várias espécies de plantas a patógenos. Assim, este trabalho avaliou o efeito da aplicação foliar desse elemento na severidade da ferrugem e na potencialização da atividade de quitinases, β-1,3-glucanases, peroxidases, polifenoloxidases, lipoxigenases e fenilalanina amônia-liases. Plantas de soja (cultivar MG/BR-46 Conquista) foram pulverizadas com água (controle), silicato de potássio (KSi) (pH 10,5), KSi (pH 5,5) e acibenzolar-S-metílico (ASM) 24 horas antes da inoculação. Não houve diferença significativa entre os tratamentos para os teores foliares de Si e potássio. A severidade foi significativamente menor em plantas pulverizadas com KSi, independente do pH, e ASM em relação ao controle. O ASM reduziu significativamente a severidade em 65,5% em relação ao controle sem diferença significativa do ASM para a aplicação de KSi pH 5,5. Aplicação de KSi, independente do pH, também reduziu a severidade. Não houve potencialização da atividade das enzimas estudadas pela aplicação de KSi, independente do pH, e do ASM, embora houve redução da severidade em relação ao controle, o que poderia ser explicado pelo possível efeito desses produtos sobre o fungo.

Soybean rust, caused by Phakopsora pachyrhizi, has been controlled by fungicide application due to the absence of resistant cultivars. Silicon (Si) has increased the resistance of many plant species to pathogens. Therefore, this study evaluated the effect of foliar application of this element on rust severity and if it can potentiate the activity of chitinases, β-1,3-glucanases, peroxidases, polyphenoloxidases, lipoxygenases, and phenylalanine ammonia-lyases. Soybean plants (cultivar "MG/BR-46 Conquista") were sprayed with water (control), potassium silicate (KSi) (pH 10.5), KSi (pH 5.5), and acibenzolar-S-methyl (ASM) 24 hours before inoculation. There was no significant difference among the treatments for content of Si and potassium in leaf tissue. Rust severity was significantly lower on plants sprayed with KSi, regardless of pH, and ASM compared to plants from control treatment. The ASM significantly decreased severity by 65.5% in comparison to control; however, there was no significant difference from ASM to KSi pH 5.5 treatment. Application of KSi, regardless of the pH, also reduced severity. There was no potentiation of the enzymes studied with KSi, regardless of pH and of ASM, even though there was severity reduction compared to the control treatment. This could be explained by the possible effect of these products on the fungus.

Plantas respondem ao ataque de herbívoros e patógenos com liberação de compostos orgânicos voláteis. Essas moléculas funcionam como defesas indiretas quando atraem inimigos naturais dos herbívoros e assim beneficiam a planta emissora. Uma questão controversa é se plantas vizinhas não-atacadas captam esses voláteis e respondem aumentando suas barreiras defensivas contra um ataque iminente. Apesar do seu forte apelo popular e da Talking Trees Hypothesis estar completando 25 anos, só recentemente os mais céticos estão sendo convencidos. Tem-se aceitado que respostas induzidas pela trasnferência de informação entre plantas ocorrem em pelo menos dois sistemas planta-herbívoro. No entanto, o grau de generalização do fenômeno e a dimensão da sua importância ecológica e evolutiva permanecem desconhecidos. Uma recente abordagem multidisciplinar, integrando Biologia Molecular, Bioquímica e Fisiologia à Ecologia, acena com novas e mais poderosas ferramentas metodológicas para esclarecer os processos de biossíntese, emissão, transporte e recepção dos sinais pelas plantas. Essa abordagem tem fornecido o suporte mecanicista adicional às evidências ecológicas da defesa induzida da planta, manifestada e mensurada mediante respostas ecofisiológicas e comportamentais dos insetos herbívoros.

Plants respond to herbivores and pathogens attack with increased emission of volatile organic compounds. These molecules act as indirect defences when attracting natural enemies of herbivores and thus benefit the plant. It remains controversial whether undamaged plants capture chemicals released by damaged neighbouring plants and respond to them by increasing their defensive barriers against an imminent attack. In spite of public appeal and of this being the 25th year of the Talking Trees Hypothesis, only recently have the most sceptical scientists been convinced. The induced response to herbivory by interplant information transfer has been found in two plant-herbivore systems. However, the universality of the phenomenon and its ecological and evolutionary relevance remain unclear. The integration of Molecular Biology, Biochemistry, Physiology, and Ecology begin to shed light on the mechanisms of the signal transfer. This integrative approach has developed new and more sensitive tools for identification of complex volatile mixtures and for understanding the process of biosynthesis, emission, transportation and reception of signals.

Neste trabalho, avaliou-se a capacidade da planta de soja de uma cultivar comercial, IAC-100, e de um genótipo IAC-100 TN que apresenta ausência de lipoxigenases nas sementes de responderem ao ataque de mosca-branca (Bemisia argentifolii) pela via das Lipoxigenases. Foi realizada a caracterização cinética do pool de lipoxigenases. Os valores de KMapp decresceram nas plantas atacadas, sugerindo uma alteração no pool de lipoxigenases foliares. Valores similares de KMapp, entre os genótipos, indicam que a remoção de lipoxigenases de sementes não interferiram na expressão de lipoxigenases em folhas. Ocorreu aumento significativo na produção de inibidores de proteases. Com esses resultados, infere-se que a produção de inibidores de proteases está envolvida no mecanismo de defesa de soja ao ataque da mosca-branca.

This work evaluated the capacity of the soybean plant, from a commercial cultivar IAC-100 and from a genotype IAC-100 TN, with absence of lipoxygenases in their seeds, to respond to the attack by whitefly (sucking insect) by lipoxygenases pathway. The kinetic characterization of the “pool” of lipoxygenases was determined. The KMapp values decreased, suggesting a change in the “pool” of lipoxygenases in response to the attack by whitefly. The similar KMapp values suggest that the removal of the lipoxygenases from the seeds does not change the expression of LOX in the leaves. There was a noticeable increase in protease inhibitors. These results suggest that the production of protease inhibitors are involved in the defense mechanism of soybean plant against whitefly injury.