RESPOSTA BIOQUÍMICA DE THYRINTEINA LEUCOCERAEA A INIBIDOR DE PROTEASES EM PLANTAS DE GOIABA

Jeanne Scardini Marinho, Maria Goreti de Almeida Oliveira, Raul Narciso de Carvalho Guedes, Angelo Pallini, Joel Antônio de Oliveira
2010 IDESIA  
As plantas têm um tipo de defesa que interfere no sistema digestivo dos insetos através da expressão de diferentes inibidores de proteases (IPs). Os IPs agem inibindo enzimas proteolíticas no intestino dos insetos, podendo até levá-los à morte. Por isso, estudos têm sido realizados visando à utilização desses compostos como método alternativo no controle de insetos fitófagos. As lagartas de Thyrinteina leucoceraea causam muitos danos em eucaliptais, mas não conseguem se desenvolver bem em
more » ... volver bem em folhas de goiabeira, portanto é interessante que a defesa desta planta seja investigada. Sendo assim, este trabalho estudou a resposta enzimática da lagarta T. leucoceraea ao aumento da concentração do IP benzamidina (IP sintético de serino-proteases) aplicado sobre as folhas de goiabeira, a fim de estudar a ação do inibidor sintético em conjunto com o inibidor natural produzido por essas plantas. Para tal investigação, foram utilizadas três diferentes concentrações de benzamidina: 0,12, 0,25 e 0,5%. Verificou-se que as goiabeiras produzem IPs como resposta de defesa e que a benzamidina aplicada nas plantas de goiaba interferiu na atividade das serino-proteases no intestino de lagartas de T. leucoceraea, entretanto, pode-se observar também que as lagartas apresentaram adaptação à ingestão dos IPs através do aumento da atividade de cisteíno-proteases em quase todos os tratamentos. ABSTRACT Plants have a type of defense that interferes with the digestive system of insects through the expression of different protease inhibitors (PIs). PIs act by inhibiting proteolytic enzymes in the gut of insects, and may even lead them to death. Therefore, studies have been conducted in order to use these compounds as an alternative method in control of phytophagous insects. The Thyrinteina leucoceraea is prague on eucalypts, but does not cause severe damage in leaves of guava, so it is interesting that the defense of this plant is investigated. Thus, this work studied the enzymatic response of the caterpillar T. leucoceraea further concentration of benzamidine PI (PI synthetic of serine proteases) applied to the leaves of guava in order to evaluate the effects of synthetic inhibitor in conjunction with the natural inhibitor produced by these plants. For this investigation, we used three different concentrations of benzamidine, 0.12, 0.25 and 0.5%. It was found that the guava produce IPs in response to defense and that the benzamidine applied on leaves of guava interfere in the activity of serine proteases in the gut of larvae of T. leucoceraea. However, it can also be observed that the caterpillars were adapted to the ingestion of PIs by increasing the activity of cysteine proteases in almost all treatments. LITERATURA CITADA ANJOS, N.; SANTOS, G.P. ; ZANUNCIO, J.C. 1996. Pragas do eucalipto e seu controle. Informe Agropecuário, 12: 50-8. APPLEBAUM, S.W. 1986. Bioche+mistry of digestion. In: G.A. Kerkut, L.L., Gilbert (Eds.). Comprehensive Insect Physiology, Biochemistry and Pharmacology. New York: Pergamon Press, 4: 279-311. BATISTA, R.B.; OLIVEIRA, M.G.A.; PIRES, C.V.; PIOVESSAN, N.D.; REZENDE, S.T.; MOREIRA, M.A. 2002. ; BARCIC, J.I.; EDWARDS, C.R. 2005. Effects of proteinase inhibitors on western corn life parameters. Journal of Applied Entomology, 192 (4): 185-190. BRADFORD, M.M. 1976. A rapid and sensitive method for the quantification of microgram quantities of proteins utilizing the principle of protein dye binding. Analytical Biochemistry, 72: 248. BROADWAY, R.M. 1995. Are insects resistant to plant proteinase inhibitors? Journal of Insect Physiology. 41(2): 107-116. CARLINI, C.R.; GROSSI-DE-Sá, M.F. 2002. Plant toxic proteins with insecticidal properties. A rewiew on their potentialities as bioinsecticides. Toxicon, 40: 1515-1539. DELLEDONNE, M.; ALLEGRO, G.; BELENGHI, B.; BALESTRAZZI, A.; PICCO, F.; LEVINE, A.; ZELASCO, S.; CALLIGARI, P.; CONFALONIERI, M. 2001. Transformation of poplar (Populus alba L.) with a Arabidopsis thaliana cysteine proteinase inhibitor and analysis of insect pest resistance. Molecular Breeding, 7: 35-42. ERLANGER, B.F.; KOKOWSKY, N.; COHEN, W. 1961. The preparation and properties of two new chromogenic substrates of trypsin. Archives of Biochemistry and Biophysics, 95: 271-278.
doi:10.4067/s0718-34292010000300013 fatcat:runu34ocpbg6bhwpedukstwuh4