Data/hora: 14/06/2024 06:02:33

Biblioteca(s): 	Embrapa Soja.	
Data corrente: 	30/09/2008	
Data da última atualização: 	01/10/2008	
Autoria: 	GRAÇA, J. P. da; SALVADOR, M. C.; MELLO, D.; MANDARINO, J. M. G.; HOFFMANN-CAMPO, C. B.	
Afiliação: 	José Perez da Graça, UNESP / Jaboticabal; Mariana Closs Salvador, UNESP / Jaboticabal / CNPSo; José Marcos Gontijo Mandarino, CNPSo; Clara Beatriz Hoffmann-Campo, CNPSo.	
Título: 	Enzymatic activity of lipoxygenases, isoflavone contents, and trichomes in soybean genotypes: implication on insect plant resistance.	
Ano de publicação: 	2008	
Fonte/Imprenta: 	In: ANNIVERSARY ISCE MEETING, 25., 2008, State College, Pennsylvania. [Abstracts]. State College, Pennsylvania: International Society of Chemical Ecology, 2008. p. 88.	
Idioma: 	Inglês	
Conteúdo: 	Soybean [Glycine max (L.) Merr.] is attacked by insects and other pests and constantly needs to activate its defenses against their injuries. Generally, plants use the synthesis 0f metabolites or morphological structures to deter or inhibit herbivorous activity. Plant lipoxygenases are enzymes involved in the biosynthesis of regulatory molecules, and in the response to insect and pathogen attacks. Trichomes are morphological structures generally related to physical plant defense. This work was carried out to evaluate lipoxygenases (LOX) enzymatic activity and density and length of trichomes in soybean genotypes ('BRS 155', 'BRS 213', 'BRS 257', 'BRS 134', 'BRS 133', 'BR 16', 'IAC 100', PI 227687, and 'Dowling'), relating these information with Nezara viridula (Hemiptera: Pentatomidae) developmental time and adult weigh. The genotypes were grown in greenhouse. Pods and seeds were morphologically and biochemically evaluated at soybean developmental stages R6, and R6 plus R8, respectively. Nymphs of stink-bugs were led with R6-pods, from the second stage to adulthood. BRS 134, BR 16, Dowling, and BRS 155 showed longer trichomes, whereas IAC 100, BRS 213, and PI 227687 presented higher density of trichomes compared with the other genotypes. At R6, seeds of BRS 155 presented the highest LOX 1 activity, BRS 155, and PI 227687 presented the highest LOX 2 and LOX 3 activities, and Dowling presented higher LOX 2 activity, At R8, BR 16, IAC 100, BRS 133, and PI 227687 presented the highest activities of LOX 1, and BRS 133 presented the highest activity of LOX 2 and 3. Adults led on BRS 155, whose seeds presented high LOXs (1, 2, and 3) activities were heavier (173,52) compared with PI 227687 (108.20 mg) and on BRS 257 (130.15 mg); developmental time varied from 21.46 to 22.57 days, but no statistical differences between treatments were detected. PI 227687 is a widely used source of insect resistance and in our trial showed higher LOX 2 and LOX 3 activities, higher trichome density and higher isoflavone contents. However, BRS-257, which presented low LOXs (1, 2, and 3) activity showed neither longer nor higher trichome density, intermediate isoflavone content compared with the other genotypes. Consequently, as indicated by this bioassay, chemical, biochemical, and mechanical factors can act synergistically on the defense of PI227687 against insect pests. Regarding BRS 257, the plant defense likely comes from other types of LOXs. Consequently, the involvement of lipoxigenases in soybean plant defense against insects is not clearly elucidated.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Soja (CNPSO)	
Exemplares: 	CNPSO - (28570-1) - UPC - SP - -- - 11495 -  - 11495 - DIS