Induced responses to pathogen infection in Norway spruce phloem: changes in polyphenolic parenchyma cells, chalcone synthase transcript levels and peroxidase activity

Abstract

Polyphenolic parenchyma cells (PP cells) in Norway spruce (Picea abies (L.) Karst.) stem phloem play important roles in constitutive and inducible defenses. To determine whether anatomical and molecular changes in PP cells are correlated with tree resistance, we infected two Norway spruce clones with the pathogenic fungus Ceratocystis polonica (Siem.) C. Moreau. The fungus induced significantly different lesion lengths in the two clones, indicating that one clone was more resistant to the fungus (short lesions) than the other (long lesions). After infection, the cross-sectional area of PP cells and their vacuolar polyphenol bodies increased in the three most recent annual rings of PP cells in both clones. The more resistant clone had larger PP cells with denser polyphenol bodies than the less resistant clone, whereas the less resistant clone accumulated relatively more polyphenols after infection. Compared with the less resistant clone, the more resistant clone contained higher starch concentrations before infection that were reduced more quickly after infection before returning to original values. Low transcript levels of chalcone synthase were detected in uninfected tissues of both clones, but the levels increased dramatically after infection. Transcript levels were higher and peaked 6 days earlier in the more resistant clone than in the less resistant clone. The activity of at least one highly basic peroxidase isoform was greatly enhanced after infection, and this increase occurred earlier in the more resistant clone.

Phenolic metabolites in the resistance of northern forest trees to pathogens — past experiences and future prospects

“…Marked intraspecific variations in disease resistance (Elamo et al 2000;Nagy et al 2004), as well as in phenolic content (Hakulinen et al 1999;Laitinen et al 2005;Haviola et al 2006), have been reported. For instance, the susceptibility of Norway spruce to Ceratocystis polonica has been shown to be under strong genetic control (Brignolas et al 1998;Evensen et al 2000).…”

HISTOPATOLOGÍA DEL PINO DE LAS ALTURAS (Pinus hartwegii Lindl.) INOCULADO CON TRES HONGOS OPHIOSTOMATOIDES

“…En este estudio no se observó el inicio de las primeras alteraciones causadas por hongos en los diferentes tejidos, debido a que los síntomas fueron evidentes a los 60 días ddi; generalmente se reporta muerte rápida de células y la acumulación de metabolitos secundarios en el sitio de daño que da como resultado una lesión necrótica (Nagy et al, 2004). Los hongos manchadores al invadir células de sus hospedantes inducen la acumulación de compuestos with its three varieties as true pathogens by causing black rot in roots of Pinus in the United States of America (Jacobs and Wingfield, 2001).…”

“…Generally rapid cell death is reported along with the accumulation of secondary metabolites in the damage site which results in a necrotic lesion (Nagy et al, 2004). The staining fungi induce the accumulation of secondary compounds when they invade cells of their hosts; such is the case of Pinus sylvestris, where there is presence of stilbenes (Pinosylvin and eter monomethylic pinosylvin) and a flavonoid (pinocembrin) when inoculated with Leptographium wingfieldii, Ophiostoma brunneociliatum and O. ips (Croisé et al, 2001).…”

“…These results agree secundarios; tal es el caso de Pinus sylvestris ,donde hay la presencia de estilbenos (Pinosylvin y éter monometilico pinosylvin) y un flavonoide (pinocembrin) al ser inoculados con Leptographium wingfieldii, Ophiostoma brunneociliatum y O. ips (Croisé et al, 2001). Las alteraciones en Pinus hartwegii fueron: colapso y necrosis como resultado del avance de la infección en corteza, floema, cambium, radios y canales resiníferos hasta la médula; estos resultados concuerdan con Nagy et al (2004) y Franceschi et al (2000, quienes además observaron cambios morfológicos e incremento de fenoles en células parenquimatosas en Picea abies en respuesta al daño que causa Ceratocystis polonica. Además, hay reducción de la humedad interna, hidrólisis de almidón, poca adhesión de with Nagy et al (2004) and Franceschi et al (2000), who also observed morphological changes and increment of phenols in parenchyma cells in Picea abies in response to the damage caused by Ceratocystis polonica.…”

“…Las alteraciones en Pinus hartwegii fueron: colapso y necrosis como resultado del avance de la infección en corteza, floema, cambium, radios y canales resiníferos hasta la médula; estos resultados concuerdan con Nagy et al (2004) y Franceschi et al (2000, quienes además observaron cambios morfológicos e incremento de fenoles en células parenquimatosas en Picea abies en respuesta al daño que causa Ceratocystis polonica. Además, hay reducción de la humedad interna, hidrólisis de almidón, poca adhesión de with Nagy et al (2004) and Franceschi et al (2000), who also observed morphological changes and increment of phenols in parenchyma cells in Picea abies in response to the damage caused by Ceratocystis polonica. In addition, there is a reduction of internal moisture, hydrolysis of starch, weak adhesion of the cortex, resinosis, traumatism of the resin canals and production of new cambium and periderm (Nagy et al, 2005).…”