Callus cultures and bark from Norway spruce clones show similar cellular features and relative resistance to fungal pathogens

Abstract

In field experiments, clones of Norway spruce [Picea abies (L.) Karst.] showed different degrees of resistance against pathogenic fungi inoculated into the bark that correlate with differences in polyphenolic parenchyma (PP) cells of the bark. Cells of spruce callus cultures, particularly towards the callus surface, resemble PP cells and this study looks at changes in callus cells during infection and the relative resistance of cultures from clones of low (weak) or high (strong) resistance to fungal infection. Callus cultures, initiated from trees with different resistance, were co-inoculated with Ceratocystis polonica (Siem.) C. Moreau and Heterobasidion annosum (Fr.) Bref. Callus cells from strong clones resemble PP cells of bark tissue from strong clones, having more polyphenolic bodies, while callus cells from weak clones are more similar to PP cells from those clones, which have less extensive phenolic bodies. Callus cultures from trees with weak resistance were more quickly overgrown by both species of pathogenic fungi than cultures from trees with strong resistance. Callus cells of infected cultures showed changes similar to activated PP cells of bark, including enhanced accumulation of polyphenolics. Phenolic bodies were more numerous and more extensive (larger and denser) in callus cells of strong versus weak clones under all conditions. Thus, callus cells may perform similar functions in defense as PP cells in the bark. Callus from trees of varying resistance seem to reflect the relative resistance of the trees from which they are derived, and this study indicates that some mechanisms of resistance can be studied using callus from trees of different resistance.

Using laser micro-dissection and qRT-PCR to analyze cell type-specific gene expression in Norway spruce phloem

“…Clone 471 has strong, but not complete resistance to C. polonica infection, as determined by phloem lesion length following experimental inoculation (Nagy et al, 2005). It shows up-regulation of the phenylpropanoid pathway in the phloem following both fungal infection and mechanical wounding (Koutaniemi et al, 2007).…”

Pinus massoniana somatic embryo maturation, mycorrhization of regenerated plantlets and its resistance to Bursaphelenchus xylophilus

“…(2000) evaluated the growth reactions of 27 Scots pine embryogenic cell lines to Gremmeniella abietina , the Scleroderris canker fungus. Nagy et al. (2005) found that the embryogenic cell lines of Picea abies responded to Ceratocystis polonica , the blue-stain fungal pathogen, and Heterobasidion annosum , the butt rot pathogen, in a manner similar to that of trees with varying susceptibility to these diseases.…”

“…Similarly, Terho et al (2000) evaluated the growth reactions of 27 Scots pine embryogenic cell lines to Gremmeniella abietina, the Scleroderris canker fungus. Nagy et al (2005) found that the embryogenic cell lines of Picea abies responded to Ceratocystis polonica, the bluestain fungal pathogen, and Heterobasidion annosum, the butt rot pathogen, in a manner similar to that of trees with varying susceptibility to these diseases. Furthermore, Hashmi et al (1993) investigated the response of peach cultures to Meloidogyne incognita, the root-knot nematode, and identified several that exhibited greater resistance than the parental cells.…”

Screen of Pinus massoniana for Resistance to Pinewood Nematode: In Vitro Propagation and Evaluation of Regenerated Microshoots

“…Although the resistance of the culture could not be demonstrated, a difference in growth rates and glucosamine levels formed in response to fungal infection were detected between the cell lines. Nagy et al treated embryogenic cell lines of Picea abies with spores of the blue-stain fungal pathogen Ceratocystis polonica and the butt rot pathogen Heterobasidion annosum [46]. The response of cell cultures was similar to trees which differ in susceptibility to these diseases.…”