The role of catechin and epicatechin in chemical defense against damping‐off fungi of current‐year Fagus crenata seedlings in natural forest

Abstract

Current-year Fagus crenata seedlings survive damping-off in the forest-edge plot compared to those in the closed-stand plot. Greater illumination found in the forest-edge plot is likely to influence the defense of seedlings against pathogenic attack, by increasing the amount of phenolic compounds and forming periderm. This study aimed to clarify the chemical defense system by (i) isolation of antifungal compounds from seedling hypocotyls in the forest-edge plot, (ii) quantification of antifungal compounds in hypocotyls in the forest-edge and closed-stand plots, (iii) estimation of their antifungal activities against Cylindrocarpon sp. and Colletotrichum dematium and (iv) clarification of localization of phenolics in the hypocotyl tissues. Catechin and epicatechin were isolated as antifungal compounds showing inhibition of microconidia germination of Cylindrocarpon sp. and mycelial growth of Cylindrocarpon sp. and C. dematium. In the beginning of July when damping-off was the most severe in the closed-stand plot, the total amount of catechin and epicatechin in the forest-edge seedlings was approximately three times greater than that in the closed-stand seedlings. Flavan-3-ols, including catechin and epicatechin, were distributed mainly in the epidermal tissue on June 1 and in cortical tissues on June 15 and July 6, all from plants harvested from the forest-edge plot. We conclude that F. crenata could survive damping-off through chemical defense via catechin and epicatechin production and its distribution in seedling hypocotyls.

Effect of Methyl Jasmonate on Phytoalexins Biosynthesis and Induced Disease Resistance toFusarium oxysporum f. sp. Vasinfectumin Cotton (Gossypium hirsutumL.)

“…Therefore, it was suggested that these two phenolic compounds production could not be stimulated by MeJA treatment in cotton. In our study, catechin and caffeoyl-D-glucose do not seem to influence cotton defence against pathogen although studies have shown their involvement in the defence of several other plants [27,28]. Gossypol maximal amount (5.91 g/g FDE) was observed in the MeJA-treated cotton, and this amount was 64 times higher than that of the control.…”

Flavan-3-ols Are an Effective Chemical Defense against Rust Infection

“…Studies also demonstrated that the biosynthesis of flavan-3-ols and PAs increased after infection by fungal endophytes in poplar (Pfabel et al, 2012) as well as after infection by pathogenic fungi in other plant species, such as bilberry (Vaccinium myrtillus; Koskimäki et al, 2009) and Fagus crenata (Yamaji and Ichihara, 2012). Increased accumulation of flavan-3-ols also has been recorded in Norway spruce (Picea abies) during infection by necrotrophic fungi (Danielsson et al, 2011;Hammerbacher et al, 2014).…”

Secondary metabolites during early development in plants

“…Aspects regarding the level of development will perhaps provide insight into the basic plant production independent of environmental pressures, both biotic and abiotic. The variation of the temporal and spatial composition between the organs and the changes during early ontogeny may provide tests for theories regarding plants' chemical defences (Schaffner et al 2003;Gregianini et al 2004;Yamaji and Ichihara 2012).…”

“…The presence of SM during these stages and their spatio-temporal distribution can be important survival strategies. In this section, the roles of SM as reservoirs of nitrogen, defence substances against phytopathogens and insects, allelopathic agents, molecules with photoprotective roles, and attraction signals for nitrogen-fixing microorganisms are documented (Niemeyer et al 1989a;Zuanazzii et al 1998;Weir et al 2003;Gregianini et al 2004;Zheng et al 2008;Milkowski and Strack 2010;Yamaji and Ichihara 2012).…”