Soil-borne microorganisms and soil-type affect pyrrolizidine alkaloids in Jacobaea vulgaris

Abstract

Secondary metabolites like pyrrolizidine alkaloids (PAs) play a crucial part in plant defense. We studied the effects of soil-borne microorganisms and soil-type on pyrrolizidine alkaloids in roots and shoots of Jacobaea vulgaris. We used clones of two genotypes from a dune area (Meijendel), propagated by tissue culture and grown on two sterilized soils and sterilized soils inoculated with 5% of non-sterilized soil of either of the two soil-types. Soil-borne microorganisms and soil-type affected the composition of PAs. By changing the composition rather than the total concentration below and aboveground, plants have a more complex defense strategy than formerly thought. Interestingly, a stronger negative effect on plant growth was found in sterilized soils inoculated with their 'own' microbial community suggesting that pathogenic and/or other plant inhibiting microorganisms were adapted to their 'own' soil conditions.

The genotype dependent presence of pyrrolizidine alkaloids as tertiary amine in Jacobaea vulgaris

“…We found consistently large amounts of tertiary amines in Jacobaea vulgaris plants (Joosten et al, 2009(Joosten et al, , 2010. However, the general tendency in literature is that tertiary amines are present only in very small amounts and maybe are due to artifacts during extraction or detection Hartmann, 1999;Hartmann and Ober, 2000).…”

“…This species is native in Europe and West Asia but invasive in North America, Australia and New Zealand. In previous studies, up to 30 different PAs were detected in J. vulgaris (Witte et al, 1992;Macel et al, 2004;Kowalchuk et al, 2006;Joosten et al, 2009). Based on their structural features, major PAs in J. vulgaris can be divided into 3 structural groups: senecionine-like, comprising senecionine, integerrimine, retrorsine and (acetyl) seneciphylline; jacobine-like, comprising jacobine, jacoline, jaconine jacozine, and dehydrojaconine; erucifoline-like, comprising erucifoline and acetylerucifoline (Table 2).…”

Defensive properties of pyrrolizidine alkaloids against microorganisms

“…The concentration and composition of PAs in plant species is genotype dependent but also affected by the environment (Vrieling et al 1993; Hol et al 2003; Macel et al 2004; Hol et al 2004; Macel and Klinkhamer 2010; Joosten et al 2009). Less is known about PA induction by pathogens aboveground.…”

Generalist <i>versus</i> Specialist Herbivores on the Invasive <i>Senecio inaequidens</i> and a Native Related Species: What Makes the Difference?

“…We did not detect any difference in total PA concentrations between the two species in adult leaves like in [9]. Nevertheless, differences in concentrations among populations have been reported [9,32,39,40]. Extracts of S. inaequidens are considered to stimulate oviposition of T. jacobaeae females [41].…”