Limits...
The effects of arbuscular mycorrhizal fungi on direct and indirect defense metabolites of Plantago lanceolata L.

Fontana A, Reichelt M, Hempel S, Gershenzon J, Unsicker SB - J. Chem. Ecol. (2009)

Bottom Line: Arbuscular mycorrhizal fungi can strongly influence the metabolism of their host plant, but their effect on plant defense mechanisms has not yet been thoroughly investigated.Thus, mycorrhizal infection did not have any effect on the levels of direct defense compounds measured in P. lanceolata.However, the large decline in herbivore-induced sesquiterpene emission may have important implications for the indirect defense potential of this species.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll Strasse 8, 07745, Jena, Germany.

ABSTRACT
Arbuscular mycorrhizal fungi can strongly influence the metabolism of their host plant, but their effect on plant defense mechanisms has not yet been thoroughly investigated. We studied how the principal direct defenses (iridoid glycosides) and indirect defenses (volatile organic compounds) of Plantago lanceolata L. are affected by insect herbivory and mechanical wounding. Volatile compounds were collected and quantified from mycorrhizal and non-mycorrhizal P. lanceolata plants that underwent three different treatments: 1) insect herbivory, 2) mechanical wounding, or 3) no damage. The iridoids aucubin and catalpol were extracted and quantified from the same plants. Emission of terpenoid volatiles was significantly higher after insect herbivory than after the other treatments. However, herbivore-damaged mycorrhizal plants emitted lower amounts of sesquiterpenes, but not monoterpenes, than herbivore-damaged non-mycorrhizal plants. In contrast, mycorrhizal infection increased the emission of the green leaf volatile (Z)-3-hexenyl acetate in untreated control plants, making it comparable to emission from mechanically wounded or herbivore-damaged plants whether or not they had mycorrhizal associates. Neither mycorrhization nor treatment had any influence on the levels of iridoid glycosides. Thus, mycorrhizal infection did not have any effect on the levels of direct defense compounds measured in P. lanceolata. However, the large decline in herbivore-induced sesquiterpene emission may have important implications for the indirect defense potential of this species.

Show MeSH

Related in: MedlinePlus

Linear regression of (Z)-3-hexenyl acetate emission and plant dry weight for mycorrhizal (solid line) and non-mycorrhizal (dashed line) plants. Black dots represent all mycorrhizal plants (herbivory-treated, mechanically wounded and untreated), while open dots represent all non-mycorrhizal plants (herbivory-treated, mechanically wounded and untreated)
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2712616&req=5

Fig2: Linear regression of (Z)-3-hexenyl acetate emission and plant dry weight for mycorrhizal (solid line) and non-mycorrhizal (dashed line) plants. Black dots represent all mycorrhizal plants (herbivory-treated, mechanically wounded and untreated), while open dots represent all non-mycorrhizal plants (herbivory-treated, mechanically wounded and untreated)

Mentions: There were significant differences between mycorrhizal and non-mycorrhizal plants. Mycorrhizal plants emitted about 55% less total terpenoids compared to non-mycorrhizal plants in the herbivory treatment (mycorrhiza: F1,171 = 5.11, P = 0.039; interaction mycorrhiza:treatment: F2,171 = 8.14, P < 0.001; Fig. 2a). Among the classes of terpenoids, the emission of sesquiterpenes was 63% lower in mycorrhizal compared to non-mycorrhizal plants after herbivory (Table 1), but the emission of monoterpene, (E)-β-ocimene, was not affected by this treatment (F1,83 = 0.04, P = 0.845, Table 2).Fig. 2


The effects of arbuscular mycorrhizal fungi on direct and indirect defense metabolites of Plantago lanceolata L.

Fontana A, Reichelt M, Hempel S, Gershenzon J, Unsicker SB - J. Chem. Ecol. (2009)

Linear regression of (Z)-3-hexenyl acetate emission and plant dry weight for mycorrhizal (solid line) and non-mycorrhizal (dashed line) plants. Black dots represent all mycorrhizal plants (herbivory-treated, mechanically wounded and untreated), while open dots represent all non-mycorrhizal plants (herbivory-treated, mechanically wounded and untreated)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2712616&req=5

Fig2: Linear regression of (Z)-3-hexenyl acetate emission and plant dry weight for mycorrhizal (solid line) and non-mycorrhizal (dashed line) plants. Black dots represent all mycorrhizal plants (herbivory-treated, mechanically wounded and untreated), while open dots represent all non-mycorrhizal plants (herbivory-treated, mechanically wounded and untreated)
Mentions: There were significant differences between mycorrhizal and non-mycorrhizal plants. Mycorrhizal plants emitted about 55% less total terpenoids compared to non-mycorrhizal plants in the herbivory treatment (mycorrhiza: F1,171 = 5.11, P = 0.039; interaction mycorrhiza:treatment: F2,171 = 8.14, P < 0.001; Fig. 2a). Among the classes of terpenoids, the emission of sesquiterpenes was 63% lower in mycorrhizal compared to non-mycorrhizal plants after herbivory (Table 1), but the emission of monoterpene, (E)-β-ocimene, was not affected by this treatment (F1,83 = 0.04, P = 0.845, Table 2).Fig. 2

Bottom Line: Arbuscular mycorrhizal fungi can strongly influence the metabolism of their host plant, but their effect on plant defense mechanisms has not yet been thoroughly investigated.Thus, mycorrhizal infection did not have any effect on the levels of direct defense compounds measured in P. lanceolata.However, the large decline in herbivore-induced sesquiterpene emission may have important implications for the indirect defense potential of this species.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll Strasse 8, 07745, Jena, Germany.

ABSTRACT
Arbuscular mycorrhizal fungi can strongly influence the metabolism of their host plant, but their effect on plant defense mechanisms has not yet been thoroughly investigated. We studied how the principal direct defenses (iridoid glycosides) and indirect defenses (volatile organic compounds) of Plantago lanceolata L. are affected by insect herbivory and mechanical wounding. Volatile compounds were collected and quantified from mycorrhizal and non-mycorrhizal P. lanceolata plants that underwent three different treatments: 1) insect herbivory, 2) mechanical wounding, or 3) no damage. The iridoids aucubin and catalpol were extracted and quantified from the same plants. Emission of terpenoid volatiles was significantly higher after insect herbivory than after the other treatments. However, herbivore-damaged mycorrhizal plants emitted lower amounts of sesquiterpenes, but not monoterpenes, than herbivore-damaged non-mycorrhizal plants. In contrast, mycorrhizal infection increased the emission of the green leaf volatile (Z)-3-hexenyl acetate in untreated control plants, making it comparable to emission from mechanically wounded or herbivore-damaged plants whether or not they had mycorrhizal associates. Neither mycorrhization nor treatment had any influence on the levels of iridoid glycosides. Thus, mycorrhizal infection did not have any effect on the levels of direct defense compounds measured in P. lanceolata. However, the large decline in herbivore-induced sesquiterpene emission may have important implications for the indirect defense potential of this species.

Show MeSH
Related in: MedlinePlus