Application of methyl jasmonate reduces growth but increases chemical defence and resistance against Hylobius abietis in Scots pine seedlings

Abstract

Scots pine ( Pinus sylvestris L., Pinaceae) produces a terpenoid resin which consists of monoterpenes and resin acids that offer protection against herbivores and pathogen attacks. Methyl jasmonate (MJ) is a potential plant elicitor which induces a wide range of chemical and anatomical defence reactions in conifers and might be used to increase resistance against biotic damage. Different amounts of MJ (control, 10 m  , and 100 m  ) were applied to Scots pine to examine the vigour, physiology, herbivory performance, and induction of secondary compound production in needles, bark, and xylem of 2-year-old Scots pine seedlings. Growth decreased significantly in both MJ treated plants, and photosynthesis decreased in the 100 m  MJ treated plants, when compared to 10 m  MJ or control plants. The large pine weevil ( Hylobius abietis L.) (Coleoptera: Curculionidae) gnawed a significantly smaller area of stem bark in the 100 m  treated plants than in the control or 10 m  treated plants. The 100 m  MJ treatment increased the resin acid concentration in the needles and xylem but not in the bark. Furthermore, both MJ treatments increased the number of resin ducts in newly developing xylem. The changes in plant growth and chemical parameters after the MJ treatments indicate shifts in carbon allocation, but MJ also affects plant physiology and xylem development. Terpenoid resin production was tissue-specific, but generally increased after MJ treatments, which means that this compound may offer potential protection of conifers against herbivores.

Evaluating methyl jasmonate for induction of resistance to Fusarium oxysporum, F. circinatum and Ophiostoma novo-ulmi

“…In the second assay, phytotoxicity was observed in seedlings treated at doses above 1 mM MeJA, and no protection occurred at lower doses. Phytotoxicity and plant mortality after exogenous application of 100 mM MeJA has been previously reported for older P. sylvestris and P. pinaster seedlings (Heijari et al, 2005;Moreira et al, 2009). Our findings do not give support to the idea of adding MeJA to irrigation water in nurseries as a method for protection against pests and pathogens, as suggested by Huber et al (2005).…”

“…However, if the pathogen is able to grow despite the deployment of localized defensive responses, the infection will progress, and the plant will become increasingly diseased. Elicitor compounds affect the synthesis of chemical compounds in plants, but this will result in constraints in carbon allocation and ultimately with reduce plant Evaluating methyl jasmonate for induction of resistance growth or even stop the shoot elongation after the elicitor treatment (Heijari et al, 2005), as observed here. MeJA increased the resin duct density of our seedlings, but despite the general effectiveness of traumatic ducts to contain and reduce damages caused by insects and pathogens (Phillips and Croteau, 1999), F. circinatum is able to tolerate the resin and even stimulate its production on pine trees (Davis et al, 2002;Kim et al, 2010).…”

“…Evaluating methyl jasmonate for induction of resistance abietis (Heijari et al, 2005;Moreira et al, 2009 …”

“…This compound is usually mixed with the surfactant Tween 20 at 0.1% (Hubber et al, 2005;Zeneli et al, 2006;Moreira et al, 2009) and directly applied by spraying or by brushing the plant. An aqueous solution of MeJA has been used to artificially induce defense responses of trees, through increasing the synthesis of terpenoid, phenolic and alkaloid compounds (Heijari et al, 2005;Zeneli et al, 2006) or by promoting the formation of traumatic resin ducts (Martin et al, 2002;Hudgins et al, 2004). Exogenous MeJA has been successfully used to enhance the resistance of trees against several insects and pathogens, i.e.…”

Prohydrojasmon treatment of lima bean plants reduces the performance of two-spotted spider mites and induces volatiles

“…Furthermore, herbivore performance is negatively affected by JA and cis-jasmone treatments (e.g. Farmer & Ryan 1992;Bruce et al 2003;Heijari et al 2005;Cooper & Rieske 2008).…”