Induction of Defense Responses in Pinus sylvestris Seedlings by Methyl Jasmonate and Response to Heterobasidion annosum and Lophodermium seditiosum Inoculation

Abstract

The induction of defense responses in Pinus sylvestris L. seedlings by methyl jasmonate (MeJA) was investigated in three experiments. Two different MeJA application methods were tested, and induction of defense responses was assayed by seedling inoculation with Heterobasidion annosum (Fr.) Bref. and Lophodermium seditiosum Minter, Staley and Millar. In the first experiment, five-year-old P. sylvestris ramets of one clone were directly treated with MeJA, followed by inoculation with H. annosum. In the second experiment, open-pollinated Scots pine seedlings were treated with MeJA by direct spraying and vaporization, and inoculation with H. annosum was done using a slightly modified protocol. In the third experiment, open-pollinated Scots pine seedlings were treated with MeJA by vaporization and inoculated with L. seditiosum. Direct application of MeJA induced seedling mortality, and in some cases, decreased resistance to inoculation with H. annosum. Application of MeJA by vaporization was less stressful for seedlings, and resulted in increased resistance to both H. annosum and L. seditiosum. In addition, an unforeseen Neodiprion sertifer (Geoffroy) and Hylobius abietis L. infestation provided anecdotal evidence of the efficacy of MeJA in inducing resistance to insect pests as well. Further studies are required on the induction of resistance to additional diseases and pests. Induced resistance could be used as a possible protective mechanism for Scots pine seedlings prior to planting during reforestation of stands to increase vitality and survival.

Function and Mechanism of Jasmonic Acid in Plant Responses to Abiotic and Biotic Stresses

“…Generally, JAs are beneficial to enhance defensive resistance, or stress tolerance, and therefore have broad application potential in agriculture and forestry as anti-stress protective agents. However, the side-effects of MeJA application, such as inducing seedling mortality and reduction height growth, should not be neglected [197,198].…”

Genotype-Dependent Jasmonic Acid Effect on Pinus sylvestris L. Growth and Induced Systemic Resistance Indicators

“…Jasmonic acid itself and related jasmonates are plant growth regulators linked with stress mediation and, more specifically, resistance to pathogen attacks and herbivores [ 23 , 24 , 25 ]. As reported by Zas et al [ 4 ], Thaler et al [ 11 ], Sabbagh et al [ 7 ] and others, jasmonates are an effective ISR elicitor that can help with plant response to abiotic and biotic stressors.…”

“…As reported by Zas et al [ 4 ], Thaler et al [ 11 ], Sabbagh et al [ 7 ] and others, jasmonates are an effective ISR elicitor that can help with plant response to abiotic and biotic stressors. Jasmonates were even shown to work in several studies on pines and other conifers [ 4 , 8 , 24 , 25 , 26 , 27 ]. However, while previous studies have examined ISR‘s importance for plant resistance mechanisms to biotic and abiotic stress, there is a gap in analyzing its impact on conifer species.…”

Transcriptome-Wide Identification of TCP Transcription Factor Family Members in Pinus massoniana and Their Expression in Regulation of Development and in Response to Stress

“…The increased expression levels of PmTCP8 and PmTCP11 under mechanical injury suggested that they may be involved in biological processes, such as preventing the invasion of pathogens. SA, MeJA, ETH, H 2 O 2, and ABA are important exogenous exciters that are induced by external stimuli and have an important role in response to stress [48]. Through gene expression levels, it was found that PmTCP7, PmTCP8, and PmTCP11 positively responded to H 2 O 2 .…”