A novel metabolomics approach as integrative strategy for understanding changes in Pinus radiata D.Don metabolome in response to infestation by Sirex noctilio F.
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Date
2022
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Publisher
Universidad de Concepción.
Abstract
The production of renewable resources in forest plantations is one of
Chile's most important industrial activities since it serves as the basis for
essential primary industries such as wood, boards, pulp and chips.
Consistent with the global trend, our country’s most extensive
commercial plantations are monoculture forests, with Pinus radiata as the
predominant planted species. Plantations of the species account for more than
fifty per cent of the commercial plantations registered by 2021.
Productivity and long-term viability of the forest economic sector in
Chile, based on P. radiata plantations, are constantly threatened by droughts,
fires, and disease outbreaks caused by exotic pests. Among these harmful pests,
the insect Sirex noctilio (S. noctilio) may cause significant economic losses
because it can kill trees quickly after just one infestation.
The primary focus of scientific research regarding S. noctilio has been its
symbiotic relationship with the fungus Amylostereum areolatum and the
composition and physiological effects of the venom injected during oviposition.
However, no studies have been published describing the biochemical processes
triggered in the plant during infection.
It is so far unknown the resistance and tolerance traits induced in Pinus
radiata metabolome after S. noctilio infestation. Therefore, in the present thesis, we report the usefulness of LC-MS-based untargeted metabolomics for
uncovering the systemic metabolome changes in needles (leaves) and wood of
14-year-old P. radiata trees in response to initial and long-term S. noctilio
infestation. Needles suffered severe consequences from the chlorosis degrading
photosystems after infestation. Photoprotection was immediately induced via
up-regulation of catechin and procyanidin B1. Also, proline serves as an
alternative substrate for respiration. In addition, extraordinary oxidative stress
was also registered by an acute decrease in ascorbate levels (90-fold).
Detoxification of venom toxin (noctilisin) via conjugation with glutathione
(dropped by 17-fold) was hypothesized preceding the inevitable premature
senescence observed within infested trees. Nonetheless, significant
overexpression of auxins was detected, suggesting the activation of a tolerance
mechanism. Finally, we evidenced that metabolomics accurately revealed the
biochemical response of trees to the woodwasp infestation, indicating, in
addition, the upstream molecular functions involved in the biochemical
processes, as well as potentially new research and breeding targets.
Description
Tesis para optar al grado de Doctor en Ciencias y Tecnología Analítica.
Keywords
Metaboloma, Sirex noctilio, Relación Insecto-Planta, Patología Vegetal, Pinos, Enfermedades