comunitat-uji-handle:10234/9
comunitat-uji-handle2:10234/2508
comunitat-uji-handle3:10234/6999
comunitat-uji-handle4:
INVESTIGACION
Resum
Background: Systemin has been extensively studied since it was discovered and is described as a peptidic hormone
in tomato plants and other Solanaceae. Jasmonic acid and systemin are proposed to act through a positive ... [+]
Background: Systemin has been extensively studied since it was discovered and is described as a peptidic hormone
in tomato plants and other Solanaceae. Jasmonic acid and systemin are proposed to act through a positive feedback
loop with jasmonic acid, playing synergistic roles in response to both wounding and insect attack. Despite its
biological relevance, most studies regarding the function of systemin in defence have been studied via PROSYSTEMIN
(PROSYS) gene expression, which encodes the propeptide prosystemin that is later cleaved to systemin (SYS). Interest‑
ingly, hardly any studies have been based on quantifcation of the peptide.
Results: In this study, a simple and accurate method for systemin quantifcation was developed to understand
its impact on plant metabolism. The basal levels of systemin were found to be extremely low. To study the role of
endogenous systemin on plant metabolism, systemin was quantifed in a transgenic line overexpressing the PROSYS
gene (PS+) and in a silenced antisense line (PS−). We evaluated the relevance of systemin in plant metabolism by
analysing the metabolomic profles of both lines compared to wildtype plants through untargeted metabolomic
profling. Compounds within the lignan biosynthesis and tyrosine metabolism pathways strongly accumulated in
PS+compared to wild-type plants and to plants from the PS− line. The exogenous treatments with SYS enhanced
accumulation of lignans, which confrms the role of SYS in cell wall reinforcement. Unexpectedly, PS+plants displayed
wild-type levels of jasmonic acid (JA) but elevated accumulation of 12-oxo-phytodienoic acid (OPDA), suggesting that
PS+should not be used as an over-accumulator of JA in experimental setups.
Conclusions: A simple method, requiring notably little sample manipulation to quantify the peptide SYS, is
described. Previous studies were based on genetic changes. In our study, SYS accumulated at extremely low levels in
wild-type tomato leaves, showed slightly higher levels in the PROSYSTEMIN-overexpressing plants and was absent in
the silenced lines. These small changes have a signifcant impact on plant metabolism. SA and OPDA, but not JA, were
higher in the PROSYS-overexpressing plants. [-]
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info:eu-repo/semantics/openAccess