Accurate and easy method for systemin quantification and examining metabolic changes under different endogenous...

Area of Science:

• Plant molecular biology
• Plant biochemistry
• Plant signaling

Background:

• Systemin (SYS) is a peptide hormone in Solanaceae, proposed to work with jasmonic acid (JA) in plant defense.
• Previous research focused on PROSYSTEMIN (PROSYS) gene expression, not direct peptide quantification.
• Understanding SYS's role in plant metabolism requires accurate peptide quantification.

Purpose of the Study:

• To develop a simple and accurate method for quantifying systemin (SYS) peptide.
• To investigate the impact of SYS levels on plant metabolism.
• To analyze metabolic profiles of plants with altered PROSYSTEMIN expression.

Main Methods:

• Development of a novel, low-sample-manipulation method for SYS quantification.
• Quantification of SYS in wild-type, PROSYS-overexpressing (PS+), and PROSYS-silenced (PS-) tomato lines.
• Untargeted metabolomic profiling to compare metabolic changes across lines.

Main Results:

• Basal SYS levels in wild-type tomato leaves are extremely low.
• PS+ plants showed significantly higher accumulation of compounds in lignan biosynthesis and tyrosine metabolism pathways.
• PS+ plants accumulated elevated 12-oxo-phytodienoic acid (OPDA) but not jasmonic acid (JA).

Conclusions:

• A straightforward method for SYS peptide quantification was established.
• Small changes in SYS levels, even if low, significantly impact plant metabolism.
• PROSYS-overexpressing plants are not suitable models for studying JA accumulation.