In:
Scientific Reports, Springer Science and Business Media LLC, Vol. 9, No. 1 ( 2019-03-18)
Abstract:
Cytosolic Ca 2+ ([Ca 2+ ] cyt ) elevation is an early signaling response upon exposure to pathogen-derived molecules (so-called microbe-associated molecular patterns, MAMPs) and has been successfully used as a quantitative read-out in genetic screens to identify MAMP receptors or their associated components. Here, we isolated and identified by mass spectrometry the dipeptide γ-Glu-Leu as a component of a Phytophthora infestans mycelium extract that induces [Ca 2+ ] cyt elevation. Treatment of Arabidopsis seedlings with synthetic γ-Glu-Leu revealed stimulatory effects on defense signaling, including a weak enhancement of the expression of some MAMP-inducible genes or affecting the refractory period to a second MAMP elicitation. However, γ-Glu-Leu is not a classical MAMP since pH adjustment abolished these activities and importantly, the observed effects of γ-Glu-Leu could be recapitulated by mimicking extracellular acidification. Thus, although γ-Glu-Leu can act as a direct agonist of calcium sensing receptors in animal systems, the Ca 2+ -mobilizing activity in plants reported here is due to acidification. Low pH also shapes the Ca 2+ signature of well-studied MAMPs (e.g. flg22) or excitatory amino acids such as glutamate. Overall, this work serves as a cautionary reminder that in defense signaling studies where Ca 2+ flux measurements are concerned, it is important to monitor and consider the effects of pH.
Type of Medium:
Online Resource
ISSN:
2045-2322
DOI:
10.1038/s41598-019-41276-0
Language:
English
Publisher:
Springer Science and Business Media LLC
Publication Date:
2019
detail.hit.zdb_id:
2615211-3
