Extracellular Alkalinization as a Defense Response in Potato Cells.
A quantitative and robust bioassay to assess plant defense response is important for studies of disease resistance and also for the early identification of disease during pre- or non-symptomatic phases. An increase in extracellular pH is known to be an early defense response in plants. In this study, we demonstrate extracellular alkalinization as a defense response in potatoes. Using potato suspension cell cultures, we observed an alkalinization response against various pathogen- and plant-derived elicitors in a dose- and time-dependent manner. We also assessed the defense response against a variety of potato pathogens, such as protists (Phytophthora infestansandSpongospora subterranea) and fungi (Verticillium dahliaeandColletotrichum coccodes). Our results show that extracellular pH increases within 30 min in proportion to the number of pathogen spores added. Consistently with the alkalinization effect, the higher transcription level of several defense-related genes and production of reactive oxygen species was observed. Our results demonstrate that the alkalinization response is an effective marker to study early stages of defense response in potatoes.
Department of Plant Pathology, Washington State University, Pullman WA, USA.
Natalia
N
Moroz
Agricultural and Food Systems, Washington State University, Pullman WA, USA.
Karen R
KR
Fritch
Department of Plant Pathology, Washington State University, PullmanWA, USA; Molecular Plant Sciences Program, Washington State University, PullmanWA, USA.
Matthew J
MJ
Marcec
Department of Plant Pathology, Washington State University, Pullman WA, USA.
Diwaker
D
Tripathi
Molecular Plant Sciences Program, Washington State University, PullmanWA, USA; Institute of Biological Chemistry, Washington State University, PullmanWA, USA.
Andrei
A
Smertenko
Department of Plant Pathology, Washington State University, PullmanWA, USA; Molecular Plant Sciences Program, Washington State University, PullmanWA, USA.
Kiwamu
K
Tanaka
apoplastic pH; defense response; extracellular alkalinization; potato; suspension cell culture