October 23, 2019 – Our article entitled “FlgII-28 is a Major Flagellin-Derived Defense Elicitor in Potato” was published in Molecular Plant-Microbe Interactions

How to cite:
Moroz N, Tanaka K (2020) FlgII-28 is a major flagellin-derived defense elicitor for potato. Molecular Plant-Microbe Interactions. doi:10.1094/MPMI-06-19-0164-R

The first layer of plant immunity is deployed by recognition of pathogen-associated molecule patterns (PAMPs) and induction of early stress responses. Flagellin is the major protein component of the flagellum. Flagellin-derived peptide fragments, such as Flg22, a short active peptide derived from the highly conserved part of the N-terminal region, are recognized as PAMPs by a specific perception system present in most higher plants. Some bacteria evade the plant recognition system by altering the Flg22 region in the flagellin. Instead, a small subset of plants (i.e., Solanaceous plants) can sense these bacteria by recognizing a second region, termed FlgII-28. The function of FlgII-28 has been well documented in tomato but not in potato plants. Here, we investigated the effect of FlgII-28 on several defense responses in potato. Cytosolic calcium (Ca2+) elevation is an early defense response upon pathogenic infection. We generated transgenic potato plants expressing aequorin, a nontoxic Ca2+-activated photoprotein. The results showed that FlgII-28 stimulated strong cytosolic Ca2+ elevation in a dose-dependent manner, whereas the response was attenuated when a Ca2+ channel blocker was added. In addition, the FlgII-28-stimulated cytosolic Ca2+ elevation was shown to subsequently promote extracellular alkalinization, reactive oxygen species production, mitogen-activated protein kinase phosphorylation, and transcriptional reprogramming of defense-related genes in potato. Interestingly, all tested defense responses caused by FlgII-28 were significantly stronger than those caused by Flg22, suggesting that FlgII-28 acts as a primary flagellar PAMP to elicit multiple defense responses in potato.