AUTHOR=Ghiasi Noei Fateme , Imami Mojtaba , Didaran Fardad , Ghanbari Mohammad Amin , Zamani Elham , Ebrahimi Amin , Aliniaeifard Sasan , Farzaneh Mohsen , Javan-Nikkhah Mohammad , Feechan Angela , Mirzadi Gohari Amir 

TITLE=Stb6 mediates stomatal immunity, photosynthetic functionality, and the antioxidant system during the Zymoseptoria tritici-wheat interaction

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1004691

DOI=10.3389/fpls.2022.1004691

ISSN=1664-462X

ABSTRACT=<p>This study offers new perspectives on the biochemical and physiological changes that occur in wheat following a gene-for-gene interaction with the fungal pathogen <italic>Zymoseptoria tritici</italic>. The <italic>Z. tritici</italic> isolate IPO323, carries <italic>AvrStb6</italic>, while <italic>ΔAvrStb6#33</italic>, lacks <italic>AvrStb6</italic>. The wheat cultivar (cv.) Shafir, bears the corresponding resistance gene <italic>Stb6</italic>. Inoculation of cv. Shafir with these isolates results in two contrasted phenotypes, offering a unique opportunity to study the immune response caused by the recognition of AvrStb6 by Stb6. We employed a variety of methodologies to dissect the physiological and biochemical events altered in cv. Shafir, as a result of the AvrStb6-Stb6 interaction. Comparative analysis of stomatal conductance demonstrated that AvrStb6-Stb6 mediates transient stomatal closures to restrict the penetration of <italic>Zymoseptoria</italic> <italic>tritici</italic>. Tracking photosynthetic functionality through chlorophyll fluorescence imaging analysis demonstrated that AvrStb6-Stb6 retains the functionality of photosynthesis apparatus by promoting Non-Photochemical Quenching (NPQ). Furthermore, the PlantCV image analysis tool was used to compare the H<sub>2</sub>O<sub>2</sub> accumulation and incidence of cell death (2, 4, 8, 12, 16, and 21 dpi), over <italic>Z. tritici</italic> infection. Finally, our research shows that the AvrStb6-Stb6 interaction coordinates the expression and activity of antioxidant enzymes, both enzymatic and non-enzymatic, to counteract oxidative stress. In conclusion, the Stb6-AvrStb6 interaction in the <italic>Z. tritici</italic>-wheat pathosystem triggers transient stomatal closure and maintains photosynthesis while regulating oxidative stress.</p>