AUTHOR=Guo Zhixin , Sun Xiaoyang , Qin Ligang , Dong Lili , Xiong Liangbing , Xie Fuchun , Qin Dong , Chen Yajun 

TITLE=Identification of Golovinomyces artemisiae Causing Powdery Mildew, Changes in Chlorophyll Fluorescence Parameters, and Antioxidant Levels in Artemisia selengensis

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.876050

DOI=10.3389/fpls.2022.876050

ISSN=1664-462X

ABSTRACT=<p><italic>Artemisia selengensis</italic> Turcz. is a valuable edible and medicinal vegetable crop widely cultivated in Northeast China. Powdery mildew (PM) disease occurs during field and greenhouse cultivation, resulting in production losses and quality deterioration. The pathogen in <italic>A. selengensis</italic> was <italic>Golovinomyces artemisiae</italic> identified using optical microscopic and scanning electron microscopic observations, morphological identification, and molecular biological analyses. Parameters of chlorophyll fluorescence (ChlF) and antioxidant system responses as well as callose and lignin contents in <italic>A. selengensis</italic> were analyzed with inoculating <italic>G. artemisiae</italic>. Obvious of PM-infected leaves were confirmed with significantly lower values in electron transport rate (ETR), non-photochemical quenching (NPQ), photochemical quenching (qP), and actual photochemical efficiency [Y(II)], but higher values in non-adjusting energy dissipation yield [Y(NO)], supposed that maximal photosystem II quantum yield (Fv/Fm) value and images could be used to monitor PM degree on infected<italic>A. selengensis</italic>. In addition, malondialdehyde (MDA), superoxide anion (O<sub>2</sub><sup>–</sup>), callose, lignin contents, and peroxidase (POD) activity increased, while superoxide dismutase (SOD) activity, catalase (CAT) activity, and ascorbic acid (AsA) content decreased significantly in infected leaves compared to mock-inoculated leaves, indicated that lignin and protective enzymes are the key indicators for detecting PM resistant in <italic>A. selengensis</italic>. These results suggest that PM caused by <italic>G. artemisiae</italic> disrupted the photosynthetic capacity and induced imbalance of antioxidant system in<italic>A. selengensis</italic>. The findings were of great significance for designing a feasible approach to effectively prevent and control the PM disease in <italic>A. selengensis</italic> as well as in other vegetable crops.</p>