AUTHOR=Dai Tingting , Xu Yue , Yang Xiao , Jiao Binbin , Qiu Min , Xue Junxin , Arredondo Felipe , Tyler Brett M. 

TITLE=An Improved Transformation System for Phytophthora cinnamomi Using Green Fluorescent Protein

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.682754

DOI=10.3389/fmicb.2021.682754

ISSN=1664-302X

ABSTRACT=<p><italic>Phytophthora cinnamomi</italic> is a destructive pathogen causing root rot and dieback diseases on hundreds of economically and ecologically important plant species. Effective transformation systems enable modifications of candidate genes to understand the pathogenesis of <italic>P. cinnamomi</italic>. A previous study reported a polyethylene glycol and calcium dichloride (PEG/CaCl<sub>2</sub>)-mediated protoplast transformation method of <italic>P. cinnamomi</italic>. However, the virulence of the transformants was compromised. In this study, we selected ATCC 15400 as a suitable wild-type isolate for PEG/CaCl<sub>2</sub> transformation using the green fluorescent protein after screening 11 <italic>P. cinnamomi</italic> isolates. Three transformants, namely, PcGFP-1, PcGFP-3, and PcGFP-5, consistently displayed a green fluorescence in their hyphae, chlamydospores, and sporangia. The randomly selected transformant PcGFP-1 was as virulent as the wild-type isolate in causing hypocotyl lesions on lupines. Fluorescent hyphae and haustoria were observed intracellularly and intercellularly in lupine tissues inoculated with PcGFP-1 zoospores. The potential application of this improved transformation system for functional genomics studies of <italic>P. cinnamomi</italic> is discussed.</p>