Rapid detection of Passalora sequoiae causing needle blight on Japanese cedar

ABSTRACT

Needle blight, caused by Passalora sequoiae (Mycosphaerellaceae, Ascomycota), is an economically significant disease that commonly affects Japanese cedar (Cryptomeria japonica) in Japan. With the increasing production of cedar saplings as part of reforestation efforts, there is concern that needle blight will become more prevalent in nursery fields. However, when visually inspected, this disease is sometimes misdiagnosed as other diseases with similar symptoms. Therefore, a prerequisite to preventing the spread of this pathogen is the development of an accurate and rapid molecular diagnostic method. In this study, species-selective primers were designed for conventional PCR and recombinase polymerase amplification (RPA) and then successfully applied for rapid detection of the pathogen in laboratory-grown cultures and diseased needles. The detection methods developed in this study should improve the control and management of needle blight in Japanese cedar.

KEYWORDS:

• Cryptomeria
• molecular detection
• PCR
• RPA

Acknowledgments

We thank Dr. Hajime Kosaka (Forestry and Forest Product Research Institute) for preparing a situation that makes this study easy to be carried out, and Dr. Chiharu Nakashima (Mie University) for his advices about the molecular detection of cercosporoid fungi. We also thank Ms. Atsuko Matsumoto (Forestry and Forest Product Research Institute) for her assistances on the molecular detection of each experiments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This study is funded by Research grant #201911 of the Forestry and Forest Products Research Institute, Tsukuba, Ibaraki Prefecture, Japan.