Pest Management Science (2022) 78, 1367-1376

Noel L. Knight, Azin Moslemi, Farhana Begum, Kejal N. Dodhia, Lorenzo Covarelli, Andrea L. Hills and Francisco J. Lopez-Ruiz (2022)
Detection of Ramularia collo-cygni from barley in Australia using triplex quantitative and droplet digital PCR
Pest Management Science 78 (4), 1367-1376
Abstract:
BACKGROUND
Ramularia leaf spot (RLS), caused by Ramularia collo-cygni, is an emerging threat to barley (Hordeum vulgare L.) production. RLS has been reported in Australia, however only minimal information is available regarding its detection and distribution. Due to initial asymptomatic growth in planta, slow growth in vitro and symptomatic similarities to net blotch and physiological leaf spots, detection of this pathogen can be challenging. Quantitative polymerase chain reaction (PCR)-based methods for R. collo-cygni-specific identification and detection have been described, however these assays have been demonstrated to lack specificity. False-positive detections may have serious implications, thus we aimed to design a robust R. collo-cygni-specific PCR method.
RESULTS
Using the phylogenetically informative RNA polymerase II second largest subunit (rpb2) and translation elongation factor 1-alpha (tef1-α) genes, along with the tef1-α gene of H. vulgare, a triplex assay was developed for both quantitative and droplet digital PCR. The triplex assay detected R. collo-cygni DNA in barley leaves from New South Wales, South Australia, Tasmania, Victoria and Western Australia. No R. collo-cygni DNA was detected in barley seed grown in Western Australia.
CONCLUSION
The presence of R. collo-cygni DNA has been confirmed in Australian barley crops, suggesting a distribution ranging across the southern barley growing regions of Australia. The R. collo-cygni-specific assay will be a valuable tool to assist with monitoring the distribution and impact of R. collo-cygni in Australia and other regions.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Lorenzo Covarelli

Research topic(s) for pests/diseases/weeds:
surveys/sampling/distribution

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Ramularia collo-cygni	Barley (Hordeum vulgare)	Australia (South+SE)