Plant Pathology (2021) 70, 722-734

Renée A. Rioux, Cameron M. Stephens, Paul L. Koch, Mehdi Kabbage and James P. Kerns (2021)
Identification of a tractable model system and oxalic acid-dependent symptom development of the dollar spot pathogen Clarireedia jacksonii
Plant Pathology 70 (3), 722-734
Abstract: Clarireedia jacksonii causes dollar spot disease of cool-season turfgrasses in the United States and produces the phytotoxin oxalic acid. The role of oxalic acid in host–pathogen interactions of C. jacksonii is unknown and there are multiple challenges to studying these interactions in natural turfgrass hosts. Consequently, identification of model plants to study C. jacksonii–host interactions and the role of oxalic acid in pathogenesis is necessary. Controlled environment inoculation assays were used to evaluate pathogenesis of C. jacksonii in various model plants and investigate the role of oxalic acid in symptom development. Observations at microscopic and macroscopic levels demonstrated that infection progressed similarly in all monocots tested (creeping bentgrass, wheat, barley, rice, Brachypodium distachyon) but not in the dicot Arabidopsis thaliana. Plant oxalic acid content increased from near zero to around 0.2–0.4 mM following inoculation with C. jacksonii in creeping bentgrass, barley, and wheat. Conversely, oxalic acid content remained near zero in A. thaliana and was not well correlated with inoculation in rice and B. distachyon, both of which had higher endogenous oxalic acid levels than other monocots. Time-course oxalic acid quantification experiments with creeping bentgrass and B. distachyon further supported a link between symptom development and in planta oxalic acid content and identified 48 hr postinoculation as a critical time-point for investigating the role of oxalic acid in C. jacksonii pathogenesis. These studies demonstrate that various monocots can serve as tractable model systems for studying C. jacksonii–host interactions and that increases in oxalic acid content are associated with C. jacksonii symptom development.
(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): Paul L. Koch, James Kerns

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
molecular biology - genes

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Clarireedia jacksonii	Barley (Hordeum vulgare)
	Clarireedia jacksonii	Wheat (Triticum)
	Clarireedia jacksonii	Rice (Oryza)
	Clarireedia jacksonii	Agrostis (crop)
	Clarireedia jacksonii	Brachypodium (crop)