What Is It? | Facts in Depth | For the Professional Diagnostician
The pathogen is soilborne, and symptoms first appear above ground as wilting and chlorotic leaves. Stunting occurs in new growth and the plant eventually dies. When the roots are examined, they are swollen, distorted, and malformed. More specifically, there is abnormal enlargement of the root system forming galls. The root malformation impairs the host plant to uptake water.
(Left: Mustard Green; Middle: Turnip; Right: Radish)
Resting spores can be observed microscopically in galled roots.
Often Confused With
- Root knot nematode – The roots are highly symptomatic when infected with clubroot and can sometimes be confused with the galls caused by root knot nematodes. The galls caused by root knot nematode are usually more spherical and are generally not as large as the clubroot galls.
Plasmodiophora brasssicae is an obligate parasite; therefore, there are no isolation or culture media available for this pathogen.
Rapid Diagnostic Tests
- PCR Primers from Khangura and Wright, 2012
- TC1F and TC1R (5′-GTGGTCGAACTTCATTAAATTTGGGCTCTT-3′ and 5′-TTCACCTACGGAACGTATATGTGCATGTGA-3′)
- TC2F and TC2R (5′-AAACAACGAGTCAGCTTGAATGCTAGTGTG-3′ and 5′-CTTTAGTTGTGTTTCGGCTAGGATGGTTCG-3′)