PT  - JOURNAL ARTICLE
AU  - Dipali Rani Gupta
AU  - Claudia Sarai Reyes Avila
AU  - Joe Win
AU  - Darren M. Soares
AU  - Lauren S. Ryder
AU  - Daniel Croll
AU  - Pallab Bhattacharjee
AU  - Md. Shaid Hossain
AU  - Nur Uddin Mahmud
AU  - Md. Shabab Mehbub
AU  - Musrat Zahan Surovy
AU  - Nicholas J. Talbot
AU  - Sophien Kamoun
AU  - M. Tofazzal Islam
TI  - The MoT3 assay does not distinguish between <em>Magnaporthe oryzae</em> wheat and rice blast isolates from Bangladesh
AID  - 10.1101/345215
DP  - 2018 Jan 01
TA  - bioRxiv
PG  - 345215
4099  - http://biorxiv.org/content/early/2018/06/14/345215.short
4100  - http://biorxiv.org/content/early/2018/06/14/345215.full
AB  - The blast fungus Magnaporthe oryzae is comprised of lineages that exhibit varying degrees of specificity on about 50 grass hosts, including rice, wheat and barley. Reliable diagnostic tools are essential given that the pathogen has a propensity to jump to new hosts and spread to new geographic regions. Of particular concern is wheat blast, which has suddenly appeared in Bangladesh in 2016 before spreading to neighboring India. In these Asian countries, wheat blast strains are now co-occurring with the destructive rice blast pathogen raising the possibility of genetic exchange between these destructive pathogens. We assessed the recently described MoT3 diagnostic assay and found that it did not distinguish between wheat and rice blast isolates from Bangladesh. The assay is based on primers matching the WB12 sequence corresponding to a fragment of the M. oryzae MGG_02337 gene annotated as a short chain dehydrogenase. These primers could not reliably distinguish between wheat and rice blast isolates from Bangladesh based on DNA amplification experiments performed in separate laboratories in Bangladesh and in the UK. In addition, comparative genomics of the WB12 sequence revealed a complex underlying genetic structure with related sequences across M. oryzae strains and in both rice and wheat blast isolates. We, therefore, caution against the indiscriminate use of this assay to identify wheat blast.