Introduction

Magnaporthe or Pyricularia?  (by Ning Zhang, 2 May 2012)

At the 2011 Melbourne International Botanical Congress, One Scientific Name for One Fungus was voted for.  According to the new Article 59, all legitimate fungal names are now treated equally for the purposes of establishing priority, regardless of the life history state of the type (The Melbourne Code should be out in the summer of 2012). 

The end of dual nomenclature for fungi will have major impact on pleomorphic species.  For Magnaporthaceae, an important question that has to be addressed is which genus name should be used for the rice blast fungus.  The rice blast fungus has Magnaporthe sexual state (teleomorph) and Pyricularia asexual state (anamorph).  

At the Amsterdam CBS “One Fungus, Which Name” symposium, the Sordariomycetes Taxonomy Discussion Group agreed that the following criteria should be considered when choosing between two generic name options:

·      Monophyly, phylogeny

·      Names in use in plant pathology, industry, etc.

·      Quarantine issues;

·      What morphology is most commonly encountered;

·      Stability;

·      Taxonomic clarity; genus name should be well defined;

·      Number of needed combinations/name changes

etc, etc.

A recently published 6-gene phylogeny (see figure attached) with selected taxa in the Magnaporthaceae indicates that the current concept of both Magnaporthe and Gaeumannomyces are polyphyletic.  Magnaporthe salvinii is the type species of Magnaporthe.  Pyricularia grisea and P. oryzae are older names than M. grisea and M. oryzae (please see the list for details on date and type information).  However, to minimize the name change for important pathogens and quarantine issues, we should consider conserving the Magnaporthe genus name for the rice blast fungus (Magnaporthe oryzae).

An option is to segregate Magnaporthe from Pyricularia and limit the usage of Magnaporthe only for the clade including M. oryzae and M. grisea. 

Alternatively, we will keep Magnaporthe for M. salvinii and use Pyricularia as the genus name for the rice blast fungus.

Other options?

Please feel free to post your comment/suggestion in this blog, which is created for Magnaporthaceae scientific community discussion purposes.  If you want to post your phylogeny or other information here, please send to me (zhang@aesop.rutgers.edu).