Magnaporthe grisea (T.T. Hebert) M.E. Barr, Mycologia 69(5): 954 (1977)
Holotype:
BPI 625033 (Oryza sp.)
Magnaporthe
oryzae
B.C. Couch, Mycologia 94(4): 692 (2002)
Holotype: BPI 841383 (Oryza sp.)
=
Pyricularia oryzae Cavara, Fung. Long. Exsicc. 2:
no. 49 (1892)
Holotype: Fungi Longobardiae #49 (Oryza sp.)
Magnaporthe
poae
Landsch. & N. Jacks., Mycol. Res. 93(1): 59 (1989)
Holotype:
DAR 59044
Magnaporthe
rhizophila
D.B. Scott & Deacon, Trans. Br. mycol. Soc. 81(1): 77 (1983)
Holotype:
PREM 45952
Magnaporthe salvinii (Catt.) R.A. Krause & R.K. Webster,
Mycologia 64(1): 110 (1972)
≡ Leptosphaeria salvinii Catt.,
Arch. Labor. Bot. Critt. Univ. Pavia 2 & 3: 115-128. 1879.
= Nakataea sigmoidea (Cavara)
Hara, Diseases Rice Plant, Edn 2: 185. 1939.
≡ Helminthosporium sigmoideum Cavara, Mat. Lomb.: 15. 1889.
= Sclerotium oryzae Catt., Arch. Triennale Lab. Bot.
Crittog. 1: 10. 1877.
Pyricularia
grisea
Sacc., Michelia 2(no.
6): 20. 1880.
Lectotype:
North American Flora #374 (Digitaria
sp.)
No doubt, 'Pyricularia oryzae' is the proper name for rice blast fungus. Because the 'pyriform' conidial fungus has not changed yet since it was described by Cavara in 1892. Only the name has been changing; from P. oryzae to P. grisea/Magnaporthe grisea, and later from Pyricularia oryzae to Magnaporthe oryzae. It is P. oryzae, the asexual state, which causes rice disease in the field, greenhouse or laboratory. M. oryzae, the sexual state, is very rare in lab and yet to found in nature. I am sure most of the people working with rice blast fungus have not seen M. grisea. They are working all the time with P. oryzae. Then why Magnaporthe, not Pyricularia?
ReplyDeleteIn the 6th IRBC at Jeju in Korea, some people asked scientific reasons for changing the name from Magnaporthe to Pyricularia. The reasons posted by Dr. Ning Zhang are more than enough to use P. oryzae. Furthermore, science believes in seeing. What we are seeing all the time is P. oryzae, not M. oryzae. In the disease cycle of the rice blast, it is P. oryzae which initiates the disease and it is again P. oryzae which ends as further inoculums for the disease. There is no obligatory intervention of M. oryzae in the disease cycle to be completed.
Some people at the 6th IRBC suggested that we should wait for some more time to find the truth before we change the name. Here, we are not changing the name. We are retaining the name which has been used for nearly one and quarter century. The name P. oryzae is still very much in use even though it was decided in 2002 to use the name M. oryzae (instead of P. oryzae). I did a very limited two-hour survey in the net for those published in 2013 only and found that the number of publications with P. oryzae was more than 60 (as of August 23). This is quite a high number and the reason is obvious to everyone.
It was said during the one and half hour long session of 'which name for the rice blast fungus, Pyricularia or Magnaporthe?' at the 6th IRBC that publications on rice blast with Magnaporthe are 10 times more than with Pyricularia. The claimed number must have been based on net survey. I am sure all the publications from 1892 have not been digitalized and documented yet in the net. What I believe is that if we count all the publications from 1892 Pyricularia will outnumber Magnaporthe in many folds.
As posted in the net the reasons for maintaining M. oryzae include (i) recognition by funding agents, (ii) quarantine issues, (iii) naming of genes using M. oryzae, and (iv) an option to adopt a very broad generic concept. Funding agents are concerned with the disease, not with the name of the disease causing organism. If the disease is of economic significance no matter what the name is. I don't think most of the funding agents know about Magnaporthe or Pyricularia unless the person-in-charge of the funding agents is of plant pathological/agricultural background. Similarly, if Magnaporthe is considered as quarantine organism Pyricularia should be treated the same way, because of its high pathogenic variations and also because of possible mating types, if any. So, whether it is Magnaporthe or Pyricularia quarantine organism is quarantine organism. So far the naming of genes are concerned, not only MoXXX but a number of Pi-genes have been in use for many years. The option to adopt a very broad generic concept may not be practical/acceptable from genetic and taxonomic point of view.
So, I do plead the global community of rice blast researchers and plant pathologists to vote for Pyricularia oryzae as the proper name for rice blast fungus.
Hira Kaji Manandhar
Nepal Agricultural Research Council
Nepal
hirakaji@gmail.com