Abstract
Five novel Candidatus Phytoplasma species were described in the previous biennium in the class Mollicutes. These were Candidatus Phytoplasma castaneae associated with chestnut witches'-broom disease, Candidatus Phytoplasma phoenicium associated with an emerging lethal disease of almond trees, Candidatus Phytoplasma oryzae associated with rice yellow dwarf disease, Candidatus Phytoplasma ziziphi, associated with jujube witches'-broom disease and Candidatus Phytoplasma ulmi associated with elm yellows. Several other descriptions are already in press and available online. Mycoplasma testudineum, isolated from the respiratory tract of the desert tortoise, was also described and Eperythrozoon ovis, an epierythrocytic agent of haemolytic anaemia in sheep and goats, was reassigned to the genus Mycoplasma as Mycoplasma ovis comb. nov. The Chairman also welcomed the publication by the Phytoplasma group of the IRPCM Phytoplasma/Spiroplasma Working Team of the new description for the novel genus Candidatus Phytoplasma.
During the last biennium K.-E. Johansson determined the 16S rRNA gene sequences of all members of the genus Acholeplasma and T. F. Knight Jr determined those of the genera Entomoplasma and Mesoplasma. This completes the sequencing for the entire spectrum of the currently recognized species of Mollicutes.
The nomenclature of the ruminant mycoplasmas is still under debate but R. A. J. Nicholas and colleagues will write a proposal to classify Mycoplasma bovigenitalium and ovine/caprine serogroup 11 as a single species.
With considerable help from J. G. Tully, the Mollicutes contribution for the International Committee of Prokaryotes (ICSP) website () was completed and a link is now available from the IOM website. The site contains information on all the recognized taxa, on subcommittee membership, Minutes of past meetings and minimum standards documents.
The Chairman drew attention to the difficulties arising from the recent amendment to Rule 27 of the Code requiring deposition of cultures of newly described species in two independent culture collections in two different countries. This item is addressed again in Minutes 4, 8 and 12 below.
Minute 4. ICSP information.
G. M. Garrity presented information on the ICSP and its Code of Nomenclature. He reported that the recent changes to Rule 27, referred to above, had also caused difficulties for workers on other bacteria, for example the spirochetes. He explained that the subcommittees are covered by the Statutes of the ICSP, which in turn are governed by the International Union of Microbiological Societies (IUMS). If the IOM were to become a voting member of IUMS then it could have more say in the affairs of these bodies and the Rules that are made. Comments on changes to the Code and to the Statutes can be introduced for discussion at upcoming meetings (the next being in San Francisco in 2005). He urged members of the subcommittee to keep up with ICSP actions, which are published in the International Journal of Systematic and Evolutionary Microbiology following the IUMS Congress, because an updated Code has not been published since 1992. It was difficult to determine the best course of action to take on Rule 27 because a Request for an Opinion could delay matters for up to 3 years, depending on the cycle of the Congresses. On another matter, and having read the minutes of the subcommittee's 2000 meeting, he pointed out that, although subspecies divisions are governed by the Code, the classification of serotypes, pathovars etc. do not come under the Code and can be very useful in some circumstances.
Minute 5. Spiroplasma taxonomy.
Phylogenetic trees presented at the 2002 subcommittee meeting by G. E. Gasparich have now been published [Gasparich et al., Int J Syst Evol Microbiol 54 (2004), 893918]. In writing the paper the authors used terminology that would satisfy both the eukaryote and prokaryote systematists. G. E. Gasparich pointed out that, although this study was a comprehensive analysis, it used only 16S rRNA gene sequences and she viewed it as a good starting point for asking questions about diversity, pathogenicity and other issues. The molecular data tied in well with much other data on morphology, biochemistry and serology.
R. F. Whitcomb reported that F. French's laboratory were in the process of characterizing many novel species of Spiroplasma. Also, G. E. Gasparich and D. R. Brown had characterization programmes underway so that it was very important that the minimum standards were revised to aid this and similar ventures.
Minute 6. Phytoplasma taxonomy.
The Phytoplasma taxonomy group of the IRPCM Phytoplasma/Spiroplasma Working Team published the description of the genus Candidatus Phytoplasma, a taxon proposed for the wall-less non-helical prokaryotes that colonize plant phloem and insects [Int J Syst Evol Microbiol 54 (2004), 12431255]. The subcommittee commended the efforts of those involved in preparing this important document.
Minute 7. Ureaplasma taxonomy.
There has been a reduction in activity in this field in the last biennium but revisions have been made to the forthcoming Bergey chapter by the authors J. A. Robertson and D. Taylor-Robinson, which will contain much useful information.
Minute 8. Mycoplasma and haemoplasma taxonomy.
J. G. Tully indicated that the main problem concerned the classification of Eperythrozoon and Haemobartonella within the genus Mycoplasma. The priority of the name Eperythrozoon had again been raised in the literature [Uilenberg et al., Exp Appl Acarol 32 (2004), 301312]. The Judicial Commission was expected to deal with this problem.