The naming of names: new grass species honours Emeritus Professor

Posted by mjs76 at Jan 02, 2012 08:00 AM |
Genetically important species identified and christened.
The naming of names: new grass species honours Emeritus Professor

Brachypodium stacei

Professor Clive Stace, Emeritus Professor of Botany in our Department of Biology, has received a very special new year’s honour – not from The Queen, but in a newly published plant name. In the journal Annals of Botany, a paper on the grass Brachypodium distachyon has split the plant into three species, one of which has been christened Brachypodium stacei.

The Brachypodium genus consists of 15 species – well, 17 now – and occurs around the Mediterranean and at similar latitudes across Asia and America. B. distachyon is the best known, sometimes called ‘purple false brome’, and has been introduced from the Mediterranean to other regions including North and South America, southern Africa, central Europe and Australia.

Typical samples of B. distachyon (A), B. stacei (B) and B. hybridum (C). The measuring bars are marked in centimetres.

It’s not much to look at, but the value of B. distachyon is that it is very similar to common agricultural crops but genetically much simpler. This makes it an excellent model species for geneticists, along with its six-week life cycle and the fact that it is really, really easy to grow. But obviously, if there’s more than one species here, that’s rather important to any genetic studies.

The new paper by researchers in Spain, Germany, Poland and Aberystwyth lead by Pilar Catalán examined B. distachyon variants, finding different numbers of chromosomes. They determined that the plants with ten chromosomes were one distinct species, the plants with 20 chromosomes were another – and the plants with 30 were a third species derived from a historical hybridisation between the first two.

From now on, B. distachyon will refer specifically to the ten-chromosome species while the 20-chromosome species will be B. stacei (the 30-chromosome species becomes B. hybridum). The paper notes: “Species dedicated to Prof. Clive A. Stace, who initiated the systematic and evolutionary studies of Brachypodium.”

Fluorescence in situ hybridisation with genomic DNA (GISH) clearly indicates the chromosomal difference between B. distachyon (D) and B. stacei (E) and how the two diploid species have combined to produce a third, tetraploid species B. hybridum (F).

At Leicester, Dr Sinéad Drea is currently researching the evolution and development of Brachypodium and will be able to use the new species to understand interactions between genes and their functioning in B. stacei and the two other species, as a model for wheat and other crops.

Professor Stace is one of the UK’s most highly regarded botanists and wrote several definitive reference works, most notably Flora of the British Isles (published in a third edition in 2010 as New Flora of the British Isles). He worked at the University of Leicester for more than thirty years, initially in the Department of Botany and later, after the botanists and zoologists agreed to join forces, in the combined Department of Biology. One of his last projects before retirement was the publication of a CD-ROM, Interactive Flora of the British Isles.

Emeritus Professor Clive Stace's definitive catalogue of British plant species.

One of our current Biology Professors, Pat Heslop-Harrison, is Chief Editor of the Annals of Botany and notes that this paper, published today, is historically important because it marks a sea-change in the way that new plant species are announced. Previously, any novel species had to be described in Latin and ‘publication’ was only considered valid in print journals. However, from 1 January 2012 there is a brave new world of flora taxonomy which allows descriptions in English and recognises online publication, critical to speed up cataloguing and measuring the diversity of plant life.

Appropriately enough, B. stacei is found in the extreme western range of the plant, mostly on the Balearic Isles where our biology undergraduates decamp each year for the ‘Island Biology and Speciation’ module field course. Now run by Dr John Bailey and Dr Richard Gornall, this course was initiated by Professor Stace so it is wonderfully appropriate that the next batch of students will actually be able to find samples of Brachypodium stacei in the wild.

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