The moss Physcomitrella patens. Annual Plant Reviews, Volume 36

Abstract

Physcomitrella patens – the so-called Arabidopsis of the moss world or ‘green yeast’ – is the first non-vascular plant to have its genome sequenced. This book is a review of previous and current research on this model moss and an invitation for others to consider using P. patens for their work. This is a beautifully produced, well edited and generally easy-to-read volume for plant scientists. Bryological terms are well explained and there is a useful glossary for those unfamiliar with some common bryological terms and concepts. More knowledge is assumed with regard to molecular techniques, and an expanded glossary for those perhaps more familiar with the bryology but less so with the experimental biology would have been useful. Such an addition might also widen the target audience somewhat from the specialist plant scientist to the interested biologist. The editors state in the preface that the book covers a broad range of topics including evolutionary and ecological studies using P. patens, its unique features and particular value in a variety of molecular work, as well as the use of P. patens to investigate standard biological processes. They have, on the whole, produced such a book and should be congratulated for this achievement. There is a focus on molecular work, which reflects the bulk of research to date on P. patens, but serious attempts are made to widen the scope and address some of the scientific gaps in recent studies. The opening chapter is an up-to-date and easy-to-understand introduction to the current state of knowledge of the evolutionary history of land plants, and the positioning of bryophytes, especially mosses, on the tree of life. Despite promises in the chapter title, ecology is scarcely covered, which highlights the main omission in this volume and also previous research. Chapter 2 gives an excellent overview of the limited amount of experimental evolutionary studies on mosses in general, suggesting that ‘classical genetic analysis of natural variation has been under utilised in the moss research community of late’. How true this is! This chapter pertinently illuminates the vast and exciting possibilities for future research in this area. Of particular interest is the recent development of P. patens mapping lines by the author. Further chapters cover a vast range of research areas, some better established than others. Topics include: genomics, gene targeting and small RNAs, development, maintenance and the stress responses of P. patens. The exploration of gametangial development is accompanied by some clear figures that nicely illustrate the different growth stages, while the explanation of gene trapping techniques to identify novel genes important in development brings this section up to date. The chapter on the role of abscissic acid in stress (particularly dehydration and desiccation) is clear and succinct, providing a good overview of the current state of knowledge. The final chapter on pathogenesis in mosses is a comprehensive view of the great potential for using P. patens in molecular plant pathology studies. Interestingly, P. patens appears to be susceptible to numerous infections in the lab, yet is much less susceptible to disease in nature – although as the authors point out, this is likely due to limited sampling in the field. The section of colour prints in the middle of the book is formed from a composite of figures from the different chapters. This was initially confusing, but the beautiful colour prints are a wonderful addition and serve to highlight the difference in detail that can be observed from the black and white photographs. This is an excellent book on P. patens and will hopefully encourage its further use by molecular plant scientists. However, the scope of this book is broader and it should also be of interest to evolutionary biologists and ecologists. Just as the value of Arabidopsis in such studies is increasing, I hope that this book is the spark that ignites greater amounts of research on the evolution and ecology of mosses.