SEB Bulletin July 2005
SEB SYMPOSIUM 2005
PLANT FRONTIERS MEETING - Sheffield, 21- 23 March 2005
Sheffield was the venue for this year's SEB Plant Symposium and comprised three major themes which are written up here. Selected papers from the meeting will be brought together in two special issues to be published later in the year in the Journal of Experimental Botany.
The Plant Meristems session was initiated with a gentle historical overview of the topic, which introduced the concepts of meristems, phyllotaxy and symmetry; subjects that have perplexed researchers since the early 20th Century, but that the speakers of the session are now resolving using novel techniques. The involvement of the meristem in both cell proliferation and cell patterning processes was outlined; a theme revisited frequently throughout the conference.
The remainder of the day was filled with talks on shoot, inflorescence and floral meristems. More specifically: Keith Lindsey discussed the functions of sterols, ethylene and auxin in determining embryonic polarity; Ruediger Simon considered the effects of altering the boundaries of meristem gene expression; Miltos Tsiantis revealed connections between auxin, KNOX genes, giberrellic acid and polarity genes, while Lucy Moore expanded on BELL and KNOX protein interactions. These presentations complemented other shoot meristem talks given by Cris Kuhlemeier, who proposed a testable model for the role of auxin and expansins in shoot primordia initiation, and Ottoline Leyser, who placed auxin response and axillary branching mutants in a signalling pathway leading to protein degradation.
Root development was the focus of the second day. Ben Scheres elucidated the role of auxin in root patterning and told of genes involved in root stem cell divisions, and Tom Beeckman related auxin and cell cycle to lateral root formation. Ÿka Helariutta spoke of interesting proteins that are involved in root cambium formation.
On the final day George Coupland told us how he used promoter::gene permutations in his comprehensive studies of flowering time pathways, and Caroline Dean demonstrated the implications of the epigenetic state of key genes for the process of vernalisation.
Also, within the session Delphine Fleury, Mike Wheeler, and Elizabeth Hatzimasoura made some lateral biological connections between a histone acetyl transferase Elongator complex and organ growth, S-protein homologues and organ separation, and MAPK signalling and meristem maintenance, respectively.
Apart from the biological implications of the results presented in the session, some important techniques were emphasised such as laser capture microdissection for gene expression analysis (Keith Lindsey), and the use of Jim Haseloff's GAL4 promoter trap lines (Ive De Smet, Laurent Laplaze). In addition, the range of plant species studied/spoken of was very impressive and included: maize (Ann Mellor); Pharbitis (George Coupland); Impatiens (Tinashe Chiurugwi); Antirrhinum (Manuela Costa); Selaginella (Nick Battey); and, of course, Arabidopsis.
Lucy Moore/Keith Lindsey
Universities of Cambridge and Durham
One of the sessions at the SEB Plant Frontiers meeting in Sheffield was entitled Phenotypic Plasticity and the Changing Environment. This session dealt with the diverse range of molecular, biochemical, morphological, and anatomical phenotypes exhibited by individual plants when grown in contrasting environments. Plastic response of a broad range of taxa and evolutionary lineages were considered (e.g. cyanobacteria, CAM, C and C plants, 4 3 with the latter including representatives of several functional groups). Above and below ground organs were considered. The session took place over two days and consisted of 20 talks (14 invited speakers plus 6 speakers selected from submitted abstracts) and a session devoted to presentation of 20 posters. In addition to speakers and poster presenters from the UK, participants came from several countries, including Australia, Canada, France, Japan, The Netherlands, Sweden and the USA. The meeting opened by considering how cyanobacteria meet the challenges of acquiring CO in variable aquatic 2 conditions (Badger) and the molecular mechanisms by which cyanobacteria sense abiotic stress (Murata). It then moved on to consider phenotypic plasticity of C and CAM plants when 4 challenged with contrasting environments (Borland, Sage), after which two talks considered responses to changes in atmospheric CO and/or 2 ozone (Long, Taylor). Systemic signaling and resultant changes in leaf phenotypes (in response to atmospheric CO and irradiance) were considered in 2 several talks (Quick, Miyazawa, Terashima); collectively, these talks highlighted leaves can alter their phenotype in response to a change in their surrounding environment, even though those leaves did not directly experience environmental change. Impacts of temperature on phenotypic plasticity were considered in several talks, where focus was placed on the response of individual organelles, intact leaves and whole plants (Armstrong, Atkin, Hikosaka). The extent to which shade and sun leaves within a forest canopy differ in construction costs and payback times, and how leaves alter phenotype to changes in irradiance were considered (Poorter, Terashima). The impact of submergence on leaf phenotypes was discussed (Mommer). The session ended by considering plastic responses of roots to variations in nutrient supply and soil physical conditions (Bengough, Grabov, Hodge, Lambers). A feature of the meeting was the highly enjoyable and thoughtful discussions that took place throughout, and the willingness of more senior participants to discuss ideas with younger scientists. The generous support of the Journal of Experimental Botany made the meeting possible (a special issue on Phenotypic Plasticity will be published later in 2005), as did the support of the SEB.
O.K. Atkin
University of York
How many times have you heard the phrase? “…but plants are boring!”. At the recent Plant Frontiers meeting held at the University of Sheffield, the series of presentations in the Visible Plant Cell sessions amply demonstrated that this is not the case. These sessions brought together researchers using imaging techniques to address fundamental questions concerning plant development and function.
The rapid development of imaging techniques coupled with the use of transgenic plants expressing fluorescent proteins and other reporters of cell function provides an invaluable insight into the dynamic nature of living plant cells. Although these techniques tend to spawn a plethora of acronyms (FRET, FRAP and FLIM to name but a few), all of the speakers took great care to illustrate how imaging techniques can be applied to basic plant biology.
All scales were considered from the growth of whole leaves and roots, the relationships between cells within tissues, the movement of organelles, right down to the location of individual molecules within the cell. Not all of these approaches require the use of transgenic plants - we saw how noninvasive 'optical flow' techniques can be used to produce maps of root and leaf growth in response to environmental signals (Uli Schurr, Jeulich), and how endogenous fluorescent signals can be used to measure photosynthesis and oxidative stress. A series of speakers addressed the importance of spatial relationships and communication between cells in governing growth and differentiation and the movement of organelles and their interactions with the cytoskeleton. The importance of studying molecular function in planta was beautifully illustrated by Gerco Angenent's study of interactions between MADS-box transcription factors.
Andrew Fleming (Sheffield), who opened the session on Monday morning, reminded us that it was Robert Hooke in 1665 who first coined the term 'cells' when studying thin sections of cork. I am sure that Hooke would be both astounded and gratified at how his pioneering work has advanced since. The Visible Plant Cell sessions were sponsored by the Journal of Experimental Botany. A special issue will appear in January 2006 with papers based on this meeting and an on-line section with many of the images and videos will be available at the journal website.
Transverse section of cells from beech wood (Fagus). The sample is part of a collection of microscope slides used for botanical teaching and research at the Department of Plant Sciences, University of Cambridge. The tissue was stained with safranin O and fast green. Fluorescence emissions were imaged using 488nm, 568nm and 633nm laser lines on a Leica SP laser scanning confocal microscope to collect green, red and far red channels. The channels were composited in Adobe Photoshop to form an RGB image (courtesy: Jim Haseloff).
Stephen Rolfe
University of Sheffield
