UK Plant Science springs forth
In a departure from the more usual geographically widely dispersed collection, this month's series of Cuttings is primarily UK-centred. However, the issues raised are global concerns that are important to plant science wherever it is practised on the planet. So, I thank you for your understanding.
The UKPSF
The United Kingdom Plant Science Federation (UKPSF) was launched on 23rd November 2011, having recognised that ‘UK Plant Science can only meet its potential through stronger engagement within and beyond the plant science community’ (Sabina Leonelli et al., New Phytologist, in press, 2012). Amongst the UKPSF's six aims (http://www.societyofbiology.org/aboutus/special-interest-groups/ukpsf/ukpsfaims) perhaps the most important are to: ‘Increase the understanding of the significance of Plant and Crop Science amongst government, funders, industry and society in general’; ‘Formulate a coordinated strategy and vision for Plant and Crop Science in the UK that will be utilised to inform policy’; and ‘Support efforts to inspire, educate and train the next generation of plant and crop scientists’. Noble aims, which are sorely needed at a time when plant sciences have probably never been more necessary in tackling – maybe even solving? – many of the most pressing global issues such as food security, and in coping with climate change (Claire Grierson et al., New Phytologist 192: 6–12, 2011), and where concerns over the supply of new plant scientists has probably never been under greater threat (Sinéad Drea, biosience education 17: 2, online). The first annual conference of this botanical trades' union was held at the John Innes Centre (Norwich, UK) on 18th and 19th April, 2012, and fittingly dealt with the twin themes of inspiring the next generation and reflecting on the importance of the whole range of plant sciences to achieve a unified goal of a better planet (well, that's how I saw it!). Thus, at one end of the phytological spectrum we had Sandra Knapp (Natural History Museum, London) emphasising the need for fieldwork and exploration to uncover the rich botanical diversity that still awaits discovery – and it is a sad fact that plant hunters are a dwindling resource in their own right (e.g. Nature 484: 436–438, 2012). And at the other end, we had Richard Mott (Wellcome Trust Centre for Human Genetics, Oxford) dealing with the latest methodology for sequencing Arabidopsis genomes. Interestingly, Mott usually works with mice. So, if we can convert a hard-core animal scientist to the cause of botany maybe things can't be too bad?
Image: http://plantsci2012.org.uk/
Stormy times ahead
Sir John Beddington (Chief Scientific adviser to the UK Government) opened the conference with his perfect storm lecture (a similar talk is available at www.bis.gov.uk/assets/goscience/docs/p/perfect-storm-paper.pdf). In that opening address he identified energy demands, food production issues, and dwindling freshwater supplies as the troublesome trio that conspire together to generate the perfect storm (http://en.wikipedia.org/wiki/Perfect_storm), and which are themselves exacerbated by global climate change and projected population growth. Not only did this set the tone for the conference, it also provided the background and context for many of the subsequent talks. It was also the ideal start because it highlighted arguably the most serious problems facing the planet, many of which will have botanical solutions. Read on …
Image: UK Government Office for Science.
Making plants work harder
Julian Hibberd (University of Cambridge; one of ‘Five crop researchers who could change the world’, Nature 456: 563–568, 2008) speculated on the prospects of engineering C4 photosynthesis into C3 crops (such as rice). Which might have a double benefit because C4 plants not only have better water use efficiency, but also better nitrogen use efficiency, relative to C3 crops; a lot of energy goes into production of N-based fertilisers, and irrigation is a major ‘drain’ on water resources. In a similar resource-frugal vein, Giles Oldroyd (John Innes Centre) presented fascinating insights into arbuscular mycorrhiza (http://en.wikipedia.org/wiki/Mycorrhiza) and nitrogen-fixing root nodules (http://en.wikipedia.org/wiki/Nitrogen-fixing_nodules). In particular, he reminded us that much of the host-plant ‘biology’ involved in these two mutually beneficial symbioses is nearly identical (though plants respond appropriately to form the correct relationship with the fungus or bacterium!). Importantly, the nodulation signalling pathway is probably present in many plant species – even if they don't nodulate in practice. This opens the possibility of engineering cereals to recognise the rhizobial symbiont and develop the N-fixing symbiosis. Which in turn might reduce cereal dependency on added – energy-expensive – fertiliser; after all, as Oldroyd pointed out, nutrient limitation is the major restriction on maize growth in sub-Saharan Africa.
Image: David Monniaux/Wikimedia Commons.
Bioenergy crops
Iain Donnison (Institute of Biological, Environmental & Rural Sciences, Aberystwyth University) regaled us with insights into the energy biomass potential of Miscanthus (http://en.wikipedia.org/wiki/Biomass_energy_crop). OK, exploiting plants in this way is not a new idea, but what was underlined was the need for basic plant biology work, e.g. identifying ‘better’ taxa as energy crops, which requires collection in China, Japan and Taiwan, and assessment of the many plant traits such as architecture and number of tillers that all contribute to overall bioenergy potential of the crop; i.e. it is not a single botanical speciality topic – experts from many different disciplines are needed to deliver the desired outcome, but which work should be boosted by Xue-Feng Ma et al.'s high-resolution map of M. sinensis (PLoS ONE 7: e33821, 2012). On a related issue, Alison Smith (University of Cambridge) considered microalgae as bioenergy crops; her angle was a more ‘ecological’ one, which also emphasised the need for a multi-discipline approach to such energy security work. Many algae need an external supply of vitamin B12 (i.e. they are auxotrophs; http://en.wikipedia.org/wiki/Auxotrophy), which is usually supplied in nature by bacteria. Although bacterial contamination of algal cultures is usually considered anathema (axenia is usually the order of the day!), Smith's work has explored co-cultivation – of algae and bacteria – systems, which are likely to improve overall productivity of the algal crop (Elena Kazamia et al., Environmental Microbiology, in press, 2012), and has led to development of the notion of ‘synthetic ecology’ (Elena Kazamia et al., Journal of Biotechnology, in press, 2012).
Image: Jon Sullivan/Wikimedia Commons. (http://pdphoto.org/PictureDetail.php?pg=8645)
New crops?
Marker-assisted selection (MAS; http://en.wikipedia.org/wiki/Marker_assisted_selection) was explored by Ian Graham (Centre for Novel Agricultural Products, University of York) in considering molecular breeding in novel crops. MAS is based not on the observable traits themselves – e.g. colour – but the genes associated therewith. A MAS approach thus allows selection of plants with desired characteristics, and often far earlier than the trait itself may be observed (provided the markers are known …). It can thus speed up breeding of ‘novel’ crops. Amongst projects Graham summarised – such as development of anti-malarial artemisinin from Artemisia annua (http://en.wikipedia.org/wiki/Artemisia_annua), and biodiesel production from Jatropha curcas (http://en.wikipedia.org/wiki/Jatropha_curcas) – was mention of Stevia rebaudiana (http://en.wikipedia.org/wiki/Stevia), which produces stevioside, a glycoside up to 300 times sweeter than sucrose (http://en.wikipedia.org/wiki/Stevioside), but which is calorie-free. Graham also reminded us that in our search for ‘new’ crops, we shouldn't ignore the existing, but easily overlooked so-called ‘orphan crops’: ‘crop species which have been under-exploited for their contribution towards food security, health (nutritional/medicinal), income generation and environmental effects’ (Ranjana Bhattacharjee, African Technology Development Forum Journal 6: 24–33, 2009). A timely – and humbling – plea to make more of what natural variety and variation we already have.
Image: Frank Vincentz/Wikimedia Commons.
Don't ignore the roots … or the soil!
Lab experiments are all well and good, but they do have their limitations. It is necessary to study plants outside, in the field – or rather below the surface! This theme was explored at the UKPSF conference by Nick Ostle (Centre for Ecology and Hydrology, Lancaster) who argued that plant–soil ecological interactions are a critical – but poorly understood! – determinant of how land ecosystems respond to global changes. His talk extended the concerns beyond the purely biological to the wider issues surrounding ecosystem services, and even introduced the intriguing notion of ‘grassland biotechnology’(!). Linked to this was Sasha Mooney (University of Nottingham) looking (literally!) at root growth, but root growth with a difference: actually examining the growth of roots in the soil. The technique used was X-ray microcomputed tomography (μCT), which allows non-invasive imaging of intact roots in situ. Whilst using CT to image plant material is not new, the breakthrough is the computer program used to assemble and interpret the images recorded – RooTrak, which permits automated recovery of 3-D plant root architecture (Stefan Mairhofer et al., Plant Physiology 158: 561–569, 2012). Too many experiments on root growth and development are performed on roots growing in agar or on a lab bench, and about as far away from soil as you can get (and whose relevance to the real world is therefore questionable). So, this is an unparalleled opportunity to get the root's perspective on life underground. As organs that support the above-ground part of the plant, that often store much of the photosynthetically generated biomass, that allow exploitation of nutrients and water reserves in the soil, and that form intimate and mutually beneficial associations with fungi and bacteria, etc (!!), the more we know about these secretive subterranean ‘systems’ the better. Accordingly, ‘RooTrak supports the computation of a range of quantitative measures and promises to facilitate future root phenotyping for trait-based crop breeding efforts’. I'm looking forward to the day when it will generate high quality images of a root and its associated mycorrhizal mycelial network – now, there's a challenge!
Image: USDA Natural Resources Conservation Service.
Thinking inside the box
The most intriguing presentation of the conference was by Charlie Paton (Seawater Greenhouse Ltd; http://seawatergreenhouse.com/aboutus.html). Essentially, his view was ‘Water crisis? What water crisis?’. The water problem is not that we don't have enough water – the Earth's surface is >68 % seawater, after all – but that we have too much of the wrong sort of water. Appropriately, his company turns seawater into freshwater. But this is not the more familiar, expensive desalination plant, instead the fabric of their greenhouses (described as ‘porous cardboard’) does the salt-removal work, converting seawater into usable fresh water to satisfy the needs of the crops grown within (Sablani et al., Desalination 159: 283–288, 2003). This work has also helped the desert bloom; not only have they generated high yields of crops inside the greenhouses in otherwise arid areas, but the evaporated water from the greenhouse irrigates the surrounding land encouraging plant growth there as well. Plus, the salt in the walls of the greenhouse act as a natural biocide protecting the precious crops. At last, a greenhouse effect we can be pleased about!
Image: Seawater Greenhouse Ltd.
Generating the next generation
So much for the exciting science that is going on. How can we ensure there will be a new generation of eager, bright plant biologists to help turn these great ideas into reality? This is another major – and global – issue and was addressed by a number of speakers within the area of ‘plant science education’. Accordingly, we heard from Celia Knight (University of Leeds) on the Gatsby Plant Science Summer Schools (http://www.gatsbyplants.leeds.ac.uk/SS/index.html), which give 1st year undergraduates from a select group of UK universities the opportunity to immerse themselves in a plant science summer school. Research suggests that this intervention helps not only to promote awareness of plant science as a career, but also has increased the number of researchers in plant biology (Aurora Levesley et al., Plant Cell, in press, 2012). To help this there is also the University of Leeds' TREE (Tool for Research-Engaged Education) – ‘an online teaching tool giving access to downloadable lecture slides, on-line lectures, practicals, movies and other material on topical plant science to support lecturers in their teaching’ (http://www.gatsby.org.uk/en/Plant-Science/Projects.aspx; http://www.gatsby.org.uk/Plant-Science/Projects/TREE-Tool-for-Research-Engaged-Education.aspx). Mary Williams (American Society of Plant Biologists, but based in Glasgow, UK) shared ideas from the USA's experiences of outreach efforts to promote plant science (http://my.aspb.org/?page=Education), which might help the UK's fledgling ‘special interest group’ inspire the next generation. Incidentally, Mary is almost single-handedly responsible for the Plant Cell's superb teaching resources – Teaching Tools in Plant Biology (http://www.plantcell.org/site/teachingtools/teaching.xhtml), several of which are freely available. And, in the hope of enthusing impressionable students before they get to university, Ginny Page (SAPS, Science and Plants for Schools; http://www.saps.org.uk/) made the point that plant scientists need to publicise the importance of their work more. Well, there's a challenge for all of us.
Image: Wikimedia Commons.
Summing up …
My appreciation of the range of plant science undertaken in the UK was certainly increased by attending the conference, but it is not people like me that the UKPSF has to win over. Its main aim must surely be to formulate a co-ordinated strategy and vision for plant and crop science in the UK that will be utilised to inform policy. If it can do that, it will be doing a grand job! And, if it can also ‘inspire, educate and train the next generation of plant and crop scientists’ – who will be needed from the full breadth of the multi-faceted discipline of botany! – along the way, so much the better! [For further background to some of the global concerns raised above, see Johan Rockström et al., Nature 461: 472–475, 2009, and Jonathan Foley et al., Nature 478: 337–342, 2011 – Ed.]
New journal
A timely boost to much of the research showcased in the previous items should come from BioMed Central's newly launched Agriculture & Food Security (http://www.agricultureandfoodsecurity.com/), a peer-reviewed, open access journal that addresses the challenge of global food security. In keeping with the multi-disciplinary approaches such issues need, Agriculture & Food Security will publish ‘cutting-edge contributions across the breadth of relevant academic disciplines, including agricultural, ecological, environmental, nutritional, and socio-economic sciences, public health and policy’.
Image: USDHHS, Centers for Disease Control & Prevention.
Don't underestimate the druse
Although known from plants for a long time, the function of mineral inclusions – included amongst the so-called ergastic substances (http://en.wikipedia.org/wiki/Ergastic_substances) of old – remains speculative. Frequently composed of calcium oxalate and rather toxic (http://en.wikipedia.org/wiki/Calcium_oxalate), it has been speculated that druses (http://en.wikipedia.org/wiki/Druse_%28botany%29) may deter would-be herbivores, and/or act as store of calcium – often needed in large amounts as a secondary messenger in many signalling pathways within plants (Peter Hepler, The Plant Cell 17: 2142–2155, 2005). Well, another role is suggested by Harry (‘Jack’) Horner in leaves of certain succulent Peperomia species (Annals of Botany, 2012, in this current issue). Horner hypothesises that vacuole-located druse crystals in the palisade mesophyll cells – which are situated below recently discovered ‘skylight-like’ regions in the overlaying hypodermal cell walls – may help to focus light on to the chloroplasts that surround the crystals (see figure above). This arrangement may be an adaptation that permits more efficient photosynthesis in the low-light environment where these plants are found. You'll need to read the paper – which is free access – to appreciate the full story, but this elegant structure–function study dramatically demonstrates how much still awaits our discovery and understanding. Plus, this paper was one of an extremely select few – ‘one in a thousand manuscripts’ – accepted for publication without any changes! Read and enjoy.
Image: Harry T. Horner.
Nigel Chaffey E-mail: n.chaffey@bathspa.ac.uk
Chaffey N. 2012. Plant Cuttings, June. Annals of Botany 109(7): iii–vi.