SAPS Secondary News & Research

Why would any plant want to bury its leaves underground? We all know that leaves are used for photosynthesis, so surely the idea makes no sense.

That's why Professor of Botany Rafael Oliviera was so intrigued when a colleague returned from a field trip and described a plant with adapatations of a very peculiar kind.

"I had never seen a plant with underground leaves before," he said. "It doesn't make a lot of sense to have leaves underground because there is less sunlight -- so we hypothesized they're getting some other kind of benefit from the leaves."

Philcoxia minensis lives in sandy soils of the Cerrado, a tropical savannah region in Brazil and one of the world's 34 'biodiversity hotspots'. Philcoxia has both 'normal' leaves on stems above ground, and a network of minature leaves, each no larger than a pinhead, underground.

It's not that the underground leaves get no sunlight at all. In fact, they can capture sunlight through the white, sandy soil. However, that's not their only function.

These underground leaves secrete a sticky substance that traps nematodes, miniscule worms in the sandy soil. To test if the plant was truly digesting the worms, the scientists fed the plants nematodes marked with an uncommon isotope of nitrogen. When they tested the plant's leaves, they found the same isotope present, confirming that the plant was indeed using enzymes to digest the worms.

This is the first time that a plant has been found which uses underground leaves to trap prey, and the first plant that has been found to digest nematodes, a common strategy in fungi. 

"It's a great example of how plants, which can't move to find food and water, are able to develop interesting mechanisms to deal [with] extreme environments," says Rafael Oliviera

It's also a reminder of how important the Brazilian Cerrado is for conservation - but it's being destroyed at faster than the Amazon rainforests, largely to grow soy and for cattle ranching.

Find out more about the Brazilian Cerrado in this video by the Royal Botanic Garden Edinburgh and the WWF.

Find out more about Philcoxia minensis at Inside Science.

17th January

We often hear about the food-fuel conflict when discussing biofuels - but a breakthrough by British plant scientists has brought us one step closer to breeding multi-use crops, which produce both food and fuel.

The majority of the energy stored in plants is contained within the woody parts, and billions of tons of this material are produced by global agriculture each year in growing cereals and other grass crops, but this energy is tightly locked away and hard to get at. This research could offer the possibility of crops where the grain could be used for food and feed and the straw, much of which is currently thrown away, used to produce energy efficiently.

Professor Paul Dupree, of the University of Cambridge’s Department of Biochemistry, explains, “Unlike starchy grains, the energy stored in the woody parts of plants is locked away and difficult to get at. Just as cows have to chew the cud and need a stomach with four compartments to extract enough energy from grass, we need to use energy-intensive mechanical and chemical processing to produce biofuels from straw.

“What we hope to do with this research is to produce varieties of plants where the woody parts yield their energy much more readily – but without compromising the structure of the plant. We think that one way to do this might be to modify the genes that are involved in the formation of a molecule called xylan – a crucial structural component of plants.”

Xylan is an important, highly-abundant component of the plant cell wall, holding the other molecules in place to make a plant robust and rigid. This rigidity locks in the energy that we need to get at in order to produce bioenergy efficiently.

Grasses contain a substantially different form of xylan to other plants. The team wanted to find out what was responsible for this difference and so looked for genes that were turned on much more regularly in grasses than in the model plant Arabidopsis. Once they had identified the gene family in wheat and rice, called GT61, they were able transfer it into Arabidopsis, which in turn developed the grass form of xylan.

Dr Rowan Mitchell of Rothamsted Research continues, “As well as adding the GT61 genes to Arabidopsis, we also turned off the genes in wheat grain. Both the Arabidopsis plants and the wheat grain appeared normal, despite the changes to xylan. This suggests that we can make modifications to xylan without compromising its ability to hold cell walls together. This is important as it would mean that there is scope to produce plant varieties that strike the right balance of being sturdy enough to grow and thrive, whilst also having other useful properties such as for biofuel production.”

The tough, fibrous parts of plants are also an important component of our diet as fibre. Fibre has a well established role in a healthy diet, for example, by lowering blood cholesterol. The team have already demonstrated that changing GT61 genes in wheat grain affects the dietary fibre properties so this research also offers the possibility of breeding varieties of cereals for producing foods with enhanced health benefits.

Teachers who attended the Biology in the Real World lecture on the future of biofuels at the ASE Annual Conference 2011 will remember Dr Jen Bromley, one of the team that made this breakthrough, talking about their research. Her presentation can be downloaded from the Society of Biology website.

A group of teachers and scientists, including Jen Bromley, have produced a set of free practical protocols and teaching resources for looking at next-generation biofuels in the classroom.

Read more about the discovery on the University of Cambridge website.

Find out more about the teams of researchers working on next generation biofuels at the BBSRC Sustainable Bioenergy Centre.

3rd Jan 2012

From the UK Plant Sciences Federation

Dormant seeds in the soil detect and respond to seasonal changes in soil temperature by changing their sensitivity to plant hormones, new research by the University of Warwick has found.

This sensitivity alters the depth of dormancy, indicating to the seed when it is the right time of year to germinate and grow.

The seeds of common weeds can survive in the soil in a dormant state for years, in some cases decades, spelling issues for food security when they emerge to compete with crops.

New DEFRA-funded research by the University of Warwick sheds light on how hormones regulate the dormancy cycle of seeds in the soil using seeds of Arabidopsis - commonly known as Thale Cress - a close relative of many common weeds and crop species.

The new insights, which come from combining modern molecular biology with traditional seed ecology, could be of long-term help in reducing the use of herbicide on farms.

It is also of interest to those working to ensure biodiversity by understanding how dormancy and germination in wild plants is regulated.

Despite the importance of dormancy cycling in nature, very little is known about its regulation at the molecular level.

Professor Bill Finch-Savage and Dr Steve Footitt in the University of Warwick’s School of Life Sciences looked at gene expression over the dormancy cycle of Arabidopsis seeds in field soils to see how it is affected by the seasons.

They found that gene sets related to dormancy and germination are highly sensitive to seasonal changes in soil temperature.

A balance between the hormones abscisic acid (ABA) and gibberellic acid (GA) is thought to be central to controlling dormancy and germination,

One set of genes is regulated by ABA, which is linked to dormancy, whereas GA controls genes which act to increase the potential for germination.

Using an Arabidopsis strain whose seedlings emerge in late summer and early autumn, they found that as the soil warms up, seeds become less sensitive to ABA and more sensitive to GA, which brings them out of dormancy and spurs them towards germination.

Once dormancy starts to recede, increased sensitivity to light, nitrate and the differences between day and night temperatures play a bigger role in signalling that it is the right time to germinate.

Dr Footitt said: “Many will have seen how the amount of weeds in their garden differs with the weather from year to year.

“Understanding how this happens will help us to predict the impact that future climate change will have on our native flora and the weeds that compete with the crops we rely on for food.”

“Our research sheds new light on how genetics and the environment interact in the dormancy cycling process.

“By looking at seeds over an annual cycle we now have a clearer idea of how seeds sense and react to changes in the environment throughout the seasons so they know the best time to emerge into plants.”

The research is published in the Proceedings of the National Academy of Sciences.

Professor Finch-Savage and Dr Footitt have been awarded a BBSRC grant to investigate further how climate has an impact on dormancy cycling and how genetics and the environment interact in the dormancy cycling process

http://www2.warwick.ac.uk/newsandevents/pressreleases/spring146s_rising_soil/

In recent months, rising food prices across the world have resulted in riots in some parts of the globe, and in a quiet unease in others. We have a growing world population, but there is a risk that factors such as pollution, changing sea levels  and other issues may in fact reduce our food supply.

A recent article by UK plant scientists in the Journal of Experimental Botany looked at the role of ozone pollution, and highlighted the ways in which it can reduce our food supply. They describe how ozone is damaging our staple food crops - including wheat, rice and potatoes - when they are growing in farmers' fields. They also report that this problem may well become worse in the future, especially in, for example, SE Asia, where much of our global food supply is sourced.

Ozone is a polluting gas in the air around us formed from emissions from motor vehicles and from industry. At ground level, ozone is damaging, even though we need it in the upper atmosphere to protect us from UV radiation. Its concentration here at ground level has been increasing since the middle of the last century, so that it is now present at levels high enough to injure plants.

Ozone can stop plants from fixing sunlight into energy via photosynthesis, can cause their leaves to die and fall off early, and can stunt their growth. All this means that the damaged plants have fewer resources (carbon and nutrients) to put towards forming their edible parts, such as wheat and rice grains, maize kernels, potato tubers, pea and bean pods and so on. Sometimes the effects are not even visible to the naked eye because they accrue over the course of the whole growing season so a farmer may not even realise why his or her yield is smaller. Also, it is difficult to tell without sophisticated monitoring equipment when the air around us has become polluted enough with ozone to affect plants.

Because ozone pollution is predicted to become worse in some areas such as Asia in the next two or three decades, the source of much of our food supply, it may soon have an even bigger impact on crops in farmers fields. Furthermore, ozone's capacity to reduce yields may be compounded by other types of climate change. For example ozone reduces the ability of some plant varieties to withstand other stresses such as drought, and we predict, says Dr. Sally Wilkinson of the Lancaster Environment Centre at Lancaster University, that the same may be true of some crop varieties. However other varieties are actually protected from some of the effects of ozone pollution by drought, because pores in the leaf surface through which ozone can enter the plant are often closed in droughted conditions. More research is needed to choose carefully which crop varieties can withstand ozone pollution, especially when it is combined with other types of environmental stress. This is particularly important for food security, given the increasing world population, which needs more, rather than less food to be grown by our farmers, despite the increasingly erratic climate that we and our food plants are being subjected to.

The research was done by plant scientists at the Lancaster Environment Centre (LEC), Lancaster University, and from the Centre for Ecology and Hydrology, Bangor.

Further information on the economic impacts of ozone damage to crops in Europe, on which crops are the most sensitive to ozone, along with a review of the implications for food supplies from SE Asia, can be found in two new reports written by Dr Gina Mills and colleagues at CEH Bangor with inputs from the Lancaster University scientists (downloadable from http://icpvegetation.ceh.ac.uk/).

An abstract of the article can be read on the JEB website.

Thanks to the UK Plant Science Federation for this article.

In this video, ecologist Dr Markus Eichhorn talks about the different christmas tree species, how they cope with the central heating in your home and why he prefers natural christmas trees to artificial ones.

http://www.plantcellbiology.com/2011/12/the-science-of-christmas-trees/

Malaria is one of the world’s most serious public health problems, claiming almost a million lives every year and undermining development in some of the world’s poorest countries. A UK science lab has been fighting against malaria for years - through plant breeding.

At present, the most effective cure for malaria is Artemisinin Combination Therapies (ACTs), whose active ingredient is artemisinin, extracted from the plant Artemisia annua. However, quality Artemisia seeds are scarce and the world’s total production of artemisinin is struggling to meet rising global demand for ACTs.

Through a marker-assisted breeding programme, and after a series of field trials in different parts of the world, the Centre for Novel Agricutural Products (CNAP) at the University of York has developed new varieties of Artemesia annua seeds, which not only yield high quality artemesinin, but are robust, resistant to pests and diseases, and perform well under a range of regional agricultural practices.  However, Professor Diana Bowles has all along argued that a scientist's job is not merely to develop the new plant variety, but to get it out into the hands of those who need it.

CNAP has now partnered with a commercial seed organisation, East-West Seed, to produce their new varieties in commerical quantities. This new supply of improved seed will help build up a robust supply chain for the production of Artemisinin Combination Therapies (ACTs), the World Health Organisation recommended treatment for malaria.

Through the partnership, large-scale commercialization and distribution of the seeds to Artemisia growers are expected in 2012, targeting 20% of the global Artemisia cultivation acreage.  Annual global demand for ACTs is expected to increase beyond the current level of 250 million treatments to up to 310 million by 2015 and the new high yielding seeds will help achieve the strategic aims of universal coverage of ACTs and access to treatments.

This provides an excellent opportunity for the new Artemisia varieties developed at York to make a real difference to the fight against malaria

 

"Plants are fundamental to all life on Earth. They provide us with food, fuel, fibre, industrial feedstocks, and medicines. They render our atmosphere breathable. They buffer us against extremes of weather and provide food and shelter for much of the life on our planet. However, we take plants and the benefits they confer for granted. Given their importance, we should pay plants greater attention and give higher priority to improving our understanding of them.

Everyone knows that we need doctors, and the idea that our best and brightest should go into medicine is embedded in our culture. However, even more important than medical care is the ability to survive from day to day; this requires food, shelter, clothes, and energy, all of which depend on plants.

Plant scientists are tackling many of the most important challenges facing humanity in the twenty-first century, including climate change, food security, and fossil fuel replacement. Making the best possible progress will require exceptional people. We need to radically change our culture so that 'plant scientist' can join 'doctor', 'vet' and 'lawyer' in the list of top professions to which our most capable young people aspire." New Phytologist, 8 September 2011

This was the statement from a group of the world's leading plant scientists, who for the last two years have been working to identify the 100 most important challenges facing the world - and facing plant science researchers as a result. They asked both scientists and members of the public from around the world, opening up a website to invite people to list the world's greatest challenges to tackle. Their list of key questions was published in the New Phytologist journal, and is available on the project website, 100PlantScienceQuestions.org

We've taken the 'top ten' questions and published them here - to what extent do you and your students agree?

The 10 questions most important to society

A1. How do we feed our children’s children?

By 2050 the world population will have reached c. 9 billion people. This will represent a tripling of the world population within the average lifetime of a single human being. The population is not only expanding, but also becoming more discerning, with greater demands for energy-intensive foods such as meat and dairy. Meeting these increasing food demands over the years to come requires a doubling of food production from existing levels. How are we going to achieve this? Through the cultivation of land currently covered in rainforests, through enhanced production from existing arable land or by changing people’s habits to change food consumption patterns and reduce food waste? The reality is probably a combination of all three. However, if we are to reduce the impact of food production on the remaining wilderness areas of the planet then we need significant investment in agricultural science and innovation to ensure maximum productivity on existing arable land.

A2. Which crops must be grown and which sacrificed, to feed the billions?

The majority of agricultural land is used to cultivate the staple food crops wheat (Triticum aestivum), maize (Zea mays) and rice (Oryza sativa), the oil-rich crops soy (Glycine max), canola (Brassica napus), sunflower (Helianthus spp.) and oil palm (Elaeis guineensis) and commodity crops such as cotton (Gossypium spp.), tea (Camellia sinensis) and coffee (Coffea spp.). As the world population expands and meat consumption increases, there is a growing demand for staples and oil-rich crops for both human needs and animal feed. Without significant improvements in yields of these basic crop plants, we will experience a squeeze on agricultural land. It is therefore essential that we address the yield gap; the difference between future yield  requirements and yields available with current technologies, management and gene pools. Otherwise we may be forced to choose between production of staple food crops to feed the world population and the production of luxury crops, such as tea, coffee, cocoa (Theobroma cacao), cotton, fruits and vegetables.

A3. When and how can we simultaneously deliver increased yields and reduce the environmental impact of agriculture?

The first green revolution of the late 1950s and early 1960s generated unprecedented growth in food production. However, these achievements have come at some cost to the environment, and they will not keep pace with future growth in the world population. We need creative and energetic plant breeding programmes for the major crops world-wide, with a strong public sector component. We need to explore all options for better agronomic practice, including better soil management and smarter intercropping, especially in the tropics. Finally, we need to be able to deploy existing methods of genetic modification that reduce losses to pests, disease and weeds, improve the efficiency of fertilizer use and increase drought tolerance. We also need to devise methods to improve photosynthetic efficiency, and move the capacity for nitrogen fixation from legumes to other crops. These are all desirable and, with public support, feasible goals.

A4. What are the best ways to control invasive species including plants, pests and pathogens?

Invasive species are an increasingly significant threat to our environment, economy, health and well-being. Most are nonindigenous (evolved elsewhere and accidentally introduced) and have been removed from the constraints regulating growth in their native habitat. The best method of control is to prevent establishment in the first place or to quickly identify establishment and adopt an eradication programme. However, if an invasive species becomes established many of the options for removal can cause environmental damage, for example chemical control or mechanical excavation. Biological control (introduction of a natural predator ⁄ pathogen) can work well as long as the control organism targets only the invasive species. Otherwise there is a risk that the control organism might also become an invasive species. Alternatives, such as manipulating existing natural enemies and ⁄ or the environment to enhance biological control, are also being developed. Sustainable solutions are required if we are to deal with the continually growing problem of invasive species.

A5. Considering two plants obtained for the same trait,  one by genetic modification and one by traditional plant breeding techniques, are there differences between those two plants that justify special regulation?

The products of traditional plant breeding are subject to no special regulations, even though the wild sources of germplasm often used by breeders may contain new components that have not been assessed before. A plant derived by genetic modification, however, is highly regulated, even though the target genotype and the modification itself may both be highly characterized and accepted as innocuous for their intended use. This is a major exception to the norm for safety regulation in food and other areas, which is normally based on the properties of the object being regulated. It is important for food safety and for the public’s perception of science and technology in general to establish whether there are any objective differences between these groups of products that justify the different approaches to their regulation.

A6. How can plants contribute to solving the energy crisis and ameliorating global warming?

Plants use solar energy to power the conversion of CO2 into plant materials such as starch and cell walls. Plant material can be burnt or fermented to release heat energy or make fuels such as ethanol or diesel. There is interest in using algae (unicellular aquatic plants) to capture CO2 emissions from power stations at source. Biomass cellulose crops such as Miscanthus giganteus (Poaceae) are already being burnt with coal at power stations. There is understandable distaste for using food crops such as wheat and maize for fuel, but currently 30% of the US maize crop is used for ethanol production, and sustainable solutions are being found. Sugarcane (Saccharum officinarum) significantly reduces Brazil’s imports of fossil fuels. Agave (Agavea fourcroydes) in hot arid regions can provide very high yields (> 30 T ha)1) of dry matter with low water inputs compared with other crops. To ameliorate global warming, CO2 must be taken out of the air and not put back. There is considerable interest in ‘biochar’ in which plant material is heated without air to convert the carbon into charcoal. In this form, carbon cannot readily re-enter the air, and, if added to the soil, can increase fertility. Carbon markets do not currently provide sufficient incentive for farmers to grow crops simply to take CO2 out of the air.

A7. How do plants contribute to the ecosystem services upon which humanity depends?

Ecosystem services are those benefits we human beings  derive from nature. They can be loosely divided into supporting (e.g. primary production and soil formation), provisioning (e.g. food, fibre and fuel), regulating (e.g. climate regulation and disease regulation) and cultural (e.g. aesthetic and recreational) services. Plants are largely responsible for primary production and therefore are critical for maintaining human well-being, but they also contribute in many other ways. The Earth receives virtually no external inputs apart from sunlight, and the regenerative processes of biological and geochemical recycling of matter are essential for life to be sustained. Plants drive much of the recycling of carbon, nitrogen, water, oxygen, and much more. They are the source of virtually all the oxygen in the atmosphere, and they are also responsible for at least half of carbon cycling (hundreds of billions of metric tons per year). The efficiency with which plants take up major nutrients, such as nitrogen and phosphorus, has major impacts on agricultural production, but the application of excess fertilizers causes eutrophication, which devastates acquatic ecosystems. Plants are already recognized as important for sustainable development (e.g. plants for clean water) but there are many other ways that plants might contribute. A combined approach of understanding both the services provided by ecosystems and how plants contribute to the functioning of such ecosystems will require interdisciplinary collaboration between plant scientists, biogeochemists, and ecologists.

A8. What new scientific approaches will be central to plant biology in the 21st Century?

Biologists now have a good general understanding of the principles of cell and developmental biology and genetics, and how plants function, change, and adapt to their environment. Addressing the questions in this list, including those related to generating crops that can deal with future challenges, will require detailed knowledge of many more processes and species. New high-throughput technologies for analysing genomes, phenotypes, protein complements, and the biochemical composition of cells can provide us with more detailed information in a week than has ever been available before about a particular process, organism or individual. This is delivering a deluge of information that is both exhilarating and daunting. The challenge is to develop robust ways of analysing and interpreting this mountain of data to answer questions and deliver new insights. The skill sets required to make full use of the new information extend far beyond those previously expected from biologists. There is general agreement that we need a new era of collaboration between all types of plant scientists, geographers, geologists, statisticians, mathematicians, engineers, computer scientists, and other biologists to evaluate complex data, find new relationships, develop and test hypotheses, and make discoveries. Challenges include understanding complex traits and interactions with the environment, generating ‘designer crops’, and using modelling to predict how different genotypes will cope with alterations in the climate.

A9. (a) How do we ensure that society appreciates the full importance of plants?

Plants are fundamental to all life on Earth. They provide us with food, fuel, fibre, industrial feedstocks, and medicines. They render our atmosphere breathable. They buffer us against extremes of weather and provide food and shelter for much of the life on our planet. However, we take plants and the benefits they confer for granted. Given their importance, should we not pay plants greater attention and give higher priority to improving our understanding of them? Awareness could be increased through the media, school education, and public understanding of science activities, but a major step-change in activity will be required to make a substantial difference.

A9. (b) How can we attract the best young minds to plant science so that they can address Grand Challenges facing humanity such as climate change, food security, and fossil fuel replacement?

Everyone knows that we need doctors, and the idea that our best and brightest should go into medicine is embedded in our culture. However, even more important than medical care is the ability to survive from day to day; this requires food, shelter, clothes, and energy, all of which depend on plants. Beyond these essentials, plants are the source of many other important products. As is clear from the other questions on this list, plant scientists are tackling many of the most important challenges facing humanity in the 21st Century, including climate change, food security, and fossil fuel replacement. Making the best possible progress will require exceptional people. We need to radically change our culture so that ‘plant scientist’ (or, if we can rehabilitate the term, ‘botanist’) can join ‘doctor’, ‘vet’ and ‘lawyer’ in the list of top professions to which our most capable young people aspire.

A10. How do we ensure that sound science informs policy decisions?

It is important that policy decisions that can affect us all, for example environmental protection legislation, are based on robust and objective evidence underpinned by sound science. Without this, the risk of unintended consequences is severe. Ongoing dialogue between policy makers and scientists is therefore critical. How do we initiate and sustain this dialogue? How do we ensure that policy makers and scientists are able to communicate effectively? What new mechanisms are needed to enable scientists to respond to the needs of policy makers and vice versa?

Read the full list of 100 Plant Science Questions online, and ask your own questions. 

“'I went to the crime scene and said, “Don’t show me where the body was, I’ll show you. And I did. I was totally gobsmacked, because I hadn’t believed I could do it. I actually picked out the spot where the body had been.’”

The words of a police detective? A forensic investigator? Or an ecologist and plant scientist?

In a fascinating (and at times disturbing) interview, one of the UK’s foremost forensic botanists talks about the role of plant science in solving some of the highest profile murder enquiries of recent years: http://bit.ly/eferBu

“A gene that controls part of the 'tick tock' in a plant's circadian clock has been identified by UC Davis researchers. And not only is the plant gene very similar to one in humans, but the human gene can work in plant cells - and vice versa. … When Harmer and colleagues made Arabidopsis plants with a deficient gene, they found that the plants' in-built circadian clock ran fast. A similar gene is found in humans, and human cells with a deficiency in this gene also have a fast-running clock. When the researchers inserted the plant gene into the defective human cells, they could set the clock back to normal - and the human gene could do the same trick in plant seedlings.”

Read more about the research, published in the Proceedings of the National Academy of Sciences, on Science Daily: