CABI Blogs: hand picked... and carefully sorted

Mystery disease in Ethiopia solved: linked to weed toxin

Imagine this…

A mysterious disease terrorising your community, not infectious but spreading nonetheless, and killing your relatives and neighbours. All you want to do is pack your bags and flee. Worse, when your plight comes to the attention of the health authorities, they are stumped and its not going to be easy or quick to solve.

A recent example of this kind of illness is “nodding disease” (South Sudan, Uganda, and Tanzania), which affects children 5-15 years old: they suffer epileptic seizures which causes their heads to nod, and they end up severely disabled and finally die. The USA’s Centre for Disease Control (CDC) is working to identify the cause: so far, the best guess is that it’s linked to the parasite that causes river blindness combined with an autoimmune reaction, and exposure to chemicals could predispose.

Other examples of non-communicable disease outbreaks

On Global Health, I found there are outbreaks going back to 1911 (epidemic dropsy) but more recent ones were in India,  Bangladesh, Nigeria, Brazil, China, Afghanistan and even the USA.

 What are the likely causes for these outbreaks? The body of research, as found on databases like Global Health, tells us that they could be contamination of food and water supply, exposure to chemicals or heavy metals in the environment, or even use of traditional medicine.

 Mystery liver disease in Ethiopia with a ‘happy’ ending

Can public health authorities in low-income countries solve & stop such outbreaks?   Yes. In 2005, in Ethiopia, a 4 year long outbreak of liver disease in Tseda Emba, a small village of the Tahtay Koraro district of Tigray, finally reached the attention of the Tigray Health Bureau (THB). Now, in 2012, the multidisciplinary and one-health approach they initiated has “solved” the mysterious illness, significantly reducing new cases. 

 The research work was the subject of an entire session at the recent World Congress Public Health (WCPH-2012) in Ethiopia, and is now published as 5 papers in the supplement to April 2012’s edition of Ethiopian Medical Journal (EMJ). [Abstracts to these papers will be available on Global Health]. It demonstrates the relevance of the one-health approach to public health in low-income countries and is a fascinating detective story….

Forests on the move

Studies on ‘natural’ and ‘forced’ migration of forests threatened by climate change.

A multi-European project trying to anticipate the effects of climate change on forests is taking shape. In parts of Europe, established forest trees are showing signs of vulnerability – such as drought stress - as their ‘climate niche’ changes. An ambitious long-term project hopes to work out which species will provide the best natural environments and commercial forestry prospects for the future.

Thousands of trees are being planted at 37 locations on the west Atlantic, covering a length of 1600 miles from the Azores to Scotland. Forest Research (part of the Forestry Commission), the UK partner in the ‘Reinforce’ project, is planting 30 species at various sites in England, Scotland and Wales. The species include familiar trees like English oak, Scots pine, silver birch and sweet chestnut as well as less usual species such as Atlas cedar and Macedonian, maritime and Monterey pines from the Mediterranean, Eastern Europe and California.

As to the time-scale of the project, growth data and responses to climatic variables like temperature and soil water will be collected and analysed regularly, but it could be 50 years before any meaningful data can be gathered for mature trees. With climate change now evident, there’s no time for delay…

Watch a video of the research on the BBC website.

The trial coincides with the findings of a 4-year survey of 15 coniferous species in 34 different ecoregions in western Canada and the USA^(1,2). Remote sensing of large areas showed that a huge natural migration of trees has already started across much of the west due to global warming, insect attack, diseases and fire, and many tree species are projected to decline or die out in regions where they have been present for centuries, while others move in and replace them. Forests are reshaping in a visible display of ‘survival of the fittest’.

Existing species are losing their competitive edge and opportunistic species are taking over. More than half of the evergreen species were found to be experiencing a significant decrease in their competitiveness in 6 ecoregions. The study projected that in some cases, once-common species such as lodgepole pine will be replaced by other trees, with perhaps a range expansion of ponderosa pine or Douglas-fir. Other areas may shift completely out of forest into grass savannah or sagebrush desert. In central California, more than half of the species now present would not be expected to persist in the climate conditions of the future (approx. 2-4°C warmer by 2080, drier summers, and wetter spring and autumn seasons).

Some of these changes are already happening quite fast and over huge areas – at a rate fast enough to detect at the landscape level – remarkable for forests.

References

1. Waring, R. H.; Coops, N. C.; Running, S. W. Predicting satellite-derived patterns of large-scale disturbances in forests of the Pacific Northwest Region in response to recent climatic variation. Remote Sensing of Environment (2011) Vol. 115 No. 12 pp. 3554-3566.

2. Coops, N. C.; Waring, R. H. Estimating the vulnerability of fifteen tree species under changing climate in Northwest North America. Ecological Modelling (2011) Vol. 222 No. 13 pp. 2119-2129 [10.1016/j.ecolmodel.2011.03.033]

See also:
Oregon State University news

And now for the world's most important plant viruses

Other than possibly the newly discovered leaping beetles of New Caledonia with a mysterious plant diet, few if any plant pests or diseases make it onto any one of the Time Top of Everything of 2011 lists.

But pests and diseases are busy making their way into their own ‘Top 10’. CABI scientists put together a list in 2011 of some of the world’s worst plant pests, and plant viruses and fungal pathogens are also getting together.

Molecular Plant Pathology has published the results of a survey amongst plant virologists, ranking plant viruses based on scientific/economic importance. The historical perspective, the science, the economics and the latest research are discussed for each of the viruses making it into the ‘Top 10’.

First place is given to Tobacco mosaic virus for its scientific importance based on its role which has extended beyond practical plant pathology (as a virus causing serious losses in a profitable crop) to its use as a model system and in molecular pathology. TMV (just to corroborate its importance) is also the highest ranking plant virus on CAB Abstracts. The database has more than 8000 records specifically on TMV since 1909 (just over 10% of all the records on plant viruses on the database), and is still going strong with about 100 records added each year.

‘Top 10 plant viruses in molecular plant pathology’ is free to download here. Now watch out for the ‘Top 10 fungal pathogens in molecular plant pathology’…coming soon…

Music enhances plant growth and keeps pests at bay

A recent AoB blog caught my eye (ear?). Do plants respond to music? The blog refers to an experiment in which plants were assembled in Cadogan Hall, London for a 3-hour recital performed by the UK’s Royal Philharmonic Orchestra to investigate the effects of music on plant growth.

Knowing that CAB Abstracts is a good source of unusual and interesting research, I had a quick look for any relevant studies. I can’t say the database is brimming with information in this area but what I found was definitely positive. One study looked at the effect of different acoustic frequencies on the growth of cowpea seedlings and concluded that sound waves with different frequency characteristics significantly increased plant height – good treatments included a 400 Hz frequency sound wave, cuckoo acoustic song, and an insect-music mixed sound⁽¹⁾. In the next paper by the same authors, a mixed combination of classical music and cricket voice (I think they mean the insect…) increased the growth, yield and nutritive value of edible fungi (including several Pleurotus spp.)⁽²⁾. Other research papers report similar effects. Some include the use of ‘green music’ to enhance the metabolism and growth of plants, ‘green music’ consisting of a classical music base along with some natural sounds such as those of birds, insects, water and wind, i.e. like music in a field.

After analysing the responses of various crop plants to different audio signals, one group of researchers suggests that it may be possible to compose specific music for specific plants⁽³⁾.

Plants, however, are not alone – ‘green music’ has been shown to enhance the milk yield of cows and increase the fermentation rate of starter cultures in probiotic yoghurt⁽⁴⁾.

Insects, it seems, find music stressful, and music could be used to control unwanted pests. In one recent study⁽⁵⁾, exposure to classical music decreased the lifespan of male Drosophila. Music appeared to affect the normal aging process rather than show overt toxicity, and the authors suggest it could be used in insect management programmes. Better still, greenhouse experiments on Chinese cabbage and aphid injury suggest a win-win situation - ‘green music’ increased Chinese cabbage yields and decreased aphid damage⁽⁶⁾.

References

(1) Huang Jun; Jiang ShiRen. Effect of six different acoustic frequencies on growth of cowpea (Vigna unguiculata) during its seedling stage. Agricultural Science & Technology – Hunan (2011) 12 (6) pp 847-851.
CAB Abstracts ref. Full text paper (in English) available on CAB Abstracts
Online ref.

(2) Jiang ShiRen; Huang Jun; Han XingHua; Zeng XianLin. Influence of audio frequency mixing of music and cricket voice on growth of edible mushrooms. Transactions of the Chinese Society of Agricultural Engineering (2011) 27 (6) pp 300-305.
CAB Abstracts ref.
Online ref.

(3) Lee KeunYoung; Hur TaeWon; Lee WonChu; Yun SongJoong. Analysis of plants response to music signals. Journal of the Korean Society for Horticultural Science (2002) 43 (1) pp 5-10.
CAB Abstracts ref.
Online ref.

(4) Mohammadi, R.; Rouhi, M.; Mortazavian, A. M. Effects of music waves on fermentation characteristics and viability of starter cultures in probiotic yogurt. Milchwissenschaft (2011) 66 (2) pp 193-196.
CAB Abstracts ref.
Online publisher

(5) Morales, R. F.; Seong KiMoon; Kim ChaSoon; Jin YoungWoo; Min KyungJin. Effects of auditory stimuli on the lifespan of Drosophila melanogaster. Entomological Research (2010) 40 (4) pp 225-228.
CAB Abstracts ref.
Online ref.

(6) Qin YuChuan; Lee WonChu; Choi YoungCheol; Ahn MiYoung. Preliminary study on the relationship among sonic, Chinese cabbage growth and aphids' injury. Journal of China Agricultural University (2001) 6 (3) pp 85-89.
CAB Abstracts ref.
Online ref.

Other references on CAB Abstracts

Effects of insect acoustic and music acoustic frequency on the growth of 6 kinds of vegetables.

The effects of different musical elements on root growth and mitosis in onion (Allium cepa) root apical meristem (musical and biological experimental study).

Measuring effects of music, noise, and healing energy using a seed germination bioassay.

Effect of musical sound of Veena on balsam plants.

Countdown to seven billion: does the world have enough water to produce food for us all?

As the world counts down to the landmark of seven billion people on the planet (a scary number predicted to happen - perhaps a little too conveniently? - on the scary day of Halloween, 31 October) we are seeing an increasing number of stories and statistics on whether the Earth's resources can cope with a population predicted to carry on increasing for the foreseeable future. The population increase has been a feature in agricultural conferences over the last weeks, and in press releases for CropWorld Global 2011, a conference set to open in London on 31 October, the day already mentioned as when our population may be officially declared to be seven billion.

Among the statistics presented by Dominic Dyer, UK Crop Protection Association chief executive, in a speech on 21 Ocotober to AgChem Asia Summit in Shanghai, China, was a figure that the amount of farmland available to feed each person on the planet has fallen from 0.5 hectares in 1950 to 0.2 hectares today. Clearly, in order to sustain a growing population on a finite amount of land (and land subject in many regions to problems of desertification, erosion and salinization) we need to maximise efficiency and reduce losses: in the strapline of CABI's Plantwise initiative, 'lose less and grow more'.

'Great things can come in small packages'

Being only 1.5 m tall, I’m aware I might seem biased; when I say I’m a firm believer in the saying ‘great things can come in small packages’. However, today I came across yet another example which might once more prove that there’s an element of truth in the above proverb.  A paper published in Plant Physiology and discussed in ScienceDaily, reports that smaller leaves are structurally and physiologically better adapted to grow in dry soil conditions because they developed distinct vein system. The size of leaves can vary by a factor of 1000 across plant species but, until now, no one knew exactly the reason for such variation.

SpongeBob Gets Taxonomical

SpongeBob SquarePants, the enthusiastic underwater animated character, is now commemorated in the scientific name of a fungus,Spongiforma squarepantsii. The fungus is in the Boletaceae family, and is described in a paper in press in the journal Mycologia, based on specimens collected in 2010 in Lambir Hills National Park, in Sarawak, Malaysia. The bright orange fungus smells “vaguely fruity or strongly musty”, according to its description in the journal. San Francisco State University researcher Dennis Desjardin felt that the the spore-bearing surface, when viewed with scanning electron microscopy, somewhat resembles a "seafloor covered with tube sponges", reminiscent of SpongeBob’s Bikini Bottom home.

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 Spongiforma squarepantsii, taken by the paper's authors

 

 

Why Washing Your Vegetables and Hands May Not Protect You from E. coli, Staphylococcus, Salmonella…?

Following the recent outbreak of E. coli food poisoning in Germany that claimed at least 37 lives as of 14 June 2011 and still counting, numerous articles have been written, but many fundamental questions still remain unanswered.

As you will remember, contaminated Spanish cucumbers were initially blamed for the outbreak of E. coli infection, which prompted the Spanish government and farmers to vehemently deny this claim (justifiably, as it turned out) and demand compensation.

As soon as “the Spanish cucumber story” was shown to be a false alarm, tomatoes, salad and vegetable sprouts (of German origin) were declared as potential culprits. It is unclear why other vegetables, such as peppers, courgettes, mushroom, to list but a few, were kept off the list of suspects, particularly because all the laboratory tests performed so far have been inconclusive.

As time goes by, it is less likely that the source(s) of this outbreak will be identified any time soon. However, even if a contaminated vegetable (or various vegetables) is identified and successfully linked with this outbreak of E. coli in humans, identifying the pathway of contamination may prove more difficult.

While looking for potential sources of vegetable contamination with pathogenic microorganisms, I searched CAB Direct database and came across a very interesting review published 20 years ago by German Professor Strauch of the Institute of Animal Medicine and Hygiene, University of Hohenheim, which explains how pathogens may contaminate food crops. He warned about the potential of pathogenic organisms to cross from manure or sewage into food crops and suggested that “the agricultural utilization of hygienically dubious sewage or sludge poses a risk for the whole national economy.”

In his 1991 review “Survival of pathogenic microorganisms and parasites in excreta, manure and sewage sludge” (Rev Sci Tech. 1991 Sep;10(3):813-46), Strauch also reported that two groups of researchers had found that pathogenic organisms can be taken up by crops that are used in human and animal nutrition.

Once pathogenic microorganisms are incorporated into crops (including vegetables), washing the outside of fresh vegetables is of little benefit, because all the pathogens from the sludge (bacteria, viruses and parasites) are inside the plant.

Recent developments in the world of biofuels

Opinions on the use of crops for biofuel and bioenergy continue to be polarized – are they a ‘good thing’ or not? When are they a ‘good thing’? Who benefits?

How do you measure the impacts and their interactions at a local, national and international level on food security, land resources, water, greenhouse gas emissions, energy security, poverty, social development, sustainability…and try to remain impartial and objective?

The Bioenergy and Food Security (BEFS) Analytical Framework developed by FAO aims to address these issues by providing an analytical framework and set of tools which can be used to measure these impacts. Using a step-by-step methodology, the goal is to help policymakers make informed decisions on whether development of bioenergy is a viable option for their country and identify suitable policies that will maximize benefits and minimize risks.

Three separate reports describe the implementation of the framework in Peru, Tanzania and Thailand, with suggestions for suitable options for each country.

Another source of information is Recent developments in the world of biofuels, a critical analysis by CABI scientists of the latest research on the potential and realities of growing and processing jatropha, algae and biomass for biofuels or bioenergy - see Biofuels Information Exchange.

Land use and poverty alleviation issues in Mozambique, Tanzania, Kenya, India, China and Brazil are discussed as well as research into using problematic invasive aquatic weeds (water hyacinth - pictured above - is a favourite) for bioenergy. The pros and cons of algal biofuels, and the latest technology for concentrating biomass energy into a more energy-dense form which makes transport to a processing plant more feasible are discussed, and more…

BIE is an impartial site for exchanging information on biofuels research – the exchange on pests of jatropha has generated the longest running discussion over the last 2 years – and the site provides open access to documents on biofuels, including the peer-reviewed Land Use Change: Science and Policy Review (copublished with Hart Energy Consulting) and abstracts of the latest research on biofuels from the CAB Abstracts database.

For a comprehensive resource of published information on research into man’s impact on the environment see CABI’s Environmental Impact which has a special section on biofuels research information – abstracts, books, book chapters, reports, reviews.

Developing crops for mild drought tolerance

Whilst we continue to have no rain in southern England (I’m sure this won’t last too long…), drought tolerance must be on the mind of many farmers. World reports on climate change and food security have identified water scarcity as a critical factor for agriculture this century. Breeding for drought tolerance is a major research aim and there have been some successes using both conventional breeding and genetic engineering. Over the last 12 months for instance, new drought-tolerant maize varieties produced by conventional breeding have been released which have shown increases in seed yields of between 5 and 15% under water-stressed field conditions.

Drought tolerance is a complex area. Crops which can withstand severe drought may not perform well under conditions of mild or no drought; the response to drought is intricately woven with other conditions such as soil nutrients, soil quality, temperature and other environmental stresses; physiological responses of plants to increase their water use efficiency depend on the development stage of the crop; and thanks to these complex interactions several hundred genes have been identified which control or modify drought response.

Most research has focused on developing crops for severe drought stress, but new studies published in Nature Biotechnology and Plant Cell focus on the physiological responses of plants to mild drought stress. The team from the University of Gent has identified a mechanism that can be used to develop crop varieties which will produce high yields under mild drought stress, more commonly found in temperate climates. In trials with the test plant Arabidopsis, ethylene inhibited leaf growth at the first sign of limited water availability, and growth resumed after water became available. Overcoming this reaction could lead to crops which keep on growing during mild and temporary spells of drought that occur in the field, avoiding unnecessary yield losses and higher crop productivity.

As an indication of the amount of research, the number of records on “drought resistance” in CAB Direct has increased steadily every year - from one paper (in 1924!) to almost 1000 papers published in 2010. And just to prove the value of older research, the one paper from 1924 is surprisingly topical:
Clark, J. A. Segregation and correlated inheritance in crosses between Kota and Hard Federation wheats for rust and drought resistance. Journal of Agricultural Research, 1924, 29:1, pp 1-45.