̽��ֱ�� of Cambridge - tomato

Virus attracts bumblebees to infected plants by changing scent

fpjl2 — Thu, 11 Aug 2016 18:05:25 +0000

Plant scientists at the ̽��ֱ�� of Cambridge have found that the cucumber mosaic virus (CMV) alters gene expression in the tomato plants it infects, causing changes to air-borne chemicals – the scent – emitted by the plants. Bees can smell these subtle changes, and glasshouse experiments have shown that bumblebees prefer infected plants over healthy ones.

Scientists say that by indirectly manipulating bee behaviour to improve pollination of infected plants by changing their scent, the virus is effectively paying its host back. This may also benefit the virus: helping to spread the pollen of plants susceptible to infection and, in doing so, inhibiting the chance of virus-resistant plant strains emerging.

̽��ֱ��authors of the new study, published today in the journal PLOS Pathogens, say that understanding the smells that attract bees, and reproducing these artificially by using similar chemical blends, may enable growers to protect or even enhance yields of bee-pollinated crops.

“Bees provide a vital pollination service in the production of three-quarters of the world’s food crops. With their numbers in rapid decline, scientists have been searching for ways to harness pollinator power to boost agricultural yields,” said study principal investigator Dr John Carr, Head of Cambridge’s Virology and Molecular Plant Pathology group.

“Better understanding the natural chemicals that attract bees could provide ways of enhancing pollination, and attracting bees to good sources of pollen and nectar – which they need for survival,” Carr said.

He conducted the study with Professor Beverley Glover, Director of Cambridge ̽��ֱ�� Botanic Garden, where many of the experiments took place, and collaborators at Rothamsted Research.

CMV is transmitted by aphids – bees don’t carry the virus. It’s one of the most prevalent pathogens affecting tomato plants, resulting in small plants with poor-tasting fruits that can cause serious losses to cultivated crops.

Not only is CMV one of the most damaging viruses for horticultural crops, but it also persists in wild plant populations, and Carr says the new findings may explain why:

“We were surprised that bees liked the smell of the plants infected with the virus – it made no sense. You’d think the pollinators would prefer a healthy plant. However, modelling suggested that if pollinators were biased towards diseased plants in the wild, this could short-circuit natural selection for disease resistance,” he said.

“ ̽��ֱ��virus is rewarding disease-susceptible plants, and at the same time producing new hosts it can infect to prevent itself from going extinct. An example, perhaps, of what’s known as symbiotic mutualism.”

̽��ֱ��increased pollination from bees may also compensate for a decreased yield of seeds in the smaller fruits of virus-infected plants, say the scientists.

̽��ֱ��findings also reveal a new level of complexity in the evolutionary ‘arms race’ between plants and viruses, in which it is classically believed that plants continually evolve new forms of disease-resistance while viruses evolve new ways to evade it.

“We would expect the plants susceptible to disease to suffer, but in making them more attractive to pollinators the virus gives these plants an advantage. Our results suggest that the picture of a plant-pathogen arms race is more complex than previously thought, and in some cases we should think of viruses in a more positive way,” said Carr.

Plants emit ‘volatiles’, air-borne organic chemical compounds involved in scent, to attract pollinators and repulse plant-eating animals and microbes. Humans have used them for thousands of years as perfumes and spices.

̽��ֱ��researchers grew plants in individual containers, and collected air with emissions from CMV-infected plants, as well as ‘mock-infected’ control plants.

Through mass spectrometry, researchers could see the change in emissions induced by the virus. They also found that bumblebees could smell the changes. Released one by one in a small ‘flight arena’ in the Botanic Gardens, and timed with a stopwatch by researchers, the bees consistently headed to the infected plants first, and spent longer at those plants.

“Bees are far more sensitive to the blends of volatiles emitted by plants and can detect very subtle differences in the mix of chemicals. In fact, they can even be trained to detect traces of chemicals emitted by synthetic substances, including explosives and drugs,” said Carr.

Analysis revealed that the virus produces a factor called 2b, which reprograms genetic expression in the tomato plants and causes the change in scent.

Mathematical modelling by plant disease epidemiologist Dr Nik Cunniffe, also in the Department of Plant Sciences at Cambridge, explored how the experimental findings apply outside the glasshouse. ̽��ֱ��model showed how pollinator bias for infected plants can cause genes for disease-susceptibility to persist in plant populations over extremely large numbers of generations.

̽��ֱ��latest study is the culmination of work spanning almost eight years (and multiple bee stings). ̽��ֱ��findings will form the basis of a new collaboration with the Royal Horticultural Society, in which they aim to increase pollinator services for cultivated crops.

With the global population estimated to reach nine billion people by 2050, producing enough food will be one of this century’s greatest challenges. Carr, Glover and Cunniffe are all members of the Cambridge Global Food Security Initiative at Cambridge, which is involved in addressing the issues surrounding food security at local, national and international scales.

̽��ֱ��use of state-of-the-art experimental glasshouses at Cambridge Botanic Garden, and equipment at Cambridge and Rothamsted, was funded by the Leverhulme Trust.

Study of bee-manipulating plant virus reveals a “short-circuiting” of natural selection. Researchers suggest that replicating the scent caused by infection could encourage declining bee populations to pollinate crops – helping both bee and human food supplies.

Modelling suggested that if pollinators were biased towards diseased plants in the wild, this could short-circuit natural selection for disease resistance

John Carr

John Carr/Alex Murphy

Researcher Sanjie Jiang inside the 'flight arena' in the glasshouse of the Cambridge ̽��ֱ�� Botanic Garden.

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Fighting prostate cancer with a tomato-rich diet

jfp40 — Thu, 28 Aug 2014 10:19:14 +0000

With 35,000 new cases every year in the UK, and around 10,000 deaths, prostate cancer is the second most common cancer in men worldwide.

Rates are higher in developed countries, which some experts believe is linked to a Westernised diet and lifestyle.

David Neal of the Department of Oncology, together with researchers at the Universities of Bristol and Oxford, looked at the diets and lifestyle of 1,806 men aged between 50 and 69 with prostate cancer and compared them with 12,005 cancer-free men.

̽��ֱ��NIHR-funded study, published in the medical journal Cancer Epidemiology, Biomarkers and Prevention, is the first study of its kind to develop a prostate cancer ‘dietary index’ which consists of dietary components – selenium, calcium and foods rich in lycopene – that have been linked to prostate cancer.

Men who had optimal intake of these three dietary components had a lower risk of prostate cancer.

Tomatoes and its products – such as tomato juice and baked beans - were shown to be most beneficial, with an 18 per cent reduction in risk found in men eating over 10 portions a week. This is thought to be due to lycopene, an antioxidant which fights off toxins that can cause DNA and cell damage.

Vanessa Er, from the School of Social and Community Medicine at the ̽��ֱ�� of Bristol and Bristol Nutrition BRU, led the research.

She said: “Our findings suggest that tomatoes may be important in prostate cancer prevention. However, further studies need to be conducted to confirm our findings, especially through human trials. Men should still eat a wide variety of fruits and vegetables, maintain a healthy weight and stay active.”

̽��ֱ��researchers also looked at the recommendations on physical activity, diet and body weight for cancer prevention published by the World Cancer Research Fund (WCRF) and the American Institute for Cancer Research (AICR).

Only the recommendation on plant foods – high intake of fruits, vegetables and dietary fibre - was found to be associated with a reduced risk of prostate cancer. As these recommendations are not targeted at prostate cancer prevention, researchers concluded that adhering to these recommendations is not sufficient and that additional dietary recommendations should be developed.

̽��ֱ��research was carried out at the National Institute for Health Research Bristol Nutrition Biomedical Research Unit in Nutrition, Diet and Lifestyle at ̽��ֱ�� Hospitals Bristol NHS Foundation Trust and the ̽��ֱ�� of Bristol (NIHR Bristol Nutrition BRU). ̽��ֱ��research was carried out as part of the ProtecT study, which is funded by the NIHR Health Technology Assessment programme.

This article was originally published by the ̽��ֱ�� of Bristol

Men who eat over 10 portions a week of tomatoes have an 18 per cent lower risk of developing prostate cancer, new research suggests.

Our findings suggest that tomatoes may be important in prostate cancer prevention. However, further studies need to be conducted to confirm our findings. Men should still eat a wide variety of fruits and vegetables, maintain a healthy weight and stay active

Vanessa Er, ̽��ֱ�� of Bristol

Ajith Kumar

Tomatoes

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Prize tomato

amb206 — Wed, 30 May 2012 07:35:29 +0000

Tomatoes are big business in Mexico, especially in the centre and north of the country. Producers range from large growers, whose farms are equipped with extensive automation and irrigation systems, to small cultivators who eke out a living with the slimmest of resources on plots as small as a single hectare. Small growers are particularly vulnerable to technology lock-ins (barriers to switching to new technologies) and re-investment limitations. They do not have access to advice about improving productivity.

With these small growers in mind, a four-strong team of graduate students on Cambridge ̽��ֱ��’s MPhil course in Engineering for Sustainable Development devised ̽��ֱ��Ethical Tomato Company, a concept that has won them first prize in the McKinsey Innovate 2012 competition. Their £5,000 award, plus access to advice from McKinsey, will help them take their project on to the next stage and pilot their ideas in one of the major tomato-producing areas of Mexico.

̽��ֱ��Ethical Tomato Company addresses two main problems: productivity and wastage. Team member Pedro Zaragoza explained: Small farmers work with a very low level of technology which results in low productivity and low incomes. We propose to give them access to simple ways of improving their yields such as building timber-framed greenhouses and using organic compost that will enable them to improve their yields whilst protecting produce from pests and extreme weather.

While in richer countries food wastage occurs chiefly at the consumer end of the market, as people buy more than they need and allow food to perish, in developing countries food wastage occurs lower down the supply chain. It is quite shocking to discover that for every tomato sold in Mexico, another one is wasted. This happens because tomatoes do not reach the market at the right moment. This high level of wastage, with the resultant loss of precious income, is another area in which we hope to be able to help, explained Jorge Garcia Moreno, also a member of the team.

We plan to work with growers in bringing their produce to market and helping them to get a fair price. We propose to do this by becoming a tomato wholesaler and providing the logistics from farm to retail. ̽��ֱ��profits generated will be fairly distributed so that farmers get a better deal and let us expand the business to other farmers.

Although Mexican farmers are highly skilled in growing salad vegetables, they do not always receive the right advice when it comes to using modern fertilisers and chemicals.

Farmers have a lack of training in the use of nutrients such as nitrogen-based fertilizers. In order to achieve high yields they apply fertilizers and herbicides in excess and much of this runs off into the neighbouring water systems where it causes eutrophication. This is both wasteful and environmentally damaging. There are sustainable ways of improving yields that have minimal environmental impact, said Zaragoza.

We plan to share the knowledge through workshops and work closely with them throughout the first planting cycle.

Both Zaragoza, who did his first degree in chemical engineering, and Garcia Moreno, who studied biomedical engineering, are Mexican nationals. Tomatoes are close to our culture and Mexican tomatoes are some of the very best in the world, benefiting from sunshine and good soils, said Zaragoza.

One of the reasons that the team is planning to set up a pilot project in the centre of Mexico is that Zaragoza has family connections with the region’s tomato growers. ̽��ֱ��other members of the winning team are Stephanie Hirmer, who is a civil engineer from Germany and Daniel Gallagher from Scotland, also a civil engineer. Hirmer has experience of working in Uganda and Gallagher experience of working in El Salvador.

Garcia Moreno said that the MPhil in Engineering for Sustainable Development has given him and his peers the tools needed to go out into the world and change things for the better. What’s great about the course is that it encourages us to understand how social, environmental and economic aspects interact as part of a whole system, allowing us to develop holistic sustainable solutions, he said.

̽��ֱ��Ethical Tomato Company is now in the process of receiving advice from McKinsey consultants to develop plans for a pilot project in Mexico.

A group of students on the ̽��ֱ�� of Cambridge’s MPhil course in Engineering for Sustainable Development has devised a project that will help Mexico’s small producers of tomatoes by improving productivity and reducing wastage.

It is quite shocking to discover that for every tomato sold in Mexico, another one is wasted.

Jorge Garcia Moreno

voliwowli

Tomato

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