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Jul 31
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Chinese plant science and Journal of Experimental Botany

By Blog, Scientific Meetings, SEB

This week’s post was written by Jonathan Ingram, Senior Commissioning Editor / Science Writer for the Journal of Experimental Botany. Jonathan moved from lab research into publishing and communications with the launch of Trends in Plant Science in 1995, then going on to New Phytologist and, in the third sector, Age UK and Mind.

 In this week of the XIXth International Botanical Congress (IBC) in Shenzhen, it seems appropriate to highlight outstanding research from labs in China. More than a third of the current issue of Journal of Experimental Botany is devoted to papers from labs across this powerhouse of early 21st century plant science.

Collaborations are key, and this was a theme that came up time again at the congress. The work by Yongzhe Gu et al. is a fine example, involving scientists at four institutions studying a WRKY gene in wild and cultivated soybean: in Beijing, the State Key Laboratory of Systematic and Evolutionary Botany at the Institute of Botany in the Chinese Academy of Sciences, and the University of the Chinese Academy of Sciences; and in Harbin (Heilongjiang), the Crop Tillage and Cultivation Institute at Heilongjiang Academy of Agricultural Sciences, and the College of Agriculture at Northeast Agricultural University. Interest here centers on the changes which led to the increased seed size in cultivated soybean with possible practical application in cultivation and genetic improvement of such a vital crop.

Crops and gardens

Botanic gardens are also part of the picture. In another paper in the same issue, Yang Li et al. from the Key Laboratory of Tropical Plant Resources and Sustainable Use at Xishuangbanna Tropical Botanical Garden in Kunming (Yunnan) and the University of the Chinese Academy of Sciences in Beijing present research on DELLA-interacting proteins in Arabidopsis. Here the authors show that bHLH48 and bHLH60 are transcription factors involved in GA-mediated control of flowering under long-day conditions.

IBC 2017

Naturally, research on rice is important. Wei Jiang et al. from the National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University (Wuhan) describe their research on WOX11 and the control of crown root development in the nation’s grain of choice, which will be important for breeders looking to increase crop yields and resilience.

The other work featured is either in Arabidopsis or plants of economic importance: Fangfang Zheng et al. (Qingdao Agricultural University, also with collaborators in Maryland) and Xiuli Han et al. (Beijing); Yun-Song Lai et al. (Beijing/Chengdu – cucumber), Wenkong Yao et al. (Yangling, Shaanxi – Chinese grapevine, Vitis pseudoreticulata), and Xiao-Juan Liu et al. (Tai-an, Shandong – apple).

Development of plant science

Shenzehn has grown rapidly and is now highly significant for life science as home to the China National GeneBank (CNGB) project led by BGI Genomics. The vision as set out by Huan-Ming Yang, chairman of BGI-Shenzhen, is profound – from sequencing what’s already here, often in numbers per species, to innovative synthetic biology.

Shenzehn is also home to another significant institution, the beautiful and scientifically important Fairy Lake Botanic Garden. At the IBC, the importance of biodiversity conservation for effective, economically focused plant science, but also for so many other reasons to do with our intimate relationship with plants and continued co-existence on the planet, was a central theme.

The research highlighted in Journal of Experimental Botany is part of the wider, positive growth of plant science (and, indeed, botany) not just in China, but worldwide. The Shenzehn Declaration on Plant Sciences with its seven priorities for strategic action, launched at the congress, will be a guide for the right development in coming years.

Jul 26
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A taste of CRISPR

By Blog, Future Directions, Research, SEB

This week’s blog was written by Dr Craig Cormick, the Creative Director of ThinkOutsideThe. He is one of Australia’s leading science communicators, with over 30 years’ experience working with agencies such as CSIRO, Questacon and Federal Government Departments.

So what do you think CRISPR cabbage might taste like? CRISPR-crispy? Altered in some way?

Participants at the recent Society for Experimental Biology/Global Plant Council New Breeding Technologies workshop in Gothenburg, Sweden, had a chance to find out, because in Sweden CRISPR-produced plants are not captured by the country’s GMO regulations and can be produced.

Professor Stefan Jansson, one of the workshop organizers, has grown the CRISPR cabbage (discussed in his blog for GPC!) and not only had it included on the menu of the workshop dinner, but also had samples for participants to take away. Some delegates were keen to pick up the samples while others were unsure how their own country’s regulatory rules would apply to them

Regulatory issues

The uncertainty some delegates felt about the legality of taking a CRISPR cabbage sample home was a good demonstration of the diversity of regulations that apply – or may apply – to new breeding technologies, such as CRISPR and gene editing – and there was considerable discussion at the workshop on how European Union regulations and court rulings may play out, affecting both the development and export/import of plants and foods produced by the new technologies.

A lack of certainty has meant many researchers are unable to determine whether their work will need to be subjected to costly and time-consuming regulations or not.

The need for new breeding technologies was made clear at the workshop, which was attended by 70 people from 17 countries, with presentations on the need to double our current food production to feed the world in 2050 and reduce crop losses caused by problems such as viruses, which deplete crops by 10–15%.

The two-day workshop, held in early July, looked at a breadth of issues, including community attitudes, gene editing success stories, and tools and resources. But discussions kept coming back to regulation.

Outdated regulations

Regulations of gene technologies were largely developed 20 years ago or so, for different technologies than now exist, and as a result are not clear enough for researchers to determine whether different gene editing technologies they are working on may be governed by them or not.

The diversity of regulations is also going to be an issue, for some countries may allow different gene editing technologies, but others may not allow products developed using them to be imported.

That led to the group beginning to develop a statement that captured the feeling of the workshop, which, when complete, it is hoped will be adopted by relevant agencies around the world to develop their own particular positions on gene editing technologies. It would be a huge benefit to have a coherent and common line in an environment of mixed regulations in mixed jurisdictions.

CRISPR cabbage

And as to the initial question of what CRISPR cabbage tastes like – just like any cabbage you might buy at your local supermarket or farmers market, of course – since it is really no different.

Want to read more about CRISPR? Check out our interview with Prof. Stefan Jansson or our introduction to CRISPR from Dr Damiano Martignago.

Jul 10
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Brazil’s transgenic sugarcane stirs up controversy

By Blog, Research

By Luisa Massarani

This article was originally published on SciDev.Net. Read the original article.

[RIO DE JANEIRO] A genetically modified (GM) cane variety that can kill the sugarcane borer (Diatraea saccharalis) has been approved in Brazil,  to the delight of some scientists and the dismay of others, who say it may threaten Brazilian biodiversity.

Brazil is the second country, after Indonesia, to approve the commercial cultivation of GM sugarcane. The approval was announced by the Brazilian National Biosafety Technical Commission (CTNBio) on June 8.

Sugarcane borer is one of the main pests of the sugarcane fields of South-Central Brazil, causing losses of approximately US$1.5 billion per year.

“Breeding programmes could not produce plants resistant to this pest, and the existing chemical controls are both not effective and severely damaging to the environment,” says Adriana Hemerly, a professor at the Federal University of Rio de Janeiro, in an interview with SciDev.Net.

“Studies conducted outside Brazil prove that protein from genetically modified organisms harms non-target insects, soil fauna and microorganisms.”

Rogério Magalhães

“Therefore, the [GM variety] is a biotechnological tool that helps solve a problem that other technologies could not, and its commercial application will certainly have a positive impact on the productivity of sugarcane in the country.”

Jesus Aparecido Ferro, a member of CTNBio and professor at the Paulista Júlio de Mesquita Filho State University, believes the move followed a thorough debate that began in December 2015 — that was when the Canavieira Technology Center (Sugarcane Research Center) asked for approval to commercially cultivate the GM sugarcane variety.

“The data does not provide evidence that the cane variety has a potential to harm the environment or human or animal health,” Ferro told SciDev.Net.

To develop the variety, scientists inserted the gene for a toxin [Cry] from the bacterium Bacillus thuringiensis (Bt) into the sugarcane genome, so it could produce its own insecticide against some insects’ larvae.

This is a technology that “has been in use for 20 years and is very safe”, says Aníbal Eugênio Vercesi, another member of the CTNBio, and a professor at the State University of Campinas.

But Valério De Patta Pillar, also a member of the CTNBio and a professor at the Federal University of Rio Grande do Sul, points to deficiencies in environmental risk assessment studies for the GM variety — and the absence of assessments of how consuming it might affect humans and animals.

According to Pillar, there is a lack of data about the frequency with which it breeds with wild varieties. Data is also missing on issues such as the techniques used to create the GM variety and the effects of its widespread use.

Rogério Magalhães, an environmental analyst at Brazil’s Ministry of the Environment, also expressed concern about the approval of the commercial transgenic cane.

“I understand that studies related to the impacts that genetically modified sugarcane might have on Brazilian biodiversity were not done by the company that owns the technology,” said Magalhães in an interview with SciDev.Net. This is very important because Brazil’s climate, species, and soils differ from locations where studies might have taken place, he explained.

Among the risks that Magalhães identified is contamination of the GM variety’s wild relatives. “The wild relative, when contaminated with transgenic sugarcane, will have a competitive advantage over other uncontaminated individuals, as it will exhibit resistance to insect-plague that others will not have,” he explained.

Another risk that Magalhães warns about is damage to biodiversity. “Studies conducted outside Brazil prove that Cry protein from genetically modified organisms harms non-target insects, soil fauna and microorganisms.”

Magalhães added that some pests have already developed resistance to the Bt Cry protein, prompting farmers to apply agrochemicals that are harmful to the environment and human health.

This piece was originally published by SciDev.Net’s Latin America and Caribbean desk.

 

This article was originally published on SciDev.Net. Read the original article.

Jun 19
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Genetics to boost sugarcane production

By Blog, Future Directions

Scientists in Brazil are taking steps towards genetically modifying sugar cane so it produces more sucrose naturally, looking to eventually boost the productivity and economic benefits of the tropical grass.

A man stacks sugarcane at the Ver-o-Peso (Check the Weight) market in Belem.

Currently, it is common for producers to raise sucrose levels in sugar cane by applying artificial growth regulators or chemical ripeners. This inhibits flowering, which in turn prolongs harvest and milling periods.

One of these growth regulators, ethephon, is used to manage agricultural, horticultural and forestry crops around the world. It is widely used to manipulate and stimulate the maturation of sugarcane as it contains ethylene, which is released to the plant on spraying.

Ethylene, considered a ripening hormone in plants, contributes to increasing the storage of sucrose in sugar cane.

“Although we knew ethylene helps increase the amount of sugar in the cane, it was not clear how the synthesis and action of this hormone affected the maturation of the plant,” said Marcelo Menossi, professor at the University of Campinas (Unicamp) and coordinator of the project, which is supported by the Brazilian research foundation FAPESP.

To study how ethylene acts on sugarcane, the researchers sprayed ethephon and an ethylene inhibitor, aminoethoxyvinylglycine (AVG), on sugar cane before it began to mature.
sucrose accumulation.jpg

After spraying both compounds, they quantified sucrose levels in tissue samples from the leaves and stem of the cane. They did this five days after application and again 32 days later, on harvest.

Those plants treated with the ethephon ripener had 60 per cent more sucrose in the upper and middle internodes at the time of harvest, while the plants treated with the AVG inhibitor had a sucrose content that was lower by 42 per cent.

The researchers were then able to identify genes that respond to the action of ethylene during ripening of the sugar cane. They also successfully identified the genes involved in regulating sucrose metabolism, as well as how the hormone acts on sucrose accumulation sites in the plant.

Based on the findings, the team has proposed a molecular model of how ethylene interacts with other hormones.

“Knowing which genes or ripeners make it possible for the plant to increase the accumulation of sucrose will allow us to make genetic improvements in sugarcane and develop varieties that over-express these genes, without the need to apply ethylene, for example,” explained Menossi.

This research could also help with spotting the most productive sugar cane, as some varieties that do not respond well to hormones, he added. “It will be possible to identify those [varieties] that best express these genes and facilitate the ripening action.”

Taken from a newsletter by FAPESP, a SciDev.Net donor, edited by our Latin America and the Caribbean desk

 

This article was originally published on SciDev.Net. Read the original article.

Jun 12
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Rise in groundwater overuse could hit food prices

By Blog, Future Directions

By Neena Bhandari

[SYDNEY] The increasing use of groundwater for irrigation poses a major threat to global food security and could lead to unaffordable prices of staple foods. From 2000 to 2010, the amount of non-renewable groundwater used for irrigation increased by a quarter, according to an article published in Nature on March 30. During the same period China had doubled its groundwater use.

The article finds that 11 per cent of groundwater extraction for irrigation is linked to agricultural trade.

“In some regions, for example in Central California or North-West India, there is not enough precipitation or surface water available to grow crops like maize or rice and so farmers also use water from the underground to irrigate,” the article says.

“When a country imports US maize grown with this non-renewable water, it virtually imports non-renewable groundwater.”

Carole Dalin,  Institute for Sustainable Resources at University College, London

The article focused on cases where underground reservoirs or aquifers, are overused. “When a country imports US maize grown with this non-renewable water, it virtually imports non-renewable groundwater,” Carole Dalin, lead author and senior research fellow at the Institute for Sustainable Resources at University College, London, tells SciDev.Net.

Crops such as rice, wheat, cotton, maize, sugar crops and soybeans are most reliant on this unsustainable water use, according to the article. It lists countries in the Middle East and North Africa as well as China, India, Mexico, Pakistan and the US as most at risk.

“Pakistan and India have been locally most affected due to groundwater depletion and exporting agricultural products grown with non-sustainable groundwater. Iran is both exporting and importing and The Philippines is importing from Pakistan, which is non-sustainable. China is importing a lot from India. Japan and Indonesia are importing, mainly from the US,” says Yoshihide Wada, co-author of the report and deputy director of the International Institute for Applied Systems Analysis’s Water Programme, Laxenburg, Austria.

Agriculture is the leading user of groundwater, accounting for more than 80 to 90 per cent of withdrawals in irrigation-intense countries like India, Pakistan and Iran, according to the report.

The researchers say efforts to improve water use efficiency and develop monitoring and regulation need to be prioritised. Governments must invest in better irrigation infrastructure such as sprinkler irrigation and introduce new cultivar or crop rotation to help producers minimise water use.

Wada suggests creating awareness by putting water labels, along the lines of food labels, “showing how much water is used domestically and internationally in produce and whether these water amounts are from sustainable or non-sustainable sources”.

Andrew Western, professor of hydrology and water resources at the University of Melbourne’s School of Engineering, suggests enforceable water entitlement systems and caps on extraction. “In recent decades, water reform in Australia has led to water having a clear economic value made explicit by a water market. This has enabled shifts in water use to cope with short-term climate fluctuations and has also driven a trend of increasing water productivity,” he says.

This piece was produced by SciDev.Net’s Asia & Pacific desk.

 

This article was originally published on SciDev.Net. Read the original article.

Jun 05
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The State of the World’s Plants 2017 by Bursary Winner Harison Andriambelo

By Blog, GPC Community, Scientific Meetings, SEB

This week’s post was written by Harison Andriambelo, a PhD student at the University of Antananarivo, Madagascar. Harison was the awardee of the Early Career Researcher travel bursary from the Society for Experimental Biology in association with the Global Plant Council, enabling him to attend the State of the World’s Plants Symposium at the Royal Botanic Gardens, Kew. Here’s how he got on!

Attending the State of the World’s Plants Symposium 2017 at the Royal Botanic Gardens, Kew, was a fantastic opportunity for me to get a detailed insight into many aspects of plant conservation, including the latest emerging research. Scientists from all over the world attended the symposium and shared results from several ecoregions, including tropical, boreal, and temperate biomes. It was also great to visit the Gardens, which were looking amazing in the British summertime.

As a botanist from Madagascar, I found the focus session on conservation in my country particularly useful, and I really enjoyed the talks by Pete Lowry and George Schatz, both from Missouri Botanic Garden.

Other sessions in the conference highlighted important issues including fires and invasive species. We heard that fire is not always bad for plants, especially in savannah systems, where plant diversity is maintained by the fire regime. I believe better scientific communication to the public is urgently needed on this issue.

Another great session concerned invasive species. I have worked across all the biomes in Madagascar, from humid forests to the dry spiny forest, and I have seen first-hand the effects invasive plants can have. A detailed assessment of invasive plant species in wetlands and in the western dry forests of Madagascar made me more aware of the potential impacts of these species. By attending this symposium, I learned about several programs and efforts by the Invasive Species Specialist Group and will spread information about invasive species management to colleagues once I return to Madagascar.

For me, the highlight of the session on medicinal plants was a talk by the President of Mauritius. It was inspirational to see that scientists can even become a head of state. Such leadership offers great promise for addressing environmental issues at national scale. I am certain that having an ecologist as President in Madagascar would allow much greater progress on conservation issues in my home country, which has many highly threatened endemic species. Scientists can bring their understanding and ability to analyze complex systems to bear on policy. Good leaders can take a long-term holistic view and accord the appropriate priority to the environment in national plans for development.

This symposium allowed me to present some results of my research activities in Madagascar and get feedback from an international group of scientists. A deep discussion with people working at RBG Kew about how to scale information on tree dispersal processes from the plot to landscape scales was very valuable. As they know the Madagascan context, they were very interested in my results and a possible collaboration is on its way.

Finally, this trip to London allowed me to spend more time with my colleague Dr Peter Long at the University of Oxford and to make good progress for my scientific research activities. I am very grateful to the Society for Experimental Biology for supporting my travel to the UK to participate in this meeting.

May 29
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The Global Plant Council visits the Australian Plant Phenomics Facility

By Blog, Interviews

This post is republished with the kind permission of the Australian Plant Phenomics Facility (APPF). 

We at the APPF love visits from our global plant science community, so it was a treat to host Ruth Bastow, Executive Director of the Global Plant Council (GPC), this week.

While she was here, we took the opportunity to ask a few quick questions:

Ruth Bastow at the Australian Plant Phenomics Facility

Ruth Bastow, Executive Director of the Global Plant Council in high-throughput phenotyping Smarthouse™ at the Australian Plant Phenomics Facility’s Adelaide node

Ruth, could you tell us a little bit about the GPC?

The GPC is a not-for-profit coalition of national, regional, and international societies and affiliates representing thousands of plant, crop, agricultural, and environmental scientists. We bring together all those involved in plant and crop research, education and training, to provide a body that can speak with a single, strong voice in the policy and decision-making arena, and to promote plant science research and teaching around the world.

What do you do there?

As Executive Director of the GPC I am responsible for the day to day management of the organisation.

What is the reason for your visit here?

To meet up and discuss GPC initiatives with colleagues here at the University of Adelaide, to further develop current collaborations and hopefully initiate new ones.

For example the Australian Plant Phenomics Facility (APPF) is partner of the Diversity Seek Initiative (DivSeek). DivSeek is a global community driven effort consisting of a diverse set of partner organisations have voluntarily come together to enable breeders and researchers to mobilise a vast range of plant genetic variation to accelerate the rate of crop improvement and furnish food and agricultural products to the growing human population. DivSeek brings together large-scale genotyping and phenotyping projects, computational and data standards projects with the genebanks and germplasm curators. The aim is to establish DivSeek as a hub to connect and promote interactions between these players and activities and to establish common state-of-the-art techniques for data collection, integration and sharing. This will improve the efficiency of each project by eliminating redundancy and increasing the availability of data to researchers around the world to address challenges in food and nutritional security, and to generate societal and economic benefit.

So, whilst I am here, I will be learning about how the APPF team collate and analyse their data and try and understand how the approaches here could be translated into solutions for the wider community. For example, the Zegami platform used in the high-throughput phenotyping Smarthouses™ at the Adelaide node is a useful visualisation tool that could benefit others.

Where else have you visited?

Whilst I am here in Australia I have been working with colleagues in Canberra including Prof Barry Pogson who is currently the chair of the Global Plant Council, Dr Xavier Sirault (APPF node based at CSIRO), Prof Justin Borevitz (APPF node based at ANU), and Dr Norman Warthmann. I will also be taking time to visit friends in Sydney and on the Central Coast.

Where do you see plant phenomics research in 5-10 years time?

High throughput and field based phenotyping has seen huge transformational change in the last decade and in the next 5-10 years I hope that it will start to become part of the everyday toolkit of plant science researchers in the way that genomics has.

If you could solve one plant science question what would it be?

I would actually like to try and solve a social/conceptual problem that effects science rather than an actual biological question and that is the sharing of data, information, knowledge and best practice. The sharing of scientific theories, including experimental data and observations has been a core concept of the scientific endeavour since the enlightenment. Sharing allows others to evaluate research (peer review), to identify errors, and allow ideas to be corroborated, invalidated and built upon. It also facilitates the transmission of concepts and theories to a wider audience and that will hopefully inspire others to get involved in science, contribute ideas and further our understanding of the world around us.

However, the current systems of reward and evaluation in science; lack of appropriate mechanisms, standard and infrastructures to easily share and access information; and in some cases the debilitating effects of ‘IP thickets’ can act as a barrier to ‘open science’. It is not all bad news. In the last decade a number of changes at the government, funder, publisher and institutional level have promoted and facilitated the concept of open science. However, if science is to be a truly open endeavour it will require a change in mind-set at many levels to migrate towards a culture where open data is the norm. Without this we will not be able to fully realise the investment in research, in terms of both finance provided and the time and intellectual contribution of the individual involved, and contribute to developing solutions that will help ameliorate current global problems.

When I am not working I am?

Walking the dog or gardening and generally enjoying the beauty of my home in South Wales in the UK.

If you could have one super power what would it be?

For my work it would probably be telepathy or omnilinguism, as most problems seems to arise from lack of understanding or miscommunication at some level, so these would be very helpful superpowers. From a personal perspective perhaps the ability to predict the future would be good.

Thanks again to the APPF for giving us permission to republish this blog post!

About the APPF

The APPF is a national facility, available to all Australian plant scientists, offering access to infrastructure that is not available at this scale or breadth in the public sectors anywhere else in the world. The APPF is based around automated image analysis of the phenotypic characteristics of extensive germplasm collections and large breeding, mapping and mutant populations. It exploits recent advances in robotics, imaging and computing to enable sensitive, high throughput analyses to be made of plant growth and function. New technologies are being developed to ensure that the APPF remains at the international forefront of plant science. Research networks and established pathways to market ensure outcomes are delivered for the long-term benefit for Australian scientists and primary producers.

May 22
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Striga hermonthica – a beautiful but devastating plant…

By Blog, Research

This week’s post was written by Caroline Wood, a PhD candidate at the University of Sheffield.

When it comes to crop diseases, insects, viruses, and fungi may get the media limelight but in certain regions it is actually other plants which are a farmer’s greatest enemy. In sub-Saharan Africa, one weed in particular – Striga hermonthica – is an almost unstoppable scourge and one of the main limiting factors for food security.

Striga is a parasitic plant; it attaches to and feeds off a host plant. For most of us, parasitic plants are simply harmless curiosities. Over 4,000 plants are known to have adopted a parasitic mode of life, including the seasonal favorite mistletoe (a stem parasite of conifers) and Rafflesia arnoldii, nicknamed the “corpse flower” for its huge, smelly blooms. Although the latter produces the world’s largest flower, it has no true roots – only thread-like structures that infect tropical vines.

When parasitic plants infect food crops, they can turn very nasty indeed. Striga hermonthica is particularly notorious because it infects almost every cereal crop, including rice, maize, and sorghum. Striga is a hemiparasite, meaning that it mainly withdraws water from the host (parasitic plants can also be holoparasites, which withdraw both water and carbon sugars from the host). However, Striga also causes a severe stunting effect on the host crop (see Figure 1), reducing their  yield to practically nothing. Little wonder then, that the common name for Striga is ‘witchweed’.

Striga-infected sorghum

Figure 1: Striga-infected sorghum. Note the withered, shrunken appearance of the infected plants. Image credit: Joel Ransom.

 

Several features of the Striga lifecycle make it especially difficult to control. The seeds can remain dormant for decades and only germinate in response to signals produced by the host root (called strigolactones) (Figure 2). Once farmland becomes infested with Striga seed, it becomes virtually useless for crop production. Germination and attachment takes place underground, so the farmer can’t tell if the land is infected until the parasite sends up shoots (with ironically beautiful purple flowers). Some chemical treatments can be effective but these remain too expensive for the subsistence farmers who are mostly affected by the weed. Many resort to simply pulling the shoots out as they appear; a time-consuming and labor-intensive process. It is estimated that Striga spp. cause crop losses of around US $10 billion each year [1].

Certain crop cultivars and their wild relatives show natural resistance to Striga. Here at the University of Sheffield, our lab group (headed by Professor Julie Scholes) is working to identify resistance genes in rice and maize, with the eventual aim of breeding these into high-yielding cultivars. To do this, we grow the host plants in rhizotrons (root observation chambers) which allow us to observe the process of Striga attachment and infection (see Figure 3). Already this has been successful in identifying rice cultivars that have broad-spectrum resistance to Striga, and which are now being used by farmers across Africa.

 

Life cycle of Striga

Figure 2: Life cycle of Striga spp. A single plant produces up to 100,000 seeds, which can remain viable in the soil for 20 years. Following a warm, moist conditioning phase, parasite seeds become responsive to chemical cues produced by the roots of suitable hosts, which cause them to germinate and attach to the host root. The parasite then develops a haustorium: an absorptive organ which penetrates the root and connects to the xylem vessels in the host’s vascular system. This fuels the development of the Striga shoots, which eventually emerge above ground and flower. Figure from [2].

 

But many fundamental aspects of the infection process remain almost a complete mystery, particularly how the parasite overcomes the host’s intrinsic defense systems. It is possible that Striga deliberately triggers certain host signaling pathways; a strategy used by other root pathogens such as the fungus Fusarium oxysporum. This is the focus of my project: to identify the key defense pathways that determine the level of host resistance to Striga. It would be very difficult to investigate this in crop plants, which typically have incredibly large genomes, so my model organism is Arabidopsis thaliana, the workhorse of the plant science world, whose genome has been fully sequenced and mapped. Arabidopsis cannot be infected by Striga hermonthica but it is susceptible to the related species, Striga gesnerioides, which normally infects cowpea.  I am currently working through a range of different Arabidopsis mutants, each affected in a certain defense pathway, to test whether these have an altered resistance to the parasite.  Once I have an idea of which plant defense hormones may be involved (such as salicylic acid or jasmonic acid), I plant to test the expression of candidate genes to decipher what is happening at the molecular level.

Striga-infected Arabidopsis

Figure 3: One of my Arabidopsis plants growing in a rhizotron. Preconditioned Striga seeds were applied to the roots three weeks ago with a paintbrush. Those that successfully attached and infected the host have now developed into haustoria. The number of haustoria indicates the level of resistance in the host. Image credit: Caroline Wood.

 

It’s early days yet, but I am excited by the prospect of shedding light on how these devastating weeds are so effective in breaking into their hosts. Ultimately this could lead to new ways of ‘priming’ host plants so that they are armed and ready when Striga attacks. It’s an ambitious challenge, and one that will certainly keep me going for the remaining two years of my PhD!

 

You can follow my journey by reading my blog and keeping up with me on Twitter (@sciencedestiny).

 

References:

[1] Westwood, J. H. et al. (2010). The evolution of parasitism in plants. Trends in Plant Science, 15(4): 227-235.

[2] Scholes, J. D. and Press, M. C. (2008). Striga infestation of cereal crops – an unsolved problem in resource limited agriculture. Current Opinion in Plant Biology, 11(2): 180-186.

May 15
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Water is key to ending Africa’s chronic hunger cycle

By Blog, Global Change

By Esther Ngumbi

For Africa to end chronic hunger, governments must invest in sustainable water supplies.

The fields are bare under the scorching sun and temperatures rise with every passing week. Any crops the extreme temperatures haven’t destroyed, the insect pests have, and for many farmers, there is nothing they can do. Now, news about hunger across Africa makes mass media headlines daily.

Globally, hunger levels are at their highest. In fact, according to the Famine Early Warning Systems Network, over 70 million people across 45 countries will require food emergency assistance in 2017, with Africa being home to three of the four countries deemed to face a critical risk of famine: Nigeria, South Sudan, Sudan and Yemen. African governments, non-governmental organisations (NGOs) and humanitarian relief agencies, including the United Nations World Food Programme, continue to launch short-term solutions such as food relief supplies to avert the situation. Kenya, for example, is handing cash transfers and food relief to its affected citizens. The UN World Food Programme is also distributing food to drought-stricken Somalia. And in Zambia, the government is employing every tool including its military to combat insect pest infestation.

But why are we here? What happened? Why is there such a large drought?

Reasons for chronic hunger

Many African smallholder farmers depend on rain-fed agriculture, and because last year’s rains were inadequate, many farmers never harvested any crops.

Indeed, failed rains across parts of the Horn of Africa have led to the current drought that is affecting Somalia, south-eastern Ethiopia and northern and eastern Kenya.

Then, even in the countries where adequate rains fell, many of the farmers had to farm on depleted soils, and consequently, the yields were lower. Degraded soils and dependence on rain-fed agriculture coupled with planting the wrong crop varieties are some of the fundamental problems that lead to poor harvests and then to hunger. Worsening the situation is the unpredictable climate. Given these fundamental and basic issues that fuel the hunger cycle in Africa, it naturally makes sense to tackle them.

It is not rocket science. Farming goes hand-in-hand with water. There can be no farming without it. While this seems easy to reason, there are few organisations working to make sure that African farmers and citizens have access to permanent water sources. Access to water sources all year round would ensure that farmers can farm year in and year out.

What African governments must do

African governments must, therefore, invest in ensuring that their citizens have access to water. Measures that can be implemented include drilling and rehabilitating boreholes, creating reservoirs and irrigation systems, constructing hand-pumps and implementing water harvesting schemes. Such measures would go a long way and ensure that countries continue to face the same problem both in the short and long term periods.

“If Africa wants to end the recurring droughts, hard decisions must be made.”

Esther Ngumbi, Auburn University in Alabama. United States

Of course it is understandable that it can be hard to choose long-term solutions such as ensuring that citizens have access to permanent water sources year round over investing in short-term solutions when there are people who need help now.

Acknowledging this dilemma, Mitiku Kassa, the Ethiopia’s commissioner for disaster risk management, is reported to have described how hard it was to direct even a fifth of his budget towards well drilling. But such decisions must be made. The Ethiopian government still made that tough decision and sunk hundreds of bore wells throughout the country.

There is a great need to ramp up water harvesting and conservation efforts across the African continent. African governments and other stakeholders need to increase investment in multiple water-storing techniques. Such techniques include rain and flood water harvesting and the construction of water storage ponds and dams. But there should be no need to reinvent the wheel.

Time to learn from others

African countries can learn from other countries. Countries in the developed world have sustained their agriculture efforts by either drilling water wells to ensure they have access to the water they need for farming or by investing in rain and flood water harvesting. In California, for example, there have been a rise in the number of wells being drilled by farmers who use well water for farming. In 2016 alone, farmers in the San Joaquin Valley dug about 2,500 wells, a number that was five times the annual average reported in the last 30 years.

Countries such as Bangladesh, China, India, Myanmar, Sri Lanka and Thailand have made progress and are working on pilot projects that capture, harvest and store flood water. Stored water is then available for use by communities when they need it the most. Harvesting and storing water and making it available for agriculture, especially during the dry seasons, will allow citizens and smallholder farmers to farm throughout the year. These would further improve the resilience of farmers to the unpredictability of climate change.

If Africa wants to end the recurring droughts, hard decisions must be made. By addressing the fundamental and basic issues of long-term availability of water for agriculture, African countries can once and for all end this never-ending cycle of hunger.

Esther Ngumbi is a postdoctoral researcher at the Department of Entomology and Plant Pathology at Auburn University in Alabama, United States. She serves as a 2015 Clinton Global University (CGI U) Mentor for Agriculture and is a 2015 New Voices Fellow at the Aspen Institute. 

This piece was produced by SciDev.Net’s Sub-Saharan Africa English desk.

 

References

Humphrey Nkonde Dramatic threat to maize harvest (Development and Cooperation, 6 March 2017)
Mohammed Yusuf UN: 17 Million People Face Hunger East Africa (Voice of America, 8 March 2017)
Karen McVeigh Somalia famine fears prompt UN call for ‘immediate and massive’ reaction (the Guardian, 3 February 2017)
Emergency food assistance needs unprecedented as Famine threatens four countries (Famine Early Warning Systems Network, 25 January 2017)
Kazungu Samuel Kenya: Red Cross Comes to the Aid of Drought-Hit Kilifi Residents (allAfrica, 2017)
Army worms invades Zambia’s farms (Azania Post, 6 February 2017)
Lesson learned? An urgent call for action in response to the drought crisis in the horn of Africa (Inter Agency Working Group on Disaster Preparedness for East and Central Africa, 2017)
Amanda Little The Ethiopian Guide to Famine Prevention (Bloomberg Business Week, 22 December 2016)
Central Valley farmers drill more, deeper wells as drought limits loom (CBS SF Bay Area, 15 September 2016)
Underground taming floods for irrigation(International Water Management Institute, 2017)

 

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