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Plant Science for Global Challenges

Category: GPC Community (page 2 of 14)

Registration open for GPC/SEB New Breeding Technologies Workshop!

New Breeding Technologies in the Plant Sciences – Applications and Implications in Genome Editing

Gothenburg, Sweden, 7-8th July 2017

REGISTRATION FOR THIS MEETING IS NOW OPEN!

Organised by: Dr Ruth Bastow (Global Plant Council), Dr Geraint Parry (GARNet), Professor Stefan Jansson (Umeå University, Sweden) and Professor Barry Pogson (Australian National University, Australia).

Targeted genome engineering has been described as a “game-changing technology” for fields as diverse as human genetics and plant biotechnology. Novel techniques such as CRISPR-Cas9, Science’s 2015 Breakthrough of the Year, are revolutionizing scientific research, allowing the targeted and precise editing of genomes in ways that were not previously possible.

Used alongside other tools and strategies, gene-editing technologies have the potential to help combat food and nutritional insecurity and assist in the transition to more sustainable food production systems. The application and use of these technologies is therefore a hot topic for a wide range of stakeholders including scientists, funders, regulators, policy makers and the public. Despite its potential, there are a number of challenges in the adoption and uptake of genome editing, which we propose to highlight during this SEB satellite meeting.

One of the challenges that scientists face in applying technologies such as CRISPR-Cas9 to their research is the technique itself. Although the theoretical framework for using these techniques is easy to follow, the reality is often not so simple. This meeting will therefore explain the principles of applying CRISPR-Cas9 from experts who have successfully used this system in a variety of plant species. We will explore the challenges they encountered as well as some of the solutions and systems they adopted to achieve stably transformed gene-edited plants.

The second challenge for these transformative technologies is how regulatory bodies will treat and asses them. In many countries gene editing technologies do not fit within current policies and guidelines regarding the genetic modification and breeding of plants, as it possible to generate phenotypic variation that is indistinguishable from that generated by traditional breeding methods. Dealing with the ambiguities that techniques such as CRISPR-Cas9 have generated will be critical for the uptake and future use of new breeding technologies. This workshop will therefore outline the current regulatory environment in Europe surrounding gene editing, as well as the approaches being taken in other countries, and will discuss the potential implications and impacts of the use of genome engineering for crop improvement.

Overall this meeting will be of great interest to plant and crop scientists who are invested in the future of gene editing both on a practical and regulatory level. We will provide a forum for debate around the broader policy issues whilst include opportunities for in-depth discussion regarding the techniques required to make this technology work in your own research.

This meeting is being held as a satellite event to the Society for Experimental Biology’s Annual Main Meeting, which takes place in Gothenburg, Sweden, from the 3–6th July 2017.

…¡y nos fuimos por las ramas! The history of plant physiology in Argentina

History of the SAFV, Argentina

…¡y nos fuimos por las ramas! The history of plant physiology in Argentina

This week we spoke with Professor Edith Taleisnik about her new book, ‘…¡y nos fuimos por las ramas!’ (‘we went along the branches’), an in-depth look at the history of plant physiology research in Argentina. (Edith previously described the activities and vision of the Argentinean Society of Plant Physiology (SAFV) on the blog – read it here).

 

Edith, you have put a huge amount of work into uncovering the history of plant physiology research in Argentina. Why did you decide to do it and how did you undertake this challenge?

The current president of the SAFV, Pedro Sansberro, asked Alberto Golberg and myself if we would be willing to document the history of the society. Unaware of the tremendous task ahead, we agreed.

The information was scattered, so the first thing we did was try to collect as many SAFV conference books as possible. Sending requests through the SAFV mailing did not work, so it was essentially through personal contacts that we were able to put together the whole collection of conference books. It is now deposited in the library of CIAP (Centro de Investigaciones Agropecuarias – contact: ciap.cd@inta.gob.ar). People also sent the minutes of past meetings and pictures.

Initially we were only going to analyze the conference books and interview some plant scientists that were among the first disciples of the “founding fathers” of Argentinian experimental plant biology, but as we worked, our book grew and diversified.

 

What was the most interesting thing you discovered while writing the book?

It’s hard to narrow down which discovery was most exciting!

Victorio Trippi, one of the disciples of the “founding fathers”, told us that many researchers initially published in the journal Phyton, which was founded in Argentina in 1951. Our inspection of the archives of this publication yielded a lot of valuable information, and was an enlightening experience. We traced great names in Argentine plant science to the very beginning of their careers, looking at their topics of interest, how they moved from one job to another, and who their co-authors were. Even earlier than this though, we managed to trace the first mention of plant hormones in Argentina to a paper written by Guillermo Covas in 1939.

Writing the book was rewarding too, because we realized that plant physiology research has steadily grown in Argentina, judging by the participation in the conferences and the amount of research groups all over the country. It was very good to reveal the significant contributions that Argentine experimental plant science has made to many topics, such as photobiology, crop ecophysiology, germination physiology, senescence, mineral nutrition and carbohydrate metabolism, among others.

 

Old papers

Image credit: Phil Roeder. Used under license: CC BY 2.0.

 

Why did you decide to include essays from the many groups researching plant physiology in Argentina?

We included them to reflect how much plant physiology has grown and diversified in Argentina. In the book we also invite those that did not have a chance to join this edition to contribute to a future one.

 

What words of wisdom did the researchers who were interviewed want to share with early career researchers for the future?

Most of them emphasized the need for team work, with people from different background joining forces to tackle a specific problem. The SAFV, they point out, has provided a friendly environment that has promoted collaboration and exchange of ideas among its members, and they hope this spirit will persist. They are moderately optimistic about the future, underscoring the need for new research paradigms both in the public and private sectors.

 

Carlos Ballaré underscored the human aspect of the history of the SAFV in his description of your book, printed on the cover. Could you elaborate on this?

Carlos meant that the book includes personal accounts from the people that have devoted their professional lives to plant physiology and ecophysiology, anecdotes of how the research groups developed and grew, and tales of how researchers replaced the lack of equipment with clever ideas. He highlights that the book has an emphasis on human endeavor, rather than being just a review of numbers, places, and dates.

Beyond the analysis of numbers and growth, the book reveals how early researchers worked on problems that largely sprang from their environment, attempting to understand the causes of issues that had an impact on crop productivity. Thus, those in Tucumán initially worked on sugar cane, those in Mendoza researched grapevines, and the focus in Buenos Aires was potatoes. As groups grew and diversified, this initial link was often blurred; young researchers joining ongoing work never realized what the initial question had been.

In a country where agricultural products or their derivatives still make a significant contribution to GDP, it is sensible to resume the link to local agricultural problems. For this task, it will be essential to adopt a systemic collaborative approach.

 

Edith Taleisnik and Alberto Golberg

The authors of the book, Edith Taleisnik and Alberto Golberg.

 

To find out more about the book, read our recent news article here.

 

The book was edited by the SAFV . Printed copies can be purchased by request – please write to Lilian Ayala.

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Aquaporins capable of functioning as all-in-one osmotic systems

Caitlin Byrt

Dr Caitlin Byrt, University of Adelaide

This week’s post was written by Dr Caitlin Byrt, University of Adelaide, whose research focuses the roles of water-channeling proteins – aquaporins – and ion transport in plants.

 

Aquaporins are water-channel proteins that move water molecules through cell membranes. They are found in every kingdom of life. Cell membranes are semi-permeable to water, but often require more rapid movements of water across membranes; cells achieve this using aquaporins.

Aquaporins play key roles in your kidneys, which typically filter each of the three liters of plasma in your body 60 times per day – that’s 180 liters of plasma each day! Around three times your body weight in water passes through your own aquaporins each day.

Water on leaf

Around 50% of global rainfall passes through plants, and half of this moves through the aquaporins. Image credit: Dennis Seiffert. Used under license: CC BY-ND 2.0.

Aquaporin function

Have you got on the scales recently? Nearly 70% of your body weight is water. Water is the major component of cells in all of your tissues and this is the same for plants. Around 50% of global precipitation passes through plants, and half of this moves through aquaporins, so aquaporins account for the largest movement of mass for any protein on earth.

Often, in cell membranes, four aquaporin proteins will come together to form a tetramer to assist with the transportation of water across the cell membrane. There are types of aquaporins that only transport water, and others that transport glycerol, neutral acids or gasses. Historically, plant science literature has reported that the molecular structure of aquaporins prevents any charged particles, such as ions, from permeating. This is different in the animal world where there are reports of aquaporins that are permeable to ions. For example, in humans one of the most highly expressed aquaporins, AQP1, can function as a dual water and ion channel.

 

Testing plant aquaporins in frog cells

Recently, we observed that one of the most highly expressed plant aquaporins is permeable to ions when expressed in heterologous systems such as Xenopus laevis (frog) oocyte (egg) cells or yeast cells. This indicates that plants may also have types of aquaporins that can function as a dual water:ion channels.

 

Xenopus oocytes

The function of plant aquaporins can be studied by expressing them in different systems such as the Xenopus laevis oocyte cells pictured here. Photo credit: Dr Caitlin Byrt.

 

If you want to know if a particular plant aquaporin can function as a water channel you can test it by expressing the aquaporin in a laboratory oocyte expression system. We use a tiny needle to inject RNA coding for plant aquaporins of interest into the oocyte, and for control oocytes we inject the same amount of water. The oocytes are kept in a saline solution and we usually study them one or two days after injecting the RNA to allow time for them to synthesize the protein.

If you place oocytes expressing an aquaporin into water alongside control oocytes, then the aquaporin-expressing oocytes will burst much quicker than the controls because water rushes in through the aquaporin and causes the cell to swell rapidly. To explore whether a protein conducts ions, we use electrodes to measure the currents generated when charged ions pass across the oocyte membrane. We can also use ion-specific electrodes to explore which ions are transported.

 

AtPIP2;1 can transport water and ions

The plant aquaporin we studied is coded in the genome of the model plant Arabidopsis; it is a plasma membrane-located protein called AtPIP2;1. The AtPIP2;1 protein is known to be highly prevalent in root epidermal cell membranes, and it also functions in the guard cells of leaves, which act like tiny valves to regulate the uptake of carbon dioxide for photosynthesis and the release of water vapor.

 

AtPIP2 Arabidopsis

The model plant Arabidopsis has an aquaporin, AtPIP2;1, that can function as a dual water:ion channel. Photo credit: Dr. Jiaen Qiu.

 

We observed that AtPIP2;1 expression induces both water and ion (salt) movement across the cell membrane of oocytes. We know that the ionic conductance can be carried in part by sodium ions and that it is inhibited by calcium, cadmium and protons. This means AtPIP2;1 is a candidate for a previously reported calcium-sensitive non-selective cation channel responsible for sodium ion entry into Arabidopsis roots in saline conditions.

We are investigating the physiological role of ion permeable aquaporins in plants, and exploring how plants regulate the coupling of ion and water flow across key membranes. The regulation of ion permeability through plant aquaporins could be important in the control of water flow and regulation of cell volume. There is increasing discussion around the hypothesis that plants could drive water transport in the absence of water potential differences using salt and water co-transport, and this makes us wonder whether ion-permeable aquaporins may be involved. Testing whether ion-permeable aquaporins can function as an ‘all-in-one’ osmotic system in plants is an exciting new direction for research in this field.

 

Caitlin Byrt and Steve Tyerman

Dr. Caitlin Byrt, Professor Steve Tyerman and colleagues are investigating whether aquaporins permeable to ions are present in a range of different plant species. Photo credit: Wendy Sullivan

 

More information:

Byrt, C.S., Zhao, M., Kourghi, M., Bose, J., Henderson, S.W., Qiu, J., Gilliham, M., Schultz, C., Schwarz, M., Ramesh, S.A., Yool, A., and Tyerman, S.D., 2016. Non‐selective cation channel activity of aquaporin AtPIP2; 1 regulated by Ca2+ and pH. Plant, Cell & Environment.

Yool, Andrea J., and Alan M. Weinstein. New roles for old holes: ion channel function in aquaporin-1. Physiology 17.2 (2002): 68-72.

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