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Banana genetics: (not-so-)Easy as ♫ABC, 123♫

Bananas, Genetics, Genomics No Responses »

Sep 202012

Getting to the core of a world-favourite dessert by unravelling banana’s origin and genealogy

GCP has enabled us to lay a credible foundation, which gave us a leg-up in the intense competition that typifies the genome sequencing arena” – Angélique D’Hont, CIRAD researcher

‘A’ is also for Angélique, as you will see once you read on…

An ‘A’ to our banana team for ushering in a new era in banana genetics. But let soup precede dessert, and don’t let this worry you: stay with us because we’re still very much on the topic and focused on bananas, which offer the whole range from soup and starters, to main course and dessert, plus everything else in between, being central for the food security of more than 400 million people in the tropics: around a third each is produced in Africa, Asia-Pacific and Latin America, and the Caribbean. About 87 percent of all the bananas produced worldwide are grown by small-scale farmers.

Moving back then to soup for starters, we’re serving up our own unique blend of alphanumeric banana ‘soup’, spiced with ABCs, a pinch of 123s, plus a dash of alpha and omega. Curious about the ABCs? Look no further:‘C’ for getting to the core of ‘B’ for bananas, and an ‘A’ score for our ace genomics team that did it.

Read how GCP seeded … and succeeded, in helping open a new era in banana genetics. An achievement by itself, and an important milestone on the road to unlocking genetic diversity for the resource-poor, which is GCP’s raison d’être.

So get your travelling gear please, for time travel with a ‘midspace checkpoint’ in Malaysia.

We start in 2004, when GCP commissioned a survey of diversity with microsatellites (or SSRs, simple sequence repeats) for all mandate food crops in the CGIAR crop research Centres. The objective of that study was to make new genetic diversity from genebank accessions available to breeders.

The endpoint is opening new research avenues to incorporate genes for disease resistance, with the added bonus of an article published in Nature online on July 11 2012, entitled The banana (Musa acuminata) genome and the evolution of monocotyledonous plants.

It may not be quite as easy as the ABC and 123 that The Jacksons promise in song, but we promise you that the science is just as exciting, with practical implications for breeding hardy disease-resistant bananas. Onwards then to the first leg of this three-step journey!

(Prefer a shorter version of this story in pictures? We’ve got it! Choose your medium between Flickr and Facebook)

1) Let’s go Greek: the alpha and omega of it

Rewinding to the beginning

The proof of the pudding is in the eating: we imagine that Jean Christophe Glaszmann just has to be saying “Yummy!” as he samples this banana.

Start point, 2004: “At that time, several research groups had developed SSR markers for bananas, but there was no coordination and only sketchy germplasm studies,” recalls Jean Christophe Glaszmann (pictured), then the leader of what was GCP’s Subprogramme 1 (SP1) on Genetic Diversity on a joint appointment with CIRAD. He stepped down as SP1 Leader in March 2010, and is currently the Director of a multi-institutional research unit Genetic improvement and adaptation of Mediterranean and tropical plants (AGAP, by its French acronym) at France’s Centre de ccoopération internationale en recherche agronomique pour le développement (CIRAD) in Montpellier.

Jean Christophe continues, “The reference studies had been conducted with RFLP* markers, a very useful tool but far too cumbersome for undertaking large surveys. We mobilised Bioversity International, CIRAD and the International Institute of Tropical Agriculture for the project. The process took time, but delivered critical products.” [*RFLP stands for restriction fragmented length polymorphism]

Fastforward to 2012, and gets just a little geeky…

Eight years down the road in 2012, the list of achievements is impressive, as evidenced by a suite of published papers which provide the details of the analysis of SSR diversity and describe how the data enabled the researchers to unravel the origin and genealogy of the most important dessert bananas. The origin of the predominant variety – Cavendish – suggested by the markers, involves two rounds of spontaneous hybridisation between three markedly differentiated subspecies. This scheme has been marvellously corroborated by linguistic patterns found in banana variety names as revealed in a paper published in 2011 in the proceedings of USA’s National Academy of Sciences.

But what else happened in between the start- and end-point? We now get to the really ‘sweet’ part of this bonanza for banana breeding!

It is now possible to conduct research to identify and incorporate genes for disease resistance within fertile populations that are close to the early progenitors, and then inter-cross them to re-establish sterility and obtain vigorous, disease-resistant and seedless progenies.

2) Of bits, bananas, breeding and breadcrumbs

Threading all these bits together for breeding better bananas is akin to following a trail of breadcrumbs, in which GCP played an important facilitating role: where in the germplasm to undertake genetic recombination is one key; and then, how to expedite incorporation of disease resistance and how to control sterility – so as to first suppress it, then re-establish it – is another set of keys that are necessary for proficient breeding.

Hei Leung in the lab at IRRI.

In 2005, Hei Leung (pictured), then Leader of GCP’s Subprogramme 2 on Comparative Genomics (until June 2007) on a dual appointment with the International Rice Research Institute (IRRI), recognised that with GCP’s main focus being drought tolerance in crops, Musa (the banana and plantain botanical genus) was somewhat on the fringe. However, it was still important that GCP support the emergence of banana genomics.

Hei is currently Programme Leader of Genetic Diversity and Gene Discovery at IRRI. He remembers, “We had a highly motivated group of researchers willing to devote their efforts to Musa. Nicolas Roux at Bioversity was a passionate advocate for the partnership. The GCP community could offer a framework for novel interactions among banana-related actors and players working on other crops, such as rice. The team led by Takuji Sasaki of Japan’s National Institute of Agrobiological Science, which had vast experience in rice genome sequencing, added the scientific power. So, living up to its name as a Challenge Programme, GCP decided to take the gamble on banana genomics and help it fly.”

Angélique D’Hont, CIRAD researcher and lead author of the article published in ‘Nature’.

Through several projects, GCP helped consolidate Musa genomic resources, contributed to the establishment of medium-throughput DArT markers as well as the construction of the first saturated genetic map. Additional contributions included the first round of sequencing of large chromosome segments (BAC clones) and its comparison with the rice sequence and a detailed analysis of resistance gene analogues. All these findings have now been published in peer-reviewed journals. And while publication takes time, it still remains a high-premium benchmark for quality and validation of results, and for efficient sharing of information. It reinforces the value of collaboration, builds capacity and gives visibility to all partners, thereby providing potential new avenues for funding.

Such was the case with bananas: using a collaborative partnership framework established with the Global Musa Genomics Consortium, animated by Nicolas Roux and now chaired by Chris Town, the community developed a case for sequencing the genome. With the mentorship of Francis Quétier, contacts were made with various major players in genomics, which in the end formalised a project between France’s CIRAD and CEA–Genoscope, funded by the Agence Nationale de la Recherche and led by Angélique D’Hont (pictured) and Patrick Wincker.

GCP contributed DArT analysis for anchoring the sequence to the genetic map. But, as stressed by Angélique, CIRAD researcher and lead author of the Nature paper: “Above all, GCP has enabled us to lay a credible foundation, which gave us a leg-up in the intense competition that typifies the genome sequencing arena. We were delighted that France rolled the dice in our favour by funding this work.”

3) Musa musings on the road to and from Malaysia checkpoint

Three years down the road, the team published a description of the genome of a wild banana from Malaysia.

Jean Christophe communes with a Musa plant, perhaps musing “What’s your family history and when will you be fully grown?”

Let’s drill down to some technical facts and figures here: the Musa genome has some 520 million nucleotides distributed across 11 chromosomes, revealing traces of past duplications and bearing some 36,000 genes. While most genes derived from duplication tend to lose their function, some develop novel functions that are essential for evolution; bananas seem to have an outstanding range of transcription factors that could be involved in fruit maturity.

And while the road ahead remains long, we now have a good understanding of banana’s genetic diversity, we have genomic templates for functional studies (a whole-gene repertoire) as well as for structural studies (the chromosome arrangement in one subspecies) aimed at unraveling the genomic translocations that could control sterility in the species complex.

It is now possible to conduct research to identify and incorporate genes for disease resistance within fertile populations that are close to the early progenitors, and then inter-cross them to re-establish sterility and obtain vigorous, disease-resistant and seedless progenies.

This is undoubtedly an inspiring challenge towards unlocking the genetic diversity in this crop, which is central to food security for more than 400 million people in the tropics.

Links

OPEN ACCESS BOOK CHAPTER: How to phenotype bananas and plantains for drought
Comparative and applied genomics
Comparative Genomics Research Initiative (maize, rice and sorghum)
Browse for Musa resources by keying in a search for ‘Musa’ on the GCP Product Catalogue
Journal articles from GCP research projects
SEE IT IN PICTURES & CHOOSE YOUR MEDIUM! Photo-story version on both Flickr and Facebook

GCP now, then, and after

Closing GCP, GCP, History No Responses »

Jul 032012

Where we’ve come from, where we are, and where we’re going

Travel with Dave from the beginning – and before the beginning – of GCP, and how the Programme will be brought to an orderly close. Dave also elaborates on the role of the Consortium Committee.

There’s no doubt that the Programme has enabled new partnerships and rekindled and rejuvenated old or existing partnerships amongst the different partners. Some of these are between the different CGIAR Centres and others are between these Centres and partners outside the CGIAR. These partnerships have been very fruitful.

People speak of GCP almost as if it were the 16th Centre. They speak of it with pride and respect. They understand the important role it can play.

GCP has a lot of credibility with national programmes. When you go to GCP’s General Research Meetings, there’s clearly a feeling of being part of the community, and that we are all improving our efficiency because of the Programme.

…I think it’s been one of the more successful Challenge Programmes.

Dave Hoisington (pictured) is the Chair of GCP’s Consortium Committee, and currently ICRISAT’s Director of Research. Dave was previously with CIMMYT, GCP’s host Centre. He has therefore been involved with GCP “since day minus one” in his words. “It’s equally exciting to be involved in the Programme’s closure, because I think that is even more important with regard to keeping its legacy alive.” Dave now walks us through the workings of the Programme today, its achievements and challenges, and what the early formative years were like….

What is the role of the GCP Consortium Committee?
GCP was set up as a multi-institutional endeavour. As an elaborate and broad partnership representing various interests, the decision at the Programme’s inception was to set up a committee representing all the key members from CGIAR Centres, developing-country programmes and advanced research institutes.

This Consortium Committee is ultimately the one that ‘owns’ GCP and oversees the basic functioning of the Programme to make sure that it is going in the right direction. We have an Executive Board which the Consortium appointed and it’s that Executive Board that Jean-Marcel [GCP Director] reports to. Because we set up the Board, they actually report to us.

…by having this Committee of the key players in research as well as an independent Board, we can all make sure GCP is going in the right direction, by giving voice to both the ‘players’ and ‘referees’.

Why have a Committee as well as a Board, and why seek broad partnerships?
During a mid-term review of GCP, the need for both a Committee and an independent Executive Board was recognised to give the Programme more structure and guidance. The Consortium Committee was established in 2008, and its precursor was the Programme Steering Committee.

GCP is not a research programme run by a single institute but really a consortium to enhance effectiveness. So, by having this Committee of the key players in research as well as an independent Board, we can all make sure GCP is going in the right direction, by giving voice to both the ‘players’ and ‘referees’.

There’s no doubt that the Programme has enabled new partnerships and rekindled and rejuvenated old or existing partnerships amongst the different partners. Some of these are between the different CGIAR Centres and others are between these Centres and partners outside the CGIAR. These partnerships have been very fruitful.

GCP’s tagline – ‘Partnerships in modern crop breeding for food security’ – what does this mean for you?
It really captures the essence of GCP – GCP is about creating opportunities for these partnerships. It’s about using a modern approach, a more integrated approach to breeding, to aid food security in the developing world.

Why is GCP’s work important?
The whole premise of setting up GCP 10 years ago was really the fact that our major crops were not registering the necessary increases in yield to meet food needs in developing countries. There are many reasons for that. The reason that became the main driving force for GCP was that we had not been able to tap the rich genetic diversity that exists for almost all of these crops. So the idea was to come up with mechanisms, methods, examples and proofs-of-concept that tap into this genetic diversity, and package it such that breeding programmes can integrate it into their operations. By so doing, we would broaden the horizon of breeding programmes for more rapid gains in yields and productivity in farmers’ fields.

Originally, the whole idea was mostly a proof-of-concept. Once we realised it could work, we realised that capacity needed to be built within national programmes since GCP’s scope was 10 years. So, the emphasis began to rightly shift from exploration and discovery to application and impact, buttressed by more training and capacity building within national programmes for sustainability. Genetic research was – and still remains – the backbone, but there has been a growing reliance on other tools including IT and molecular breeding. Now the technology has matured, costs have decreased, making it more viable for public research.

Unfortunately, we don’t have the alternative case of what it would have been like without GCP… but I think that many institutes within and outside CGIAR are trying to use genomics as a technology, and I think a lot of that can be traced back to projects that GCP supported.

What have been the major outcomes of GCP so far?
The greatest overall outcome is a stronger awareness and use of genomics in our research programmes across the board.

Unfortunately, we don’t have the alternative case of what it would have been like without GCP, which we could compare to, but I think that many institutes within and outside CGIAR are trying to use genomics as a technology, and I think a lot of that can be traced back to projects that GCP supported and encouraged.

In the early years, characterisation of genetic resources was very beneficial and it’s encouraging to see it still continues, with characterising genetic resources now considered routine.

What outcomes are you most looking forward to?
I think one of the most promising, and potentially important outcomes will be the adoption of GCP’s Integrating Breeding Platform.

‘Challenge’ is in GCP’s name. What are the major challenges that the Programme has so far overcome?
When GCP was being designed, there was no definition or case study for what a Challenge Programme had to do. The preliminary idea was that for projects to succeed and overcome major challenges, partnerships were key and no single institute could do it alone: they needed to do business differently, whether among the CGIAR Centres, or with partners outside the CGIAR. We had all these genebanks, all this diversity, genetic and genomic tools for some crops but not all crops. So, we put our heads together and asked ourselves, “What if we combine these modern molecular approaches used in one crop and apply them to another crop? Can we unlock the genetic diversity within it to improve quality and yield? How do we get all partners to work together towards a common goal?”

At the beginning, GCP had probably way too many facets and we were trying to move ahead on all the different fronts, so I think the mid-term reshaping and redefinition of the Programme helped it gain more focus to actually do what it set out to do.

GCP has built capacity, tools, methodologies and technologies. All these need to continue so as to increase and improve outputs and enhance outcomes.

What future challenges must the Programme overcome to remain sustainable?
Ensuring its achievements are sustained. While it was a time-bound programme from day one, the results and successes are not time-bound. They should be sustained and continued in other shapes and forms.

The challenge now is filtering these successes and figuring out how best to continue them. GCP has built capacity, tools, methodologies and technologies. All these need to continue so as to increase and improve outputs and enhance outcomes.

What are the main lessons learnt so far?
Partnerships are not easy. They take a lot of time. It’s one thing to write a proposal and say we will work together but it’s another thing to make that work effectively. I know GCP has had some instances where partners brought in have not been effective. I’m sure the GCP management has learnt lessons on how to deal with that.

People work together because they trust and respect one another and recognise and understand each other’s roles. They don’t view it as a competition. Some partnerships occur spontaneously, while others take time. They have to build trust, understanding and communication.

We’ve all learnt lessons from the research side, such as what does and doesn’t work. Focussing was a good lesson that GCP and all of us have learnt. At the beginning, we just spread ourselves too thin, trying to do too many things, making it very difficult to measure progress.

What is the most enjoyable aspect of your involvement with GCP?
I’ve been involved in GCP from day minus one. I used to be at CIMMYT and was involved in the ‘pre-pre-birth’ of the Programme, even before it had been conceptualised. Through the years since then, I’ve had different levels of engagement – and even periods of disengagement – but have always enjoyed my involvement.

It’s always been a good group of people working together, even when there have been problems. I think the Programme has scored high on successes. Jean-Marcel and his team deserve a lot of credit. They’ve really been able to keep the momentum going.

It’s equally exciting to be involved in the Programme’s closure, because I think that is even more important with regard to keeping its legacy alive.

People speak of GCP almost as if it were the 16th Centre. They speak of it with pride and respect. They understand the important role it can play.

GCP has a lot of credibility with national programmes… Ithink it’s been one of the more successful Challenge Programmes.

Jean-Marcel talks of the ‘GCP spirit’ and how successful partners share this spirit. What are your thoughts on this?
GCP definitely has a strong ‘entity’, although I’m not sure if this is a spirit! People speak of GCP almost as if it were the 16th Centre. They speak of it with pride and respect. They understand the important role it can play.

GCP has a lot of credibility with national programmes. When you go to GCP’s General Research Meetings, there’s clearly a feeling of being part of the community, and that we are all improving our efficiency because of the Programme.

I think it’s been one of the more successful Challenge Programmes.

Relevant links