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EDITORIAL

21st Century Plant Biology: Viva la Revolución?

raj{at}ag.arizona.edu

Apple's recent introduction of the iPhone reminds us of the essential distinction between incremental and revolutionary change. Incremental improvements usually result in linear gains in the utility of tools and products, whereas truly revolutionary developments may fundamentally change the way people interact with the world, often by bringing together existing tools and information in a way that creates newly emergent properties and novel capabilities. For instance—to continue with examples from Apple—the marriage of the mouse to the desktop computer to create the Macintosh, of the click wheel to a hand-held computer to create the iPod, and perhaps now of a "multitouch" display to a telephone- and Web-enabled version of the iPod to create the iPhone are wonderful examples of how creativity and insight, properly applied, can change the way we live and work. Of course, these revolutionary products were also made possible by a revolution of a different type (i.e., one based on continuous incremental improvements like the enhanced power of microprocessors that eventually open up new possibilities).

In the late 20th century, biologists witnessed revolutionary developments of both types: recombinant DNA, the polymerase chain reaction, and the sequencing of whole genomes. The first two arose from insights that brought things together in a new way to create a powerful new tool, whereas genome sequencing is an example of numerous incremental improvements producing logarithmic increases in efficiency—as if the technology itself were being PCR-amplified—until new possibilities emerge that previously had been impractical. It is widely anticipated that this process will march onward until the complete genome sequence of any individual (person or plant) will be available in a quarter century for about the present cost of an HIV test.

Biology is now at the threshold of an even greater revolution, built on a foundation of numerous individual insights creating novel tools and concepts that are being brought together in myriad ways such that new properties and new ways of doing science emerge. The key point is that the efficiency of biology research as a whole is increasing not merely linearly, but logarithmically, and in consequence, the number of these new tools and concepts is also increasing logarithmically. The result, within our lifetime, will surely be a biological research enterprise with capabilities that we can hardly imagine.

At some point in their careers, today's students will undoubtedly possess truly revolutionary computational tools capable of generating a "virtual plant"—here, we may as well call it an "iPlant"—a representation extracted from all extant knowledge about plant biology that can be customized to "grow" and "develop" under any user-specified conditions and to "evolve" through user-specified "mutations." The iPlant will not eliminate experimental work with living plants but will become an essential tool that experimental plant biologists will use in conjunction with their experiments to analyze and interpret results. Plant biologists will routinely run simulations, both to test and to generate hypotheses, which will then be subjected to experimental test with living plants. Importantly, users will be able to specify what knowledge they believe is or is not reliable so they can "personalize" their iPlant. And, of course, the iPlant itself will be able to evolve as new information is acquired and shared. Biologists will be theorists at the same time they are experimentalists; theory will be interwoven so tightly with practice that we cannot easily foresee what it will be like to be a plant biologist, to be so intimately connected to and immersed in the biology of a plant. Inevitably, our students' students will take their iPlants for granted in much the same way as our students now do their iPods—and more aptly, their laptops. Future students will remark to their mentors, "I just can't imagine how you could have done research without an iPlant!" shaking their heads in disbelief. "It must have been awfully slow...Wasn't it really, really boring?"

Of course, the iPlant is only one of many possibilities, but hopefully serves to illustrate how different the conduct of biology research is likely to be a quarter century from now. Whole-genome genetic-association studies are already becoming a reality through chip-based resequencing technologies (http://msqt.weigelworld.org/), and with the inevitable cost and efficiency gains that will be achieved over time, the implications of such analyses, both for genetic research and for crop breeding, are mind-boggling. Genetic improvement of crop plants will be transformed into a high-precision information science with little resemblance to what it was a quarter century ago.

Importantly, the coming revolution in crop breeding will not only be exciting for the scientists involved, it is also essential if society is to successfully address the immense challenge of producing sufficient food, fiber, and energy for an eventual population of some nine billion humans, each aspiring to live the equivalent of a present-day European lifestyle with respect to the abundance and quality of food, living conditions, and opportunities for recreation.

Although the transformation of biology through its marriage to the computer and information sciences creates seemingly endless possibilities for biologists and for humanity, there will still remain limits that must be understood and respected. Some of these are physical in nature: For instance, there is a finite amount of space available for agriculture, cities and towns, and natural ecosystems. There are physical laws that rule the cycles and fluxes of energy, heat, elements, and molecules on both local and global scales. Agriculture cannot be expanded to produce as much energy and as much high quality food as we might like without negatively impacting natural ecosystems and global processes that are beyond our full control and upon which humanity's survival obviously depends, as was noted by Norman Borlaug in his Perspectives of Science Leaders lecture at ASPB's Annual Meeting in 2002 (http://www.aspb.org/downloads/borlaug.rm).

Regarding physical limitations, it is being hotly debated how and whether the planet will be able to sustain anything close to the needs, expectations, and desires of the nine billion humans who will inhabit the planet by mid century. Regulation of planetary temperatures is an emergent property of a complex network of interactions among numerous systems and inputs with both positive and negative feedback characteristics that we are only beginning to understand. The latest consensus scientific assessment of the current understanding of climate change (Intergovernmental Panel on Climate Change 4th Assessment Report; http://www.ipcc.ch/) concludes at least a 90% probability that the recent 50-year global warming is human-caused and suggests a further 1.8 to 4°C warming this century due to increasing atmospheric concentrations of greenhouse gases (compared with a 5°C warming since the last ice age). Such a rapid change may have unpredictable and unprecedented consequences. The IPCC estimates are cautious, and one has to acknowledge that there also exists some possibility that James Lovelock and others are correct when they warn that these greenhouse gas concentrations could reach a "tipping point" that triggers a large, sudden shift in temperatures to a new steady state "perhaps six to eight degrees hotter than now" and perhaps within the lifetimes of the current generation of plant biology students.

Despite the wide range of uncertainties, it is important to ask how humanity's activities and needs will be balanced with the physical realities of our planet's regulatory systems and whether balancing will occur through foresight and preparation or whether we will allow it to be imposed as a consequence of an unpredictable, drastic change in climate, forcing a rapid decline in agricultural productivity and the human population. From this perspective, it is difficult not to wonder whether the revolution that most affects the well-being of our grandchildren will be the revolution in biology research discussed above or instead the kind of revolution that could arise out of severe economic dislocation and result in extensive social disintegration.

Thus, despite the exciting possibilities that abound everywhere in biology, we cannot merely sit back and "let the good times roll," sipping our cappuccinos and playing with our iPlants. We must also pay careful attention to how plant biology fits into the world around us. At least as important as the iPlant will be the iEcosystem, which will integrate diverse iOrganisms, and the iPlanet, which will be comprised of diverse iEcosystems. Which problems the readers of The Plant Cell choose to explore in their plant biology research will have an impact on the whole of biology, whether they choose to think about it or not. The conversations in the hallways and lunchrooms of our research laboratories, in the walkways and gardens of our campuses, and at the coffee breaks and pubs at our scientific conferences must not be limited to realizing our dreams of understanding plants well enough to create and use an iPlant, they must also extend to trying to understand our place in the world as biologists, our impact on it—positive, negative, or indifferent—and how we might use our knowledge, skills, and talents most effectively in the full context of planetary biology.

What will be the consequences of the conversion of large tracts of agricultural lands from food and fiber to energy production and to cities, towns, and highways? What will be the consequences of the continuing conversion of natural ecosystems to agricultural lands, reducing the resiliency of natural processes and cycles that maintain our environment within a livable range of temperatures? How will choices of crops, cropping systems, and land uses affect carbon dioxide and methane levels in the atmosphere? How will they impact natural ecosystems, locally and globally?

Though the answers lie partly in the realm of politics and societies, plant biology can and will contribute greatly to their answers. These answers, in turn, will help us to find answers to bigger questions that are especially difficult, including what size human population will be sustainable beyond the 21st century and beyond the 3rd millennium? Will it be possible for humanity to participate harmoniously and effectively in the regulation of planetary environmental conditions? If we find ourselves burdened with such an awesome responsibility, will we be able to understand and respect the limitations of physical and biological realities well enough to provide effective biological solutions such that all people can lead fulfilling lives, nourished and enriched by the natural world to which we all belong? This is perhaps the largest, most important question of our time, one that would seem to transcend all others and on which the future health and prosperity of humanity ultimately depends. How will plant biologists contribute to its answer? Merely by happenstance or with vision and foresight? What is your answer?

Footnotes

www.plantcell.org/cgi/doi/10.1105/tpc.107.190280

This Article Full Text (PDF) All Versions of this Article: 19/2/389    most recent tpc.107.190280v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Jorgensen, R. Search for Related Content PubMed PubMed Citation Articles by Jorgensen, R. Agricola Articles by Jorgensen, R.