Plant Sciences

Publication Analysis 2005-2011
by Kathleen Gransalke, Labtimes 04/2013

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Neglected in the US, plant sciences are still pretty strong in Europe, especially in Germany, which leads the nations’ ranking and provides the most-cited author. Hot topics are wide-ranging, from gene silencing over disease resistance to plant ecology.

Peacefully lock’d in itself, ‘neath the integument lay / Leaf and root, and bud, still void of colour, and shapeless / Thus doth the kernel, while dry, cover that motionless life. / Upward then strives it to swell, in gentle moisture confiding / And, from the night where it dwelt, straightway ascendeth to light. [from Goethe’s Metamorphosis of Plants, 1790]

Already more than 200 years ago, plants and especially their development from a seemingly dead particle to a blossoming miracle of life fascinated poets and scientists alike. Numerous poems were written in their name, not to forget the scientific insights they inspired. In recent times, though, research results from plant scientists have, in many cases, been simply swept under the carpet as we reported in the previous Lab Times issue (3-2013).

In her article, Karin Hollricher talked to many frustrated plant researchers who are dissatisfied with the current situation but amidst all this exasperation, there’s reason to celebrate. In May, biotechnologists commemorated “thirty years of transgenic plants”. In a celebratory comment in Nature, Wim Grunewald, Jo Bury and Dirk Inzé recently wrote, “Genetic engineering has revolutionized fundamental plant research and accelerated strategic improvements in crops. More than 170 million hectares of genetically modified crops were grown worldwide last year, to the benefit of the environment and society.”

Frustration and celebration

To give plant scientists the credit they deserve, we hereby dedicate an entire publication analysis to their discipline. We have done this once before. In issue 1-2007, we dissected all publications (articles, reviews and proceedings papers) authored by plant scientists between 2000 and 2006. Now, in the second round, we have attempted to highlight the years from 2005 to 2011. As always, to assemble the nations’ ranking, we relied on so-called ‘expert journals’. These journals, in contrast to multidisciplinary journals like Nature or Science, are characterised by a rather narrow topical scope and are listed in the “Plant Sciences” subject category of Thomson Reuters’ Web of Knowledge database, which we used for this publication analysis. To determine our top 30 most-cited plant scientists, however, we were able to access the entire journal database without any restrictions. It remains to be mentioned that, whenever available, we took advantage of the Researcher ID, now called Author Identifiers. Fortunately, many plant researchers revealed their identity willingly, facilitating our analysis and contributing greatly to its accuracy.

Now, let’s get started with a few numbers. According to Web of Knowledge, the three most important plant sciences expert journals are Annual Review of Plant Biology (IF: 25.962), Trends in Plant Science (IF: 11.047) and Annual Review of Phytopathology (IF: 9.875). During the period from 2005 to 2011, European plant researchers published about 55,000 articles in these specialist journals. Most of them, 6.2%, in the journal Planta Medica, followed by Plant Physiology (3%) and New Phytologist (2.9%).

And where exactly were these articles written? Mostly in Germany, as our nations’ ranking reveals. With more than 11,000 articles, researchers affiliated with German universities and institutes published almost twice as many articles as their peers in England, France and Spain. All four countries held their positions when compared to the plant sciences ranking from 2007. Beyond the top 4, there is also little movement. The biggest winners are Italy and Poland, gaining two spots, the Czech Republic and Portugal climbing three spots, and Turkey is now seven spots closer to the top. When it comes to the citations per article ratio, the UK clearly triumphs over the rest of Europe, with England achieving on average 17.6 citations per article and Scotland 16.9.

US scientists bad off

What were US plant scientists up to between 2005 and 2011? Not much it seems. Here, we have one of the very rare scenarios, where European scientists outdo their US colleagues across the entire board. More articles, more citations, more citations per article. Battling with drastically cut funding for years, US plant scientist are extremely bad off and our publication analysis reflects that bitter truth in naked numbers. Also Canada is pretty far behind this time, overtaken by not less than three countries: China, Japan and Australia.

Let’s now move to our top 30 most-cited authors of plant sciences in Europe. Altogether, seven scientists set up their research camps in Germany, more specifically in Max Planck Institutes in Jena, Potsdam and Tübingen. Other hotspots for plant research in Europe are Zürich, Ghent and Umeå. To single out true plant scientists in the vast pool of researchers working with plants, amongst other things, we came up with a few selection criteria. For ecologists, this meant that they had to almost exclusively work with plants; for plant pathologists, it meant we only considered those scientists to be suitable for our ranking, who approach the issue from the plant side, not the pathogen side, which brings us to the hot topics of plant sciences within our time frame.

Between 1999 and 2005, RNA interference was the most highly-cited topic. Papers about RNAi placed 1st and 4th in the top papers’ category and five RNAi researchers made the top 30. But science moves fast. No RNAi paper published between 2005 and 2011 gathered enough citations to be among the top five plant sciences papers and only four researchers working on post-transcriptional gene silencing entered our top 30 most-cited authors: Detlef Weigel (1st), Olivier Voinnet (7th), David Baulcombe (20th) and Hervé Vaucheret (26th).

With 122 articles, Weigel collected close to 9,000 citations. What’s the secret of his success? Most likely, the art of getting the mind off the job for a while as a video on youtube shows. In it, Weigel and his group members shake a leg or two to the sounds of Gangnam Style. Meanwhile, Voinnet, who spent his predoc time in the lab of David Baulcombe, recently won one of the much-sought after ERC Advanced Grants. Using the money, he intends to investigate ARGONAUTE 1 (AGO1), the central protein of miRNA function, in the root system of Arabidopsis thaliana. His ultimate goal: to better understand the connection between ­miRNAs, RNA silencing and metabolic pathways.

Speaking of metabolic pathways, plant metabolism is central to the research of quite a few top 30 plant scientists, like Alisdair Fernie (4th), who specialises in metabolite profiling; Joachim Kopka (21st), who develops in silico models for plant root primary metabolism and Thomas Moritz (30th), who directs the Swedish Metabolomics Centre and is interested in the metabolic variations occurring in response to hormonal and photoperiodic changes.

Argonautes, water channels and PSY

Another important line of research deals with crops. Jonathan Jones (3rd), expert of plant immunity and author of our most-cited paper, studies how plants, like potato, defend themselves against pathogens and parasites. Two other top 30 researchers, Fangjie Zhao (24th) and Steve McGrath (29th), work at Rothamsted Research, “the longest running agricultural research station in the world”. McGrath is interested in soil-plant systems, while Zhao deciphers the modes of action of a group of plant-specific water channels, the Nodulin-26 like Intrinsic Protein group, to, ultimately, decrease toxic accumulation of arsenic in rice.

Last but not least, there are quite a number of plant ecologists – e.g. Antoine Guisan (6th), Josep Penuelas (9th), Nina Buchmann (14th) and Petr Pyšek (15th) – who want to understand how plants cope with the climate change and the causes and effects of alien plant invasions.

Contrary to popular belief (among animal scientists), there’s a lot to expect from plant scientists in the coming years. Hopefully, funding agencies see it the same way.

And altogether now everybody in Gangnam… Weigel Style: RAD seq library, it’s not so scary / We won’t fall, we do it all / Pop. Genetics, we won’t sweat it / We won’t fall, we do it all / We’ll use any technique out there, we don’t caaaare / Workin’ Weigel style / Aaaaaaaa thaliana, work work work work, work, workin’ Weigel Style.

View the Tables: Europe...and the World, Most Cited Authors...and Papers

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Last Changed: 04.07.2013