Contemporary Citation Classics: Winkel-Shirley, B (2001) Flavonoid biosynthesis. A colorful model for genetics, biochemistry, cell biology, and biotechnology. Plant Physiology 126, 485-493. [1,839 citations]
A while ago, I compiled a list of Contemporary Citation Classics in Plant Sciences. My intention was not just to identify key papers in Plant Sciences but also to discover something about their conception, the authorsβ motivations in writing them, and why the authors thought their papers had become so well cited. Amongst these Contemporary Citation Classics was a fine review by Brenda Winkel (Virginia Tech, USA) that contained an eye-catching illustration of a metabolic pathway (Figure 1). I was curious how this iconic illustration had arisen, so I asked her to comment on its origins.
Philip White
Commentary by Brenda Winkel
One of my fondest memories of writing has to be putting words on paper, literally, in the library at the University of Nantes (France) in the summer of 2000. Left to my own devices while my husband conferred with Parasitic Plant Society colleagues, I started on the daunting task of plowing through the literature of the past decade or so for what would eventually become, βFlavonoid biosynthesis. A colorful model for genetics, biochemistry, cell biology, and biotechnologyβ. The review, published in Plant Physiology in 2001, somehow continues to attract growing numbers of citations.

Writing involved a rather different approach back then. Although PubMed had gone public four years earlier, it did not (and to some degree still does not) index the plant literature comprehensively; Web of Science was also in its infancy and not widely available; and Google Scholar was still to come. There was certainly no easy access to pdfβs, or formatted citations for that matter, from a computer in your office. Instead, there was something else that weβve lost, that particular serenity of wandering through the stacks, hunting for a certain βcall numberβ that led to shelves of heavy bound volumes or a pile of recently-arrived issues. Then the search for that one article was on, which, if it turned out to actually be of interest, meant the entire volume was lugged to the nearest copy machine β unless, of course, you were somewhere like Nantes, without your trusty βcopy cardβ and you were left to take notes right from the original. It was impossible to imagine the world in which we now find ourselves, one in which, wherever we are, we can instantly navigate through oceans of information, spinning webs of interconnected data and ideas that are reasonably certain to encompass most, if not all, of what is publicly available. How times have changed for the better in that regard. Still, when Iβm in need of a place to sit and think β and particularly when writerβs block strikes β I will often head for the top floors of Virginia Techβs Newman Library, where the book stacks have not yet made way for cavernous, noisy study lounges, and you can still find the dust-and-paper aroma and heavy silence of libraries past.
But enough nostalgia. It was not simply time spent taking notes and cogitating in a far-away library that is responsible for the longevity of that 2001 review. After digging through, I hesitate to admit, dozens of folders stashed in an old filing cabinet, I found the two-decades-old paper copies of the reviewersβ comments and a key suggestion that I remember so well. Reviewer #1 wrote, and I quote, βI think that the author could have made the pathway shown in Fig. 1 a bit less dry by showing a few pictures of the colors that each class of flavonoids provide to the different plant parts. From an instructional point of view, it may enrich the figure quite a lot.β Kudos to editor Ann Hirsch for agreeing. I recall being a bit baffled as to how to tackle the challenge, but thanks to Ann and several other generous colleagues (Erich Grotewold, Cathie Martin, and Francesca Quattrochio) who shared their beautiful photographs, as well as some technical corrections from both reviewers, this depiction of the flavonoid pathway, though now a bit out-of-date, remains pinned above student desks far and wide.
Iβm afraid that no such wistful memories surround another well-cited review, βFlavonoids and the Response to Stressβ, that was written the following year, and for good reason: the deadline coincided with travel to Cambodia for the adoption of twins. Digging through old emails I recall now that Ken Keegstra, who edited the volume with Mike Thomashow, was kind enough to give me a one-month reprieve. Somehow, with overnighting paper copies in February and the corrected proof in March, they still managed to get the chapter included in a volume published on June 1st. Lacking in beautiful figures – this one only has lots of arrows and some chicken wire – I have surmised that the focus on plant stress has kept this article on the radar, particularly now from an environmental perspective. However, a quick search on Web of Science shows that recent citations are still largely from a mix of plant biochemistry and biomedical sources. So, the formula for success remains a mystery in this case, though for sure having βflavonoidsβ and βstressβ in the title is a good startβ¦

Coincidentally, I am writing once again in France, on a nine-month research leave at the Laboratoire de Recherche en Sciences VΓ©gΓ©tales and University of Toulouse – Paul Sabatier. Although there is no library on site and I rely every day on electronic access to university collections, we are not far from the expansive libraries on the Paul Sabatier campus, as well as some of the most beautiful public libraries in the world, including the Bibliotheque DβΓtude et du Patrimoine, a short walk from our Toulouse apartment. I have to admit Iβve yet to make it to either one, however, having found that an office shared with three French faculty colleagues is another kind of very agreeable writing environment.
Contemporary Citation Classics by Brenda Winkel:
1 Winkel-Shirley, B (2001) Flavonoid biosynthesis. A colorful model for genetics, biochemistry, cell biology, and biotechnology. Plant Physiology 126, 485-493. [1,839 citations] https://doi.org/10.1104/pp.126.2.485
2 Winkel-Shirley, B (2002) Biosynthesis of flavonoids and effects of stress. Current Opinion in Plant Biology 5, 218-223. [993 citations] https://doi.org/10.1016/S1369-5266(02)00256-X