Quantitative analysis of auxin sensing in leaf primordia argues against proposed role in regulating leaf dorsoventrality (eLIFE)

This is an interesting paper that touches on several topics. Bhatia et al. address the question of how polarity in leaves is first established: essentially, which comes first, polarity in auxin concentration or polarity in gene expression? The authors conclude that in the earliest leaf primordia, there is no gradient of auxin sensing (suggesting perhaps no gradient in auxin). This finding contradicts several other recent papers, which is one of the reasons it is so interesting. Other studies used different reporters of auxin response, and slightly different methods for analysis, and also looked at slightly older leaves. The dialog between the reviewing editor and the authors, which like all eLIFE papers is included, provides insights into not only leaf polarity but also how scientific knowledge advances incrementally and by refining and sometimes contradicting the findings of others. (Summary by Mary Williams)  eLIFE 10.7554/eLife.39298