Retraction Watch

Tracking retractions as a window into the scientific process

Authors retract plant biology paper after they realized sample was contaminated

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Plant biologists from China have retracted a 2013 paper in The Plant Cell after discovering that some of the plant material used was “inadvertently contaminated.”

According to the retraction notice, the authors believe the contamination affects the main conclusion of their paper.

In the paper, the corresponding author, Ying Fu, a professor at China Agricultural University in Beijing, and her co-authors reported a novel property of the protein complex AUGMIN Subunit 8 (AUG8). Fu and her colleagues found that AUG8 can bind to rod-shaped structures called microtubules, which regulate the transport of materials inside cells as well as a cell’s shape and structure.

Further observations yielded another interesting feature of AUG8: The protein could bind to plant microtubules in a special way—specifically at the “plus-end”—which had “a striking effect on the orientation of microtubules.”

But the authors found that the materials — which led them to conclude that AUG8 is a microtubule plus-end protein — had been contaminated by a known microtubule plus-end protein. According to the notice, none of the other experiments used the contaminated material, but given that the paper now lacks evidence to support the main conclusion, the authors requested a retraction.

Here’s the notice, published in September, for “Arabidopsis AUGMIN Subunit 8 Is a Microtubule Plus-End Binding Protein That Promotes Microtubule Reorientation in Hypocotyls:”

The authors request that this article be retracted due to the discovery of contamination of some of the materials used. In the original article, we reported that AUG8 localized at the plus end of growing microtubules. Unfortunately, we have found that the material used in this study was inadvertently contaminated by an Arabidopsis transgenic line expressing GFP-fused EB1b. Because EB1b is an established microtubule-binding protein localized at the plus end of microtubules, some of our observations using this plant material misled us to conclude that “AUG8 is a microtubule plus-end protein”. Now we realize that this conclusion lacks evidence.

We apologize and accept the responsibility for these errors. Except for the experiment used to show that AUG8 was localized at the plus end of growing microtubules, none of the other experiments used the contaminated material. Therefore we believe that all other results remain reliable, showing that the mean hypocotyl lengths of two complemented lines were shorter than that of the aug8 mutant. We have also demonstrated that the twisted epidermal cells of the aug8 mutant were rescued by the coding sequence of AUG8. Thus, the longer hypocotyl of the aug8 mutant was attributed to the loss of AUG8 function and the conclusion remains reliable that AUG8 is a microtubule associated protein that promotes microtubule reorientation by regulating the dynamic instability of microtubules. We are completing follow up experiments to verify the major findings and further clarify the role of AUG8 in microtubule reorientation.

All authors agree to this retraction.

The 2013 paper has been cited 19 times, according to Clarivate Analytics’ Web of Science,

Nancy Eckardt, senior editor at The Plant Cell, told us that the authors first contacted the journal about this matter on June 6, 2017:

Most of the findings of the paper seem to be fine, i.e. to the extent that AUG8 is a microtubule binding protein that promotes microtubule reorientation in hypocotyls – which is a significant finding …

We emailed and called Fu to ask how the contamination occurred and how the authors discovered it. We will update the post if we hear back.

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Comments
  • Lee Rudolph September 29, 2017 at 1:49 pm

    Who’s “Yu”?

    • Alison McCook September 29, 2017 at 2:08 pm

      Fixed, thanks!

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