Sample tampering leads to plant scientist’s 7th retraction

Plant scientist Jorge Vivanco has earned his seventh retraction, after an investigation found data from soil samples were “intentionally fabricated by a third party.”

Vivanco and his former postdoc Harsh Bais made a name for themselves by discovering the secret behind a nasty invasive plant: It secretes a harmful form of catechin, which kills everything around it, suggesting it could serve as a new herbicide. The findings earned the researchers a story in the New York Times.

In the newly retracted paper, published in 2005, first author Laura Perry — then a postdoc at Colorado State University — further explored the role of the plant-killer, working with Vivanco as the last author. However, when a team working in the building next door had trouble finding catechin in their samples, Perry took another look, and concluded that her samples had been tampered with.

In other words, Perry told us:  

Someone put catechin into my samples.

Indeed, an investigation by CSU concluded that the concentrations of catechin in the field soil samples in Perry’s paper were intentionally fabricated by a “third party,” according to the retraction note in the Journal of Ecology.

A recent notice from the National Science Foundation’s Office of Inspector General concluded that Vivanco and Bais (who was not an author on the newly-retracted paper) had published research containing “falsification and fabrication.” The OIG recommended retracting a total of eight papers, but did not specify which ones in its report.

Back in 2006, just after the Journal of Ecology paper was published, Perry saw other researchers were having trouble finding catechin in their samples. As she continued to look at samples she modified her experiment, including controls that shouldn’t contain the compound. Here’s how she normally prepares the samples:

The way that the extraction process worked is you have these tubes of soil. I put methanol in…let them sit overnight…centrifuged them down…decanted the liquid and dried that.

When she added controls that contained only methanol through the extraction process — labeled blindly, so they weren’t distinguishable from the samples with soil — she found a “visible white powder:”

It was catechin. Milligrams of catechin…that was when I started to become concerned. Here was this catechin in my blanks, and what does that mean for my previous [work]?

At a lab meeting, she explained what she had found. After that, she could no longer find catechin in most of her samples the way she had before. And she was unable to find “any possible way” that it could have gotten there by accident. Her suspicion: During the initial project, someone added catechin to her samples, so that she would generate the data needed for the paper.

She said she doesn’t know who might have tampered with the data. But she suspects it likely happened during a window of about three days, in which the samples were sitting out overnight, or drying.

We contacted Bais, now at the University of Delaware, who categorically denied tampering with the samples:

I absolutely did not. I would also like to add that I was not a co-author or contributor to this paper.

Vivanco told us that he asked the Journal of Ecology to retract the paper “Dual role for an allelochemical: (±)-catechin from Centaurea maculosa root exudates regulates conspecific seedling establishment” in 2011:

This was an unfortunate and complex situation by which we suspected that one former member of my lab had been altering his research and the research of others to fulfill an agenda (self-promotion); this situation happened 12 years ago.  My university did an investigation and as a result of that investigation we undertook a process to retract some papers to clean the literature.  In this particular case, some of the co-authors did not agree with the retraction.

At the time, the request was declined by the journal. But earlier this week, it published a retraction note:

The Executive Editor and Managing Editor of the Journal of Ecology and authors Laura G. Perry, Ragan Callaway and Jorge Vivanco are retracting this article (Perry et al. 2005). A formal investigation by Colorado State University Research Integrity Office has found that (±)-catechin concentrations reported as being found in field soil samples in this article (Fig. 2) (Perry et al. 2005) were intentionally fabricated by a third party. The investigation therefore concluded that the results of this article are not reproducible and its scientific validity has been undermined.

The paper has been cited 84 times, according to Thomson Reuters Web of Science. Thirty of those citations were added since 2010.

We asked the Journal of Ecology why they declined to retract the paper in 2011. Executive editor David Gibson told us:

I am unable to comment on previous investigations but can confirm that, in this most recent case, the confidential information shared with Journal of Ecology led us to believe retraction was the appropriate course of action.

We asked Ellen Fisher, Colorado State University’s researcher integrity officer, for more information on the investigation, and if the school had shared information with the journal since 2011. She told us:

It is Colorado State University’s policy and practice to keep all aspects of any research misconduct allegations or procedures confidential.  As such, I am not in a position to share any of the information you have requested.

After Perry — now based at the US Geological Survey — couldn’t find catechin in her samples, she published those results in a 2007 Journal of Chemical Ecology paper with Vivanco, “Concentrations of the Allelochemical (±)-Catechin IN Centaurea maculosa Soils.” The discussion section notes that it’s the “most extensive study of soil catechin to date,” and failed to find catechin at the levels of previous experiments from Vivanco’s lab, but that the new results were in line with those produced in other labs:

The infrequency with which we detected catechin differs from many previous studies of catechin in C. maculosa soils in which catechin was detected in most samples regardless of site or date (Bais et al. 2002, 2003; Perry et al. 2005b; Thelen et al. 2005; Weir et al. 2006) but is similar to results from Blair et al. (2005, 2006), who reported no catechin or only trace amounts (<0.0001 mg g−1 ) on eight of 10 dates.

In the discussion section of that paper, the authors explain the potential issues with the previous work:

The high catechin concentrations reported previously also could have been caused by undetected catechin contamination. Throughout the present study, we included blanks that contained only methanol as negative controls with our samples during extraction…Given the potential for catechin contamination demonstrated by the current study, previous results not including blanks should be regarded with caution.

Perry told us that another one of her papers has been affected by the issues with catechin: a highly-cited review article, “The role of root exudates in rhizosphere interactions with plants and other organisms,” published in the Annual Review of Plant Biology in 2006. The authors posted an erratum in 2010, noting that later work found lower levels of the compound:

Recently, several of the original articles about knapweeds cited in this review have been retracted or amended, and we therefore felt it appropriate to revisit some of the topics presented…the Vivanco laboratory and other researchers have had difficulty re-isolating [compounds like catechin] from plants grown in vitro. Catechin has been detected in the soil sporadically according to recent reports (Blair et al. 2006; Perry et al. 2007), but there is no reliable way to determine if it was deposited there as plant exudates or was produced by an external source (i.e., microbes in the rhizosphere). This calls into question whether C. maculosa produces catechin in the field and therefore renders moot recent arguments over whether or not the compound has a biological role in invasions (Inderjit et al. 2008, 2009; Duke et al. 2009; Pollack et al. 2009; Thorpe et al. 2009).

Vivanco and Bais are authors on the article (Bais is the first author), but Bais is not listed on the addendum. The review article has 948 citations.

Hat tip: Rolf Degen

Like Retraction Watch? Consider making a tax-deductible contribution to support our growth. You can also follow us on Twitter, like us on Facebook, add us to your RSS reader, sign up on our homepage for an email every time there’s a new post, or subscribe to our new daily digest. Click here to review our Comments Policy.