UM professor's study probes the secrets of mealy bugs and bacteria

2013-07-06T22:00:00Z 2013-07-06T22:57:02Z UM professor's study probes the secrets of mealy bugs and bacteriaBy KRYSTI SHALLENBERGER for the Missoulian

Mealy bugs are a common sight on plants, sucking the sap for food.

But few people wonder what actually goes on inside their little gray bodies.

John McCutcheon, an assistant professor in the Division of Biological Sciences at the University of Montana, recently published a two-year study about citrus mealy bugs and their symbiotic relationship with two bacteria in the prestigious science journal Cell.

Though these bland insects fade from human eyesight, McCutcheon finds them fascinating because they don’t have a typical symbiotic relationship with the bacteria living inside them. Nor do they make amino acids, an essential nutrient in all animals, the most common way, McCutcheon said.

“There are 20 amino acids and most animals make 10 of them,” McCutcheon said.

The other 10 are usually supplied through the food animals ingest. But some, like the mealybug, need extra help when they can’t generate the necessary nutrients on their own or obtain them from their food supply, McCutcheon said.

So that’s where the two bacteria emerge in the amino acid assembly line. Known as Moranella and Tremblaya, these bacteria dwell within mealy bugs’ cells.

The bacterium Tremblaya is one of the smallest genomes ever discovered, containing only 120 genes, compared to E. coli, which holds 4,000, McCutcheon said.

But a closer look revealed that another bacterium, Moranella, resides in the Tremblaya cytoplasm.

“It’s a version of Russian nesting dolls,” McCutcheon said.

All three combine in the amino acid process, but also get more genetic assistance from an additional three genomes from the mealy bug, creating a complicated six-way relationship that McCutcheon hopes to examine further.

The study grew out of another paper published in 2011 that McCutcheon worked on. Filip Husnik, lead author and Czech Republic doctoral student, propelled the study further that summer, which resulted in the paper published in Cell.

It’s only been recently that scientists have looked at the complex relationships between animals, insects and bacteria, McCutcheon said. The deceptively straightforward process contains more questions that McCutcheon hopes to continue asking.

“We’re trying to figure out how the world works,” McCutcheon said. “We study the extreme relationships to explain generalities.”

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(2) Comments

  1. chaffincreek
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    chaffincreek - July 08, 2013 11:39 am
    johnny dollar: The study was cited in “Science Daily”, June 30, 2013. (

    It is also published: Filip Husnik, Naruo Nikoh, Ryuichi Koga, Laura Ross, Rebecca P. Duncan, Manabu Fujie, Makiko Tanaka, Nori Satoh, Doris Bachtrog, Alex C.C. Wilson, Carol D. von Dohlen, Takema Fukatsu, John P. McCutcheon. Horizontal Gene Transfer from Diverse Bacteria to an Insect Genome Enables a Tripartite Nested Mealybug Symbiosis. Cell, 2013; 153 (7): 1567 DOI: 10.1016/j.cell.2013.05.040

    I think a little research will answer your burning questions quite nicely.
  2. johnny Dollar
    Report Abuse
    johnny Dollar - July 07, 2013 10:18 pm
    This is fascinating John. Couple of questions:

    First - WHO funded your mealy bug project? Be specific please.

    Second - What benefit, product or social good came out of your research?

    Third - Did your papers, reports or studies WIN any AWARDS? Written in any journals?

    Please reply back John.......the so called reporter didn't ask any of these important questions, so post them here please.
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