R. Howard Berg, Ph.D.
Director, Integrated Microscopy Facility, Associate Member
The Integrated Microscopy Facility has a repertoire of instrumentation for live
cell light microscopy and electron microscopy, striving to furnish state of the art
imaging for plant scientists within the institute and regionally.
Structural studies in plant cell biology are commonly oriented The facility is moving forward in several projects using electron
to the use of fluorescence microscopy, optical sectioning, tomography to analyze cell structure at high resolution, in 3D,
and 3D and 4D digital reconstructions from these data. The with raw data acquired at the University of Chicago. These
resulting imagery is often outstanding and provides compelling include analysis of feeding tubes in root-knot giant cells, study
evidence for plant cell function. The Danforth Center’s of TMV in plant cells (in collaboration with Roger Beachy),
Integrated Microscopy Facility’s array of optical sectioning and modeling oil body formation in soybean cotyledons (in
light microscopes produce high quality data for users and collaboration with Eliot Herman).
collaborators. Services for transmission electron microscopy
(TEM) of plant cells are of specific note. Facility Director Howard
Berg has 35 years experience in TEM and, using instruments
purchased with support from the NSF, provides services
that include high pressure rapid freezing and transmission
electron microscopy using resin sections of freeze substituted
samples. A few examples of projects currently making use of
this technology follow.
In a project with the Cahoon lab (Dietrich et al. 2008),
TEM provided evidence that in plants with knockdowns in
sphingolipid synthesis membranes of the endomembrane
system are significantly altered, producing cells with little or no
endoplasmic reticulum or Golgi stacks in developing Arabidopsis
In collaboration with Chris Taylor and Gary Stacey
(University of Missouri-Columbia), TEM is being used to
phenotype soybean root nodule cell biology in various nodule
development-related gene knockdowns. Freeze substituted
nodule cells (please see the figure) are well-preserved relative
to traditional chemically fixed material. In Govindarajulu et
al. (2009), apyrase knockdowns are shown to produce empty
nodules unless ADP is supplied during infection, implying
a crucial role for this cell membrane enzyme in establishing
bacteroids within infected cells. Thin section electron micrograph of a soybean root nodule cell containing
Root-knot nematode-induced giant cells are nitrogen fixing Bradyrhizobium cells. This sample was prepared by high
complicated stories in cell biology. A collaboration with Chris pressure freezing and freeze substitution. The paper by Govindarajulu
Taylor produced the book “Cell biology of plant nematode et al. (2009) identifies an ATPase-like protein required for bacterial entry
parasitism” and a chapter therein on the cell biology of giant
into these cells.
Huifen Zhu, Guo-Jing Li, Lei Ding, Xiangqin Cui, Howard Berg, Sarah M. Assmann, Yiji Xia (2009). Arabidopsis Extra Large G Protein 2
(XLG2) interacts with the G beta subunit of heterotrimeric G protein and functions in disease resistance. Molecular Plant, In Press.
Manjula Govindarajulu, Sung-Yong Kim, Marc Libault, R. Howard Berg, Kiwamu Tanaka, Gary Stacey, Christopher G. Taylor (2009). GS52
ecto-apyrase plays a critical role during soybean nodulation. Plant Physiology, 149: 994-1004.
Dietrich, C.R., H. Gongshe, M. Chen, H. Berg, T.M. Dunn, and E. B. Cahoon. (2008) Loss-of-Function Mutations and Inducible RNAi
Suppression of Arabidopsis LCB2 Genes Reveal the Critical Role of Sphingolipids in Gametophytic and Sporophytic Cell Viability.
Plant Journal, 54: 284-298.
Fester, T., R.H. Berg, and C. G. Taylor. (2008) An easy method using glutaraldehyde-introduced fluorescence for the microscopic analysis of
plant biotrophic interactions. Journal of Microscopy, 231: 342-348.
Berg, R. Howard and C.G. Taylor (editors). (2009) Cell biology of plant nematode parasitism. Plant Cell Monographs, Volume 15, Springer:
Berlin. 273 pages.
Berg, R. Howard, Thomas Fester, and Christopher G. Taylor. (2009) Development of the root-knot nematode feeding cell. In: R.H. Berg and
C.G. Taylor (eds.), Cell biology of plant nematode parasitism, Springer, pp 115-152.
Silvester, W.B., R.H. Berg, C.R. Schwintzer, J.D. Tjepkema. (2008) Oxygen responses, hemoglobin and the structure and function of vesicles.
In: K. Pawlowski and W.H. Newton (eds.), Actinorhizal symbioses, Springer, pp 105-146.
Berg, R. Howard, Roger N. Beachy. (2008) Fluorescent protein applications in plants. In: Kevin Sullivan (ed.), Fluorescent Proteins, 2nd
edition, Methods in Cell Biology, Volume 85, Elsevier Inc.. pp. 153-177.
2008 Scientific Report The Donald Danforth Plant Science Center 29
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