1021-4437/01/4806- $25.00 © 2001
Russian Journal of Plant Physiology, Vol. 48, No. 6, 2001, pp. 749–754. Translated from Fiziologiya Rastenii, Vol. 48, No. 6, 2001, pp. 863–868.
Original Russian Text Copyright © 2001 by Kudryavtseva, Borodenko, Zhiznevskaya, Kosenko, Sof’in, Izmailov.
are gram-negative bacteria belonging to the family
Rhizobiaceae. Root inoculation of leguminous plants
with strains of these bacteria results in the formation of
root nodules varying in nitrogen-ﬁxing efﬁciency. In
the course of nodule development, the rhizobia are
changed and converted into bacteroids located within
symbiosomes. The term “symbiosome” was coined by
Roth and Stacey . The symbiosome includes one or
several bacteroids, a peribacteroid space, and a peri-
bacteroid membrane (PBM).
The functioning of symbiosome depends on the
structure and properties of PBM and bacteroid mem-
brane (BM) and is controlled by protein and lipid com-
position of these membranes. The protein/lipid ratio
and the lipid composition determine the physical prop-
erties of membranes. The less saturated the FA residue
in the lipid bilayer, the higher the membrane ﬂuidity,
which is believed to affect the activity of membrane-
bound proteins . Changes in the membrane lipid
bilayer reﬂect plant cell responses to stress and favor
their adaptation to changing environment .
In its lipid composition, the mature PBM is appar-
ently similar to the microsomal membrane rather than
to the plasmalemma (PL). When compared to the PL,
PBM contains more phosphatidylcholine, but less
phosphatidylethanolamine. The content of sterols in
PBM of pea nodules was ﬁve times lower than in the
root PL. These results suggest that PBM exceeds PL in
its ﬂuidity, and this suggestion is conﬁrmed by the
greater unsaturation of FAs in PBM .
The FA composition of the endoplasmic reticulum
and the Golgi apparatus as possible PBM components
was determined in the soybean nodules inoculated with
various strains of
. It was shown that, in
their composition, the FAs of PBM were similar to the
FAs of endoplasmic reticulum rather than to those of
the Golgi apparatus .
According to our previous data, lupine nodule PBM,
in its FA composition, is similar to both the PL and the
bacterial cell membranes [6, 7].
In this work, our goal was to determine the effect of
the microsymbiont on the PBM biogenesis. To this end,
we analyzed the bound FAs of bacteroid membranes
and PBM using the symbiotic pairs, which differed in
their nitrogen-ﬁxing efﬁciency, and compared the
Effect of Inoculation with Various Rhizobia Strains
on the Fatty Acid Composition of Peribacteroid
and Bacteroid Membranes of the Nodule Symbiosomes
N. N. Kudryavtseva*, L. I. Borodenko**, G. Ya. Zhiznevskaya**,
L. V. Kosenko***, A. V. Sof’in*, and S. F. Izmailov**
*Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow, Russia
**Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya ul. 35, Moscow, 127276 Russia;
fax: 7 (095) 977-8018; e-mail: firstname.lastname@example.org
***Zabolotnii Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, Kiev, Ukraine
Received December 26, 2000
—The fatty acid (FA) composition of bacteroid and peribacteroid membranes was studied in the sym-
biotic pairs differing in their nitrogen-ﬁxing efﬁciency; the results are compared with the FA composition of
plasmalemma and free-living rhizobia. The experiments involved lupine plants inoculated with strains of
) and 400 (Nod
Fix L) manifesting high and low nitrogen-ﬁxing efﬁ-
ciency, respectively, and broad bean plants inoculated with strains of
and 87 (Nod
Fix L) of high and low nitrogen-ﬁxing efﬁciency, respectively. We showed that the rhizobia of the
strains 359a and 97 were able to form nodules with peribacteroid membranes containing FA mainly or exclu-
sively of plant origin. These strains were able to develop effective symbiotic pairs with legume plants. The use
of strains 400 and 87 resulted in the formation of nodules with peribacteroid membranes containing typical bac-
terial (branched-chain) FAs; these strains were characterized by an ineffective symbiosis.
Key words: Lupinus luteus - Vicia faba - Rhizobiaceae - fatty acids - membranes - peribacteroid membrane -
: BM—bacteroid membrane; FA—fatty acids:
index; PBM—peribacteroid membrane; PL—plasmalemma.