Plant Molecular Biology 38: 1089–1099, 1998.
© 1998 Kluwer Academic Publishers. Printed in the Netherlands.
Desiccation- and abscisic acid-responsive genes encoding major intrinsic
proteins (MIPs) from the resurrection plant Craterostigma plantagineum
Jean-Baptiste Mariaux, Christine Bockel, Francesco Salamini and Dorothea Bartels
Max-Planck-Institut für Züchtungsforschung, Carl-von-Linn´e-Weg 10, 50829 Köln, Germany (
Received 10 October 1997; accepted in revised form 19 June 1998
Key words: abscisic acid, aquaporin, Craterostigma plantagineum, drought, plasma membrane intrinsic proteins
(PIP), tonoplast intrinsic protein (TIP)
Major intrinsic proteins (MIPs) are a family of channel proteins that are mainly represented by aquaporins in
plants. These are divided into TIPs (tonoplast intrinsic proteins) and PIPs (plasma membrane intrinsic proteins)
according to their subcellular localization. Homologues to PIPs and TIPs were isolated from the desiccation-
tolerant resurrection plant Craterostigma plantagineum by two approaches: ﬁrstly, a cDNA library constructed
from RNA of dehydrated C. plantagineum leaves was screened with an Arabidopsis thaliana Ath-PIP1b cDNA
probe and, secondly, a cDNA library was screened differentially to isolate early drought-induced transcripts. Ac-
cording to sequence homologies the isolated cDNA clones were grouped as follows: Cp-PIPa, Cp-PIPb, Cp-PIPc
Cp-PIPa, Cp-PIPc and Cp-TIP transcript accumulation was regulated by dehydration and abscisic acid (ABA).
Within the Cp-PIPa group transcripts were regulated either by drought only or by drought and ABA, indicating
that ABA-dependent and -independent signal transduction pathways lead to Cp-PIPa expression. Comparison of
Cp-PIPa expression in detached leaves and in whole plants suggested the involvement of a signal transmitted in
the whole plant in response to drought. Cp-PIPb transcript levels were constitutive in all organs tested.
Antibodies raised against a Cp-PIPA protein recognized a polypeptide with an apparent molecular mass of
28 kDa. Using these antibodies it was shown that both Cp-PIPA and Cp-PIPB proteins were localized to the
plasma membrane. The role of different members of the MIP group in the dehydration response is discussed.
A major problem encountered by plants during a pe-
riod of water deﬁcit is the maintenance of cell turgor.
Most of the adaptations to such conditions involve
mechanisms limiting water loss. These include mor-
phological or physiological mechanisms such as re-
stricting gas exchange to the dark phase (crassulacean
acid metabolism) or intracellular accumulation of ac-
tive solutes . A small group of plants, termed resur-
rection plants, shows extreme tolerance to dehydration
The nucleotide sequence data reported will appear in the
EMBL, GenBank and DDBJ Nucleotide Sequence Database under
the accession numbers: AJ001292 (Cp-PIPa2), AJ001293 (Cp-
PIPb), AJ001294 (Cp-PIPc).
and is able to recover completely upon rehydration
from severe dehydration . The genetic programme
involved in desiccation tolerance of vegetative tissues
in the resurrection plant Craterostigma plantagineum
is similar to that of seeds, in that both accumulate
late embryogenesis-abundant (LEA) proteins and sol-
uble sugars . The products of some of these genes,
as well as some carbohydrates, are thought to play
a role in protecting essential cell structures. In addi-
tion, several lines of evidence suggest that abscisic
acid (ABA) is important in triggering gene expression
during dehydration (see  for review).
Water transport through vegetative tissues is
thought to occur through transcellular and intercellu-
lar pathways [7, 33]. Major Intrinsic Proteins (MIPs)