Abstract:
Pigeonpea (
Cajanus cajan
(L) Millsp.) is a drought tolerant legume widely gr
own in the
arid and semi-arid tropics of the world which posse
sses a deep and extensive root system
that succors a number of important physiological an
d metabolic functions to cope with
drought. Application of available functional genomi
cs approaches to improve
productivity under water deficit requires a better
understanding of the mechanisms
involved during pigeonpea’s response to water defic
it stress. In order to identify the genes
associated with water deficit in pigeonpea, Suppres
sion Subtractive Hybridization cDNA
library was constructed from polyethylene glycol-in
duced water deficit young root tissues
from pigeonpea and 157 high quality ESTs were gener
ated by sequencing of 300 random
clones which resulted in 95 unigenes comprising 37
contigs and 58 singlets. The cluster
analysis of ESTs revealed that the majority of the
genes had significant similarity with
known
proteins
available
in
the
databases
along
wit
h
unique
and
hypothetical/uncharacterized proteins. These differ
ential ESTs were characterized and
genes relevant to the specific physiological proces
ses were identified. Northern blot
analysis revealed the up regulation of ornithine am
inotransferase, cyclophilin, DREB and
peroxidase. The differentially expressed sequences
are conceived to serve as a potential
source of stress inducible genes of the water defic
it transcriptome and hence may provide
useful information to understand the molecular mech
anism of water deficit management
in legumes.
Keywords
:
cDNA, drought,
PEG, Polyethylene glycol.
