ANNUAL REPORT - Department of Biotechnology

medicinal plant Catharanthus roseus: The ongoing
work on Catharanthus roseus concerns (a) analysis
of genetic and epigenetic regulation of the plant
growth and development traits and terpenoid indole
alkaloid metabolism, and (b) construction of new
horticultural varieties and genotypes where roots,
stem and leaves are rich in one or more
pharmaceutically important alkaloids. Importantly, a
gene responsible for the peroxidase enzyme called
CrPrx was cloned and sequenced and found to be
present in multiple copies in situ and expressed in
multiple organs, with highest specific activity in the
roots, in a stress responsive manner.
3) Functional genomics in other plant systems:
a) Genetics of compound leaf morphogenesis in
Pisum sativum: Bulked Segregant Analysis (BSA)
allowed mapping of pea leaf morphogenetic genes
MULTIFOLIATE PINNA (MFP) and LEAFLET
DEVELOPMENT (LLD) in respect of molecular
markers and the latter gene could be placed on the
linkage group 3 of Pisum sativum.
b) Analysis of light signal transduction pathway in
Arabidopsis thaliana: ZBF2 (a bZIP transcription
factor; GBF1), another Z-box binding factor has been
recently characterized in Arabidopsis. The DNAprotein
interaction studies revealed that ZBF2/GBF1
interacts with the Z- and G-box light responsive
elements of light regulated promoters. Genetic
analyses of gbf1 mutants and over-expression
studies demonstrated that GBF1/ZBF2 acts as a
repressor of blue light mediated inhibition in
hypocotyl elongation, however it acts as a positive
regulator of cotyledon expansion during
photomorphogenic growth. Further studies
demonstrated that GBF1/ZBF2 is a unique
transcriptional regulator of light signaling in
Arabidopsis. Based on the knowledge about the
roles of ZBF-1 and -2 genes in Arabidopsis thaliana,
a project has been initiated to clone and hyper
express corresponding genes in tomato for the crop
yield.
c) Genes for increasing shelf life in fruits and
vegetables: The determining factor in the postharvest
deterioration of fruits and vegetables is the
rate of softening, which influences shelf-life and
limits transportation and storage. The presence of
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high activity of α-D-mannosidase and βhexosaminidase
in ripening fruits and vegetables
suggest their possible role in softening process.
Thus, α-mannosidase and β-hexosaminidase have
been identified as target genes for genetic
engineering to increase shelf life of fruits and
vegetables. Towards this, the genes have been
cloned from tomato as well as capsicum plants and
their RNAi analogues have been synthesized for
genetic manipulations to understand the roles of
counterpart enzymes.
d) Oxalate deficiency imparts fungal resistance:
Oxalic acid, besides being a major antinutrient factor
in many crops, the degradation of oxalic acid in
transgenic plants should lead to fungal tolerant.
Towards this, an oxalic catabolizing enzyme oxalate
decarboxylase from edible mushroom, Flammulina
velutipes has earlier shown to protect transgenic
tobacco and tomato from fungal diseases. Thus,
fungal tolerant OXDC tomato was developed which
have successfully completed to restricted plot trial
experiment.
e) Characterization of mitogen activated protein
kinases (MAPK) in rice: Twelve genetic components
of MAPK cascade in rice, 8 MAPKs and 4 MAPKKs
were characterized for their expression in response
to heat, cold, salinity and drought conditions.
f) Comparative genome analysis among cereals:
Comparative genomics investigations on wheat,
foxtail millet, tomato, chilies, Medicago and Brassica
were initiated and QTLs for grain weight were
mapped on wheat genome. In addition, comparative
genomics techniques are being used to recover
paralogues of DREB (CAP2 included) genes of
chickpea in the drought tolerance of foxtail millet
Setaria italica for their characterization.
D) Expressed Sequence Tag (EST) sequencing:
Progress has been made in the EST database
development by sequencing of 12000 cDNA clones
in chickpea and periwinkle.
E) Tomato Genome Sequencing:
As a part of international SOL initiative, the Centre
has already completed sequencing and annotation of
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