Gene expression
Expression of chlorophyll biosynthesis genes: To
understand the reasons for increased Chl biosynthesis (see above) inFbβCA overexpressor plants, the expression of a few selected
genes involved in Chl biosynthesis pathway was monitored. In comparison
with the VC, the message abundance of PBGS(porphobilinogen
synthase), involved in the synthesis of the pyrrole ring
porphobilinogen, was found to be 1.7 and 2.2 fold higher in CAx3 and
CAx5, respectively, than in the VC (Fig. 5a ). The transcript
expression of UROD (uroporphyrinogen decarboxylase), responsible
for the synthesis of coproporphyrinogen, was 2.0 and 2.2 fold higher in
CAx3 and CAx5 as compared to VC (Fig. 5a) . The gene expression
of PPOX (protoporphyrinogen oxidase), responsible for
protoporphyrin IX synthesis, increased 1.4-3 fold in the transgenics
(Fig. 5a ). The message abundance of CHLI(protoporphyrin-IX Mg-chelatase), one of the 3 genes responsible for Mg
insertion to protoporphyrin IX moiety, increased by 1.4 and 1.5 fold in
CAx3 and CAx5, respectively, than in the VC (Fig. 5a ). The
expression of light-inducible PORC (protochlorophyllide
oxidoreductase) was 1.8-2.5 fold higher in transgenics than in the VC
plants (Fig 5a) .
Expression of photosynthesis-related
genes : The gene expression of Lhcb1 and Lhcb2.1encoding components, of the light harvesting complex associated with
PSII, was 2.1-2.5 and 1.9-2.5 fold higher in the transgenics(Fig 5b) . The gene expression of Lhca1 and Lhca2(encoding components of the light harvesting complex associated with
PSI) increased by 2- 3.45 and 1.2 –1.4 fold in the overexpressors(Fig. 5b) . Expression of two core proteins PsbA, and, PsbD,
encoding photosystem II D1 and D2 proteins, was 3.2-3.6 and 1.7-2.3 fold
higher in the transgenics (Fig. 5b) . PsbO (encoding for
OEC33, the oxygen-evolving complex) increased, as compared to that in
the VC plants, by 1.4 and 2.4 fold in CAx3 and CAx5 as compared to VC