Agriculture Reference
In-Depth Information
R3-1
was 2.0-fold higher than those of the wild-type. The
R3-1
showed
phenotypes of seedlings standing in the upward direction and the first leaf
opening was very fast. In the case of wild-type the seedlings showed clear
bending by fook formation. The
R3-1
mutant also showed slow growth in
the upward direction, showing low response to negative gravitropism.
The
R3-1
mutant showed a high temperature-resistant phenotype
compared to that of wild-type, when the seedlings were grown at 35C
under illumination. The phosphorylation of soluble fractions in the wild
type and the
R3-1
of leaves of field grown plants showed an increase in
the high-molecular weight histidine kinases with molecular masses of 40,
48, 63 and 70 kDa in the mutant, and in the case of membrane fractions
63 and 72 kDa. The increase in the phosphorylation of these high-
molecular weight histidine kinases may be the result of the
photoresponses partly via the phytochrome, because the phytochrome
mediated increase in the phosphorylation of NDPK2 was established. The
molecular mechanisms including singlet oxygen and the resulting calcium
release to cytosol from vacuole, microsome and plasma membranes were
discussed.
Keywords
: High temperature resistant, High yielding, Singlet oxygen (
1
O
2
),
Super oxide (O
2
-
), Phytochrome mediated photoresponse, High and
low-molecular weight histidine kinases, Unsaturated fatty acids
I
NTRODUCTION
Global warming caused by the increase in the concentration of
atmospheric CO
2
by the over-usage of fossil fuels such as petroleum, coal and
natural gases, and also the over production of cement by heating CaCO
3
promoted us a critical research to accelerate fixing atmospheric CO
2
as
carbohydrates providing bio-fuels such as bio-ethanol, bio-oil and bio-gases by
use of crop plants (Hasunuma et al., 2011).
To increase the rates of photosynthesis by crop plants we must develop
methods to create high yielding mutants of crop plants. We have reported the
isolation of an ROS-resistant mutant of
Pisum sativum
cv.‟Alaska‟ (Haque et
al., 2008; Haque et al., 2010), harboring point mutations in small-histidine
kinases of transit peptide-NDPK2 Ile12Leu and Glu205Lys, and leader
sequence-NDPK3 Pro45Ser (Haque et al. 2010). Transit peptide-NDPK2
localized in cytosol and on the surface of chloroplast showed a two-fold-
increase in the phosphorylation and enzymatic activities by the two point
mutations, Ile12Leu in the transit peptide, and Glu205Lys in the C-terminus
