enhancement of phosphorus uptake
TRANSCRIPT
Enhanced phosphorus uptake in transgenic
tobacco plants that overproduce citrate
Presented by group 1st
Out lines
• Role of Phosphorus.
• Problem of Phosphorus in Alkaline soil.
• citrate synthase [Pseudomonas aeruginosa], ACCESSION NP_250271, 1.7kbp.
• 35S CaMV Promoter
• Experimental Results
Abstract
• Phosphorus a most important nutrients
• Forms insoluble compounds
• Not available to plants
• 30 m tons of P fertilizer applied every year
• development of novel plant varieties
• That over produce organic acid
Introduction
• P an important nutrient after N
• Produce ATP, Nucleic acid and phospholipids
• Extremely reactive
• Only available at a narrow range pH values
• Highly immobilized
• React with AL, Fe and CA ,Mg in acid and basic pH respectively
• Required for enhancement of reproductive part
• Novel plants can reduce the use of synthetic p
• Citrate exudation can increase uptake of p in alkaline soil
• Citrate can displace P from insoluble complexes
• Increase 2 to 3 fold uptake of soil P
Experimental protocol
• Plant selection
• Biochemical analysis by srere method
• P-soluble experiments.
• Use of hydroxyapatite
• P determinations
• In vitro phosphate uptake experiments
• Rhizospheric changes in transgenic plants.
• Mycorrhizal colonization experiments.
Results & discussion
• Transgenic plants of tobacco were produced
• Having expression of citrate over producing sequence(Pseudornonas aeruginosa)
• 35s CaMV promoter
• By Agrobacterium-mediated transformation
• Analysis showed that citrate-overproducing lines (CSb-4 and CSb- 18)
• Produce 3 to 4 fold more citrate than control line
conti…
• CSb lines produce more yield in alkaline soil
• Control line unable to produce flower
• Experiment was conducted to confirm that it is due to citrate over production or not
• Plant were grown in control environment
• 3 treatments of water soluble P was applied (NaH2P04a t 22,44, and 108 mg kg-' soil).
• Analysis was made after 30 days and at flowering
• Significant differences between CSb and control
Conti…
• At high level of P no significant difference
• P concentration of leaves were determine
• To ensure that it was due to P acquisition
• Significant differences at flowering
• Other experiment was made
• Two treatment of soluble hydroxyapatite applied
• CSb lines produce more fruit biomass
• It was due to citrate excretion
Conti…
• For confirmation
• Plant grown in media having insoluble p
• Plants were grown in presence & absence of 1mM citrate
• No difference in CSb and control having citrate in media
• It indicate that citrate dissolve the insoluble P
• It was because of
• Rhizosphere acidification
• Reduction of Ca by the formation of calcium citrate
Conti…
• Symbiosis with mycorrhizal fungi also help in P acquisition
• It has additive effect with citrate in p uptake
• Our results demonstrated the importance of transgenic plants in acquisition of soluble P
• Which help to uptake reserve P
• We can meet P requirement by little application