Microbial Tools for Phosphate Acquisition Flashcards
What do microbial inoculants do?
Have the potential to release P ions from P
What is solubilisation?
Conversion of INORGANIC P to labile P.
Caused by indirect enzyme processes, consequence of metabolism.
Organic acids produced by enzymes lower H and separate molecules.
What is mineralisation?
Breakdown of organic P to inorganic P by phosphotases which cleave the phosphoester bond.
How many phosphatase does one crop have?
2-8
What are the 2 enzyme classes of organic P?
- Phosphodiesterase
- Phosphomonoesterase
What are the 4 sites of phosphate localisation?
And what is it transported by?
- Extracellular
- Outer membrane anchors
- Periplasmic
- Cytoplasmic
Transported by phosphase and inorganic phosphorus transporters.
What does inefficient consumption of phosphatase mean?
Labile P is released outside the cell which increases Pi availability in the rhizosphere.
What are microbial tools for phosphate acquisition?
- Engineer plants
- Promote beneficial bacteria and enzyme production
- Enzyme addition to soil / feed
What can be used to increase P use efficiency whilst engineering plants?
- Fungal phytases
Phosphate acquisition
How is phosphatase activity quantified?
Colorimetric assay
Incubate cells with PNPP.
only works for promiscuous phosphatases. e.g. PhoX, PhoA, PhoD
When is pseudomonas putida active?
Under low phosphate
What is the PHO regulon?
Bacteria senses drop in concentration of labile P which causes a cellular response.
How can novel microbial tools be used?
Artificially induce P mineralising enzymes
Find novel microbes that do not have this regulation
Clone microbial enzymes into plants
What do bacteriodetes posses?
Unique phosphates
What does PaFA do?
Phosphate insensitive, produces large quantities of labile P
