Difference between revisions of "Part:BBa K2384005"

Latest revision as of 22:38, 1 November 2017

ACC deaminase

Usage and Biology

ACC deaminase can catalyze the ethylene precursor ACC, which affects the ethylene level at the time of plant growth.When the rhizosphere is planted into the seed coat or plant roots, it will synthesize and secrete IAA (auxin). The newly synthesized IAA will be absorbed by the plant to form endogenous auxin, which will stimulate the division and extension of plant cells The At the same time, IAA stimulates the activity of ACC synthase and converts S-adenosylmethionine to 1-aminocyclopropane-1-carboxylic acid. S-adenosylmethionine is involved in numerous intracellular responses, and some S-adenosylmethionine is converted to ACC and does not affect the level of S-adenosylmethionine.And ACC deaminase is one of the indicators to determine the ability of rhizosphere to promote plant growth. ACC deaminase use a wide range of metabolites will not have adverse effects on plant growth and other traits, and the enzyme in the animal body soon degraded, there is no one worried about the "safety", although with the activity of D-serine deaminase, did not show ACC deaminase activity.

Figure 1: ACC pathway

ACC deaminase contains two domains. Each containing an open subunit similar to the tryptophan synthase, rather than other pyridine-related phosphorylation-related enzymes, and the pyridoxal phosphate coenzyme is deeply buried in the protein molecule.

Increased ability of transgenic Arabidopsis thaliana expressing the ACC deaminase to accumulate Cd

ACC is the immediate precursor of ethylene in plants. The bacterial enzyme ACC deaminase is the only non-plant enzyme that metabolizes ACC; the enzyme converts ACC to α-ketobutyrate and ammonia. In our project’s phyto-route, we planned to use transgenic plant increasing ability of accumulating heavy metals. However, it is relatively hard to construct transformation system of hyperaccumulator——Sedum alfredii Hance, in this regard, we utilized transgenic model plant Arabidopsis thaliana under the control of 35S promoter as the role of phyto-route.

Figure 2: Primary root length	Figure 3: Fresh weight

The blue bar is non-transgenic Arabidopsis thaliana and the yellow bar is transgenic Arabidopsis thaliana. Each of the three transgenic Arabidopsis thaliana contained a single copy. We made of assay from primary root length and fresh weight those two aspects under Cd treatment. The short term effects of the presence of Cd was monitored following 15d in sterile growth plates. For the most part, the growth of the transgenic plants was inhibited to a lesser extent by the presence of the Cd than was the growth of the non-trans-formed plants. From fresh weight graph, we could see the ability of accumulation of transgenic plants are more better than NT. Under this circumstance, we just could say that in the lab condition, we got ideal results while in real life the conditions are much complex; soil environment, combined pollution and other stresses those effect factors are so complicated to captured.

Sequence and Features