|
Trichoderma is a widespread saprophytic fungi in soil, plant rhizosphere and foliage of a variety of plant pathogenic fungi with antagonism. Therefore be treated as a biocontrol bacteria to use, and caused many microbiologists and plant disease researchers attach great importance to. Study comparative study, compared to the control strain, the test strains were cultured to illustrate the main difference from the macro level of the colony, mycelium, cell morphology; environmental substances from fungi absorption, transport and utilization, shed light on adjustable selective absorption of environmental substances: synthetic type and amount of the desired product from the analysis to clarify the gene expression capacity and the effect of variation; provide technical parameters for the production practice. Using the test strains with the original strain point connected to the PDA medium plate, 30 ° C and cultured for 3 days, fungi cylindrical porphyritic naked eye, most of the plaque on the mycelium white plaque local pigment synthesis, showing pale yellow. In a liquid medium, Trichoderma mycelia intertwined together, spherical, which was a pale yellow. Ordinary optical microscope showed that the Trichoderma mycelium criss-cross, was the network-like. Scanning electron microscopy showed that the control strain the spores is substantially circular, rough surface, a slight depression in the middle, the test strain spores smooth surface, edges and corners clearly was the bread-like, some even a square, a slight depression in the middle. Determination of the fermentation broth residual sugar content, the test strains were cultured reducing sugar concentration in the liquid was significantly lower than the control strain, the test strains on the absorption of carbon source utilization rate is significantly higher than the control strain. Test during production of chitinase and cellulase, respectively, in colloidal chitin and sodium carboxymethyl cellulose as the sole carbon source in the corresponding enzyme production in the culture medium, determined by measuring chitinase enzyme Activity and enzymatic hydrolysis of the size of the ring, mutagenesis of the ion beam is derived, the gene expression of the enzyme production of the test strain than the control strains have been greatly enhanced, the enzyme activity of the test strain chitinase up 0.292U / ml, the control strain enzyme activity only 0.228U/ml therefore production The chitinase best medium in 1.0% yeast powder is added to the original medium; another enzyme preparation of cellulase of Trichoderma antibacterial, text of sodium carboxymethyl cellulose (CMC) as a sole carbon source of the cellulase production medium, to measure the enzymatic activity of the cellulase on the size of the circle of CMC hydrolysis, hydrolysis of the diameter of the circle of the test strain high in the control strains. . Through the tests show that the ion beam transformation of a positive impact on the biological characteristics of Trichoderma adapter after 20 generations, the genetic stability of Trichoderma no significant recession, increased Trichoderma selective absorption conversion and use of environmental substances; chitinase, cellulase activity were directed to improve. Summarize the above, the ion beam implantation plays a major role in the improvement of biocontrol strains of Trichoderma, improved strains than the control strain to improve the adaptability of the external environment, genetic traits than the control strain stability test strains on pH , enhanced tolerance of high temperature and osmotic pressure, all of these features show that the strain is more suitable for use as a biocontrol strains after transformation.
|