| Anthracnose caused by Collgtotrichum gloeosporioides is an important common disease in the production of Mango. The disease is controlled mainly on agricultural practice and fungicide application. Prochloraz is a common agent for control of mango anthracnose.In this study, the resistant molecular basis of C. gloeosporioides was investigated using a mutant (MCGM2) resistant to prochloraz, gernerated by xx; physiological characteristic was in comparison as well among prochloraz resistant isolate and other isolates carrying varied functional genes including a GFP transformants MCGG, wild-type isolate MCGW and CYP51 deleted transformant MCGD. The objective of this study is to explore the characteristic of C. gloeosporioides, and provide a theoretical basis for management of prochloraz resistance in C. gloeosporioides. The results are as follows:The complementary genenotype strain MCGD whose CYP51 gene was replaced by hygromycin gene was obtained using SOE-PCR technology, according to homologous recombination principle. Sensitivity of MCGD to prochloraz, either mycelium or conidia, was very strong, with EC50 of 0.4606 μg/mL and 0.376 μg/mL respectively; while EC50 for prochloraz-resistant mutant MCGM2 was 4.9844 μg/mL and 4.9703 μg/mL, EC50 for MCGW was 0.1191 μg/mL and 0.6622 μg/mL, respectively, the resistant factor of prochloraz on both EC50 is greater than 10. The results showed that significant difference in sensitivity to prochloraz. was observed between MCGD and MCGM2 strain carring different CYP51 genotype, which confirmed that mutated CYP51 gene was a determinant for the resistance of C. gloeosporioides to prochloraz.On colony morphology, MCGW, MCGM2 and MCGD all have white villous aerial hyphae; MCGW has dense aerial mycelia and obvious pink pigmentation; MCGD also has dense aerial mycelia but with little pink pigmentation; while MCGM2 has thin aerial mycelia and no pink pigment produced.The appressorium of MCGW is circular in dark gray; MCGM2 is circular in light gray; MCGD is u shaped in light gray; MCGG is oval in dark gray which is lighter than MCGW. MCGW has the largest size of appressorium whicle MCGM2 is in smallest size.For mycelium growth rate of four isolates is:MCGD(0.843 cm/d)>MCGG (0.796 cm/d)>MCGW (0.689 cm/d)>MCGM2 (0.617 cm/d); for sporulation, MCGW (20.37×106)>MCGG (17.6×106)>MCGD (10.79×106)>MCGM2 (6.12×106.); for conidia germination rate, MCGM2 is highest with 91%, MCGD is similar to MCGM2 which is 90.31%, while the lowest germination rate is MCGW with 85.71%; for the information of appressorium, MCGW has a best rate which is 97.93%, while MCGM2 has a worst rate thar is 40.2%.For osmotic sensitivity, the four strains with different genotypes have no significant difference in mycelium growth either under high glucose or high salt environments. All four isolates was not sensitive to high glucose environment where the colony diameter was greater than control, and protein content in mycelium was increased when the glucose dose was higher. All four isolates was sensitive to high salt condition where mycelium growth was inhibited and protein content in mycelium was decreased..The protein content in four genotypes are:MCGG (0.6721 mg/g)> MCGD (0.6712 mg/g)>MCGM2 (0.6189 mg/g)>MCGW (0.5222 mg/g). Fluorescent protein inserted isolate has more protein in mycelium.In conclsion, a major causal agent of MCGM2 resistant to prochloraz was the mutation in CYP51 gene. The fitness penalty was observed in MCGM2 due to the change of CYP51 genotype, compared to wild-type isolate MCGW.Mutated CYP51 leads to the change of physiological characteristics, Concrete performance in the reduce of adaptability and pathogenicity... |
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