Abstract:
Objective To isolate and screen out bacteria from the soil of a fragrant pear garden that possess inhibitory properties against Alternariaalternata. We also aim to identify the species and classification status of these bacteria and test their effectiveness in inhibiting Alternariaalternata. Evaluated in vitro the potential of these antagonists to control the disease caused by Alternaria alternata.
Methods Using strain A923 of Alternaria alternata as the test pathogen, the antagonistic bacteria were isolated and screened by gradient dilution method and plate confrontation method. Meanwhile, the antagonistic species were identified by molecular data combined with morphological features, and their impact was evaluated against pear black spot by in vitro fruit evaluation experiment.
Results 15 bacterial strains were isolated, and the results of plate inhibition experiment showed that strains AW-28, 24-HS-12, Shi233 and Shi213 had better inhibition effect on the tested pathogens. These strains were identified as Bacillus mobilis(OR835289), Bacillus albus(OR835281), Paenibacillusottowii (PP762202), and Pseudomonas chlororaphis (PQ241669) respectively. Strains AW-28 (inhibitory rate 75.01% ± 2.07%) and 24-HS-12 (inhibitory rate 73.37% ± 1.71%) with good bacteriostatic effect were further selected for in vitro fruit control test. The results showed that the control effect of spraying antagonistic fermentation solution for 7 days could reach the effects 43.82% and 32.58%.
Conclusion Strains AW-28 and 24-HS-12 have certain control potential, which provides a theoretical basis and potential bacterial biocontrol resources for the subsequent biological control of this disease.
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