Objective P. aegyptiaca is an all-parasitic weed, which mainly harms the melon crops and processed tomatoes in Xinjiang, resulting in a large amount of yield reduction, so it is important to select the microorganisms against the seed germination of the P. aegyptiaca for the biological control.To isolate biocontrol microorganisms with high inhibition on seed germination from the rhizosphere soil of processed tomato fields in Xinjiang, and their biocontrol effects were verified so as to provide biocontrol bacteria resources for the biological control of P. aegyptiaca in Xinjiang.

Methods The actinomycetes were isolated from soil by gradient dilution method, and the strains with high inhibition on seed germination of P. aegyptiaca were screened by culture dish method. The strains were identified by biochemical and 16S rRNA gene sequencing technology, and the biocontrol effect of the strains on P. aegyptiaca was verified by pot experiment.

Results 70 strains of actinomycetes were isolated from the rhizosphere soil of the processed tomato field. The germination inhibition rates of GA6-2, GB3-1, GB3-2, GB5-7 and GB5-8 were 100% when the fermentation broth concentration was 1×10⁶～1×10⁹ CFU/mL. The fresh weight of tomato plants treated with GB5-8 (12.86 g/ plant) and GB5-7 (11.56 g/ plant) was significantly higher than those by other treatments, and the number of nodules of P. aegyptiaca in the roots of tomato plants treated with GB5-8 (5.71 per plant) and GB5-7 (5.88 per plant) was significantly lower than those by other treatments. The biomass of P. aegyptiaca with GB5-8 (15.07 g) and GB3-1 (15.68 g) was significantly lower than those by other treatments. Based on colony morphology, physiological and biochemical characteristics and phylogenetic tree analysis, GB5-8 was identified as A. lurida.

Conclusion Amycolatopsis lurida GB5-8 can effectively inhibit the seed germination and reduce the parasite amount of P. aegyptiaca, which has the potential to control P. aegyptiaca.