Identification and Application of Streptomyces rapamycinicus CQUSh011 against Potato Late Blight

Using chemical fungicides is the main strategy for controlling
potato late blight (PLB), a devastating pre- and postharvest disease
caused by Phytophthora infestans, resulting
in environmental pollution and health risks. It is of great importance
to develop a biofungicide from microorganisms. Through isolating potato
rhizosphere microorganisms, CQUSh011 was found to have antioomycete
activity with strong inhibition on vegetative growth and virulence
of P. infestans. Morphological and
molecular identification indicated that CQUSh011 belongs to Streptomyces rapamycinicus. Based on genome, metabolome,
and HPLC quantification, rapamycin and salicylic acid were found to
be the two active metabolites against P. infestans. Continuous field trials showed that CQUSh011 has sustainable control
efficiency against PLB, and the efficiency was better when combined
with Infinito, along with an increased endophytic microbial community
and biodiversity in potato roots. The results demonstrated the potential
of CQUSh011 as a biofungicide against PLB and provided an alternative
strategy for reducing the application of chemical fungicides.