Antagonism of Rhizosphere Streptomyces yangpuensis CM253 against the Pathogenic Fungi Causing Corm Rot in Saffron (Crocus sativus L.)

Abstract

Plant diseases lead to a significant decline in the output and quality of Chinese herbal medicines. Actinomycetes play a vital role in the rhizosphere ecosystem. This is especially true for Streptomyces, which have become a valuable biological control resource because of their advantages in producing various secondary metabolites with novel structures and remarkable biological activities. The purpose of this study was to isolate an effective antagonistic actinomycete against the pathogen of corm rot in saffron. An antagonistic actinomycete, CM253, was screened from the rhizosphere soil samples of Crocus sativus, by plate co-culture with four pathogenic fungi (Fusarium oxysporum, Fusarium solani, Penicillium citreosulfuratum, and Penicillium citrinum). CM253 inhibited the growth and development of F. oxysporum hyphae by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Furthermore, by analyzing the degrading enzyme, the growth-promoting performance, and the whole genome of strain CM253, it was identified as Streptomyces yangpuensis, which produces NH3, protease, glucanase, cellulase, IAA, and ACC deaminase. In addition, 24 secondary metabolite synthesis gene clusters were predicted in antiSMASH. We identified genes encoding 2,3-butanediol; methionine; isoprene (metH, mmuM, ispEFH, gcpE, idi, and ilvABCDEH); biofilm formation; and colonization (upp, rfbBC, efp, aftA, pssA, pilD, fliA, and dhaM). Above all, S. yangpuensis CM253 showed the potential for future development as a biocontrol agent.

Biological Control of Phytopathogens: Mechanisms and Applications

“…The biocontrol of pathogenic fungi-based Corm Rot disease of Saffron ( Crocus sativus L.) was demonstrated by a novel rhizosphere actinomycete, Streptomyces yangpuensis CM253 [ 7 ]. The antagonistic actinomycete inhibits the growth and development of, e.g., Fusarium solani .…”

Developing Plant-Growth-Promoting Rhizobacteria: A Crucial Approach for Achieving Sustainable Agriculture

“…Bacillus subtilis secretes chitinase, protease and cellulase, which can lyse Rhizoctonia solani, among other enzymes [22]. Other enzymes, such as glucanase, xylanase and pectinase, were also found to be responsible for inhibiting mycelial growth [23][24][25].…”