title: [Identification and antagonistic activities of an endophytic bacterium MGP3 isolated from papaya fruit].
abstract: OBJECTIVE
  Postharvest decay resulted from anthracnose caused by pathogens Colletotrichum gloeosporioides and blight diseases caused by Phytophthora nicotianae leads to significant loss of papaya fruits. In order to reduce such loss, we isolated endophytic bacteria that may possess powerful antagonistic activities toward these pathogens for effective biological control of anthracnose and blight diseases.
  
  
  METHODS
  The methods of dilution and inhibition circle were used for isolating and screening endophytic bacteria from papaya fruit. Based on morphological, physiological and biochemical characteristics, and homology analysis of the partial sequence of 16S rDNA, an endophytic bacterium was identified. The colonization of the antagonistic endophyte in papaya was detected by inoculating suspension of strains in caudices of papaya plant after Rifampicin-resistant mutants (rif(r)) induction. The effects on diseases caused by Colletotrichum gloeosporioides and Phytophthora nicotianae were tested by preharvest and postharvest experiments.
  
  
  RESULTS
  One of the endophytic bacteria named MGP3 was selected from the papaya pericarp and identified as Pseudomonas aeruginosa (Accession No. JF708186). This bacterium was able to colonize in the laminae, leafstalk or pericarp of papaya, and strongly inhibit 10 phytopathogens. In the postharvest experiment, MGP3 inhibited 50% anthracnose and 71% blight of harvested papaya fruits. The application of MGP3 at five preharvest stages of papaya significantly reduced latent infection rate of Colletotrichum gloeosporioides and disease index of anthracnose.
  
  
  CONCLUSIONS
  Antagonistic endophytic bacterium MGP3 isolated from papaya fruit had potential application value as a biological control agent.
authors: College of Food Science and Engineering, Shandong Agricultural University, Taian 271018, China. jyshi2003@gmail.com
authors: Jingying
authors: J
authors: Shi
authors: Aiyuan
authors: A
authors: Liu
authors: Xueping
authors: X
authors: Li
authors: Weixin
authors: W
authors: Chen
mesh_terms: D061046:Biological Control Agents; D029441:Carica / Q000382:microbiology*; D060026:Endophytes / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology / Q000517:prevention & control; D011550:Pseudomonas aeruginosa / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D061046:Biological Control Agents; D012336:RNA, Ribosomal, 16S