title: Lysobacter capsici AZ78 produces cyclo(L-Pro-L-Tyr), a 2,5-diketopiperazine with toxic activity against sporangia of Phytophthora infestans and Plasmopara viticola.
abstract: OBJECTIVE
  To investigate low molecular weight compounds produced in vitro by Lysobacter capsici AZ78 and their toxic activity against sporangia of plant pathogenic oomycetes.
  
  
  RESULTS
  Assays carried out in vitro showed that L. capsici AZ78 drastically inhibits the growth of plant pathogenic oomycetes. Accordingly, the preventive application of culture filtrates of L. capsici AZ78 on grapevine and tomato plants reduced the infections, respectively, caused by Plasmopara (Pl.) viticola and Phytophthora infestans. The subsequent chemical analysis of the culture filtrates of L. capsici AZ78 by spectroscopic (essentially 1D and 2D (1)H NMR and (13)C NMR and ESI MS spectra) and optical methods led to the identification of the 2,5-diketopiperazine cyclo(L-Pro-L-Tyr) that inhibited the development of P. infestans sporangia in vitro and on tomato leaves. Furthermore, a genomic region with high sequence identity with genes coding for a hybrid polyketide synthase and nonribosomal peptide synthetase was detected in L. capsici AZ78.
  
  
  CONCLUSIONS
  Lysobacter capsici AZ78 produces cyclo(L-Pro-L-Tyr) in vitro that was effective in killing the sporangia of P. infestans and Pl. viticola in vitro. Moreover, this low molecular weight compound prevents the occurrence of late blight lesions when applied on tomato leaves.
  
  
  CONCLUSIONS
  The application of L. capsici AZ78 cells or its own culture filtrates effectively controls both P. infestans and Pl. viticola. Cyclo(L-Pro-L-Tyr) produced by L. capsici AZ78 is toxic against sporangia of both these oomycetes. These data enforce the potential in the use of Lysobacter members for the control of plant pathogenic oomycetes and provide the basis for the development of new low-impact fungicides based on cyclo(L-Pro-L-Tyr).
authors: Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre, Fondazione Edmund Mach (FEM), S. Michele all'Adige (TN), Italy.
authors: G
authors: G
authors: Puopolo
authors: A
authors: A
authors: Cimmino
authors: M C
authors: MC
authors: Palmieri
authors: O
authors: O
authors: Giovannini
authors: A
authors: A
authors: Evidente
authors: I
authors: I
authors: Pertot
mesh_terms: D005659:Fungicides, Industrial / Q000494:pharmacology*; D018551:Solanum lycopersicum; D053528:Lysobacter / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D009868:Oomycetes / Q000187:drug effects* / Q000254:growth & development; D010456:Peptides, Cyclic / Q000378:metabolism; D055750:Phytophthora infestans / Q000187:drug effects*; D010879:Piperazines / Q000378:metabolism; D010935:Plant Diseases; D048630:Polyketide Synthases / Q000378:metabolism; D058432:Sporangia / Q000187:drug effects
chemical_list: D005659:Fungicides, Industrial; D010456:Peptides, Cyclic; D010879:Piperazines; C085319:maculosin; D048630:Polyketide Synthases
keywords: Lysobacter capsici; Phytophthora infestans; Plasmopara viticola; anti-oomycete activity; cyclo(l-Pro-l-Tyr)