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A Functional Screen to Characterize the Secretomes of Eukaryotic Pathogens and Their Hosts In Planta

December 2006 , Volume 19 , Number  12
Pages  1,368 - 1,377

Sang-Jik Lee , 1 Brendan S. Kelley , 1 Cynthia M. B. Damasceno , 1 Bonnie St. John , 1 Byung-Soo Kim , 2 Byung-Dong Kim , 3 and Jocelyn K. C. Rose 1

1Department of Plant Biology, Cornell University, Ithaca, NY 14853, U.S.A.; 2Department of Horticulture, Kyungpook National University, Daegu 702-701, Korea; 3Center for Plant Molecular Genetics and Breeding Research, Seoul National University, Seoul 151-921, Korea

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Accepted 26 July 2006.

Complex suites of proteins that are secreted by plants and phytopathogens into the plant apoplast play crucial roles in surveillance, assault, defense, and counter-defense. High-throughput genome-scale strategies are being developed to better understand the nature of these “secretomes” and the identity of pathogen-derived effector proteins that subvert plant defenses and promote pathogenicity. Although combined bioinformatic and experimental approaches recently have provided comprehensive coverage of secreted proteins from bacterial phytopathogens, far less is known about the secretomes and batteries of effectors of eukaryotic phytopathogens; notably fungi and oomycetes. The yeast secretion trap (YST) represents a potentially valuable technique to simultaneously target pathogen and host secretomes in infected plant material. A YST screen, using a new vector system, was applied to study the interaction between tomato (Solanum lycopersicum) and the oomycete Phytophthora infestans, revealing sets of genes encoding secreted proteins from both pathogen and host. Most of those from the oomycete had no identifiable function and were detectable in planta only during pathogenesis, underlining the value of YST as a tool to identify new candidate effectors and pathogenicity factors. In addition, the majority of the P. infestans proteins had homologs in the genomes of the related oomycetes P. sojae and P. ramorum.

Additional keywords: cell wall , signal peptide .

© 2006 The American Phytopathological Society