Cronartium quercuum. [Descriptions of Fungi and Bacteria].

A description is provided for Cronartium quercuum. Information is included on the diseases caused by the organism, i.e. stem gall rust of Pinus species and leaf rust of Quercus species. Details are given of its transmission, geographical distribution (Canada (Ontario), Mexico, USA (Alabama, Arizona, Arkansas, California, Connecticut, Florida, Georgia, Idaho, Iowa, Kansas, Kentucky, Louisiana, Maryland, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New Jersey, North Carolina, Oklahoma, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Virginia, Washington DC [District of Columbia], Wisconsin and Wyoming), Belize, Costa Rica, El Salvador, Honduras, Nicaragua, Panama, Guyana and Cuba) and hosts (Pinus banksiana, P. caribaea, P. clausa, P. echinata, P. elliottii, P. glabra, P. halepensis, P. kesiya, P. leiophylla var. chichuahuana, P. massoniana, P. montezumae, P. nigra, P. oocarpa, P. palustris, P. patula, P. pinaster, P. ponderosa, P. pungens, P. radiata, P. resinosa, P. rigida, P. serotina, P. sylvestris, P. taeda, P. thunbergii, P. virginiana, Castanea dentata, Castanopsis chrysophylla, Quercus agrifolia, Q. alba, Q. bicolor, Q. chrysolepis, Q. coccinea, Q. dumosa, Q. garryana, Q. ilicifolia, Q. imbricaria, Q. laurifolia, Q. macrocarpa, Q. marilandica, Q. myrtifolia, Q. nigra, Q. palustris, Q. phellos, Q. prinoides, Q. prinus [Quercus montana], Q. pumila, Q. rubra, Q. stellata, Q. suber, Q. velutina, Q. virginiana, Castanea mollissima, Castanea pumila, Castanea sativa, Castanopsis argentea and Castanopsis diversifolia).

Differential Expression of Pine and Cronartium quercuum f. sp. fusiforme Genes in Fusiform Rust Galls

ABSTRACT Cronartium quercuum f. sp. fusiforme is the causative agent of fusiform rust disease of southern pines in the United States. This disease is characterized by the formation of woody branch and stem galls. Differential display was used to identify pine genes whose expression is altered by C. quercuum f. sp. fusiforme infection and to identify C. quercuum f. sp. fusiforme genes that are expressed in fusiform rust galls. Six pine cDNAs that appeared to be differentially expressed in galled and healthy stems and 13 C. quercuum f. sp. fusiforme cDNAs expressed in galled tissues were identified. A probe that hybridizes specifically to C. quercuum f. sp. fusiforme 18S rRNA was used to estimate that 14% of the total RNA in fusiform rust galls was from C. quercuum f. sp. fusiforme. This finding was used to calibrate gene expression levels in galls when comparing them to expression levels in uninfected pines or in isolated C. quercuum f. sp. fusiforme cultures. According to Northern analysis and reverse transcriptase PCR analysis, all six of the pine clones were expressed at lower levels in galls than in healthy tissues. Seven of the nine C. quercuum f. sp. fusiforme clones that were assayed were expressed at higher levels in galls than in axenic culture. A number of the cDNAs encode proteins that are similar to those that play roles in plant development, plant defense, or fungal stress responses.