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Decreased defense gene expression in tolerance versus resistance to Verticillium dahliae in potato

Tai, Helen H., Goyer, Claudia, Platt, H. W. (Bud), De Koeyer, David, Murphy, Agnes, Uribe, Pedro, Halterman, Dennis A.
Functional & Integrative Genomics 2013 v.13 no.3 pp. 367
Verticillium dahliae, alleles, biosynthesis, chlorophyll, chlorosis, clones, diploidy, fungi, gene expression, genetic variation, leaves, pathogens, plant hormones, potatoes, senescence, transcription factors, vascular tissues, wilting
Verticillium dahliae Kleb. is a soil-borne fungi that colonizes vascular tissues and induces early senescence in potato in a disease called Verticillium wilt. A diploid potato clone, 07506-01, was infected at high levels with V. dahliae but did not develop symptoms, indicating tolerance to the pathogen. Tolerance was not associated with the Ve2 resistance gene as 07506-01 was found to carry susceptible alleles. 07506-01 was compared to another diploid clone, 12120-03 which carried the Ve2 resistance allele, using gene expression profiling with the Potato Oligonucleotide Chip Initiative (POCI) microrarray. The results demonstrated that infection with V. dahliae affected 07506-01 and 12120-03 in different ways. Growth and photosynthesis were maintained at higher levels in the tolerant 07506-01 compared to 12120-03 and there was evidence for suppression of defense responses in the former clone. Expression of Ve resistance genes and defense phytohormone biosynthetic enzyme genes was found to be decreased in 07506-01 compared to 12120-03. Transcription factor gene expression differences pointed to the WRKY family of transcription factors as regulators of V. dahliae responses in potato.