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Advisor(s)
Abstract(s)
The compatible interaction between Erysiphe necator and Vitis vinifera induces significant alterations in
the host transcriptome, affecting essentially those genes involved in signalling and secondary metabolite
biosynthetic pathways. The precise transcriptomic changes vary from the early events to later stages of
infection. In the present work, suppressive subtraction hybridization (SSH) was used to identify several
differentially expressed transcripts in symptomatic and asymptomatic leaves from powdery mildew
infected grapevines following a long term interaction. The detected transcripts show little or no correlation
with similar expression studies concerning the early stages of infection which suggests distinct
host responses occur before and after the infection is established. The transcription level of thirteen
genes was assessed through qRT-PCR using appropriately selected and validated normalization genes.
With one exception, all these genes underwent moderate levels of differential transcription, with log2-
fold change values ranging from 2.65 to 4.36. The exception, a dirigent-like (DIR) protein, was upregulated
over 180 fold in symptomatic leaves, suggesting an important role for stereochemical selectivity
in the compatible interaction E. necatoreV. vinifera. DIR copy number was determined in the genome of
three grapevine cultivars exhibiting high (Carignan), moderate (Fernão Pires) and low (Touriga Nacional)
sensitivity to E. necator. It was found to be a two-copy gene in all cultivars analyzed. Further analysis
involving DIR metabolic neighbourhood transcripts was performed. The possible physiological significance
of the detected DIR upregulation is discussed
Description
Keywords
Vitis vinifera Erysiphe nacator dirigent proteins secondary metabolism
Pedagogical Context
Citation
"Plant Physiology and Biochemistry". ISSN 0981-9428. 68 (2013) p. 71-80
Publisher
Elsevier