Published in Scientific Papers. Series B, Horticulture, Vol. LXIV, Issue 1
Written by Oana-Alina BOIU-SICUIA, Sorina DINU, Lavinia BARBU
The most devastating bacterial infection of grapevine is crown gall disease, especially for young vineyards and orchards. Considering these, a better understanding of the pathogen physiology will improve the diagnostic of the causal agent of tumours induction. Therefore, small tumours collected from young grapevine plants of Italian Riesling and Fetească neagră cultivars were analyzed in order to identify and characterize the causal pathogenic bacteria. Several bacteria were isolated from grapevine tumours of Miniş-Măderat vineyard. Only four isolates were selected (vv1, vv2, vv3, vv4) for their identical or similar colony morphology to a phytopatogenic reference strain of Agrobacterium tumefaciens. The isolates vv1, vv2 and vv3 were positive for esculinase and urease, but negative for 3- ketolactose. In the tumour inducing tests, the isolates vv1, vv3, vv4 and the reference At12 were found to induce hyperplasia on carrot slices. The isolates vv1, vv2 and vv3 were identified as Rhizobium vitis bv 3 (formerly known as Agrobacterium biovar 3 or Agrobacterium vitis, comb. nov. Allorhizobium vitis). The fourth isolate (vv4) was identified as Pantoea agglomerans. In vitro assay revealed that cooper sulphate inhibits bacterial growth at less than 5% concentration, and completely suppresses their growth at 5% or higher concentration.
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