Morphological identification of Ilyonectria liriodendri and its interaction with plant growth-promoting bacteria in grapevine rootstocks

In order to analyze the pathogenicity and antagonism between grapevine rootstocks and soil microorganisms, plant growth-promoting bacteria with antibiotic effect were selected from the phytopathogen Ilyonectria liriodendri, 2T-VSC-101 isolated monosporic, in in vitro antibiosis tests. The bacterial access that produced the largest zone of inhibition was used in the seedling biotization of the grapevine rootstocks P1103, IBBT481 and VR039-16. From the interaction between isolates of plant growth-promoting bacteria and Ilyonectria liriodendri isolate resulted in three bacterial isolates with control of the mycelial growth of the phytopathogen, all of the Burkholderia gender. However, the highest control bacterium, Burkholderia catarinensis sp. nov. isolated POA 89, was found to be detrimental to the in vitro development of rootstocks, causing them to die. The cultivation through culture medium modified with sand was adequate for the in vitro growth of the rootstocks and appropriate for the observation of the black foot disease's characteristic symptoms. From the ex vitro cultures with the IBBT481 rootstock and the microorganisms, there were results in favorable effects to the plants inoculated with the bacterium in combination with the phytopathogen. It also demonstrated the difficulty of acclimatization and growth of this access in a greenhouse.