Author(s): L Chalak, A Elbitar, N Mourad, C Mortada and E Choueiri
Background and Aims: Bois Noir phytoplasma is one of the most widespread yellows in grape industry in the European and Middle Eastern countries causing damages of increasing concern for the growers. So far, traditional before hot water therapy was not totally successfully in controlling this disease as it interfered with the vitality of woody propagation material leading to a weak recovery of grafted vines. This study examined the efficiency of tissue culture techniques to eliminate Bois Noir phytoplasma from grapevines. Methods: Six tissue culture protocols were tested on Chardonnay grapevine infected by Bois Noir by using stem cuttings and shoot tips associated or not to heat treatment at 38 ± 1°C for 40 days from culture initiation; and stem cuttings combined with a hot water bath at 50°C for 15 and 30 min prior to culture initiation. Key results: The protocols were all suitable, either for shoot regeneration or for phytoplasma elimination. Stem cutting culture coupled with heat or hot water treatments appeared to be the most effective treatments leading to a correct rate of survival explants and yielding to 100% sanitized shoots. Conclusion: On the basis of these results, the stem cutting culture coupled with heat or hot water treatment and followed by micropropagation of sanitized explants, appears to be a good candidate to become a routine technique for producing phytoplasma-free vines within certification programs.
