Effect of the type of inoculation medium on chimeric chitinase gene transfer to lisianthus (Eustoma grandiflorum [Raf.] Shinn) for resistance to the fungal disease Fusarium solani

Lisianthus is in the top ten flowers in the world and in 2017, it was the fifth largest exporter and seller of ornamental plants in the world. Resistance to fungal diseases, especially Fusarium, is one of the most important breeding objectives for lisianthus. Little work has been done on the modification of resistance to fungal diseases in this ornamental plants. Therefore, gene transfer of chimeric chitinase to lisianthus will be an important contribution to achieve this important goal. The transfer and expression of chitinase gene in plants show a high level of resistance to fungal infections and a delay in the onset of symptoms when exposed to fungal pathogens. The researchers showed that the activity of chimeric chitinase in destroying fungal walls is significantly different from that of Chit42 chitinase. The aim of this study was to achieve resistance to Fusarium solani in lisianthus by transfer of chimeric chitinase gene using Agrobacterium tumefactions. In this study, the effect of different culture media, MS, ½MS and LB, two pH values of 5.2 and 5.8 and 30 and 15 mg L-1 sucrose and 30 mg L-1 maltose in the inoculation medium were investigated. The results showed that the B treatment with MS inoculation medium containing 30 g L-1 maltose with a pH of 5.2 gave the best response in gene transfer to lisianthus and the presence of a more stringent selection medium containing 100 mg L-1 of kanamycin was superior to the other treatments with an average regeneration of 11.13 plantlets per leaflet. The results of this study show that MS medium is more efficient than LB medium for gene transfer to lisianthus. Lowering the pH and changing the carbohydrate source from sucrose to maltose in the inoculum medium increased the transformation efficiency. In this study, 471 plantlets were generated from 45 leaf explants during gene transfer of chimeric chitinase to lisianthus in a more stringent selection medium and out of 21 randomly selected plantlets and lines, 10 lines were selected by PCR and 8 lines responded positively to bioassay test. This is the first report of chimeric chitinase gene transfer in lisianthus.