Development of a protocol for genetic transformation of Malus spp

Abstract

In this work, a protocol to produce transgenic shoots of Malus X domestica cv Greensleaves was finalized using gene constructs that have been already already used to create parthenocarpic tomato. These gene constructs were: Ino-IaaM and DefH9-IaaM The aim was to obtain a sufficient nº of transgenic shoots that will be in vitro multiplicated, transferred in soil, grafted and tested for parthenocarpy in the next years. We investigated the effects of two modifications of a previous published protocol: 1) the use of co-transformation with an agrobacterium containing “VIP” genes in the gene construct and 2) the use of two different hormone or hormone combinations were tested. The results showed that a greater regeneration of shoots was obtained when the combination of three hormones (BA:NAA:TDZ) was used in co-coltivation step instead of IBA and no co-transformation was performed using VIP gene. For DefH9-IaaM transgene, a percentage of regeneration of 21.04% was achieved for this treatment instead of 8.95% achieved with “IBA treatment” and 4.42% (“Agrobacterium co-transformation treatment”). An increased number of regeneration of shoots was obtained when the combination of three hormones (BA:NAA:TDZ) were used instead of only IBA and no co-transformation was performed using VIP gene.