Development of efficient regeneration/transformation systems for plum

Stone fruit is recalcitrant to genetic transformation due to the low efficiency of adventitious regeneration from in vitro leaf disks and mature tissues. Therefore, the aim of the project was to develop a regeneration and transformation system for stone fruit. Apricots (Prunus armeniaca) and plums (P. salicina) were used as model systems.

Adventitious regeneration was obtained from immature apricot cv. Soldonné cotyledons and from immature plum embryos. Particle bombardment using the GUS marker gene induced transformation. However, transgenic plants were not raised. The apricot leaf disks produced copious amounts of callus but no adventitious shoots.

In the case of Marianna plum rootstock, the media compositions influenced the growth response of leaf disks. High auxin levels (> 1 mg/L IBA) resulted in adventitious root regeneration, whereas high cytokinin levels resulted in shoot primordia. The results obtained using this medium identified was not reproducible. Transformation with marker genes using Agrobacterium-mediation was reproducible and resulted in transgenic calli.

Stone fruit remains recalcitrant to adventitious leaf disk regeneration and / or transformation, and for the future, a collaborative project is being explored to join the South African, Hungarian and Italian efforts.