Preliminary evaluation of antimicrobial activity of some chemicals on in vitro apple shoots infected by 'Candidatus Phytoplasma mali'.

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The horse chestnut lines harboring the rol genes

An Agrobacterium rhizogenes-mediated transformation system for Aesculus hippocastanum L. has been developed. Wounded androgenic embryos of A. hippocastanum were inoculated with bacteria containing the pRiA4 plasmid, with the uid A sequence as a reporter gene. The hairy roots emerging from the wounded sites of androgenic embryos were isolated and maintained in Murashige and Skoog's (MS) liquid hormone-free medium. Five hairy root lines have been maintained in vitro for 4 years with unchanged growth rate and might be a suitable source for secondary metabolite production. The transformation events have been confirmed by a polymerase chain reaction specific to the rol A, B, C and D genes. The absence of residual contaminating bacteria has been shown by a polymerase chain reaction specific to the vir D1 sequence.nul

Agrobacterium rhizogenes-mediated DNA transfer to Aesculus hippocastanum L. and the regeneration of transformed plants

Hairy roots were induced from androgenic embryos of horse chestnut (Aesculus hippocastanum L.) by infection with Agrobacterium rhizogenes strain A4GUS. Single roots were selected according to their morphology in the absence of antibiotic or herbicide resistance markers. Seventy-one putative transformed hairy root lines from independent transformation events were established. Regeneration was induced in MS liquid medium supplemented with 30 muM 6-benzylaminopurine (BA), and the regenerants were multiplied on MS solid medium containing 10 muM BA. Following elongation on MS medium supplemented with 1 muM BA and 500 mg/l polyvinylpyrrolidone, the shoots were subjected to a root-inducing treatment. Stable integration of TL-DNA within the horse chestnut genome was confirmed by Southern hybridization. The copy number of transgenes was estimated to be from two to four.nul