Novartis Agribusiness Biotechnology, Inc. (NABRI), 3054 Cornwallis Road, Research Triangle Park, Durham, NC 27709, U.S.A.
Agrobacterium spp. can genetically transform most dicotyledonous plant cells whereas many monocot species are recalcitrant to Agrobacterium-mediated transformation. One major obstacle is that co-cultivation of Agrobacterium spp. with plant tissues often results in cell death. Report here is that, in maize tissues, this process resembles apoptosis, with characteristic DNA cleavage into oligonucleosomal fragments and morphological changes. Two anti-apoptotic genes from baculovirus, p35 and iap, had the ability to prevent the onset of apoptosis triggered by Agrobacterium spp. in maize tissues. p35 is reported to act as a direct inhibitor of a certain class of proteases (caspase) whereas iap may act upstream to prevent their activation. This evidence raises the possibility that caspase-like proteases may also be involved in the apoptotic pathway in plant cells.