Transformation of Rice via PEG-Mediated DNA Uptake into Protoplasts

For stable transformation of cereals through PEG-mediated
DNA
uptake into protoplasts, the two most critical requisites are the ability to isolate and culture protoplasts in large numbers, and the development of an efficient and reliable system for routine plant regeneration from protoplasts (
1
–
3
). Based on early success with mesophyll protoplasts of some dicotyledonous species, extensive efforts were made to induce sustained division in protoplasts isolated from leaves or young shoots of different cereal plants. However, there is still no convincing evidence of sustained divisions in protoplasts isolated from leaves or shoots of any cereal In contrast, protoplasts isolated from embryogenic suspension cultures could be induced to divide in culture (
4
). Obtaining a fast-growing and highly embryogenic suspension culture is the most important factor for cereal plant regeneration from protoplasts (
4
–
8
). Microspore cultures, and immature or mature embryos may be used to obtain embryogenic calh which can eventually be used to establish embryogenic cell suspensions ECS (
2
,
7
).