Wheat dicotyledonous plants

Fig. 3. The scheme of the precipitates formed by the crude protein extracts of plants of the groups monocotyledons (1-11, table 1) and dicotyledons (12-23 table 1) with antibodies against wheat chitin-binding proteins (I) and with antibodies against wheat anionic PO (H).

In the quest to find other plants that are suitable as bioreactors, various monocoty-ledonous and dicotyledonous species have been tested. These include corn [16], rice and wheat [17], alfalfa [18], potato [19, 20], oilseed rape [21], pea [22], tomato [23] and soybean [24]. The major advantage of cereal crops is that recombinant proteins can be directed to accumulate in seeds, which are evolutionar specialized for storage and thus protect proteins from proteolytic degradation. Recombinant proteins are reported to remain stable in seeds for up to five months at room temperature [17] and for at least three years at refrigerator temperature without significant loss of activity [25]. In addition, the seed proteome is less complex than the leaf proteome, which makes purification quicker and more economical [26]. 

The use of seed-specific promoters appears to be the most promising (see Table 6.1). Seeds are also an attractive choice for molecular farming because they can be transported and stored for downstream processing, without any significant loss of yield or quality of the recombinant protein. Several seed-specific promoters from dicotyledonous and monocotyledonous plants have been isolated and used for expression of recombinant proteins in rice [32, 33], com [34—36], barley [14], wheat [37], tobacco [13], and even Arabidopsis [38]. The yield of recombinant proteins in seeds can reach up to 45% of TSP, as was shown in... 

To date, most examples of plant produced antibodies have been in tobacco. This is simply because it is eaq to transform and rapid to regenerate, and is one of the best studied and mderstood of the plant species. Historically, plants of the dicotyledonous group have been the easiest to transform, using Agrobacterium, consequently most of the early work has been concentrated in these plants. Other examples are Arabidopsis (another model plant), potato, tomato, and soy. More recently, with the development of ballistic bombardment techniques for plant transformation, many other plant species have become amenable to transformation, including important crop plants such as maize, rice, and wheat. The range of plants that could be used as vehicles for antibody production is now close to including all the commercially important crop species. 

Lignins are natural polymers occurring in plant cell walls - wood and other plants (878940) [a.447]. It has been shown that the structnres of lignins are very different from various sources, such as gymnosperm, dicotyledonous angiosperm and wheat straw (Scheme 32) among many others [a.223]. 

More recently Avila and Wallsgrove (1990) have shown that the antisera raised to barley ferredoxin-dependent glutamate synthase are able to inhibit the enzyme activity isolated from a range of plant sources. However, clear precipitation lines were detected only by Ouchterlony double-difiusion analysis with extracts from barley, wheat, rye, and rice. The enzyme from dicotyledonous and C4 plants appeared to have major differences in the amino acid composition from that purified from barley. 

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