Protein monocots

The primary walls of growing plant cells are composed of 90% carbohydrate and 10% protein (51). Carbohydrate in the primary wall is present predominantly as cellulose, hemicellulose, and pectin. The pectic polysaccharides, are defined as a group of cell wall polymers containing a-l,4-linked D-galactosyluronic acid residues (62,76). Pectic polysaccharides are a major component of the primary cell waU of dicots (22-35%), arc abundant in gymnosperms and non-graminaceous monocots, and are present in reduced amounts (-10%) in the primary walls of the graminaceae (27,62). 

In contrast to dicots, 65-75% of the hydroxy-L-prolyl residues in the hydroxy-L-proline-rich proteins from the primary wall of four monocot species, including Zea mays (pericarp), Avena sativa (coleoptile), Iris kaempferi (pericarp), and Allium porum (pericarp), are reported to have no arabinoside residues attached.231 Of the glycosylated hydroxy-L-prolyl residues, the majority are bonded to triarabinosides, although smaller proportions of tetra-, di-, and mono-arabinosides have also been detected.231... 

Mutations of SSIIa have been observed in wheat and rice.208 In wheat, each of the three wheat genomes were mutated to entirely eliminate expression of the SSIIa gene product, Sgp-1 protein in one line 209 the result was reduced starch amounts and an altered starch structure. In rice, two classes of starch have been found. In Indica rices, the starch is of the long chain variety, while in Japonica, it is of the short chain variety.208 Genetic analysis showed that the mutation in Japonica rice led to a loss of starch synthase II.209 Thus, in higher plants, it seems that loss of SSII activity in dicots and SSIIa activity in monocots have the same results with respect to reduced starch content, due to a lowered amount of amylopectin and altered amylopectin chain size distribution. Thus, these genes may have the same function in starch biosynthesis. 

Non-protein amino acids (NPAAs) are especially abundant in the family Fabaceae, but are also present in several monocots (families Alliaceae, Iri-daceae, Liliaceae), Gucurbitaceae, Euphorbiaceae, Resedaceae, Sapindaceae and Gycadaceae. NPAAs are also toxic components of some fungi (e.g. coprine... 

In strategy II monocots, the key transcriptional regulator of genes involved in phytosiderophore synthesis and iron uptake is the BHLH protein, IR02. A model of the regulatory network has been established. In response... 

Fig. 2. (A) A hydropathy plot of the amino-acid sequence of pea LHC II. (B) A sketch of the amino-acid sequence of the LHC II from Lemna gibba (an aquatic monocot). (A) from R Bargi, F Suter and H Zuber (1987) Arrangement of the light-harvesting Chlorophyll a/b protein complex in the thylakoid membrane. Biochim Biophys Acta 890 348 (B) from GA Karlin-Neumann, BD Kohorn, JP Thornber and EM Tobin (1985) A chlorophyll a/b-protein encoded by a gene containing an Intron with characteristics of a (rans-posable element. J Mol AppI Genet. 3 58.

K. Pallet, H. Schaller et al. (2000). Increasing expression of P450 and P450-reductase proteins from monocots in heterologous systems. Arch. Biochem. Biophys. 379, 161-169. 

In the early 1990s the two main monocot crops, maize and rice, were successfully transformed to express Cry proteins. Maize transformed with a truncated modified crylAb gene [47], driven by either a constitutive CaMV 35S promoter or the combination of a green tissue and pollen specific promoter, was reported to result in plants with high levels of expression (up to 4 pg mg total plant pro-... 

FAB19 Complete chlorophyll a/b protein coding region and 5 and 3 flanking nucleotides for the aquatic monocot Lemna gibba, courtesy of Dr. Elaine M. Tobin (Karlin>-Neumann,G A., et ai., 1985). 

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