Nicotiana tabaccum

In plants at the present time, SA is thought to be derived from phenylalanine, via trans-cinnamic acid (CA) and benzoic acid (BA) as shown in Fig. 2 [17-19]. In tobacco plants (Nicotiana tabaccum) the accumulation of SA has been studied in some more detail and various stress factors, such as UV-irradiation, ozone [20], hydrogen peroxide [21] and elicitation with a Phytopthora megasperma preparation [22], have been shown to induce SA accumulation. 

Yalpani et al. [31] have shown conclusively that the biosynthetic pathway of SA in healthy and virus-inoculated tobacco (Nicotiana tabaccum) and tobacco cell-suspension cultures occurs via CA and BA. Unlabelled o-coumaric acid was detected after feeding with [ C]-CA. Moreover, it was shown that BA and not o-coumaric acid was incorporated in SA. 

Barton, K.A., Whiteiey, H.R. and Yang, N.-S. (1987). Bacillus thuringiensis 8-endotoxin expressed in transgenic Nicotiana tabaccum provides resistance to Lepidopteran insects. Plant Physiol. 85,1103-1109. 

Tanaka et al. (1966) detected choline kinase activity in leaves of barley (A. saliva L.), wheat (Triticum vulgare), tobacco (Nicotiana tabaccum L.), spinach Spinacea oleracea L.), and squash Cucurbita pepo L.). The characteristics of the enzyme were very similar to those described for rapeseed. A nonspecific phosphatase which hydrolyzed phosphorylcholine was also described. These authors pointed out that these two enzyme activities were far from sufficient to account for the rapid equilibration of POi with the large reserves of phosphorylcholine found in plants. There is still no satisfactory answer to this problem. 

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