Study On The Phenylalanine Ammonia-lyase In Brassica Napus L. And Its Inhibitors

Oilseed rape is one of the four major oil plants in the world and is one of the most important oil plants in China, too. It is possessed of important station in producing crops. In recent years yellow-seeded Brassica napus L. attracts researchers' interests in that it has many good properties compared with the black-seeded B. napus L.under the same hereditary background. Such as higher oil content and better oil quality, thinner testa, a little or no pigment accumulation in the testa, higher protein content in the meal (used as fodder) , lower content of fibre and polyphenol and so on. Tens years have witnessed the development of yellow-seeded rape breeding since the first yellow-seeded B. napus L. was bred but the unambiguous interpretation to the instability of yellow-seeded hereditary characteristic cannot be gained up to the present, which has hampered the breeding process of rapeseed.Phenylalanine ammonia-lyase (PAL. EC4.3.1.5) mostly catalyzes the spontaneous nonoxidative deamination of L-phenylalanine (L-Phe) to trans -Cinnamic acid, which provides precursors for phenolics, flavanoids and isoflavanoids. It links primary metabolism to phenylpropanoid metabolism and it is the key enzyme and rate-limit enzyme in that it catalyses the first reaction in phenylpropanoid pathway which produces many secondary metabolites such as anthocyanins, lignins, phytoalexins etc.. These secondary metabolites play important roles in plant development, disease and adversity defense. Some researches indicate the differentiation of rapeseed testa color between black and yellow lines is related to PAL activity. PAL may be the key factor for the yellow seed testa formation of B. napus L. Study on B. napus L. PAL and its inhibitors can interpret the function of PAL in formation of seed testa color, help to understand the mechanism of the yellow seed testa formation of B. napus L., and can lay the base for artificially creating stable yellow-seeded B. napus L. by routine breeding or genetic engineering, In this research, the Phenylalanine Ammonia-lyase was isolated and purified from B. napus L. and the characterization of the PAL and its inhibitors was studied and explored. The results are as follows:...