Prof. Rachel Amir
Areas of Interest
The research deals with plant biotechnology with an emphasis on plant metabolism. We focus on two main subjects:
A. The metabolism of methionine in plants
Methionine is a nutritionally essential, sulfur-containing amino acid. Methionine levels in plants are low, therefore it often limits the plant’s nutritional value as a source of dietary protein for humans and animals. Methionine is also a fundamental metabolite in plant cells since, through its first metabolite, S-adenosyl-methionine (SAM), it controls the level of several key metabolites, such as ethylene, polyamines and biotin. These metabolites in turn, control many processes in plants. The group studies the factors that regulate methionine synthesis and catabolism in vegetative tissues and in seeds. In addition we study the role of cysteine, which is a substrate for methionine and glutathione synthesis that has a major role in protecting plants during stresses. The group also studies the regulatory role of the first committed enzyme of methionine biosynthesis, cystathionine gamma synthase, in methionine synthesis in plants and the effect of metabolites of the aspartate family on methionine synthesis and its accumulation.
B. Elucidation the bioactive compounds in pomegranate fruits and the factors that regulate their content
Pomegranate fruits and juice contain high levels of health benefiting compounds. Our group studies different aspects of pomegranate biology, focusing on the identification of the compounds that contribute to the pomegranate’s antioxidant and antifungal activities, as well as the ability of extracts prepared from different fruit parts to inhibit the proliferation of several cancer cell lines. In addition, we also study the effects of different growth conditions and the developmental stage of the fruit on the level of these compounds.
A) Cell biology
B) Plant Science
C) Plant Genetic Engineering and Plant Tissue Culture
D) Plant Biotechnology (for MSc students)
1. Tzulker R, Glazer I, Bar-Ilan I, Holland D, Aviram M, Amir R. (2007) Antioxidant activity, polyphenol content and related compounds in different fruit juices and homogenates prepared from 29 different pomegranate accessions. Journal of Agricultural and Food Chemistry 55: 9559-9570.
2. Hacham Y, Matityahu I, Schuster G, Amir R. (2008) Overexpression of mutated forms of aspartate kinase and cystathionine -synthase in tobacco leaves resulted in the high accumulation of methionine and threonine. The Plant Journal 54: 260-71.
3. Amir R. (2010) Current understanding of the factors regulating methionine content in vegetative tissues of higher plants. Amino Acids 39: 917- 931.
4. Galili G, Amir R. (2013) Fortifying plants with the essential amino acids lysine and methionine to improve nutritional quality. Plant Biotechnology Journal 11: 211-222.
6. Song S, Hou W, Godo I, Wu C, Yu Y, Matityahu I, Hacham Y, Sun S, Han T, Amir R. (2013) Soybean seeds expressing feedback-insensitive cystathionine γ-synthase exhibit a higher content of methionine. Journal of Experimental Botany 64: 1917-1926.
7. Matityahu I, Godo I, Hacham Y, Amir R. (2013) Tobacco seeds expressing feedback-insensitive cystathionine gamma-synthase exhibit elevated content of methionine and altered primary metabolic profile. BMC Plant Biology 13: 206-220.
8. Orgil O, Schwartz E, Baruch L, Matityahu I, Mahajna J, Amir R. (2014) The antioxidative and anti-proliferative potential of non-edible organs of the pomegranate fruit and tree. LWT - Food Science and Technology 58: 571-577.
9. Cohen H, Israeli H, Matityahu I, Amir R. (2014) Seed-specific expression of a feedback-insensitive form of cystathionine γ-synthase in Arabidopsis stimulates metabolic and transcriptomic responses associated with desiccation stress. Plant Physiology 166: 1575-1592.
10. Frank A, Cohen H, Hoffman D, Amir R. (2015) Methionine and S-methylmethionine exhibit temporal and spatial accumulation patterns along the Arabidopsis life cycle. Amino Acids (In Press).