Michal Oren-Shamir Ph.D Email: vhshamir@volcani.agri.gov.il Tel: +972-3-9683840/1 Fax: +972-3- 9669583

Research Interests Temperature effect on anthocyanin accumulation in ornamentals Temperature is one of the main external factors affecting anthocyanin accumulation in plant tissues. One of our goals is to increase anthocyanin concentrations in ornamental plants under unfavorable conditions such as increased temperatures. Since several metals have been shown to increase the half life time of anthocyanins by forming complexes with them, we studied the combined effect of elevated temperatures and increased metal concentration in the accumulation of anthocyanins. The results of our study show that increasing magnesium levels in aster flowers and other ornamental plants prevented the deleterious effect of elevated temperatures on anthocyanin accumulation, thus enhancing flower color. These results suggest that the stability and degradation of anthocyanins in plants may play an important role in plant pigmentation. Active anthocyanin degradation The biosynthesis of anthocyanins as part of the larger pheynlpropanoid pathway has been characterized in great details. However, very little is known about the catabolism of anthocyanins in growing plants. We have chosen Brunfelsia, belonging to the Solanaceae family, as a model system for studying anthocyanin degradation, since its flowers undergo a rapid color change from dark purple to white. We have demonstrated that anthocyanin degradation in Brunfelsia is dependant on de-novo mRNA and protein synthesis. A major goal of our lab is to gain a broad view of the events taking place before and during anthocyanin degradation. At the present we are combining biochemical, genomic and proteomic approaches to achieve this goal. The effect of colored net shading on the growth characteristics of ornamental plants Plants can sense the quality, quantity and direction of light and use it as a signal to optimize their growth and development in a given environment. We have taken advantage of these plant characteristics in an attempt to improve the quality and yield of commercially grown ornamentals. We have studied the effect of colored shade nets (produced by Polysack Plastic Industries) on the quality and yield of plants. Colored nets were found to change both vegetative and flowering characteristics of ornamentals, and by that improve their quality. One of our early results, in a collaborative study with Y. Shahak, was the dramatic effect of the colored nets on Pittosporum plants. These findings were applied commercially by Israeli growers, and have resulted in a significant increase their profit. We are now studying the effect of colored nets on the quality of cuttings, including their rooting efficiency. Group members Current Former Ada Nissim-Levi, Technician Rinat Ovadia, MSc Research Assistant Ayelet Bar-Akiva, PhD student Hila Vaknin, MSc student Maya Sapir, MSc student Liat Shahar, MSc Gal Dela, MSc Liat Shaked-Sachray, MSc

Selected publications (since 1995)

• Oren-Shamir M., P.S Maruthi Sai, M. Edelman and A. Scherz. (1995) Isolation and spectroscopic characterization of the Photosystem II reaction centers from the cyanobacteria Synechosystis Sp. 6803. Biochemistry 34, 5523-5526.
• Oren-Shamir M. and Levi-Nissim A. (1997). Temperature effect on the leaf pigmentation of Cotinus coggygria 'Royal Purple'. J. Hort. Sci. 72 (3), 425-432.
• Oren-Shamir M. and Levi-Nissim A. (1997) UV-Light effect on the leaf pigmentation of Cotinus coggygria 'Royal Purple'. Sci. Hort. 71, 59-66.
• Oren-Shamir M., Shaked-Sachray L, Nissim-Levi A and Ecker R. (1999) Anthocyanin pigmentation of lisianthus flower petals. Plant Sci. 140, 81-86.
• Oren-Shamir M. and Nissim-Levi A. Temperature and gibberellin effect on growth and anthocyanin pigmentation in Photinia leaves J. Hort. Sci. Biotech. 74, 355-360.
• Oren-Shamir M., Weiss D., and Shaked-Sachray L., Nissim-Levi A. Effect of growth temperature on Aster flower development HortScience 35, 28-29
• Oren-Shamir M., Dela G., Ovadia R., Nissim-Levi A., Philosoph-Hadas S. and Meir S. (2001) Differentiation between petal blueing and senescence of cut 'Mercedes' rose flowers. J. Hort. Sci. Biotech., 76, 195-200.
• Oren-Shamir M., Gussakovsky E. G., Shpiegel E., Nissim-Levi A, Ratner K., Giller Y. E., Ovadia R. and Shahak Y. Colored shade nets can improve the yield and quality of green decorative branches of Pittosporum variegatum. J. Hort. Sci. Biotech. 76: 353-361
• Shaked-Sachray L., Weiss D., Reuveni M., Nissim-Levi A. and Oren-Shamir M. (2002). Increased anthocyanin accumulation in aster flowers at elevated temperatures due to Magnesium treatment. Physiol. Plant, 114: 559-565.
• Dela G., Or E., Ovadia R., Nissim-Levi A., Weiss D. and Oren-Shamir M. (2003). Changes in anthocyanin concentration and composition in 'Jaguar' rose flowers due to transient high-temperature conditions. Plant Sci., 164, 333-340.
• Nissim-Levi A., Kagan S., Ovadia R. and Oren-Shamir M. (2003). Effects of temperature, UV-light and magnesium on anthocyanin pigmentation in Cocoplum leaves. J. Hort. Sci Biotech., 78, 61-64.
• Oren-Shamir M., Nissim-Levi A, Ovadia R, Kagan S. and Shaked-Sachray, L. (2003). Increased anthocyanin accumulation in flowers and foliage at elevated temperatures, due to magnesium treatment. Acta Hort. 624, 171-176.
• Borovsky Y., Oren-Shamir M., Ovadia R., De Jong W. and Paran I. (2004). The A locus that controls anthocyanin accumulation in pepper encodes a MYB transcription factor homologous to Anthocyanin2 of Petunia TAG, 109, 23-29.
• Ben-Yehudah G., Korchinsky R., Redel G., Ovadia R, Oren-Shamir M., and Cohen Y. (2005). Colour accumulation patterns and anthocyanin biosynthetic pathway in 'Red Delicious' apple variants. J. Hort. Sci. Biotech., 80, 187-192.
• Vaknin H., Bar-Akiva A., Ovadia R., Nissim-Levi A., Forer I., Weiss D. and Oren-Shamir M. (2005) Active anthocyanin degradation in Brunfelsia calycina (Yesterday-Toda-Tomorrow) flowers. Planta, 222, 19-26.

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