Dear Nadine

Yes, plats do contain micro RNA. In fact there is a data base

http://bioinformatics.cau.edu.cn/PMRD/ I am pasting some example s

< 1 > Gustafson, A.M., Allen, E., Givan, S., Smith, D., Carrington, J.C. and Kasschau, K.D. (2005) ASRP: the Arabidopsis Small RNA Project Database. Nucleic acids research, 33, D637-640. [NCBI]

< 2 > Rajagopalan, R., Vaucheret, H., Trejo, J. and Bartel, D.P. (2006) A diverse and evolutionarily fluid set of microRNAs in Arabidopsis thaliana. Genes & development, 20, 3407-3425. [NCBI]

< 3 > Baulcombe, D. (2004) RNA silencing in plants. Nature, 431, 356-363. [NCBI]

< 4 > Li, A. and Mao, L. (2007) Evolution of plant microRNA gene families. Cell research, 17, 212-218. [NCBI]

< 5 > Rhoades, M.W., Reinhart, B.J., Lim, L.P., Burge, C.B., Bartel, B. and Bartel, D.P. (2002) Prediction of plant microRNA targets. Cell, 110, 513-520. [NCBI]

< 6 > Griffiths-Jones, S., Grocock, R.J., van Dongen, S., Bateman, A. and Enright, A.J. (2006) miRBase: microRNA sequences, targets and gene nomenclature. Nucleic acids research, 34, D140-144. [NCBI]

< 7 > Jones-Rhoades, M.W., Bartel, D.P. and Bartel, B. (2006) MicroRNAS and their regulatory roles in plants. Annual review of plant biology, 57, 19-53. [NCBI]

< 8 > Archak, S. and Nagaraju, J. (2007) Computational prediction of rice (Oryza sativa) miRNA targets. Genomics, proteomics & bioinformatics / Beijing Genomics Institute, 5, 196-206. [NCBI]

< 9 > Barakat, A., Wall, P.K., Diloreto, S., Depamphilis, C.W. and Carlson, J.E. (2007) Conservation and divergence of microRNAs in Populus. BMC genomics, 8, 481. [NCBI]

< 10 > Sunkar, R., Chinnusamy, V., Zhu, J. and Zhu, J.K. (2007) Small RNAs as big players in plant abiotic stress responses and nutrient deprivation. Trends in plant science, 12, 301-309. [NCBI]

< 11 > Sunkar, R., Zhou, X., Zheng, Y., Zhang, W. and Zhu, J.K. (2008) Identification of novel and candidate miRNAs in rice by high throughput sequencing. BMC plant biology, 8, 25. [NCBI]

< 12 > Yao, Y., Guo, G., Ni, Z., Sunkar, R., Du, J., Zhu, J.K. and Sun, Q. (2007) Cloning and characterization of microRNAs from wheat (Triticum aestivum L.). Genome biology, 8, R96. [NCBI]

< 13 > Zhou, X., Wang, G. and Zhang, W. (2007) UV-B responsive microRNA genes in Arabidopsis thaliana. Molecular systems biology, 3, 103. [NCBI]

< 14 > Lindow, M., Jacobsen, A., Nygaard, S., Mang, Y. and Krogh, A. (2007) Intragenomic matching reveals a huge potential for miRNA-mediated regulation in plants. PLoS computational biology, 3, e238. [NCBI]

< 15 > Jones-Rhoades, M.W. and Bartel, D.P. (2004) Computational identification of plant microRNAs and their targets, including a stress-induced miRNA. Molecular cell, 14, 787-799. [NCBI]

< 16 > Wang, J.F., Zhou, H., Chen, Y.Q., Luo, Q.J. and Qu, L.H. (2004) Identification of 20 microRNAs from Oryza sativa. Nucleic acids research, 32, 1688-1695. [NCBI]

< 17 > Chen, Z., Zhang, J., Kong, J., Li, S., Fu, Y., Li, S., Zhang, H., Li, Y. and Zhu, Y. (2006) Diversity of endogenous small non-coding RNAs in Oryza sativa. Genetica, 128, 21-31. [NCBI]

< 18 > Enright, A.J., John, B., Gaul, U., Tuschl, T., Sander, C. and Marks, D.S. (2003) MicroRNA targets in Drosophila. Genome biology, 5, R1. [NCBI]

< 19 > Hofacker, I.L., Fontana, W., Stadler, P.F., Bonhoeffer, L.S., Tacker, M. and Schuster, P. (2004) Fast folding and comparison of RNA secondary structures. Monatsh.Chem, 125, 167-188. [Linkage]

< 20 > Lee, R.C., Feinbaum, R.L. and Ambros, V. (1993) The C. elegans heterochronic gene lin-4 encodes small RNAs with antisense complementarity to lin-14. Cell, 75, 843-854. [NCBI]

Thanks for your help. But I did not mean the plant itself, but the plant extracts. When parts of a plant are treated with water, oil, alcohol or other solvents in order to create an extract (for a example a tea), do some of these extracts contain miRNAs?