engleski

Gene expression patterns of TROL deficient plants

Photosynthesis, one of the primary processes on Earth, involved in converting solar to chemical energy takes place in the thylakoid membrane of chloroplasts, where embedded proteins are responsible for oxygen production, synthesis of reductants and energy. As sessile organisms, plants are often subjected to environmental changes of light quality and quantity, drought, pathogens and other stresses by various mechanisms which plants seek to compensate by activating signaling pathways and changing gene expression patterns. In this way, photosynthesis derived signals alter nuclear gene expression. By using reverse genetics and functional genomics approach, transcriptome of A. thaliana pathogen-associated protein TROL (thylakoid rhodanase like protein) knock-out plants were analyzed to detect changes in the transcript abundance, and identify genes involved in potential metabolic or signaling pathways. Experiments were performed using Affymetrix ATH1 oligonucleotide arrays. For gene chip analysis, 5 µg of total RNA from wild-type and TROL deficient plants were hybridized to Affymetrix ATH1 Arrays. Collected raw CEL files in the data set were analyzed using GeneSpring v10 software and Bioconductor packages, and quantile normalized using GCRMA method. Bioconductor-based statistical analysis of expression array data revealed a list of 638 genes with altered transcriptional patterns. Further data mining was performed using MADnet software and list of statistically changed metabolic KEGG pathways (62) was generated. Among highly scored pathways in TROL plants were lignin biosynthesis, starch and sucrose metabolism, porphyrin and chlorophyll metabolism. Citosolic NADP-malic enzyme, protochlorophyllide B reductase, pathogen and defence-related genes, also AMY1 alpha-amylase (EC 3.2.11.1) involved in sucrose degradation were found to be induced in TROL plants. Depletion of protein TROL, necessary for sustaining linear electron transport and required for tethering of FNR in vascular plants, modulates the expression of genes involved in glucose accumulation (AMY1) and export (transporters). Possibly low sugar content in chloroplasts acts as a signal which carries the information (retrograde signal) through the citosol, for enhanced transcription of nuclear encoded photosynthetic genes and for the modulation of plant growth. References Jurić, S., Hazler-Pilepić, K., Tomašić, A., Lepeduš, H., Jeličić, B., Puthiyaveetil, S., Bionda, T., Vojta, L., Allen, J. F., Schleiff, E. and Fulgosi, H. (2009) Plant Journal 60(5): 783-794. Sheen, J., Zhou, L., and Jang, J.-C. (1999) Current Opinion in Plnat Biology 2 ; 410-418. Šegota, I., Bartoniček, N., Vlahovicek, K. (2008) Nucleic Acids Research 36 ; 332-335.

photosynthesis; gene expression; Affymetrix; Arabidopsis

nije evidentirano