1st International and 10th National Iranian Conference on Bioinformatics
Home Accepted Papers
Toward elucidation of shoot-root communications involved in the developmental transition of C3 to C4 photosynthesis by comparative transcriptome analysis of hypocotyls in Halimocnemis mollissima
Paper ID : 1102-ICB10
Authors:
Mahdis Zolfaghar *1, محمد رضا غفاری2, علی محمد بنایی-مقدم3
1Biochemistry, Biochemistry and Biophysics institute, University of Tehran, Tehran, Iran
2سامانه های زیستی، موسسه تحقیقاتی بیوتکنولوژی کشاورزی (َAbrii)، کرج، ایران
3بیوشیمی، موسسه بیوشیمی و بیوفیزیک، دانشگاه تهران، تهران، ایران
Abstract:
C4 photosynthesis increases carbon fixation efficiency by separating photosynthesis phases into the mesophyll and bundle sheath cells and concentrating CO2 around Rubisco, reducing photorespiration in arid and hot environments. Consequently, C4 plants have higher water and nitrogen use efficiency with increased photosynthesis rates than C3 species [1]. As a striking instance of convergent evolution, evolving unique anatomical and biochemical features from C3 progenitors in more than 60 independent lineages ensures these characteristics. Nevertheless, exploring the evolutionary paths and identifying the global regulators of crucial components of C4 photosynthesis are constrained by the phylogenetic noises in comparative studies [2]. H. mollissima switches C3 (in cotyledons) to C4 photosynthesis (in first leaves) during its life cycle [3]. Such species provided an excellent model for studying the C3 to C4 transition regulations.
Here, we aimed to investigate probable long-distance communication pathways involved in this developmental transition through transcriptome analysis of hypocotyls. Thus, high-quality RNA was extracted from hypocotyls before and after the first leaves’ formation and sequenced by Illumina Hi-seq 2000 sequencer. After de novo assembly, we identified differentially expressed genes between two developmentally different hypocotyls. They belonged to biosynthesis, transport, and signaling of phytohormones, various transcription factors (TFs), and plant signaling peptides. Two members of the GRAS family of TFs, SHORT-ROOT (SHR) and SCARECROW (SCR), and one member of the bZIP TFs, HY5, were more expressed in hypocotyls after the formation of first leaves. It has already been shown that SHR is a mobile transcription factor and SCR controls Kranz anatomy in maize leaves [4]. Moreover, HY5 is a master regulator and a phloem-mediated shoot-to-root signal that adjusts the carbon-nitrogen balance in Arabidopsis [5]. Our findings show the possible signaling pathways involved in the emergence of more advantageous features of C4 photosynthesis.
Keywords:
C4 photosynthesis, Halimocnemis mollissima, Long-distance signaling, RNA sequencing, Shoot-root coordination
Status : Paper Accepted (Poster Presentation)