We validated 11 con served targets of six known miRNA families which code for transcription factors known to control key steps in plant development miR156 SPL, miR159 Myb, miR164 NAC, miR167 ARF, miR169 CBF and miR172 AP2like. We also found evidence for miRNA regulation of the DOF plant specific transcription factor selleck chemical family. Its expression seems to be restricted to the early development of Inhibitors,Modulators,Libraries the grain since degradation products were observed only during stage A. DOFs are plant specific transcription factors known to play a crit ical role in growth and development. In maize and finger millet, DOF proteins are thought to be involved in carbon metabolism and the accumulation of storage proteins. In rice, RPBF which contains a DOF domain, was shown to be involved in the regulation Inhibitors,Modulators,Libraries of endosperm expressed genes.
Energy mobilization The early development of the seed is associated with an elevated metabolic activity limited by energetic resources. Photosynthesis related genes Inhibitors,Modulators,Libraries are mainly expressed during the first 5 DPA within the pericarp tis sue. Four of the potential miRNA targets are likely to be involved in chloroplast function. An EST coding for a PGlcT homolog is also cleaved by a pot miRNA during the early development of the grain. PGlcT is involved in the export of stored starch into the cytoplasm at night. The level of PGlcT degradation products in our dataset increases during grain development which correlates with a previous observation in rice that expression of a PGlcT homolog gene increases in the endosperm during the first 15 DPA.
Signalling pathways The control of seed development involves a cross talk between three key phytohormones ABA, GA and auxin, which are tightly linked to the master regulators LEC1 AFL that govern many seed specific traits, such as embryogenesis, grain filling, desiccation tolerance, and dormancy induction. Auxin concentration Inhibitors,Modulators,Libraries together with other local factors, contributes to cell differentiation and specification of cell fate and is known to be involved in embryo pat terning. In Arabidopsis, the auxin signal is tightly linked to the miRNA pathway, with four conserved miRNA families regulating the auxin receptor TIR1 and different subgroups of ARF genes. We identified a TIR1 homolog and 7 ARF genes potentially regulated by miR NAs and tasiRNAs during seed development.
Our data shows that in the barley grain Inhibitors,Modulators,Libraries the regulation of TIR1 and potentially 3 ARF genes by the miR393 and miR167 families is conserved. We noticed that hvu miR167a and d, which are the highest expressed mem bers in this family, show a reciprocal accumulation pattern which could suggest they are expressed in dif ferent tissues where they differentially selleck inhibitor regulate the same target genes. We also identified smRNAs homologous to the tasiR ARFs which regulate four ARFs.