![]() ![]() The present study investigated the origin, through duplication, of the angiosperm NAM and CUC3 lineages, and the presence or absence of post-transcriptional regulation in these lineages in the last common ancestor of the extant angiosperms. This work is complementary to an earlier study of miR164 evolution, which identified the presence of at least two MIR164 genes in the last common ancestor of the extant angiosperms ( Jasinski et al., 2010). In particular, we focused on Amborella trichopoda, a shrub endemic to New Caledonia, which, as the only representative of Amborellales, is the probable sister to all other extant angiosperms. ![]() To make conclusions on the CUC genes that were present in the last common ancestor of the extant angiosperms, we included in our analyses representatives of the ANA grade (ANA for Amborellales, Nymphaeales and Austrobaileyales), which, according to molecular phylogenetic analyses ( Bremer et al., 2009), comprises the first three extant lineages to have diverged from a common remaining lineage from which all other living angiosperms are descended. To provide insights into the early evolution of CUC genes in the angiosperms, we studied their phylogenetic relationships, in both angiosperms and their sister group, the gymnosperms. The regulation of CUC genes by miR164 thus seems to form a conserved genetic module that has been repeatedly recruited during angiosperm evolution to both leaf dissection and floral organ fusion. Interestingly, a similar mechanism controls leaf dissection and compound leaf formation in several distantly related eudicots in which these morphological traits were clearly shown to be of independent origin ( Blein et al., 2008 Berger et al., 2009). thaliana is necessary for fusion to take place between the two carpels of the syncarpic gynoecium, while the balance of CUC2 and miR164 expression also controls the depth of leaf lobes ( Nikovics et al., 2006 Sieber et al., 2007 Larue et al., 2009). For example, the post-transcriptional regulation of CUC2 in Ar. This regulatory mechanism appears to control the balance between tissue separation and fusion in various different situations in the plant. majus CUP also possess target sites for this microRNA. thaliana any two of the genes CUC1, CUC2 and CUC3 must be mutated to produce the equivalent phenotype ( Aida et al., 1997 Hibara et al., 2006).Īrabidopsis thaliana CUC1 and CUC2 are post-transcriptionally regulated by miR164 ( Laufs et al., 2004 Mallory et al., 2004), and both P. hybrida ( Souer et al., 1996) and CUPULIFORMIS ( CUP) in Antirrhinum majus ( Weir et al., 2004) causes cotyledon fusion and prevents SAM formation, whereas in Ar. For example, the inactivation of the single genes NAM in P. The degree of genetic redundancy among CUC genes varies between species. ![]() In ovule development, CUC genes are expressed at and define the boundary between the nucellus and chalaza in several distantly related eudicots ( Souer et al., 1996 Ishida et al., 2000 Weir et al., 2004 Hibara et al., 2006). Accordingly, the inactivation of CUC genes reveals a range of unique, redundant and partially overlapping phenotypes in processes including: shoot apical meristem (SAM) establishment, lateral meristem formation, lateral organ separation, leaf lobing and ovule development ( Souer et al., 1996 Aida et al., 1997 Ishida et al., 2000 Vroemen et al., 2003 Hibara et al., 2006 Nikovics et al., 2006). NAM, CUC3 and their respective orthologues in diverse angiosperms, which are here referred to generically as CUC genes, are expressed at, and control the formation of, tissue boundaries both within and between plant organs. NAC proteins contain a highly conserved, DNA-binding ‘NAC’ domain at their N terminus, and a more variable C-terminal region ( Ernst et al., 2004). Automatic fan control with built-in thermal sensor or manual mode/3 levels of speedġ x USB 3.The genes NO APICAL MERISTEM ( NAM) in Petunia hybrida and CUP-SHAPED COTYLEDON3 ( CUC3) in Arabidopsis thaliana encode distinct members of the large NAC family of plant-specific transcription factors ( Ooka et al., 2003).Sleeping mode in synchronization with PC.Flexible interface selection (USB 3.0 and eSATA).Internal RAID controller (no additional hardware needed).Suitable for 4 x 3.5" SATA hard diskInternal RAID controller (no additional hardware needed)Flexible interface selection (USB 3.0 and eSATA)Sleeping mode in synchronization with PCStatus LED displayAutomatic fan control with built-in thermal sensor or manual mode/3 levels of speed ![]()
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