Meristems
From Purdue Genomics Database Facility
Contents |
Shoot meristem
Y. Hiwatashi, T. Aoyama, M. Iwata, S. Miyazaki, S.-I. Morinaga, N. Onodera, N. Sumikawa, and T. Nishiyama
hiwatash@nibb.ac.jp, tomoakin@kenroku.kanazawa-u.ac.jp
An indeterminate shoot meristem in the diploid generation is a vascular plant-specific developmental characteristic (Raven et al., 2005); however, P. patens forms an indeterminate shoot meristem in its haploid generation. In A. thaliana, the indeterminate meristem at the shoot apex is maintained by a feedback loop composed of WUS and the CLV1, 2 and 3 genes (Williams and Fletcher, 2005). We found possible WUS land plant orthologues in both S. moellendorffii and P. patens, whilst CLV1 and 2 orthologues were found in S. moellendorffii but not in P. patens. These suggest that a CLV-WUS feedback loop does not function in the indeterminate meristems of P. patens, although several genes paralogous to the CLVs may serve those functions. In all of the land plant lineages, we found transcription factors and chromatin factors that function in WUS regulation: PHB, PHV, REV, and HAN as the former and NFB2/FAS1, NFB1/MUB3/FAS2, and CHR3/SYD as the latter. It remains to be determined whether these genes regulate WUS homologue transcription in S. moellendorffii and P. patens. The class 1 KNOX genes encode essential transcription factors for the indeterminate shoot apical meristem (Williams and Fletcher, 2005), and their regulation by AS1 and AS2 is indispensable for proper leaf development. The class 1 KNOX gene expression is partly regulated by CUC transcription factors. We found putative class 1 KNOX genes and CUC orthologues in all of the land plant lineages, whilst putative AS1 orthologues were found in S. moellendorffii but not in P. patens. No putative AS2 orthologues were found in S. moellendorffii nor P. patens. These data suggest that the genes regulating shoot apical meristem development vary in land plants.
Axillary meristem
Y. Hiwatashi, T, Aoyama, and T, Nishiyama
hiwatash@nibb.ac.jp, tomoakin@kenroku.kanazawa-u.ac.jp
The emergence of a branched sporophyte is one of the key evolutionary events in land plants (Kenrick and Crane, 1997). Bryophyte sporophytes do not branch, whilst extant vascular plants have branched sporophytes, although lycopods have a bifurcated branch system, which is different from the seed plant branch system with axillary meristems. Putative orthologues of the A. thaliana MAX1, 2, 3, and 4 genes, which regulate axillary branching (Bennett et al. 2006) were found in S. moellendorffii, whilst all except MAX1 were present in P. patens. The RAX and LAS genes encode transcription factors that function in axillary meristem development (Muller et al., 2006). We found putative orthologues of LAS in both S. moellendorffii and P. patens and putative orthologues of RAX in S. moellendorffii. These results indicate that most genes for axillary meristem development existed before the evolution of the axillary meristem, and that the evolution of their interaction might have been important for the development of the new trait.
References
Bennett T, Sieberer T, Willett B, Booker J, Luschnig C, Leyser O. The Arabidopsis MAX pathway controls shoot branching by regulating auxin transport. Curr Biol. 2006 Mar 21;16(6):553-63.
Kenrick, P., and Crane, P.R. (1997). The Origin and Early Diversification of Land Plants: A Cladistic Study. (Washington, DC: Smithsonian Institution Press).
Muller, D., Schmitz, G., and Theres, K. (2006). Blind homologous R2R3 Myb genes control the pattern of lateral meristem initiation in Arabidopsis. Plant Cell 18, 586-597.
Raven, P.H., Evert, R.F., and Eichhorn, S.E. (2005). Biology of Plants. (New York: W. H. Freeman and Company).
Williams, L., and Fletcher, J.C. (2005). Stem cell regulation in the Arabidopsis shoot apical meristem. Curr. Opin. Plant Biol. 8, 582-586.
Table of gene numbers
| Gene functions | Gene | Gene used as a query | The number of putative orthologs | |||
|---|---|---|---|---|---|---|
| Arabidopsis thaliana | Oryza sativa | Selaginalla moellendorffii (a) | Physcomitrella patens | |||
| Shoot meristem | WUS and WOX1 to 14 | WUS | 16 | 10 | 9 (16) | 3 |
| Shoot meristem | CLV1 | CLV1 | 4 | 6 | 3 (3) | 0 |
| Shoot meristem | CLV2 | CLV2 | 2 | 3 | 2 (2) | 0 |
| Shoot meristem | STM, BP, KNAT1, and 6 | KNAT1 | 4 | 9 | 3 (3) | 3 |
| Shoot meristem | KNAT3 to 5, and 7 | KNAT3 | 4 | 4 | 2 (2) | 2 |
| Shoot meristem | AS1 | AS1 | 1 | 1 | 1 (2) | 0 |
| Shoot meristem | AS2 | AS2 | 1 | 2 | 0 | 0 |
| Shoot meristem | BOP1 and 2 | BOP1 | 2 | 2 | 2 (3) | 3 |
| Shoot meristem | CUC1, 2, and 3 | CUC1 | 11 | 12 | 3 (6) | 8 |
| Shoot meristem/Gynoecium | BEL1, BLR, PNF, and PNY | BLR | 13 | 13 | 2 (2) | 4 |
| Shoot meristem | TPL | TPL | 5 | 2 | 3 (6) | 2 |
| Shoot meristem | HAN | HAN | 3 | 2 | 2 (3) | 4 |
| Shoot meristem | ULT1 | ULT1 | 2 | 1 | 0 | 0 |
| Shoot meristem | BBM1 | ANT | 8 | 11 | 1 (2) | 3 |
| Axillary meristem | MAX1 | MAX1 | 1 | 5 | 1 (2) | 0 |
| Axillary meristem | MAX2 | MAX2 | 1 | 1 | 1 (2) | 1 |
| Axillary meristem | MAX3 | MAX3 | 1 | 1 | 1 (2) | 3 |
| Axillary meristem | MAX4 | MAX4 | 1 | 2 | 1 (2) | 1 |
| Axillary meristem | RAX1 | RAX1 | 6 | 8 | 1 (2) | 0 |
| Axillary meristem | LAS | LAS | 1 | 2 | 1 (2) | 2 |
footnote: The number of putative orthologs here refers to number of genes that is included in a clade that corresponds to all genes derived from a single gene in the last common ancestor of P. patens, S. moellendrffii, A. thaliana, and O. sativa based on phylogenetic analyses. The alignments and trees are available through http://moss.nibb.ac.jp/treedb/ (a) number of putative loci at first and number of putative alleles detected in parentheses. That is, 1 (2), indicates we found two sequences that likely represent two alleles of one locus.
Table of gene models in the assembly
| protein id | gene name | annotated by |
| WUSCHEL like homeobox genes | ||
|---|---|---|
| 417553 | WOX5-1 | |
| 419270 | WOX5-2 | |
| 451352 | WOX2-1 | |
| 404134 | WOX3-1 | |
| 407131 | WOX3-2 | |
| 451015 | WOX4-1 | |
| 84885 | WOX1-1 | |
| 451353 | WOX1-2 | |
| 115439 | WOX6-1 | |
| 438787 | WOX7-1 | |
| 451355 | WOX7-2 | |
| 404178 | WOX8-1 | |
| 407157 | WOX8-2 | |
| 451357 | WOX9-1 | |
| 451358 | WOX9-2 | |
| KNOTTED1-like homeobox genes | ||
| 415291 | SmKN1-1 | |
| 268085 | SmKN1-2 | |
| 159366 | SmKN2-1 | |
| 448401 | SmKN2-2 | |
| 90744 | SmKN3-1 | |
| 173857 | SmKN3-2 | |
| 135843 | SmKN4-1 | |
| 137260 | SmKN4-2 | |
| CLAVATA1-related genes | ||
| 146738 | CLV1A-1 | |
| 121783 | CLV1A-2 | Saori Miyazaki |
| 186143 | CLV1B-1 | |
| 172284 | CLV1B-2 | Saori Miyazaki |
| 83051 | CLV1C-1 | |
| 77558 | CLV1C-2 | Saori Miyazaki |
| CLAVATA2 like genes | ||
| 425288 | CLV2L1-1 | |
| 128564 | CLV2L1-2 | |
| BLADE ON PETIOLES related | ||
| 107813 | BOP1-1 | |
| 125007 | BOP1-2 | |
| 74877 | BOP2-1 | |
| 91240 | BOP2-2 | |
| NAM/CUC related genes | ||
| 104940 | NAM1-1 | |
| 125472 | NAM1-2 | |
| 71303 | NAM2-1 | |
| 67245 | NAM2-2 | |
| 77371 | NAM3-1 | |
| 95019 | NAM3-2 | |
| BELL-like homeobox genes | ||
| 80869 | BLH1-1 | |
| 414952 | BLH1-2 | |
| 68227 | BLH2-1 | |
| 48157 | BLH2-2 | |
| TPL related genes | ||
| 404377 | TPLa-1 | Yuji HIWATASHI |
| 79194 | TPLa-2 | Yuji HIWATASHI |
| 163891 | TPLb-1 | Yuji HIWATASHI |
| 439915 | TPLb-2 | Yuji HIWATASHI |
| 88677 | TPLc-1 | Yuji HIWATASHI |
| 115161 | TPLc-2 | |
| HAN related genes | ||
| 405209 | HANa-1 | Yuji HIWATASHI |
| 415035 | HANa-2 | Yuji HIWATASHI |
| 451362 | HANb-1 | |
| 107936 | HANb-2 | |
| ASYMMETRIC LEAVES 1 / ROUGH SHEETH 2/ PHANTASTICA related genes | ||
| 140962 | ARP-1 | |
| 270481 | ARP-2 | |
| OBERON related genes | ||
| 158800 | OBE1-1 | |
| 162596 | OBE1-2 | |
| ANT related | ||
| 1154 | ANT-1 | |
| 107288 | ANT-2 | |
| MAX1 related | ||
| 96541 | MAX1-1 | Tsuyoshi Aoyama |
| 97512 | MAX1-2 | Tsuyoshi Aoyama |
| MAX2 related | ||
| 90091 | MAX2-1 | Tsuyoshi Aoyama |
| 130722 | MAX2-2 | Tsuyoshi Aoyama |
| MAX3 related | ||
| 11120 | MAX3-1 | Tsuyoshi Aoyama |
| 42070 | MAX3-2 | Tsuyoshi Aoyama |
| MAX4 related | ||
| 173016 | MAX4-1 | Tsuyoshi Aoyama |
| 127411 | MAX4-2 | Tsuyoshi Aoyama |
| RAX1 related | ||
| 39509 | RAX1-1 | Yuji HIWATASHI |
| 39504 | RAX1-2 | Yuji HIWATASHI |
| LAS related | ||
| 84560 | LAS-1 | |
| 95651 | LAS-2 | |
