scholarly journals KNOX HOMOLOGS SHOOT MERISTEMLESS (STM) and KNAT6 are epistatic to CLAVATA3 (CLV3) during embryonic meristem development in Arabidopsis thaliana

2020 ◽  
Author(s):  
Sharma Nidhi ◽  
Liu Tie
Keyword(s):  
Arabidopsis Thaliana ◽  
Shoot Apex ◽  
Double Mutant ◽  
Genetic Interaction ◽  
Homeobox Gene ◽  
The Other ◽  
Shoot Meristem ◽  
Published Data ◽  
Meristem Development ◽  
Shoot Meristemless

AbstractIn Arabidopsis, the genes SHOOT MERISTEMLESS (STM) and CLAVATA3 (CLV3) antagonistically regulate shoot meristem development. STM is essential for both development and maintenance of the meristem, as stm mutants fail to develop a shoot meristem during embryogenesis. CLV3, on the other hand, negatively regulates meristem proliferation, and clv3 mutants possess an enlarged shoot meristem. Genetic interaction studies revealed that stm and clv3 dominantly suppress each other’s phenotypes. STM works in conjunction with its closely related homologue KNOTTED1-LIKE HOMEOBOX GENE 6 (KNAT6) to promote meristem development and organ separation, as stm knat6 double mutants fail to form a meristem and produce a fused cotyledon. In this study, we show that clv3 fails to promote post-embryonic meristem formation in stm-1 background if we also remove KNAT6. stm-1 knat6 clv3 triple mutants result in early meristem termination and produce fused cotyledons similar to stm knat6 double mutant. Notably, the stm-1 knat6 and stm-1 knat6 clv3 alleles lack tissue in the presumed region of SAM. stm knat6 clv3 also showed reduced inflorescence size and shoot apex size as compared to clv3 single or stm clv3 double mutants. In contrast to previously published data, these data suggest that stm is epistatic to clv3 in postembryonic meristem development.HighlightSTM and KNAT6 genes determine post-embryonic meristem formation and activity in Arabidopsis. clv3 mutation is unable to rescue the stm knat6 meristemless phenotype.

scholarly journals The CLAVATA and SHOOT MERISTEMLESS loci competitively regulate meristem activity in Arabidopsis

Development ◽  
1996 ◽  
Vol 122 (5) ◽  
pp. 1567-1575 ◽  
Author(s):  
S.E. Clark ◽  
S.E. Jacobsen ◽  
J.Z. Levin ◽  
E.M. Meyerowitz
Keyword(s):  
Cell Division ◽  
Cell Differentiation ◽  
Embryonic Development ◽  
Genetic Interactions ◽  
Floral Meristem ◽  
Shoot Meristem ◽  
Meristem Development ◽  
Undifferentiated Cells ◽  
Floral Meristems ◽  
Shoot Meristemless

The CLAVATA (CLV1 and CLV3) and SHOOT MERISTEMLESS (STM) genes specifically regulate shoot meristem development in Arabidopsis. CLV and STH appear to have opposite functions: c1v1 and Clv3 mutants accumulate excess undifferentiated cells in the shoot and floral meristem, while stm mutants fail to form the undifferentiated cells of the shoot meristem during embryonic development. We have identified a weak allele of stm (stm-2) that reveals STM is not only required for the establish- ment of the shoot meristem, but is also required for the continued maintenance of undifferentiated cells in the shoot meristem and for proper proliferation of cells in the floral meristem. We have found evidence of genetic interactions between the CLV and STM loci. clv1 and c1v3 mutations partially suppressed the stm-1 and stm-2 phenotypes, and were capable of suppression in a dominant fashion. clv stm double mutants and plants homozygous for stm but heterozygous for clv, while still lacking an embryonic shoot meristem, exhibited greatly enhanced postembryonic shoot and floral meristem development. Although stm phenotypes are recessive, stm mutations dominantly suppressed clv homozygous and heterozygous phenotypes. These results indicate that the stm phenotype is sensitive to the levels of CLV activity, while the clv phenotype is sensitive to the level of STM activity. We propose that these genes play related but opposing roles in the regulation of cell division and/or cell differentiation in shoot and floral meristems.

Control of phyllotaxy in maize by the abphyl1 gene

Development ◽  
1999 ◽  
Vol 126 (2) ◽  
pp. 315-323 ◽  
Author(s):  
D. Jackson ◽  
S. Hake
Keyword(s):  
Apical Meristem ◽  
General Structure ◽  
Homeobox Gene ◽  
The Other ◽  
Shoot Meristem ◽  
Regular Pattern ◽  
Expression Domain ◽  
Geometric Patterns ◽  
Maize Plants ◽  
Shoot Meristems

Organogenesis in plants occurs at the shoot apical meristem, a group of indeterminate stem cells that are organized during embryogenesis. Regulated initiation of leaves or flowers from the shoot meristem gives rise to the familiar geometric patterns observed throughout the plant kingdom. The mechanism by which these patterns, termed phyllotaxies, are generated, remains unclear. Maize plants initiate leaves singly, alternating from one side to the other in a regular pattern. Here we describe a recessive maize mutant, abphyl1, that initiates leaves in opposite pairs, in a pattern termed decussate phyllotaxy. The decussate shoot meristems are larger than normal throughout development, though the general structure and organization of the meristem is not altered. abph1 mutants are first distinguished during embryogenesis, prior to true leaf initiation, by a larger shoot meristem and coincident larger expression domain of the homeobox gene knotted1. Therefore, the abph1 gene regulates morphogenesis in the embryo, and plays a role in determining the phyllotaxy of the shoot.

Formation of the shoot apical meristem in Arabidopsis thaliana: an analysis of development in the wild type and in the shoot meristemless mutant

Development ◽  
1993 ◽  
Vol 119 (3) ◽  
pp. 823-831 ◽  
Author(s):  
M. K. Barton ◽  
R. S. Poethig
Keyword(s):  
Tissue Culture ◽  
Arabidopsis Thaliana ◽  
Embryo Development ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Adventitious Shoot ◽  
Shoot Meristem ◽  
Wild Type ◽  
In The Wild ◽  
Shoot Meristemless

The primary shoot apical meristem of Arabidopsis is initiated late in embryogenesis, after the initiation of the cotyledons. We have identified a gene, called SHOOT MERISTEMLESS, which is critical for this process. shoot meristemless mutant seedlings lack a shoot apical meristem but are otherwise healthy and viable. The anatomy of mutant embryos demonstrates that the shoot meristemless-1 mutation completely blocks the initiation of the shoot apical meristem, but has no other obvious effects on embryo development. The failure of shoot meristemless tissue to regenerate shoots in tissue culture suggests that this gene regulates adventitious shoot meristem formation, as well as embryonic shoot meristem formation.

scholarly journals Systematic analyses of the MIR172 family members of Arabidopsis define their distinct roles in regulation of APETALA2 during floral transition

PLoS Biology ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. e3001043
Author(s):  
Diarmuid S. Ó’Maoiléidigh ◽  
Annabel D. van Driel ◽  
Anamika Singh ◽  
Qing Sang ◽  
Nolwenn Le Bec ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Gene Regulatory Networks ◽  
Shoot Apex ◽  
Regulatory Networks ◽  
Floral Induction ◽  
Mature Mirnas ◽  
Floral Transition ◽  
Shoot Meristem ◽  
Gene Regulatory

MicroRNAs (miRNAs) play important roles in regulating flowering and reproduction of angiosperms. Mature miRNAs are encoded by multiple MIRNA genes that can differ in their spatiotemporal activities and their contributions to gene regulatory networks, but the functions of individual MIRNA genes are poorly defined. We functionally analyzed the activity of all 5 Arabidopsis thaliana MIR172 genes, which encode miR172 and promote the floral transition by inhibiting the accumulation of APETALA2 (AP2) and APETALA2-LIKE (AP2-LIKE) transcription factors (TFs). Through genome editing and detailed confocal microscopy, we show that the activity of miR172 at the shoot apex is encoded by 3 MIR172 genes, is critical for floral transition of the shoot meristem under noninductive photoperiods, and reduces accumulation of AP2 and TARGET OF EAT2 (TOE2), an AP2-LIKE TF, at the shoot meristem. Utilizing the genetic resources generated here, we show that the promotion of flowering by miR172 is enhanced by the MADS-domain TF FRUITFULL, which may facilitate long-term silencing of AP2-LIKE transcription, and that their activities are partially coordinated by the TF SQUAMOSA PROMOTER-BINDING-LIKE PROTEIN 15. Thus, we present a genetic framework for the depletion of AP2 and AP2-LIKE TFs at the shoot apex during floral transition and demonstrate that this plays a central role in floral induction.

The homeobox gene ATK1 of Arabidopsis thaliana is expressed in the shoot apex of the seedling and in flowers and inflorescence stems of mature plants

1995 ◽  
Vol 28 (4) ◽  
pp. 723-737 ◽  
Author(s):  
Jan Dockx ◽  
Nicolette Quaedvlieg ◽  
Gerbienne Keultjes ◽  
Patricia Kock ◽  
Peter Weisbeek ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Shoot Apex ◽  
Homeobox Gene ◽  
Inflorescence Stems

Problems of species and the features of geographical distribution in colonial volvocine algae (Chlorophyta)

2020 ◽  
Vol 54 (2) ◽  
pp. 299-311
Author(s):  
A. G. Desnitskiy
Keyword(s):  
New Species ◽  
Geographical Distribution ◽  
World Literature ◽  
The Other ◽  
Disjunct Distribution ◽  
Published Data ◽  
Species Problem ◽  
Comprehensive Review ◽  
Volvocine Algae ◽  
Cryptic Taxa

More than ten new species of colonial volvocine algae were described in world literature during recent years. In present review, the published data on taxonomy, geographical distribution and the species problem in this group of algae, mainly from the genera Gonium, Pandorina, Eudorina, and Volvox, are critically discussed. There are both cosmopolitan volvocalean species and species with local or disjunct distribution. On the other hand, the description of new cryptic taxa in some genera of the colonial family Volvocaceae, such as Pandorina and Volvox, complicates the preparation of a comprehensive review on their geography.

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