The maize mutant narrow sheath fails to establish leaf margin identity in a meristematic domain

The maize mutant narrow sheath (ns) displays a leaf shape and plant stature phenotype that suggests the preprimordial deletion of a leaf domain. The ns mutant phenotype is inherited as a recessive, duplicate-factor trait, conditioned upon homozygosity for each of the two unlinked mutations narrow sheath-1 (ns1) and narrow sheath-2 (ns2). Mutant leaves are missing a large domain including the leaf margin, and mutant internodes are shortened on the marginal side of the stem. This domain deletion extends from the internode to beyond the longitudinal mid-length of the blade, and corresponds to an alteration in the organization of a specific region of the shoot apical meristem. The premargin region of mutant founder cells fail to down-regulate expression of Knox genes, markers of nonleaf meristematic identity. Our results indicate that leaf domains may acquire identity in the meristem itself, and that the subdivision of preprimordial developmental fields into differential domains is a common feature of both plant and animal organogenesis.

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How repeated epiphylly correlates with gene expression of resident knox1 in the leaves of tobacco epiphyllous shoots

Open Life Sciences ◽

10.2478/s11535-006-0012-8 ◽

2006 ◽

Vol 1 (2) ◽

pp. 263-274 ◽

Cited By ~ 1

Author(s):

Kai Müller ◽

Jinxing Lin ◽

Rainer Fischer ◽

Dirk Prüfer

Keyword(s):

Gene Expression ◽

Transgenic Plant ◽

Shoot Apical Meristem ◽

Plant Material ◽

Apical Meristem ◽

Leaf Primordia ◽

Wild Type ◽

Expression Domain ◽

Enhanced Expression ◽

Founder Cells

AbstractThe tobacco knox1 genes tokn1 and tokn2 were isolated and their neomorphic capacities were tested while expressed in tobacco and potato. In addition, their neomorphic capacities were compared to barley bkn3 transgenic plant material. While tokn2 and bkn3 induced epiphylly in tobacco and supercompound leaves in potato, tokn1 failed to produce such prominent knox1 specific phenotypes. In wild type tobacco, alleles of the tokn genes were found to be expressed within distinct zones of the shoot apical meristem (SAM), leaving out regions that correlated with leaf founder cells [1]. In contrast, the expression of the tokn genes was detected throughout the meristem and in leaf primordia of epiphyllous shoots that developed in tobacco over-expressing the barley hooded gene bkn3. It was determined that such extended expression domains of resident tobacco knox1 genes were mediated through an enhanced expression domain of bkn3 within the tissue confined to the epiphylls, and this contributed to “repeated epiphylly”, i.e. an iterated development of epiphyllous shoots on leaves of progenitor epiphylls.

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Molecular and cellular aspects of the shoot apical meristems organization of vascular plants

Biological Communications ◽

10.21638/spbu03.2015.402 ◽

2015 ◽

Author(s):

Ekaterina Klimova ◽

Olga Voitsekhovskaja

Keyword(s):

Transcription Factors ◽

Shoot Apical Meristem ◽

Vascular Plants ◽

Apical Meristem ◽

Flowering Plants ◽

Knox Genes ◽

Apical Meristems ◽

Autonomous Regulation ◽

Shoot Apical Meristems

Transfer of developmental regulators, such as miRNA and transcription factors, through plasmodesmata represents one of the key mechanisms regulating morphogenesis in angiosperms. This mechanism has been termed non-cell-autonomous regulation. At present it is not known whether this process is involved in the morphogenesis of plants belonging to the evolutionarily ancient taxa. Importantly, structure and symplastic organization of apical meristems in the representatives of such taxa significantly differ from those in flowering plants. The non-cell-autonomous transcription factors encoded by the KNOX genes which regulate functions of the shoot apical meristem may become a promising model to study this issue. Refs 102. Figs 3.

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ASYMMETRIC LEAVES1 reveals knox gene redundancy in Arabidopsis

Development ◽

10.1242/dev.129.8.1957 ◽

2002 ◽

Vol 129 (8) ◽

pp. 1957-1965 ◽

Cited By ~ 10

Author(s):

Mary E. Byrne ◽

Joseph Simorowski ◽

Robert A. Martienssen

Keyword(s):

Shoot Apical Meristem ◽

Apical Meristem ◽

Cell Function ◽

The Novel ◽

Knox Gene ◽

Knox Genes ◽

Lateral Organs ◽

Gene Redundancy ◽

Lateral Organ ◽

Meristem Maintenance

The shoot apical meristem comprises undifferentiated stem cells and their derivatives, which include founder cells for lateral organs such as leaves. Meristem maintenance and lateral organ specification are regulated in part by negative interactions between the myb domain transcription factor ASYMMETRIC LEAVES1, which is expressed in lateral organ primordia, and homeobox transcription factors which are expressed in the shoot apical meristem (knox genes). The knox gene SHOOT MERISTEMLESS (STM) negatively regulates ASYMMETRIC LEAVES1 (AS1) which, in turn, negatively regulates other knox genes including KNAT1 and KNAT2, and positively regulates the novel gene LATERAL ORGAN BOUNDARIES (LOB). Genetic interactions with a second gene, ASYMMETRIC LEAVES2 (AS2), indicate it acts at the same position in this hierarchy as AS1. We have used a second-site suppressor screen to isolate mutations in KNAT1 and we show that KNAT1 is partially redundant with STM in regulating stem cell function. Mutations in KNAT2 show no such interaction. We discuss the regulation and evolution of redundancy among knox genes.

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Faculty Opinions recommendation of Restoration of DWF4 expression to the leaf margin of a dwf4 mutant is sufficient to restore leaf shape but not size: the role of the margin in leaf development.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1096017.554691 ◽

2007 ◽

Author(s):

Lieven De Veylder

Keyword(s):

Leaf Development ◽

Leaf Shape ◽

Leaf Margin

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An integrated analysis of cell-type specific gene expression reveals genes regulated by REVOLUTA and KANADI1 in the Arabidopsis shoot apical meristem

PLoS Genetics ◽

10.1371/journal.pgen.1008661 ◽

2020 ◽

Vol 16 (4) ◽

pp. e1008661 ◽

Cited By ~ 2

Author(s):

Hasthi Ram ◽

Sudeep Sahadevan ◽

Nittaya Gale ◽

Monica Pia Caggiano ◽

Xiulian Yu ◽

...

Keyword(s):

Gene Expression ◽

Shoot Apical Meristem ◽

Apical Meristem ◽

Integrated Analysis ◽

Specific Gene ◽

Cell Type ◽

Specific Gene Expression ◽

Cell Type Specific

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Sample preparation for laser-microdissection of soybean shoot apical meristem

International Journal of Plant Biology ◽

10.4081/pb.2012.e3 ◽

2012 ◽

Vol 3 (1) ◽

pp. 3 ◽

Cited By ~ 1

Author(s):

Chui E. Wong ◽

Mohan B. Singh ◽

Prem L. Bhalla

Keyword(s):

Sample Preparation ◽

Shoot Apical Meristem ◽

Apical Meristem ◽

Laser Microdissection ◽

Specific Cell ◽

Legume Crop ◽

Continuous Formation ◽

Molecular Events ◽

Depth Analysis ◽

Specialized Equipment

The shoot apical meristem houses stem cells responsible for the continuous formation of aerial plant organs including leaves and stems throughout the life of plants. Laser-microdissection in combination with high-throughput technology such as next generation sequencing permits an in-depth analysis of molecular events associated with specific cell type of interest. Sample preparation is the most critical step in ensuring good quality RNA to be extracted from samples following laser-microdissection. Here, we optimized the sample preparation for a major legume crop, soybean. We used Farmer’s solution as a fixative and paraffin as the embedding medium for soybean shoot apical meristem tissue without the use of any specialized equipment. Shorter time for tissue fixation (two days) was found to be critical for the preservation of RNA in soybean shoot apical meristem. We further demonstrated the utility of this method for different tissues derived from soybean and rice. The method outlined here shall facilitate studies on crop plants involving laser-microdissection.

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