scholarly journals Coordination of Leaf Development Across Developmental Axes

Plants ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 433 ◽  
Author(s):  
James W. Satterlee ◽  
Michael J. Scanlon
Keyword(s):  
Leaf Development ◽  
Molecular Genetic ◽  
Transcriptional Network ◽  
Cell Type ◽  
Leaf Morphogenesis ◽  
Apical Meristems ◽  
Shoot Apical Meristems ◽  
Developmental Patterning ◽  
Genetic Mechanisms ◽  
Type Specification

Leaves are initiated as lateral outgrowths from shoot apical meristems throughout the vegetative life of the plant. To achieve proper developmental patterning, cell-type specification and growth must occur in an organized fashion along the proximodistal (base-to-tip), mediolateral (central-to-edge), and adaxial–abaxial (top-bottom) axes of the developing leaf. Early studies of mutants with defects in patterning along multiple leaf axes suggested that patterning must be coordinated across developmental axes. Decades later, we now recognize that a highly complex and interconnected transcriptional network of patterning genes and hormones underlies leaf development. Here, we review the molecular genetic mechanisms by which leaf development is coordinated across leaf axes. Such coordination likely plays an important role in ensuring the reproducible phenotypic outcomes of leaf morphogenesis.

scholarly journals Class I KNOX Is Related to Determinacy during the Leaf Development of the Fern Mickelia scandens (Dryopteridaceae)

2020 ◽  
Vol 21 (12) ◽  
pp. 4295 ◽  
Author(s):  
Rafael Cruz ◽  
Gladys F. A. Melo-de-Pinna ◽  
Alejandra Vasco ◽  
Jefferson Prado ◽  
Barbara A. Ambrose
Keyword(s):  
Leaf Development ◽  
Apical Meristem ◽  
Class I ◽  
Seed Plants ◽  
Histone H4 ◽  
Knox Genes ◽  
Apical Meristems ◽  
Cell Divisions ◽  
Shoot Apical Meristems

Unlike seed plants, ferns leaves are considered to be structures with delayed determinacy, with a leaf apical meristem similar to the shoot apical meristems. To better understand the meristematic organization during leaf development and determinacy control, we analyzed the cell divisions and expression of Class I KNOX genes in Mickelia scandens, a fern that produces larger leaves with more pinnae in its climbing form than in its terrestrial form. We performed anatomical, in situ hybridization, and qRT-PCR experiments with histone H4 (cell division marker) and Class I KNOX genes. We found that Class I KNOX genes are expressed in shoot apical meristems, leaf apical meristems, and pinnae primordia. During early development, cell divisions occur in the most distal regions of the analyzed structures, including pinnae, and are not restricted to apical cells. Fern leaves and pinnae bear apical meristems that may partially act as indeterminate shoots, supporting the hypothesis of homology between shoots and leaves. Class I KNOX expression is correlated with indeterminacy in the apex and leaf of ferns, suggesting a conserved function for these genes in euphyllophytes with compound leaves.

Understanding the Genetic Basis of C4 Kranz Anatomy with a View to Engineering C3 Crops

2018 ◽  
Vol 52 (1) ◽  
pp. 249-270 ◽  
Author(s):  
Olga V. Sedelnikova ◽  
Thomas E. Hughes ◽  
Jane A. Langdale
Keyword(s):  
Genetic Basis ◽  
Genetic Regulation ◽  
Crop Productivity ◽  
Research Field ◽  
Leaf Cell ◽  
Cell Type ◽  
Kranz Anatomy ◽  
Genetic Mechanisms ◽  
Metabolic Reactions ◽  
Type Specification

One of the most remarkable examples of convergent evolution is the transition from C3 to C4 photosynthesis, an event that occurred on over 60 independent occasions. The evolution of C4 is particularly noteworthy because of the complexity of the developmental and metabolic changes that took place. In most cases, compartmentalized metabolic reactions were facilitated by the development of a distinct leaf anatomy known as Kranz. C4 Kranz anatomy differs from ancestral C3 anatomy with respect to vein spacing patterns across the leaf, cell-type specification around veins, and cell-specific organelle function. Here we review our current understanding of how Kranz anatomy evolved and how it develops, with a focus on studies that are dissecting the underlying genetic mechanisms. This research field has gained prominence in recent years because understanding the genetic regulation of Kranz may enable the C3-to-C4 transition to be engineered, an endeavor that would significantly enhance crop productivity.

The shoot apical meristem: an historical perspectiveThis review is one of a selection of papers published on the Special Theme of Shoot Apical Meristems.

2006 ◽  
Vol 84 (11) ◽  
pp. 1629-1633 ◽  
Author(s):  
Taylor A. Steeves
Keyword(s):  
Genetic Analysis ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Molecular Genetic ◽  
Molecular Genetic Analysis ◽  
Seed Plants ◽  
Shoot Apices ◽  
Early 19Th Century ◽  
Apical Meristems ◽  
Shoot Apical Meristems

Although much of the current investigation of shoot apical meristems is in the realm of molecular genetic analysis, it is important that previous structural and functional studies not be overlooked as essential background to these studies. Since Caspar Friedrich Wolff described the shoot apical meristem in 1759, many and varied interpretations have arisen. In the early 19th century, the apical cell was recognized in seedless vascular plants and this interpretation was extended to seed plants. However, by the 1860s, this view was replaced in seed plants by the histogen concept, which recognized meristem layers in the apical meristem giving rise to specific tissues. In 1924, the tunica–corpus interpretation of angiosperm shoot apices became widespread, the two regions being distinguished by different planes of cell division. In the 1950s, the “méristème d’attente” concept appeared in France, which argued that the central region of the apex remained essentially inactive until the onset of flowering. Meanwhile, the recognition of zonation patterns in angiosperm and gymnosperm shoot apices assumed growing functional importance. Clonal analysis based on chimeras in the meristem indicated the presence of initial cells but also their replacement. Surgical experimentation and culture of excised apices in vitro stressed the autonomy of the shoot apex and its role in shoot development. Present molecular genetic analysis may help to resolve some of the persistent questions concerning the organization and functioning of shoot apical meristems.

Molecular genetic approaches to leaf development: Knotted and beyond

1994 ◽  
Vol 72 (5) ◽  
pp. 617-625 ◽  
Author(s):  
Laurie G. Smith ◽  
Sarah Hake
Keyword(s):  
Molecular Genetics ◽  
Shoot Apex ◽  
Leaf Development ◽  
Molecular Basis ◽  
Leaf Surface ◽  
Molecular Genetic ◽  
Leaf Morphogenesis ◽  
Promising Alternative ◽  
Recessive Mutations ◽  
Experimental Approaches

Molecular genetics provides a promising alternative to other experimental approaches for furthering our understanding of the mechanisms controlling leaf development. We investigated the molecular basis of dominant Knotted (Kn1) mutations in maize, which cause cells associated with the lateral veins of the leaf blade to acquire characteristics of sheath or auricle and sporadically form outgrowths called knots. The kn1 gene encodes a homeodomain, a DNA-binding domain shared by many transcription factors that regulate developmental processes in animals and fungi. In normal plants, the expression of kn1 is confined to the shoot apex, but in Kn1 mutants, the gene is also expressed ectopically in the veins of developing leaves, apparently causing cells to change their developmental fates. The kn1 gene may function in the shoot apex of normal plants to promote indeterminate growth. Consistent with this hypothesis, when kn1 is expressed constitutively at high levels in the leaves of transgenic tobacco, shoots are formed on the leaf surface. Thus, our results indicate that while the kn1 gene may normally have no function in leaf development, it can alter the development of maize and tobacco leaves when it is expressed in the leaf inappropriately. Genes that normally play a role in leaf development are more likely to be defined by recessive mutations that alter leaf morphogenesis and histogenesis. Key words: leaf development, molecular genetics, Knotted.

Differentiation of Multiple Shoot Apical Meristems in Mutant Rice with One Embryo Causing Multiple Plumuples

2012 ◽  
Vol 37 (12) ◽  
pp. 2251-2260
Author(s):  
Jing-Yu GUO ◽  
Zhi-Xiong CHEN ◽  
Bing-Yao YANG ◽  
Xin-Fen CHEN ◽  
Xiang-Dong LIU ◽  
...  
Keyword(s):  
Multiple Shoot ◽  
Apical Meristems ◽  
Shoot Apical Meristems

scholarly journals Genome-wide analysis of changes in miRNA and target gene expression reveals key roles in heterosis for Chinese cabbage biomass

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Peirong Li ◽  
Tongbing Su ◽  
Deshuang Zhang ◽  
Weihong Wang ◽  
Xiaoyun Xin ◽  
...  
Keyword(s):  
Chinese Cabbage ◽  
Leaf Development ◽  
Target Genes ◽  
Expression Patterns ◽  
Seedling Stage ◽  
Differentially Expressed ◽  
Small Rna Sequencing ◽  
Leaf Morphogenesis ◽  
Expression Levels ◽  
Parental Lines

AbstractHeterosis is a complex phenomenon in which hybrids show better phenotypic characteristics than their parents do. Chinese cabbage (Brassica rapa L. spp. pekinensis) is a popular leafy crop species, hybrids of which are widely used in commercial production; however, the molecular basis of heterosis for biomass of Chinese cabbage is poorly understood. We characterized heterosis in a Chinese cabbage F1 hybrid cultivar and its parental lines from the seedling stage to the heading stage; marked heterosis of leaf weight and biomass yield were observed. Small RNA sequencing revealed 63 and 50 differentially expressed microRNAs (DEMs) at the seedling and early-heading stages, respectively. The expression levels of the majority of miRNA clusters in the F1 hybrid were lower than the mid-parent values (MPVs). Using degradome sequencing, we identified 1,819 miRNA target genes. Gene ontology (GO) analyses demonstrated that the target genes of the MPV-DEMs and low parental expression level dominance (ELD) miRNAs were significantly enriched in leaf morphogenesis, leaf development, and leaf shaping. Transcriptome analysis revealed that the expression levels of photosynthesis and chlorophyll synthesis-related MPV-DEGs (differentially expressed genes) were significantly different in the F1 hybrid compared to the parental lines, resulting in increased photosynthesis capacity and chlorophyll content in the former. Furthermore, expression of genes known to regulate leaf development was also observed at the seedling stage. Arabidopsis plants overexpressing BrGRF4.2 and bra-miR396 presented increased and decreased leaf sizes, respectively. These results provide new insight into the regulation of target genes and miRNA expression patterns in leaf size and heterosis for biomass of B. rapa.

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