Tissue distribution and developmental patterns of NADH-dependent and ferredoxin-dependent glutamate synthase activities in maize (Zea mays) kernels

1991 ◽  
Vol 81 (4) ◽  
pp. 481-488 ◽  
Author(s):  
Michael J. Muhitch
Keyword(s):  
Zea Mays ◽  
Tissue Distribution ◽  
Glutamate Synthase ◽  
Developmental Patterns

Enzymes of nitrogen assimilation during seed development in normal and high lysine mutants in maize (Zea mays, W64A)

1981 ◽  
Vol 59 (12) ◽  
pp. 2735-2743 ◽  
Author(s):  
Santosh Misra ◽  
Ann Oaks
Keyword(s):  
Zea Mays ◽  
Glutamine Synthetase ◽  
Nitrogen Assimilation ◽  
Glutamate Synthase ◽  
Asparagine Synthetase ◽  
Developmental Sequence ◽  
Normal Variety ◽  
High Lysine ◽  
Rapid Accumulation ◽  
Low Levels

Enzymes involved in nitrogen metabolism in endosperms of a normal variety of maize (W64A) and isogenic high lysine mutants (opaque-2 and floury-2) were examined. Glutamate synthase (GOGAT), glutamate dehydrogenase (GDH), asparaginase, asparagine synthetase, and glutamine synthetase were present in the immature endosperm in all three genotypes; increased in activity just prior to the onset of zein biosynthesis; and remained at maximal levels during the period of rapid accumulation of nitrogen. With the exception of GOGAT trends and levels of activities were similar in all cases. Opaque-2 mutants had higher levels of GOGAT (29 ± 0.5 nmol∙min−1 endosperm−1 at day 20 postpollination) than floury-2 (19 ± 0.07) or W64A (13 ± 0.6). Levels of aspartate, asparagine, glutamate, and glutamine were also higher in the high lysine mutants throughout the developmental sequence. NH4+ in the endosperm rose from low levels at day 5 (0.1 μmol∙endosperm−1) to significant levels (1.3, 1.7, and 1.98 μmol∙endosperm−1 in normal, floury-2, and opaque-2, respectively) between 20 and 25 days and then declined. The decline was less apparent in the mutants. Levels of an endopeptidase increased initially in the control and then declined. In the mutants the decline in activity was less apparent and this resulted in higher levels of protease activities at later stages of development. RNAase activities were higher in the mutants throughout the developmental sequence. Where differences were observed, they were more apparent in the opaque-2 than in the floury-2 mutants.

scholarly journals The maize Hairy Sheath Frayed1 (Hsf1) mutant alters leaf patterning through increased cytokinin signaling

2019 ◽  
Author(s):  
Michael G. Muszynski ◽  
Lindsay Moss-Taylor ◽  
Sivanandan Chudalayandi ◽  
James Cahill ◽  
Angel R. Del Valle-Echevarria ◽  
...  
Keyword(s):  
Zea Mays ◽  
Biochemical Analysis ◽  
Binding Pocket ◽  
Missense Mutations ◽  
Cytokinin Signaling ◽  
Leaf Morphogenesis ◽  
Developmental Patterns ◽  
Normal Morphology ◽  
Leaf Patterning ◽  
Margin Analysis

ABSTRACTLeaf morphogenesis requires growth polarized along three axes - proximal-distal, medial-lateral and abaxial-adaxial. Grass leaves display a prominent proximal-distal (P-D) polarity consisting of a proximal sheath separated from the distal blade by the auricle and ligule. Although proper specification of the four segments is essential for normal morphology, our knowledge is incomplete regarding the mechanisms which influence P-D specification in monocots like maize (Zea mays). Here we report the identification of the gene underlying the semi-dominant, leaf patterning, maize mutant Hairy Sheath Frayed1 (Hsf1). Hsf1 plants produce leaves with outgrowths consisting of proximal segments – sheath, auricle and ligule – emanating from the distal blade margin. Analysis of three independent Hsf1 alleles revealed gain-of-function missense mutations in the ligand binding domain of the maize cytokinin (CK) receptor Zea mays Histidine Kinase1 (ZmHK1) gene. Biochemical analysis and structural modeling suggest the mutated residues near the CK binding pocket affect CK binding affinity. Treatment of wild type seedlings with exogenous CK phenocopied the Hsf1 leaf phenotypes. Results from expression and epistatic analyses indicated the Hsf1 mutant receptor appears to be hypersignaling. Our results demonstrate that hypersignaling of CK in incipient leaf primordia can reprogram developmental patterns in maize.SummaryIncreased cytokinin signaling in the maize Hairy Sheath Frayed1 mutant modifies leaf development leading to changes in pattering, growth and cell identity.

scholarly journals Tissue Distribution of Glutamate Synthase and Glutamine Synthetase in Rice Leaves

1992 ◽  
Vol 100 (3) ◽  
pp. 1427-1432 ◽  
Author(s):  
Tomoyuki Yamaya ◽  
Toshihiko Hayakawa ◽  
Keisuke Tanasawa ◽  
Kazunari Kamachi ◽  
Tadahiko Mae ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Tissue Distribution ◽  
Glutamate Synthase ◽  
Rice Leaves

Ultrastructure of Plant Leaf Tissue Infected with Mite-Borne Viral-Like Pathogens

1970 ◽  
Vol 28 ◽  
pp. 178-179 ◽  
Author(s):  
O. E. Bradfute ◽  
R. E. Whitmoyer ◽  
L. R. Nault
Keyword(s):  
Triticum Aestivum ◽  
Zea Mays ◽  
Electron Microscope ◽  
Hordeum Vulgare ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Leaf Tissue ◽  
Leaf Ultrastructure ◽  
Double Membrane ◽  
Aceria Tulipae

A pathogen transmitted by the eriophyid mite, Aceria tulipae, infects a number of Gramineae producing symptoms similar to wheat spot mosaic virus (1). An electron microscope study of leaf ultrastructure from systemically infected Zea mays, Hordeum vulgare, and Triticum aestivum showed the presence of ovoid, double membrane bodies (0.1 - 0.2 microns) in the cytoplasm of parenchyma, phloem and epidermis cells (Fig. 1 ).

Identification of maize mosaic virus by immunoelectron microscopy

1986 ◽  
Vol 44 ◽  
pp. 240-241
Author(s):  
O. E. Bradfute
Keyword(s):  
Zea Mays ◽  
Mosaic Virus ◽  
Immunoelectron Microscopy ◽  
Severe Disease ◽  
Maize Mosaic Virus ◽  
The World ◽  
Plant Rhabdovirus

Maize mosaic virus (MMV) causes a severe disease of Zea mays in many tropical and subtropical regions of the world, including the southern U.S. (1-3). Fig. 1 shows internal cross striations of helical nucleoprotein and bounding membrane with surface projections typical of many plant rhabdovirus particles including MMV (3). Immunoelectron microscopy (IEM) was investigated as a method for identifying MMV. Antiserum to MMV was supplied by Ramon Lastra (Instituto Venezolano de Investigaciones Cientificas, Caracas, Venezuela).

Identification of Maize Rayado Fino Virus by Immunoelectron Microscopy

1985 ◽  
Vol 43 ◽  
pp. 636-637
Author(s):  
O. E. Bradfute
Keyword(s):  
Electron Microscopy ◽  
Zea Mays ◽  
Costa Rica ◽  
Severe Disease ◽  
Rabbit Serum ◽  
Normal Rabbit Serum ◽  
Virus Particles ◽  
Far North ◽  
Maize Rayado Fino Virus ◽  
Antibody Coating

Maize rayado fino virus (MRFV) causes a severe disease of corn (Zea mays) in many locations throughout the neotropics and as far north as southern U.S. MRFV particles detected by direct electron microscopy of negatively stained sap from infected leaves are not necessarily distinguishable from many other small isometric viruses infecting plants (Fig. 1).Immunosorbent trapping of virus particles on antibody-coated grids and the antibody coating or decoration of trapped virus particles, was used to confirm the identification of MRFV. Antiserum to MRFV was supplied by R. Gamez (Centro de Investigacion en Biologia Celular y Molecular, Universidad de Costa Rica, Ciudad Universitaria, Costa Rica).Virus particles, appearing as a continuous lawn, were trapped on grids coated with MRFV antiserum (Fig. 2-4). In contrast, virus particles were infrequently found on grids not exposed to antiserum or grids coated with normal rabbit serum (similar to Fig. 1). In Fig. 3, the appearance of the virus particles (isometric morphology, 30 nm diameter, stain penetration of some particles, and morphological subunits in other particles) is characteristic of negatively stained MRFV particles. Decoration or coating of these particles with MRFV antiserum confirms their identification as MRFV (Fig. 4).

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