Coordinate Expression of Transcriptionally Regulated Isocitrate Lyase and Malate Synthase Genes in Brassica napus L.

Comai, Lucio; Dietrich, Robert A.; Maslyar, Daniel; Baden, Catherine S.; Harada, John J.

doi:10.2307/3869009

Cited by 41 publications

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“…Figure 2 shows that GUS activity encoded by each of the fusion genes in a11 plants tested was low in dry seeds, maximal in seedlings, and undetectable or very low in young expanded leaves that had not attained full size. These patterns of transgene expression were qualitatively similar to those of the endogenous genes in B. napus and corresponded to the presence of endogenous isocitrate lyase and malate synthase enzyme activities in tobacco (Comai et al, 1989; T. Nguyenle, P. Togioka, D.L. Laudencia-Chingcuanco, and J.J. Harada, unpublished results).…”

Section: Regulated Activities Of Lsocitrate Lyase and Malate Synthasementioning

confidence: 65%

“…Harada, 1991). Although the precise role of the glyoxylate cycle enzymes in seed development remains unclear, isocitrate lyase and malate synthase are first detected during the sporophytic life cycle in the late stages of seed development (Comai et al, 1989;Ettinger and Harada, 1990;Turley and Trelease, 1990). During germination and postgerminative growth, the levels of these enzymes increase dramatically and peak several days after imbibition (Gerhart and Beevers, 1970;Trelease et al, 1971;Weir et al, 1980).…”

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confidence: 99%

“…Our previous studies showing that accumulation of these enzymes in Brassica napus L. is controlled primarily at the transcriptional leve1 indicate that the activity of these genes is an indicator of glyoxysomal function (Comai et al, 1989;Ettinger and Harada, 1990). To maximize the sensitivity of our assays, we fused the 5' flanking regions of the isocitrate lyase and malate synthase genes with the protein-coding region of the gene encoding GUS and transferred Plant Physiol.…”

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Isocitrate Lyase and Malate Synthase Genes from Brassica napus L. Are Active in Pollen

Zhang

Laudencia‐Chingcuanco

Comai

et al. 1994

Plant Physiol.

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To investigate if pollen possesses glyoxysomal function, we analyzed the activities of isocitrate lyase and malate synthase genes. Because the activities of these enzymes were exceedingly low in pollen extracts, we constructed fusion genes encoding j3-glucuronidase (CUS) that are regulated by isocitrate lyase or malate synthase promoters from Brassica napus L. to increase the sensitivity of our assays. Expression of the fusion genes in transgenic tobacco was qualitatively similar to that of the endogenous genes; CUS activity was low in dry seeds, maximal in seedlings, and very low or undetectable in leaves, indicating that the promoters are regulated correctly. We showed that isocitrate lyase and malate synthase genes are active at specific stages of pollen development and that their activities are not enhanced during pollen germination in transgenic tobacco. We also confirmed that the endogenous genes are active by showing that the corresponding mRNAs could be detected in pollen at specific stages of development. The activation of the isocitrate lyase and malate synthase genes suggests that glyoxysomal function is induced during pollen development.Glyoxysomes are specialized peroxisomes that play a pivotal role in the postgerminative growth of oilseed plants (Beevers, 1979;Huang et al., 1983;Trelease and Doman, 1984). These organelles contain the glyoxylate cycle and /3-oxidation enzymes that catalyze the net conversion of fatty acids into succinate and, thus, account for the ability of plants to utilize lipids as a carbon source for carbohydrate synthesis. The carbohydrates generated as a result of these reactions serve as nutrients for seedlings until they become photosynthetically active.Glyoxysomal function is induced at several stages of the plant life cycle when peroxisomes with different metabolic roles are converted into glyoxysomes. The induction of glyoxysomal function is generally monitored using two key glyoxylate cycle enzymes, isocitrate lyase and malate synthase, which are required for glyoxysomal function and are associated exclusively with glyoxysomes (reviewed by Olsen and

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Section: Regulated Activities Of Lsocitrate Lyase and Malate Synthasementioning

confidence: 65%

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confidence: 99%

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Isocitrate Lyase and Malate Synthase Genes from Brassica napus L. Are Active in Pollen

Zhang

Laudencia‐Chingcuanco

Comai

et al. 1994

Plant Physiol.

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“…This pattern is seen with a cucumber MS gene (Graham et al, 1990) and has been inferred for the sunflower IL gene (Allen et al, 1988). In oilseed rape seedlings, IL and MS mRNAs accumulate primarily in the axis and cotyledons; in late postgerminative seedlings, IL transcripts accumulate to high levels throughout cotyledon parenchyma cells (Comai et al, 1989;Dietrich et al, 1989). Thus, not surprisingly, the accumulation patterns of IL and MS transcripts parallel the lipid mobilization patterns within the cotyledon.…”

Section: Germination Gene Expression Programsmentioning

confidence: 69%

“…The expression of genes encoding these enzymes has been studied in a number of plants, including sunflower, cucumber, and oilseed rape (Allen et al, 1988;Comai et al, 1989;Graham et al, 1990). IL and MS are expressed coordinately at high levels in oilseed rape seedlings; there is significant but lower expression in developing oilseed rape embryos.…”

Section: Germination Gene Expression Programsmentioning

confidence: 99%

Gene expression during plant embryogenesis and germination: an overview.

Thomas

1993

Plant Cell

229

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INTRODUCTIONSeed development represents a unique transition state in the life cycle of higher plants, providing the physical link between parenta1 and progeny sporophytic generations. During embrye genesis, the root and shoot apical meristems are specified, thus establishing the basic architecture of the seedling, and differentiation of vegetative tissue and organ systems occurs. Maturation events prepare the seed for germination and subsequent development of the mature plant. During maturation, the developing seed increases dramatically in volume and mass due to significant cell expansion and the concomitant accumulation and storage of protein and lipid to be used as nitrogen and carbon sources during germination. Early during the maturation phase, abscisic acid (ABA) levels reach a maximum, suppressing precocious germination and modulating gene expression. Desiccation ensures seed dormancy even in the absence of ABA and serves as the boundary between seed maturation and germination. Following imbibition, germination and seedling growth ensue, driven metabolically by the hydrolysis of protein and lipid stored during maturation.This review will provide an eclectic overview of gene expression in angiosperm embryogenesis and germination. I will focus primarily on dicot plants and will address only a small number of the more than 3 x 104 different genes expressed in embryos and seedlings. First, gene expression in early embryogenesis will be reviewed, focusing on selected results obtained with carrot somatic embryos. Control of gene expression during seed maturation will then be discussed, with an emphasis on cis-and tfans-acting factors involved in regulating maturation phase genes. A brief description of gene expression during germination and the relationship of embryonic and vegetative gene expression programs will follow. The review will conclude with a prospectus for the study of global gene expression patterns in early embryos. GENE EXPRESSION IN EARLY EMBRYOSAlthough most of the major discernible morphogenetic events in plants occur after germination, the overall architectural pattern of the mature plant is established during embryogenesis (see West and Harada, 1993, this issue). Following fertilization, an asymmetric division of the zygote of many dicots yields a basal cell that will produce the suspensor and an apical cellthe first embryonic cell. Ensuing cleavages of the apical cell yield a radially symmetric globular embryo with a differentiated protoderm, or dermatogen. Further cell divisions and subsequent morphogenesis break radial symmetry, yielding the bilaterally symmetric, heart stage embryo with root and shoot apices, incipient cotyledons, and provascular tissue (for recent reviews, se8 Meinke, 1991;Van Engelen and De Vries, 1992;De Jong et al., 1993a;West and Harada, 1993, this issue). So far, few genes have been identified that are expressed specifically during early embryogenesis, primarily because of technical difficulties associated with the mass ratios of the embryo and the surrounding mate...

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Regulation of expression of the cucumber isocitrate lyase gene in cotyledons upon seed germination and by sucrose

Reynolds

Smith

1995

Plant Mol Biol

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A 6.5 kb cucumber genomic DNA fragment containing the icl gene was introduced into Nicotiana plumbaginifolia and shown to direct isocitrate lyase (ICL) mRNA synthesis in transgenic seedlings upon germination, in a temporally regulated manner. Two putative icl promoter fragments, of 2900 and 572 bp, were subsequently linked to the GUS reporter gene and introduced into N. plumbaginifolia. Both constructs directed GUS expression after transgenic seed germination, and although the 572 bp fragment gave only 1% of the activity of the 2900 bp fragment, it directed expression in the same cotyledon-specific and temporally regulated pattern. Seedlings were transferred to darkness after 18 days growth in the light, to induce a starvation response. The 2900 bp construct was activated by starvation and repressed by exogenous sucrose, whereas the 572 bp construct was not starvation-responsive. To localize the region of the 2900 bp promoter fragment which is responsible for regulation by sucrose, further deletions were made, linked to GUS, and assayed in a cucumber protoplast transient assay system. Constructs with promoters of 2900, 2142 and 1663 bp were activated by starvation and repressed by sucrose, but promoters of 1142 and 572 bp showed no such response. We conclude that the icl gene promoter contains at least two distinct cis-acting elements, one required for the response to sucrose and the other which participates in expression upon seed germination.

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Coordinate Expression of Transcriptionally Regulated Isocitrate Lyase and Malate Synthase Genes in Brassica napus L.

Cited by 41 publications

References 0 publications

Isocitrate Lyase and Malate Synthase Genes from Brassica napus L. Are Active in Pollen

Isocitrate Lyase and Malate Synthase Genes from Brassica napus L. Are Active in Pollen

Gene expression during plant embryogenesis and germination: an overview.

Regulation of expression of the cucumber isocitrate lyase gene in cotyledons upon seed germination and by sucrose

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