Common amino acid sequence domains among the LEA proteins of higher plants

Dure, Leon S.; Crouch, Martha L.; Harada, John J.; Ho, Tuan‐Hua David; Mundy, John; Quatrano, Ralph S.; Thomas, Terry L.; Sung, Z. Renee

doi:10.1007/bf00036962

Cited by 746 publications

(547 citation statements)

References 13 publications

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“…Four names have been designated for this protein family-RAB, LEA D-11, LEA (II) and DHNs (dehydrins) (Baker et al, 1988;Dure et al, 1989). Dehydrins (dehydration induced) are water deficit-induced genes customarily expressed in the embryos during the late stages of embryogenesis and are also induced in vegetative tissues during normal growth conditions and in response to stress leading to cellular dehydration (e.g.…”

Section: Group 2 Lea Protein/dehydrins (Dhns)mentioning

confidence: 99%

Genetic approaches towards overcoming water deficit in plants - special emphasis on LEAs

Khurana

Vishnudasan

Chhibbar

2008

Physiol Mol Biol Plants

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Water deficit arises as a result of low temperature, salinity and dehydration, thereby affecting plant growth adversely and making it imperative for plants to surmount such situations by acclimatizing/adapting at various levels. Water deficit stress results in significant changes in gene expression, mediated by interconnected signal transduction pathways that may be triggered by calcium, and regulated via ABA dependent and/or independent pathways. Hence, adaptation of plants to such stresses involves maintaining cellular homeostasis, detoxification of harmful elements and also growth alterations. Stress in general cause excess production of reactive oxygen species (ROS) and the plants overcome the same by either preventing the accumulation of ROS or by eliminating the ROS formed. Ion homeostasis includes processes such as cellular uptake, sequestration and export in conjunction with long distance transport. Requisite amounts of osmolytes are hence synthesized under stress to maintain turgor along with maintaining the macromolecular structures and also for scavenging ROS. Another noteworthy response is the accumulation of novel proteins, including enzymes involved in the biosynthesis of osmoprotectants, heat-shock proteins (HSPs), late embryogenesis abundant (LEA) proteins, antifreeze proteins, chaperones, detoxification enzymes, transcription factors, kinases and phosphatases. The LEAs belong to a redundant protein family and are highly hydrophilic, boiling-soluble, non-globular and therefore have been defined and classified accordingly. The precise function of LEAs is still unknown, but substantial evidence indicates their involvement in dessication tolerance as the expression of LEAs confers increased resistance to stress in heterologous yeast system and also significantly improves water deficit tolerance in transgenic plants. Genetic manipulation of plants towards conferring abiotic stress tolerance is a daunting task, as the abiotic stress tolerance mechanism is highly complex and various strategies have been exploited to address and evaluate the stress tolerance mechanism, and the molecular responses to water deficit via complex signaling networks. Genomic technologies have recently been useful in integrating the multigenicity of the plant stress responses through, transcriptomics, proteomics and metabolite profilling and their interactions. This review deals with the recent developments on genetic approaches for water stress tolerance in plants, with special emphasis on LEAs.

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Section: Group 2 Lea Protein/dehydrins (Dhns)mentioning

confidence: 99%

Genetic approaches towards overcoming water deficit in plants - special emphasis on LEAs

Khurana

Vishnudasan

Chhibbar

2008

Physiol Mol Biol Plants

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“…lea genes are ubiquitous in monocots and dicots (Dure et al, 1989). They are characterized by their ABA-modulated expression in late maturation phase embryos and by their ABA-induced expression in response to various environmental stresses, including desiccation (Skriver and Mundy, 1990).…”

Section: Regulation Of Lea Genesmentioning

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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“…The existence in other species of sequence homologs of many of the lea genes became apparent shortly thereafter (collated in Dure et al, 1989), suggesting that they are ubiquitous in the seeds of higher plants. Further, it was found that severa1 of these gene families could be induced to high levels of expression in nonseed organs by ABA andlor water stress (reviewed by Skriver and Mundy, 1990).…”

Section: Introductionmentioning

confidence: 99%

Cellular Concentrations and Uniformity of Cell-Type Accumulation of Two Lea Proteins in Cotton Embryos.

et al. 1993

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The levels and cell-type distribution of late embryogenesis abundant (Lea) proteins D-7 and 0-113 have been determined in mature cotton embryos by immunochemical methods. The two proteins were expressed in and purified from Escherichia coli and utilized for antibody production in rabbits. The antiserum to each protein was found to interact with all members of each protein family in cotton extracts by protein gel blotting. Using these antibodies in quantitative "rocket" immunoelectrophoreses, D-7 proteins were found to accumulate to -8 x 1015 molecules per embryo, which is equivalent to mlO9 molecules per "average cell." D-113 proteins accumulate to ~1 0~6 molecules per embryo, which equates to 4 . 3 x 109 molecules per average cell. These values calculate to concentrations of about 226 and 283 pM, respectively, in the cell aqueous phase immediately prior to seed desiccation. In immunocytochemical studies using the fluorophor rhodamine linked to the secondary antibody, both proteins appeared to be evenly present in the cytosol of all cell types present in the embryo, including both cotyledon and axis epidermal cells. Thus, their function does not appear related to unique functions of specific cell or tissue types. The very high molar concentrations of the two proteins, coupled with their unusual predicted structure and their cytosol location, would seem to reduce the number of their conceivable functions.

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Common amino acid sequence domains among the LEA proteins of higher plants

Cited by 746 publications

References 13 publications

Genetic approaches towards overcoming water deficit in plants - special emphasis on LEAs

Genetic approaches towards overcoming water deficit in plants - special emphasis on LEAs

Gene expression during plant embryogenesis and germination: an overview.

Cellular Concentrations and Uniformity of Cell-Type Accumulation of Two Lea Proteins in Cotton Embryos.

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