Reactive oxygen species and antioxidant machinery in abiotic stress tolerance in crop plants

BIOE 402. Medical Technology Assessment. 2 or 3 hours. Bioentrepreneur course. Assessment of medical technology in the context of commercialization. Objectives, competition, market share, funding, pricing, manufacturing, growth, and intellectual property; many issues unique to biomedical products. Course Information: 2 undergraduate hours. 3 graduate hours. Prerequisite(s): Junior standing or above and consent of the instructor.

“Bioinformatics” 특집을 내면서

We have produced a draft sequence of the rice genome for the most widely cultivated subspecies in China, Oryza sativa L. ssp. indica, by whole-genome shotgun sequencing. The genome was 466 megabases in size, with an estimated 46,022 to 55,615 genes. Functional coverage in the assembled sequences was 92.0%. About 42.2% of the genome was in exact 20-nucleotide oligomer repeats, and most of the transposons were in the intergenic regions between genes. Although 80.6% of predicted Arabidopsis thaliana genes had a homolog in rice, only 49.4% of predicted rice genes had a homolog in A. thaliana. The large proportion of rice genes with no recognizable homologs is due to a gradient in the GC-content of rice coding sequences.

/pdf/a-draft-sequence-of-the-rice-genome-oryza-sativa-l-ssp-5212kgt1ff.pdf

A draft sequence of the rice genome (Oryza sativa L. ssp indica)

Phenylpropanoid compounds encompass a wide range of structural classes and biological functions. Limiting discussion to stress-induced phenylpropanoids eliminates few of the structural classes, because many compounds thst are constitutive in one plant species or tissue can be induced by various stresses in another species or in another tissue of the same plant (Beggs et al., 1987; Christie et al., 1994).

/pdf/stress-induced-phenylpropanoid-metabolism-3mfsiitk82.pdf

Stress-Induced Phenylpropanoid Metabolism.

The transient gene expression system using Arabidopsis mesophyll protoplasts has proven an important and versatile tool for conducting cell-based experiments using molecular, cellular, biochemical, genetic, genomic and proteomic approaches to analyze the functions of diverse signaling pathways and cellular machineries. A well-established protocol that has been extensively tested and applied in numerous experiments is presented here. The method includes protoplast isolation, PEG-calcium transfection of plasmid DNA and protoplast culture. Physiological responses and high-throughput capability enable facile and cost-effective explorations as well as hypothesis-driven tests. The protoplast isolation and DNA transfection procedures take 6-8 h, and the results can be obtained in 2-24 h. The cell system offers reliable guidelines for further comprehensive analysis of complex regulatory mechanisms in whole-plant physiology, immunity, growth and development.

/pdf/arabidopsis-mesophyll-protoplasts-a-versatile-cell-system-3i7d0dbqvh.pdf

Arabidopsis mesophyll protoplasts: a versatile cell system for transient gene expression analysis.

We have developed a general method for electrically introducing DNA into plant cells. Gene transfer occurs when a high-voltage electric pulse is applied to a solution containing protoplasts and DNA. Carrot protoplasts were used as a model system to optimize gene-transfer efficiency, which was measured 24-48 hr after electroporation by the amount of chloramphenicol acetyltransferase activity resulting from the expression of the introduced chimeric plasmids. Gene-transfer efficiency increased with the DNA concentration and was affected by the amplitude and duration of the electric pulse as well as by the composition of the electroporation medium. Our optimized gene-transfer conditions were effective when applied to tobacco and maize protoplasts, demonstrating that the method is applicable to both monocot and dicot protoplasts.

https://www.pnas.org/content/pnas/82/17/5824.full.pdf

Expression of genes transferred into monocot and dicot plant cells by electroporation

http://directory.umm.ac.id/Data%20Elmu/jurnal/P/PlantScience/Plant%20Science_BioMedNet/041-060/052.pdf

Plant glutathione S-transferases: enzymes with multiple functions in sickness and in health.

Using electroporation-mediated gene transfer, the gene encoding the Slow (S) migrating polypeptide of the maize (Zea mays L.) alcohol dehydrogenase-1 (Adhl) enzyme has been introduced stably and transiently into maize cells containing an endogenous Fast (F) ADH1 electromorph. In stable transformants an l l.5-kb fragment was sufficient to program normal S expression relative to the endogenous F allele. In transient assays, Adhl-S gene constructs lacking the 9 Adhl-S intervening sequences (introns) were expressed at levels 50- to 100-fold less than the intact gene; the presence of intron 1 alone restored levels of gene expression to those found with the intact gene. The last two introns also stimulate Adhl-S expression, but the level is threefold below that of the intact gene. The expression of a chimeric chloramphenicol acetyltransferase (CAT) gene utilizing the 5' promoter and 3' polyadenylation regions of the Adhl gene was increased 100-fold by the addition of sequences containing the Adhl intron 1. The Adhl intron 1 sequences did not stimulate CAT expression when located outside the transcribed region. When located within the transcribed region, the Adhl intron 1 region efficiently stimulated CAT expression only when located between the promoter and the CAT coding region. A construct containing the Adhl intron 1 fragment produced 40-fold more mRNA than a construct containing an equivalent cDNA fragment. Both the Adhl intron 1 and the intron from a second maize gene, Bronzel, stimulated expression from other promoters (cauliflower mosaic virus 355 and nopaline synthase) and of other coding regions (luciferase and neomycin phosphotransferase II) as well. These results indicated that introns increase both Adhl and chimeric gene expression in maize and the optimal location for such an intron is near the 5' end of the mRNA.

/pdf/introns-increase-gene-expression-in-cultured-maize-cells-2fw5myfxog.pdf

Introns increase gene expression in cultured maize cells.

The graminaceous monocots, including the economically important cereals, seem to be refractory to infection by Agrobacterium tumefaciens, a natural gene transfer system that has been successfully exploited for transferring foreign genes into higher plants. Therefore, direct transfer techniques that are potentially applicable to all plant species have been developed using a few dicot and monocot species as model systems. One of these techniques, electroporation, uses electrical pulses of high field strength to permeabilize cell membranes reversibly so as to facilitate the transfer of DNA into cells. Electroporation-mediated gene transfer has resulted in stably transformed animal cells and transient gene expression in monocot and dicot plant cells. Here we report that electroporation-mediated DNA transfer of a chimaeric gene encoding neomycin phosphotransferase results in stably transformed maize cells that are resistant to kanamycin.

Stable transformation of maize after gene transfer by electroporation

This book brings together information and techniques for working with maize (com), a plant of enormous significance as a crop and as a model system for studies in plant genetics, biochemistry, and molecular biology. A distinguished editorial board has coordinated the compilation of protocols on maize cell biology, genetic methods and maps, tissue culture, and molecular biology. This book should be useful to those involved in maize research and scienitists working on other plants.

Virginia Walbot

Papers

Expression of genes transferred into monocot and dicot plant cells by electroporation

Plant glutathione S-transferases: enzymes with multiple functions in sickness and in health.

Introns increase gene expression in cultured maize cells.

Stable transformation of maize after gene transfer by electroporation

The maize handbook