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The evolution of modern agriculture and its future with biotechnology.

Since the dawn of agriculture, humans have been manipulating crops to enhance their quality and yield. Via conventional breeding, seed producers have developed the modern corn hybrids and wheat commonly grown today. Newer techniques, such as radiation breeding, enhanced the seed producers' ability to develop new traits in crops. Then in the 1980's-1990's, scientists began applying genetic engineering techniques to improve crop quality and yield. In contrast to earlier breeding methods, these techniques raised questions about their safety to consumers and the environment. This paper provides an overview of the kinds of genetically modified crops developed and marketed to date and the value they provide farmers and consumers. The safety assessment process required for these crops is contrasted with the lack of a formal process required for traditionally bred crops. While European consumers have expressed concern about foods and animal feeds containing ingredients from genetically modified crops, Americans have largely been unconcerned or unaware of the presence of genetically modified foods on the market. This difference in attitude is reflected in Europe's decision to label foods containing genetically modified ingredients while no such labeling is required in the U.S. In the future, genetic modification will produce a variety of new products with enhanced nutritional or quality attributes.

Agriculture↗

The Triticeae genetic resources of central Italy: collection, evaluation and conservation.

One hundred and six landraces belonging to 7 species of the Triticeae tribe were collected in central Italy by DBVBA (Perugia University), DIBIAGA (Ancona University) and ARSSA (Abruzzo Region Agricultural Development Agency) in different individual and joint missions. A few accessions were supplied by private and other public organisations. Triticum dicoccum Schubler is the most widespread species, followed by T. aestivum L., T. monococcum L., T. spelta L., T. turgidum var. durum Desf., Secale cereale L. and Hordeum vulgare L. Besides the presence of landraces reproduced by farmers over generations, information related to on-farm management and to qualitative/organoleptic traits as well as information related to their local names, uses, traditions and social context was gathered during the missions. The majority of the accessions was characterised by morphological and phenological traits and molecular markers. This work shows the presence of morpho-phenologic and genetic differences among landraces and the importance of some species in the agricultural systems and food customs of the investigated area. Particularly for emmer three well distinct landraces are present, "Farro Italia Centrale", "Farro della Garfagnana" and "Farro Italia Meridionale". Other interesting and traditional landraces are the "Solina" common wheat in Abruzzo and the "Orzo mondo" naked barley in Marche. Most of the populations are still cultivated in marginal lands and under low input or organic agronomic conditions; nevertheless, in many cases, they are found near modern varieties in conventional agriculture systems. Moreover, the in situ (on-farm) conservation of Triticeae landraces in central Italy is strictly linked to elderly farmers.

Conservation of Natural Resources↗

Polymerase chain reaction-single strand conformational polymorphism analysis of intra- and interspecific variations in organellar DNA regions of Aegilops mutica and related species.

In order to study the phylogeny of Aegilops mutica in the genera of Triticum and Aegilops, variations in chloroplast and mitochondrial DNA regions were investigated by polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) analysis. Nine lines, each of Ae. mutica and Ae. speltoides, were studied together with nine other Triticum and Aegilops species, including T. aestivum. By analyzing 9.7-kb chloroplast and 13.1-kb mitochondrial DNA regions, a total of 268 bands were detected, of which 176 (65.7%) showed variation within and/or between species. The level of intraspecific variation of Ae. mutica was lower than that of Ae. speltoides. The low level of the intraspecific variation of Ae. mutica was contrary to the expectation from previous studies on morphological and cytolo-gical characters. In the phylogenetic trees based on SSCP, Ae. mutica, Ae. speltoides and the other four species of the section Sitopsis (the subsection Emarginata) were separated into three different clusters. In addition, T. aestivum was included in the cluster of Ae. speltoides in the phylogenetic trees. This result suggests that Ae. speltoides is the cytoplasmic donor of common wheat.

DNA, Plant↗

[Chromosomal location of the genes conferring the tolerance to phosphorus deficiency stress in Lophopyrum elongatum genome] [In Process Citation]

Identification and genetic analysis were conducted on the tolerance to phosphorus deficiency stress by using a set of alien disomic addition lines (DA lines) and disomic substitution lines (DS lines) of common wheat Chinese Spring-Lophopyrum elongatum (2n = 2x = 14, EE), a closely related wheat species. The results indicated that chromosomes 4E and 6E in L. elongatum may carry the genes conferring the tolerance to phosphorus deficiency stress with much stronger effect over the background parent Chinese Spring. DA lines derived from chromosomes 2E and 3E behaved quite different from the corresponding DS lines. Although DA2E and DA3E were susceptible to phosphorus deficiency, the DS lines performed much better than Chinese Spring, DA2E and DA3E under both control and the deficiency conditions. However, the strongly repressed stress tolerance was located on chromosome 5E. In addition, the possible reasons for the different reponses to phosphorus deficiency between DA and DS lines of chromosomes 2E and 3E are discussed.

Journal Article↗

[New morphological marker for chromosomes of the fourth homologous group of Triticinae].

The character "hairy leaf sheath" was studied in two groups of introgressive common wheat lines. The first group involves lines containing genetic material of Aegilops sharonensis, the second one includes lines with chromatin of Triticum miguschovae. The gene controlling hairy leaf sheath, Hs, was located by us on chromosomes 4S1 (Ae. sharonensis) and 4D (T. miguschovae) due to its joint transfer with beta-Amy-S(1)1, beta-Amy-D1, Acph-S(1)1 and Acph-D1 genes situated on the and 4D chromosomes. The possibility to use the identified gene as a morphological marker for these chromosomes was shown.

Chromosome Mapping↗

[Identification, mapping, and application of a chromosome-specific RAPD marker from Haynaldia villosa].

Random amplified polymorphic DNA (RAPD) analysis was performed on common wheat of Chinese Spring, addition lines of H. villosa chromosome in CS and H. villosum from different accessions with 100 random 10-base primers. A chromosome-specific polymorphic DNA segment for H. villosa, OPF02(750), was obtained from all addition lines of H. villosa chromosome in CS and H. villosum which belong to different accessions. The result amplified by primer OPF02 of all addition lines of H. villosa chromosome in CS indicated that all the seven pairs of H. villosa chromosomes contain OPF02(750) segment. There was no OPF02(750) in all Triticum aestivum and T. durum tested. Using OPF02, We confirmed that NAU302, an addition line of H. villosa chromosome 3V, had lost its chromosome 3V of H. villosa. Therefore, OPF02(750) is specific to chromosomes of H. villosa, and could be used as a molecular marker for detection of chromosome of H. villosa in wheat.

Chromosome Mapping↗

[The effect of genotypes of parental rye lines on the development of quantitative traits in primary octoploid Triticale: spike fertility].

The number of seeds and seed setting in the main spike were studied in primary octoploid triticale obtained from crosses between the common wheat cultivar Chinese Spring and 66 inbred rye lines. In some rye lines, the mutations of self-fertility were identified in the S, Z, or T incompatibility loci. The number of seeds was determined under controlled self-pollination of the main spike. In the set of triticale examined, each trait exhibited high variation. Hence, the rye lines were suggested to carry gene alleles both increasing and decreasing these traits in triticale. All the traits studied were significantly influenced by environmental conditions. Ten triticale lines were identified, which had the largest seed setting under self-pollination. Seven out of ten samples with the high number of seeds carried mutations in the T locus and in the three samples, the unidentified self-fertility mutations were present. The triticale lines with mutations in the S and Z loci displayed much lower self-fertility on average. The ways and means of identifying and mapping the rye gene responsible for distinctions between the triticale quantitative traits are discussed.

Crosses, Genetic↗

[Development and application of a genome specific PCR marker for Haynaldia villosa].

Random amplified polymorphic DNA (RAPD) analysis was performed on common wheat Chinese Spring, H. villosa, addition lines of H. villosa chromosome in CS, substitution line 3V of H. villosa chromosome in Triticum aestivum. A genome specific polymorphic DNA segment from H. villosa, OPF02757, was obtained. On the basis of cloning and sequencing of OPF02757, two PCR primers were designed and a genome specific PCR marker for H. villosa was established. The PCR marker including 677 bp was localized on all the seven pairs of H. villosa chromosomes. The result of PCR amplification by the primers indicated that there was a specific band of 677 bp in the materials containing H. villosa Chromosome such as T. aestivum-H. villosa addition, T. aestivum-H. villosa substitution, T. aestivum-H. villosa amphidiploid, T. durum-H. villosa amphidiploid and H. villosum from different accessions, and there was no specific band of 677 bp if the materials did not contain H. villosa chromosome, such as T. aestivum, T. durum, Secale cereale, Hordeum vulgare, Thinopyrum elongatum, Thinopyrum intermedium. Therefore, the PCR maker of 677 bp is specific to H. villosa genome, and could be used as molecular marker for detection of chromosomes of H. villosa in wheat.

Base Sequence↗

[Epigenetic variability induced by nicotinic acid in Triticum aestivum L].

The effect of nicotinic acid (NA) on hereditary traits of spring common wheat cultivar Kazakhstanskaya 126 (K.126) were studied under the laboratory and field conditions. Treatment of seeds and vegetating plants with 0.01-0.1% NA (aqueous solution) induced heritable epigenetic changes in wheat. As a result, strong tall plants with the long productive spike, large seeds, and several quantitative and qualitative characters other than in the original cultivar were obtained in the second and further generations after treatment. Crosses of changed plants with each other did not result in segregation with respect to leaf downiness or anthocyan stem color in F2-F4, suggesting the same epigenetic state of genes responsible for changed characters. In crosses with the original cultivar, characters of the changed plants always dominated in F1. Basing on the current views, the changes were attributed to a transition of the hl1 and pc recessive marker genes into new, dominant epiallelic states Hl1 and Pc, which respectively determine downy leaves and the colored stem. The NA effect was specific, since only one type of the variation was observed. The changed characters were stable, and no reversion to the original phenotype was detected in 57 generations.

Genes, Plant↗

[Phylogenetic relationships and intraspecific variation of D-genome Aegilops L. as revealed by RAPD analysis].

RAPD analysis was carried out to study the genetic variation and phylogenetic relationships of polyploid Aegilops species, which contain the D genome as a component of the alloploid genome, and diploid Aegilops tauschii, which is a putative donor of the D genome for common wheat. In total, 74 accessions of six D-genome Aegilops species were examined. The highest intraspecific variation (0.03-0.21) was observed for Ae. tauschii. Intraspecific distances between accessions ranged 0.007-0.067 in Ae. cylindrica, 0.017-0.047 in Ae. vavilovii, and 0.00-0.053 in Ae. juvenalis. Likewise, Ae. ventricosa and Ae. crassa showed low intraspecific polymorphism. The among-accession difference in alloploid Ae. ventricosa (genome DvNv) was similar to that of one parental species, Ae. uniaristata (N), and substantially lower than in the other parent, Ae. tauschii (D). The among-accession difference in Ae. cylindrica (CcDc) was considerably lower than in either parent, Ae. tauschii (D) or Ae. caudata (C). With the exception of Ae. cylindrica, all D-genome species--Ae. tauschii (D), Ae. ventricosa (DvNv), Ae. crassa (XcrDcrl and XcrDcrlDcr2), Ae. juvenalis (XjDjUj), and Ae. vavilovii (XvaDvaSva)--formed a single polymorphic cluster, which was distinct from clusters of other species. The only exception, Ae. cylindrica, did not group with the other D-genome species, but clustered with Ae. caudata (C), a donor of the C genome. The cluster of these two species was clearly distinct from the cluster of the other D-genome species and close to a cluster of Ae. umbellulata (genome U) and Ae. ovata (genome UgMg). Thus, RAPD analysis for the first time was used to estimate and to compare the interpopulation polymorphism and to establish the phylogenetic relationships of all diploid and alloploid D-genome Aegilops species.

Genome, Plant↗

Zinc, a neurotoxin to cultured neurons, contaminates cycad flour prepared by traditional guamanian methods.

We have used cultured ventral mesencephalic and cerebellar granule cells to test the toxicity of extracts of cycad seeds (genus Cycas) and cycad-derived flours traditionally prepared in Guam. There was no significant difference in the toxicity of extracts prepared from the female gametophyte tissue of C. circinalis, C. revoluta, and C. media, common wheat flour, and 13 of 17 cycad flour samples. However, extracts prepared from 4 of 17 Guamanian flour samples exhibited marked dose-dependent neurotoxicity to mesencephalic and granule cell cultures. There was no correlation between toxicity and 2-amino-3-(methylamino)-propanoic acid (BMAA) content, and the concentration of BMAA in the medium arising from these extracts was far below that required to be neurotoxic. Toxicity of extracts was not blocked by the NMDA receptor antagonist MK-801 or the non-NMDA receptor antagonist 6-cyano-7-dinitroquinoxaline-2,3-dione, indicating that toxicity was not mediated by excitatory amino acid receptors. Analysis of the four toxic processed flour samples indicated high zinc content. Zinc produced a concentration-dependent neurotoxic response in mesencephalic and granule cell cultures that paralleled the calculated concentrations of zinc in the cultures derived from the four toxic flour samples. When sliced C. circinalis gametophyte tissue was "processed" in our laboratory by soaking in a galvanized container, there was a time-dependent increase in zinc content.

Animals↗

[Cytogenetic analysis of alloplasmic recombinant lines (H. vulgare)-T. aestivum with unstable fertility and viability].

Comparative cytogenetic analysis was performed with four alloplasmic recombinant (Hordeum vulgare)-Triticum aestivum lines differing in morphological traits, number of seeds per spike, and seed plumpness. None of the lines displayed introgression of the barley genetic material: the karyotypes included only common wheat chromosomes. Two lines, 79(B) and 79(D), were cytogenetically stable. Plants of lines 79(A) and 79(C) displayed a high frequency of unbalanced chromosome aberrations, including dicentric and polycentric chromosomes, terminal deletions varying in size, acentric fragments, and multiple unidentifiable translocations. Previous studies of the mitochondrial genome showed that the two cytologically unstable lines, which were also unstable in fertility and viability, are characterized by heteroplasmy at the mitochondrial 18S-5S locus (simultaneous presence of barley and wheat fragments). Stable lines 79(B) and 79(D) with normal fertility contained only wheat mitochondrial markers. It was assumed that the substantial instability of the nuclear genome in lines 79(C) and 79(A) was a result of nuclear-cytoplasmic incompatibility and was associated with heteroplasmy, while elimination or considerable reduction of barley material in the mitochondrial genome stabilized the nuclear genome of lines 79(B) and 79(D). In turn, the instability of the nuclear genome was responsible for a decrease in viability and fertility of plants.

Chimera↗

[Additional limitations of the Shrikhande method and their verification].

Shrikhande's method was checked on linear-variety common wheat Lutescens 62. Two causes for a distortion of the ratio of genotypic and paratypic components of the variance were established: parameter b of Smith's law is not constant for a given field and depends on the method of parcelling: Smith's law is not confirmed at all. A two-stage test of Shrikhande's method correctness is suggested for checking its limitations in practice. The analysis of variance for any given parcelling is done at the first stage. Significant ratios of between-cluster mean squares and within-cluster mean squares indicate that Smith's law is confirmed. The second stage consists in the analysis of variance of lg V(X) linear regression by lg X or in the graphical analysis of the function lg V(X) = = f (lg X).

Genetic Techniques↗

Stimulation of cell division in mouse fibroblast line 3T3 by an extract derived from Triticum vulgare.

The ability of an extract derived from Triticum vulgare, the common wheat plant, to stimulate cellular proliferation of mouse 3T3 fibroblast cells was investigated. Cellular response to Triticum extract (TE) was most evident in sparse cultures made quiescent by growing cells on low concentrations (0.6%) of calf serum. The growth-promoting activity in the extract was lost after dialysis but was resistant to heat treatment and digestion with trypsin or chymotrypsin, suggesting a low-molecular-weight non-protein substance(s). Growth-curve experiments showed that TE was capable of supporting continuous cell division. Cellular proliferation showed a dose-dependent response in the range of 2%-10% TE, and addition of 10% TE to cell culture medium caused a level of cell-growth stimulation approximately 72% that of 20 ng/ml fibroblast growth factor (FGF). Measurement of ornithine decarboxylase (ODC) activity of 3T3 cells after addition of 10% TE showed a significant rise in the specific activity of the enzyme.

Animals↗

[Hydrous and photosynthetic adaptations of common and durum wheat to saline stress].

Seven varieties of bred wheat and seven varieties of durum wheat were cultivated in three different sites from the area of Errachidia (southeastern Morocco). These sites differ by the degree of salinity in the irrigation water. Results obtained showed that the reduction in leaf area is the principal strategy that makes it possible to attenuate the effects of the reduction in the availability of water under saline stress. Bread wheat, which limited the reduction in the leaf area, with the risk to undergo some hydrous problems, seems to better preserve its photosynthetic potentialities and grain productivity.

Adaptation, Physiological↗

[Plant resistance inductors and active forms of oxygen. I. The influence of salicylic acid on hydrogen peroxide production in common cultures of wheat callus and bunt pathogen].

The influence of salicylic acid (SA) on cell resistance to bunt pathogen in wheat calluses has been studied. Cell staining by diaminobenzidin substratum (DAB-cells) was conditioned by hydrogen peroxide (H2O2) generation with the involvement of oxalate oxidase (OO). In the control group, DAB-staining was typical only of rhizoid cells (up to 50%). The infection caused no significant increase in the number of such cells; however, in the zone of fungus penetration parenchyma-like DAB-stained cells were observed (up to 24%). Under the influence of SA, the number of DAB-stained cells did not change, but increased in the zone of fungus penetration (up to 36%). Besides, SA increased OO activity and accelerated proembyogenic complex formation in the calluses, which, unlike rhizoids, were not sensitive to the phytopathogen. The infection caused an increase of OO activity in the cytoplasm and in an intercellular fraction, and an inhibition of an extracellular fraction of the enzyme.

3,3'-Diaminobenzidine↗

[Plant resistance inductors and active forms of oxygen. II. The influence of chitooligosaccharides on the production of hydrogen peroxide with the involvement of oxalate oxidase in common cultures of wheat calluses and bunt pathogen].

We have studied the influence of various concentrations of chitooligosaccharides (CO) on hydrogen peroxide (H2O2) generation, with the involvement of oxalate oxidase (OO), in rhizoids and in zones of hard brand pathogen penetration, as well as on oxalate oxidase activity in wheat calluses. In the control group, diaminobenzidin (DAB)-staining was typical of 30% of peripheral rhizoid cells, which provided their resistance during infection. In the zone of fungus penetration, the appearance of DAB-stained parenchyma-like cells was observed. Simultaneously, the activity OO cytoplasmic fraction increased, whereas OO activity in its ion-bound fraction was suppressed. Low concentrations of medication induced rhizoid formation, increased the number of DAB-stained cells in the pathogen penetration zone, and induced OO activity in cytoplasmic and ionically cell wall-bound fractions. On the contrary, a high concentration of CO (100 mg/ml) suppressed rhizoid formation, Oo activity and the fungus growth. The discovered correlation between enzymatic activation under CO influence, the high level of protective response during infection, and the intensity of rhizoid formation may suggest the community of protective and morphogenetic mechanisms of reactions in plant cells in respect to hydrogen peroxide production.

3,3'-Diaminobenzidine↗

500-MHz proton homonuclear Overhauser evidence for additional base pair in the common arm of eukaryotic ribosomal 5S RNA: wheat germ.

A "common-arm" fragment from wheat germ (Triticum aestivum) 5S RNA has been produced by enzymatic cleavage with RNase T1 and sequenced via autoradiography of electrophoresis gels for the end-labeled fragments obtained by further RNase T1 partial digestion. The existence, base pair composition, and base pair sequence of the common arm are demonstrated for the first time by means of proton 500-MHz nuclear magnetic resonance. From Mg2+ titration, temperature variation, ring current calculations, sequence comparisons, and proton homonuclear Overhauser enhancement experiments, additional base pairs in the common arm of the eukaryotic 5S RNA secondary structure are detected. Two base pairs, G41 X C34 and A42 X U33 in the hairpin loop, could account for the lack of binding between the conserved GAAC segment of 5S RNA and the conserved Watson-Crick-complementary GT psi C segment of tRNAs.

Base Composition↗