PubMed · 910149
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C M Stowe, T P O'Leary, T Kommedahl. 1977-11-18. Amaranth: use as food.. https://doi.org/10.1126/science.198.4318.668
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BACKGROUND: Grain amaranth has recently gained global attention as a promising crop alternative to traditional cereals due to its nutritional value and adaptability to various growing conditions. Although gene banks conserve extensive collections of amaranth germplasm, the genomic and phenotypic characterization of these resources is limited, which hinders their full utilization in breeding programs. A major challenge is the lack of high-throughput genotyping assays essential for comprehensive genomic characterization and trait mapping. High-density SNP arrays have become standard tools for genome-wide analysis across multiple loci, enabling molecular breeding across a range of crop species. RESULTS: In this study, we developed a 64 K high-throughput SNP genotyping array named "AmahySNP", using Affymetrix® Axiom® technology. The array contains 64,069 high-density SNPs distributed across both genic (55.17%) and non-genic (44.83%) regions of the Amaranthus hypochondriacus genome. The genic region includes 8,879 genes, which consist of 4,830 single-copy genes and 4,049 multi-copy genes distributed across 16 scaffolds. These genes cover various functional regions, including exons (10.5%), introns (40.1%), 5'UTRs (1.6%), and 3'UTRs (2.9%), respectively. The AmahySNP array was effectively utilized for population structure analysis, genetic diversity studies, core development, and genome wide association studies (GWAS) in amaranth germplasm. A representative core set of 112 accessions was identified, which includes two released varieties (Annapurna and Suvarna) and 100 diverse accessions from 12 different regions, representing 12% of the total 917 accessions evaluated. Phylogenetic analysis revealed three major genetic clusters, independent of their geographical origins. GWAS conducted using 22,763 polymorphic SNPs from 540 genotypes identified 13 novel loci associated days to flowering (DTF) trait, seven of which were located within annotated genes. CONCLUSIONS: The AmahySNP 64 K SNP chip a valuable genomic tool for amaranth research and breeding with a strong potential to accelerate its genetic improvement. It enables high-throughput genotyping for a wide range of applications, including GWAS and other genomic studies, and will significantly advance the exploration of natural genetic variations. Ultimately, this resource will empower amaranth breeders to develop improved amaranth cultivars with enhanced crop yield, resilience, and nutritional quality, contributing to global food security and sustainable agriculture.
Cyclotides are small disulphide-rich peptides found in plants from the violet (Violaceae), coffee (Rubiaceae) and cucurbit (Cucurbitaceae) families. They have the distinguishing structural features of a macrocyclic peptide backbone and a cystine knot made up of six conserved cysteine residues, which makes cyclotides exceptionally stable. Individual plants express a suite of cyclotides in a wide range of tissue types, including leaves, flowers, stems and roots and it is thought that their natural function in plants is as defence agents. This proposal is supported by their high expression levels in plants and their toxic and growth retardant activity in feeding trials against Helicoverpa spp. insect pests. This review describes the structures and activities of cyclotides with specific reference to their insecticidal activity and compares them with structurally similar cystine knot proteins from peas (Pisum sativum) and an amaranthus crop plant (Amaranthus hypocondriancus). More broadly, cystine knot proteins are common in a wide range of organisms from fungi to mammals, and it appears that this interesting structural motif has evolved independently in different organisms as a stable protein framework that has a variety of biological functions.
BACKGROUND AND AIMS: Determining the mode of action of allelochemicals is one of the challenging aspects in allelopathic studies. Recently, allelochemicals have been proposed to cause oxidative stress in target tissue and induce an antioxidant mechanism. alpha-Pinene, one of the common monoterpenoids emitted from several aromatic plants including forest trees, is known for its growth-inhibitory activity. However, its mechanism of action remains unexplored. The aim of the present study was to determine the inhibitory effect of alpha-pinene on root growth and generation of reactive oxygen species, as indicators of oxidative stress and changes in activities of antioxidant enzymes. METHODS: Effects of alpha-pinene on early root growth were studied in five test species, Cassia occidentalis, Amaranthus viridis, Triticum aestivum, Pisum sativum and Cicer arietinum. Electrolyte leakage, lipid peroxidation, hydrogen peroxide generation, proline accumulation, and activities of the enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), catalase (CAT) and glutathione reductase (GR) were studied in roots of C. occidentalis. KEY RESULTS: alpha-Pinene inhibited the radicle growth of all the test species. Exposure of C. occidentalis roots to alpha-pinene enhanced solute leakage, and increased levels of malondialdehyde, proline and hydrogen peroxide, indicating lipid peroxidation and induction of oxidative stress. Activities of the antioxidant enzymes SOD, CAT, GPX, APX and GR were significantly elevated, thereby indicating the enhanced generation of reactive oxygen species (ROS) upon alpha-pinene exposure. Increased levels of scavenging enzymes indicates their induction as a secondary defence mechanism in response to alpha-pinene. CONCLUSIONS: It is concluded that alpha-pinene inhibits early root growth and causes oxidative damage in root tissue through enhanced generation of ROS, as indicated by increased lipid peroxidation, disruption of membrane integrity and elevated antioxidant enzyme levels.