Bread wheat (or common wheat, Triticum aestivum) is an allohexaploid (AABBDD, 2n = 6x = 42) that arose by hybridization between a cultivated tetraploid wheat T. turgidum (AABB, 2n = 4x = 28) and the wild goatgrass Aegilops tauschii (DD, 2n = 2x = 14). Polyploidization provided niches for rigorous genome modification at cytogenetic, genetic, and epigenetic levels, rendering a broader spread than its progenitors. This review summarizes the latest advances in understanding gene regulation mechanisms in newly synthesized allohexaploid wheat and possible correlation with polyploid growth vigor and adaptation. Cytogenetic studies reveal persistent association of whole-chromosome aneuploidy with nascent allopolyploids, in contrast to the genetic stability in common wheat. Transcriptome analysis of the euploid wheat shows that small RNAs are driving forces for homoeo-allele expression regulation via genetic and epigenetic mechanisms. The ensuing non-additively expressed genes and those with expression level dominance to the respective progenitor may play distinct functions in growth vigor and adaptation in nascent allohexaploid wheat. Further genetic diploidization of allohexaploid wheat is not random. Regional asymmetrical gene distribution, rather than subgenome dominance, is observed in both synthetic and natural allohexaploid wheats. The combinatorial effects of diverged genomes, subsequent selection of specific gene categories, and subgenome-specific traits are essential for the successful establishment of common wheat.
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http://dx.doi.org/10.1016/j.molp.2015.02.016 | DOI Listing |
Physiol Mol Biol Plants
December 2024
Department of Bioengineering and Biotechnology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand 835215 India.
BMC Plant Biol
November 2024
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
J Genet Genomics
October 2024
State Key Lab of Crop Genetics & Germplasm Enhancement and Utilization, Cytogenetics Institute, Nanjing Agricultural University/JCIC-MCP/Zhongshan Biological Breeding Laboratory, Nanjing, Jiangsu 210095, China. Electronic address:
Polyploidization in plants often leads to increased cell size and grain size, which may be affected by the increased genome dosage and transcription abundance. The synthesized Triticum durum (AABB)-Haynaldia villosa (VV) amphiploid (AABBVV) has significantly increased grain size, especially grain length, than the tetraploid and diploid parents. To investigate how polyploidization affects grain development at the transcriptional level, we perform transcriptome analysis using the immature seeds of T.
View Article and Find Full Text PDFJ Agric Food Chem
February 2024
School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China.
Common wheat ( L.) is a global staple food, while nitrogen (N) limitation severely hinders plant growth, seed yield, and grain quality of wheat. Genetic variations in the responses to low N stresses among allohexaploid wheat (AABBDD, 2 = 6 = 42) genotypes emphasize the complicated regulatory mechanisms underlying low N tolerance and N use efficiency (NUE).
View Article and Find Full Text PDFCurr Genomics
December 2023
Morden Research and Development Centre, Agriculture and Agri-Food Canada, Morden, MB R6M 1Y5, Canada.
Wheat, a crucial crop for the pursuit of food security, is faced with a plateauing yield projected to fall short of meeting the demands of the exponentially increasing human population. To raise global wheat productivity levels, strong efforts must be made to overcome the problems of (1) climate change-induced heat and drought stress and (2) the genotype-dependent amenability of wheat to tissue culture, which limits the success of recovering genetically engineered plants, especially in elite cultivars. Unfortunately, the mainstream approach of genetically engineering plant protein-coding genes may not be effective in solving these problems as it is difficult to map, annotate, functionally verify, and modulate all existing homeologs and paralogs within wheat's large, complex, allohexaploid genome.
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