Rajendran Sathishraj, Yoonha Ju, Bikram S Gill, Dal-Hoe Koo
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引用次数: 0
Abstract
Glyphosate resistance in crop weeds is commonly attributed to rapid evolution through the amplification of the target gene, EPSPS (5-enolpyruvylshikimate-3-phosphate synthase). This amplification typically occurs through mechanisms such as unequal recombination, segmental duplications within the target chromosome, or the formation of ring chromosomes and extrachromosomal circular (ecc) DNA elements containing EPSPS. However, structural abnormalities in chromosomes not directly associated with EPSPS amplification have not been documented in the glyphosate-resistant weed population. Here, we describe the presence of a large chromosome found exclusively in the glyphosate-resistant Amaranthus tuberculatus (waterhemp) population but absent in susceptible counterparts. This large chromosome (~ 6 μm) is approximately twice the size of normal chromosomes (~ 2-3 μm) and is present in both male and female euploid plants (2n = 32) in a heteromorphic state. It aroses through pericentromeric heterochromatin expansion and duplications of the 5S rDNA locus but notably lacks the EPSPS gene. The large chromosome pairs with its normal homolog but was not transmitted to progeny in controlled greenhouse matings, suggesting a fitness cost in the absence of glyphosate selection pressure. This large chromosome offers a potential resource for the investigation of chromosome evolution of adaptive traits for glyphosate resistance in A. tuberculatus.
期刊介绍:
Chromosome Research publishes manuscripts from work based on all organisms and encourages submissions in the following areas including, but not limited, to:
· Chromosomes and their linkage to diseases;
· Chromosome organization within the nucleus;
· Chromatin biology (transcription, non-coding RNA, etc);
· Chromosome structure, function and mechanics;
· Chromosome and DNA repair;
· Epigenetic chromosomal functions (centromeres, telomeres, replication, imprinting,
dosage compensation, sex determination, chromosome remodeling);
· Architectural/epigenomic organization of the genome;
· Functional annotation of the genome;
· Functional and comparative genomics in plants and animals;
· Karyology studies that help resolve difficult taxonomic problems or that provide
clues to fundamental mechanisms of genome and karyotype evolution in plants and animals;
· Mitosis and Meiosis;
· Cancer cytogenomics.