PubMed · 15281464
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
Richard W Weber. 2004. Johnson grass, Sorghum halepense.. https://doi.org/10.1016/s1081-1206(10)61441-x
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Johnsongrass [Sorghum halepense (L.) Pers.] is an allopolyploid, rhizomatous, perennial grass species and one of the most troublesome weeds in global agriculture. We assembled the first Johnsongrass genome to clarify poorly understood genetic factors influencing variable rates of crop-wild hybridization with cultivated sorghum [S. bicolor (L.) Moench]. The draft genome assembly has a total size of 3.26 Gb and BUSCO completeness of 95.3%. We also report the first evolutionary analysis of INHIBITION OF ALIEN POLLEN (IAP), the only known cross-(in)compatibility locus in the genus. Our results reveal an evolutionary history of genome instability, including the loss of distinct parental subgenomes, and suggest that Nebraska accession 'J-37,' the genome donor, is a segmental allotetraploid that may function as a diploid or aneuploid during meiosis. Genome instability could explain observations of variable ploidies in Johnsongrass and facilitate ongoing hybridization with sorghum where gamete ploidies and IAP alleles match. Given this information, we provide a suggested research framework for studying evolution and gene expression in the Sorghum genus where crop-wild hybridization occurs and for predicting the potential for hybridization between specific crossing partners. Collectively, this work will bolster efforts to study and manage reproductive biology in other crop-wild polyploid complexes.
Polyploidy has repeatedly shaped grass evolution, yet direct observations of how polyploid-derived chromosomes behave when returned to diploidy remain rare. Interspecific crosses between diploid Sorghum bicolor and tetraploid hybrids derived from Sorghum halepense generate mixed-ploidy progeny, providing an opportunity to examine chromosome transmission during the early stages of diploidization. Using genome-wide SNP markers, we characterized chromosomal inheritance patterns in 2 diploid and 2 tetraploid families derived from these crosses. Genotype-dosage profiles alone distinguished diploids from tetraploids with complete accuracy, reflecting strong ploidy-dependent differences in dosage-class distributions. Although diploid progeny retained much of the halepense-derived genomic background, several genomic intervals exhibited extended, nonrandom runs of S. bicolor homozygosity that remained polymorphic in corresponding tetraploid populations. These patterns, together with recurrent segregation distortion across independent families, suggest that the transition from tetraploidy to diploidy can expose allelic combinations that differ in transmission or viability. Analyses of flowering time further indicated that diploid and tetraploid derivatives possess distinct genomic architectures, with major association peaks occurring in different chromosomal regions across ploidy levels. Collectively, these results indicate that early diploidization involves nonrandom retention and loss of parental haplotypes shaped by both selective and structural constraints. The diploid extractions characterized here provide a rare empirical system for investigating the early stages of diploidization and a practical framework for studying and eventually mobilizing polyploid-derived variation for sorghum germplasm development. However, broader integration into elite breeding programs will require additional evaluation of cross-fertility, meiotic behavior, and chromosomal stability across diverse breeding backgrounds.
The Ankyrin-repeat proteins (ANKs) play a key role in plant development and in response to abiotic stress. This research identified family members of the ANK genes in Sorghum bicolor at the whole-genome level, analyzed their sequence characteristics, evolutionary relationships, and expression patterns, and provided a scientific basis for elucidating the functionality of SbANK genes and for salt-tolerant breeding. Using bioinformatics methods, this study conducted a comprehensive identification of the SbANK gene family, analyzing its physicochemical properties, domain composition, chromosomal distribution, colinearity relationships, promoter cis-acting elements, and conserved protein motifs. Transcriptomic data and qRT-PCR were used to detect changes in their expression under salt stress. A total of 186 ANK family members were identified in the Sorghum bicolor genome, classified into 13 subfamilies and unevenly distributed across 10 chromosomes. Intra-species colinearity analysis revealed 7 pairs of duplicated genes, while inter-species colinearity analysis showed that S. bicolor and Oryza sativa share 88 pairs of orthologs, far exceeding the number found in Arabidopsis thaliana (11 pairs). Promoter analysis indicated that SbANK genes are enriched with cis-acting elements associated with hormone responses (particularly MeJA elements, accounting for 51.7%) and stress responses (particularly anaerobic-inducible elements, accounting for 60.9%). Transcriptomic expression analysis revealed that SbANK genes exhibit distinct tissue specificity, with the ANK-IQ subfamily highly expressed in leaves and the ANK-M subfamily showing the most widespread response under salt stress. Expression levels of the 10 candidate genes showing the most significant responses to salt stress were analyzed using qRT-PCR. The results indicated that SbANK91, SbANK135, and SbANK136 were significantly upregulated under 200 mmol/L NaCl treatment. The SbANK family is distinguished by a large number of member genes and structural diversity, with the ANK-M subfamily being the primary group responding to salt stress. SbANK91, SbANK135, and SbANK136 are identified as putative candidate genes for salt stress responses.