Crinum thaianum, commonly known as water onion, is an endangered species which is primarily threatened by flood-control-related habitat destruction and illegal harvesting for export, resulting in a sharp population decline; its genetic data still remains poorly studied. Retrotransposon-based markers have received significant
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Crinum thaianum, commonly known as water onion, is an endangered species which is primarily threatened by flood-control-related habitat destruction and illegal harvesting for export, resulting in a sharp population decline; its genetic data still remains poorly studied. Retrotransposon-based markers have received significant attention due to their higher potential informativeness compared to conventional marker methods in genetic diversity studies. This study focused on the screening of Ty1-
copia retrotransposons, which have been widely studied and are commonly used as molecular markers in various plant species. Ty1-
copia reverse transcriptase (
rt) fragments were amplified using degenerate primers targeting conserved regions, followed by cloning and sequencing. Sequences were screened for
rt gene homology and translated into amino acid sequences. Lineages were assigned by alignment, and phylogenetic analysis was performed for each isolated sequence with a set of well-classified
rt genes. The p-distance values were calculated between the isolated sequences and their closest homologous sequences. A total of 123 isolated sequences were analyzed, representing conserved domains in the
rt gene of Ty1-
copia elements from
C. thaianum and four other
Crinum species. The results revealed sequence homology to the Ale, TAR, or Angela lineages, which showed the closest resemblance to 9, 4, and 110 isolated
rt sequences, respectively. The conserved
rt domain SIYGLKQA was mostly found in Angela (87.27%), while SLY/HGLKQS/L and SLYG/ELKQF/S were mostly found in Ale (66.67%) and TAR (75.00%), respectively. The p-distance values obtained from comparisons with Ty1-
copia elements in other plants suggest that the Angela and TAR lineages are more evolutionarily conserved than the Ale lineage. Whilst our study sheds light on the variety of Ty1-
copia retrotransposons in
C. thaianum and other
Crinum species, further research on additional
Crinum species and other plants is required to enhance our understanding and facilitate future retrotransposon-based marker development.
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