The Construction of a Standard Karyotype of Intermediate Wheatgrass and Its Potential Progenitor Species

The genome composition of intermediate wheatgrass (IWG; <i>Thinopyrum intermedium</i> (Host) Barkworth and D.R. Dewey; 2n = 6x = 42) is complex and remains to be a subject of ongoing investigation. This study employed fluorescence in situ hybridization (FISH) to analyze the karyotype of...

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Bibliographic Details
Main Authors: Lin Wang, Shuang Liang, Fei Qi, Yinguang Bao, Richard R.-C. Wang, Xingfeng Li
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Plants
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Online Access:https://www.mdpi.com/2223-7747/14/2/196
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Summary:The genome composition of intermediate wheatgrass (IWG; <i>Thinopyrum intermedium</i> (Host) Barkworth and D.R. Dewey; 2n = 6x = 42) is complex and remains to be a subject of ongoing investigation. This study employed fluorescence in situ hybridization (FISH) to analyze the karyotype of <i>Th. intermedium</i> and its related species. With the St<sub>2</sub>-80 probe derived from <i>Pseudoroegneria strigosa</i> and the pDb12H probe from <i>Dasypyrum breviaristatum</i>, FISH analysis classified the chromosomes of <i>Th. intermedium</i> as <b>J<sup>vs</sup>J<sup>vs</sup>J<sup>r</sup>J<sup>r</sup>StSt</b>. FISH karyotype was established using pSc119.2-1, (GAA)<sub>10</sub>, AFA-3, AFA-4, pAs1-1, pAs1-3, pAs1-4, and pAs1-6 as a combined multiplex oligonucleotide probe. MATO software was used to analyze chromosome length, arm ratio, and karyotype structure. The karyotype formula of <i>Th. intermedium</i> is K(2n) = 6X = 42 = 36m + 6sm, and that of <i>Th. junceiforme</i> is K(2n) = 4X = 28 = 22m + 6sm. The karyotype formula of <i>Th. elongatum</i> and <i>Th. bessarabicum</i> is K(2n) = 2X = 14 = 12m + 2sm, of <i>Ps. spicata</i> is K(2n) = 2X = 14 = 2M + 12m, and of <i>Da. villosum</i> is K(2n) = 2X = 14 = 12m + 2sm. Based on the results of FISH, standard karyotypes of <i>Th. intermedium</i> and its potential progenitor species were constructed. These standard karyotypes revealed that there was evolutionary parallelism between genome and karyotype, but due to the complexity of evolution, the FISH signal of <i>Th. intermedium</i> was abundant and asymmetrical.
ISSN:2223-7747