Five Fabaceae Karyotype and Phylogenetic Relationship Analysis Based on Oligo-FISH for 5S rDNA and (AG3T3)3

Abstract

Most Fabaceae have nitrogen fixation abilities and are valuable forage and medicinal resources. However, cytogenetic data of many Fabaceae species are unclear. Karyotypes reveal cytological characteristics and are crucial to understanding the organization and evolution of chromosomes in species. Oligo-FISH can reveal genetic composition and karyotype variation patterns with rapid and efficient results. Karyotype analysis of five Fabaceae species by oligonucleotide probes showed that: Robinia pseudoacacia, karyotype formula 2n = 2x = 20m + 2sm, cytotype 2B, arm ratio 3.4821, eight chromosomes distributed 5S rDNA signal. The karyotype formula of Robinia pseudoacacia ‘idaho’ was 2n = 2x = 20m + 2sm, cytotype 1A, arm ratio 1.8997, and 5S rDNA signal was distributed on six chromosomes. Karyotype of Robinia pseudoacacia f. decaisneana 2n = 2x = 20m + 2sm, cytotype 1B, arm ratio 2.0787, the distribution of eight chromosomes with 5S rDNA signal. Karyotype formula of Styphnolobium japonicum 2n = 2x = 14m + 12sm + 2st, cytotype 2B, arm ratio 2.6847, two chromosomes have 5S rDNA signal. Amorpha fruticose karyotype 2n = 2x = 38m + 2sm, cytotype 1B, arm ratio 3.2058, four chromosomes possessed 5S rDNA signal. Both ends of all species’ chromosomes have (AG3T3)3 signals. The results of this study provide chromosome numbers and a physical map, contributing to the construction of the Oligo-FISH barcode and providing molecular cytogenetics data for Fabaceae.

FISH Mapping of Telomeric and Non-Telomeric (AG3T3)3 Reveal the Chromosome Numbers and Chromosome Rearrangements of 41 Woody Plants

“…Overall, (AG 3 T 3 ) 3 was found to occur in Z. mays and 41 woody plants, belonging to 37 species, 27 genera, and 18 families. Previous research has reported the occurrence of (AG 3 T 3 ) 3 in 14 woody species, including A. fruticose [ 51 ], B. soulieana [ 50 ], B. diaphana [ 50 ], C. campanulatus [ 52 ], F. pennsylvanica [ 49 ], H. mutabilis [ 47 ]), H. rhamnoides [ 11 ], J. regia [ 48 ], J. sigillata [ 48 ], L. lucidum [ 49 ], L. × vicaryi [ 49 ], R. pseudoacacia [ 51 ], S. oblata [ 49 ], and S. japonicum [ 51 ].…”

“…The location of (AG 3 T 3 ) 3 at chromosome termini may indicate the integrality of the chromosome, thus ensuring the accuracy of chromosome counting. Occasionally, (AG 3 T 3 ) 3 has been detected not only at chromosome termini, but also as intercalary bands in A. fruticose , R. pseudoacacia , S. japonicum [ 51 ], C. campanulatus [ 52 ], and H. rhamnoides [ 11 ]. In A. fruticose , R. pseudoacacia , and S. japonicum, only two weak non-telomeric signals have been described, while H. rhamnoides presented two very strong, two clear, and another two weak non-telomeric signals in six chromosomes.…”

“…Next, the samples were fixed in glacial acetic acid for 5–10 min, then kept in 75% ethyl alcohol. Chromosome preparation was carried out according to the procedure described by Luo et al [ 51 ]. As these techniques have been described elsewhere, they will be detailed briefly here.…”

“…Subsequently, hybridized chromosomes were washed with 2× SSC and ddH 2 O twice for 5 min at room temperature, and air-dried. Finally, they were counterstained with 4,6-diamidino-2-phenylindole (DAPI, Vector Laboratories, Inc., Burlingame, CA, USA) for 5 min, referring to the procedure described by Luo et al [ 51 ]. Slides were checked using an Olympus BX-63 microscope (Olympus Corporation, Tokyo, Japan), and FISH images were captured by a DP-70 CCD camera connected to the microscope.…”

“…sinensis [ 11 ], Robinia pseudoacacia L., R. pseudoacacia ‘idaho’, R. pseudoacacia f. decaisneana (Carr.) Voss, Styphnolobium japonicum (L.) Schott, Amorpha fruticose L. [ 51 ], and C. campanulatus R.H. Chang and C.S. Ding [ 52 ].…”