Ribosomal DNA locus variation and REMAP analysis of the diploid and triploid complexes ofLilium lancifolium

Abstract

Lilium lancifolium Thunb. (2n = 2x = 24) is a cytologically conspicuous species with both diploids and triploids in nature. Cytological and molecular genetic analyses were carried out in both diploids and triploids that were collected from 55 geographical locations in Korea, Japan, and China. While the 5S rRNA gene loci were located at duplicated loci on the long arm of chromosome 2, the 45S rRNA gene loci were present in chromosomes 1, 2, 4, 6, 7, and 11. While the loci on chromosomes 1 and 7 were constant, the loci on chromosomes 2, 4, 6, 7, and 11 were variable in some plants so that the L. lancifolium accessions were grouped into 7 cytotypes in diploids and 12 cytotypes in triploids. REMAP marker analysis revealed that the diploids were classified into seven clusters, and the triploids were classified into a large cluster. Geographic, cytological, and genetic differentiations were not related in both the diploid and triploid accessions of L. lancifolium. Thus, current genetic variations occurred prior to the geographic differentiation in both diploids and triploids, and the 45S rDNA cytotype variations occurred after geographic differentiation in the current habitats of L. lancifolium.

Karyotype and Fluorescence In Situ Hybridization Analysis of 15 Lilium Species from China

“…One possible explanation is that the tandem repeats of rDNA clusters permit chromosomal rearrangements that move the nuclear organization regions (NORs) to other chromosomes that did not previously have rDNA sequences. Nguyen et al (2016) studied diploid and triploid L. lancifolium and reported that the 45S rRNA genes were located on chromosomes 1, 2, 4, 6, 7, and 11, which did not conform to our results, particularly the loci located on chromosomes 3, 4, and 7. In our research, we did not find 45S rRNA signals on chromosomes 4 and 7, but we found signals located on chromosome 3, even though three of their materials were collected from the same region as ours.…”

“…3I,4I,and 5I). This phenomenon has only been observed in one other Chinese Lilium species, L. rosthornii (Liu et al, 2016), but Nguyen et al (2016) also reported this phenomenon in several diploid L. lancifolium materials distributed in Korea. It has also been observed in other plant species (Liu et al, 2006).…”

“…In addition to karyotypes, FISH is another technique providing chromosomal markers that show the positions of specific genes, thereby permitting chromosomal identification. The use of FISH with 5S and 45S rDNA probes has provided molecular cytogenetic markers for the identification of somatic chromosomes in different Lilium species (Lee et al, 2014;Liu et al, 2006;Nguyen et al, 2016;Sultana et al, 2010Sultana et al, , 2011. FISH has been used for the verification of Lilium hybrids for many years (Lee et al, 2014;Lim et al, 2001aLim et al, , 2001bSultana et al, 2011).…”

Climatic niche characteristics of native and invasive Lilium lancifolium

“…(= L. tigrinum Ker Gawl.) constitutes a polyploid complex involving diploid (2 n = 2 x = 24) and triploid (2 n = 3 x = 36) forms 39–43 , which are morphologically hardly distinguishable 44 (see Chung et al . 42 for the full description of the plant).…”

“…Although the origin of the triploid cytotype of L. lancifolium has been a matter of debate during the past half century, most of the studies carried out during the last decade strongly support an autopolyploid origin, including classical and modern cytogenetic approaches 45–47 and genetic diversity studies 42,48 . The diploid cytotype, despite being locally common, has a very narrow distribution, occurring in western and southern coastal areas of the Korean Peninsula (including Jeju Island and surrounding smaller islands), and in the Japanese islands of Tsushima and Iki 41,43 , although it has also been once cited in Russia, near Vladivostok, in Primorsky Region 49 . Compared to the relatively limited distribution of diploid L. lancifolium , triploid forms would have a much broader distribution occurring in the inland areas of the Korean Peninsula, in coastal areas of eastern Korea, and in Jeju and Tsushima islands 41,43 .…”