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United States Department of Agriculture

Agricultural Research Service

Title: Confirmation of the Hybrid Status of Ilex X Wandoensis Using Molecular Markers

Authors
item Lee, Nam Sook - FORMER ARS EMPLOYEES
item Roh, Mark
item Yeau, Sung Hee - EWHA WOMANS UNIV, KOREA
item Park, Jae Ok - FRUIT CROPS EXT STA,KOREA

Submitted to: Journal of Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 6, 2006
Publication Date: December 27, 2006
Citation: Lee, N.S., Yeau, S.H, Park, J.O. and Roh, M.S. 2006. Molecular evidence for hybridization of Ilex x wandoensis (Aquifolianceae)by RAPD analysis. J. Plant Biological. 49:491-497.

Interpretive Summary: Evergreen I. integra and I. cornuta are reported from the southern parts of the Korean peninsula. A new evergreen, putative hybrid between I. cornuta and I. integra was discovered on Wando, Korea, by Carl Miller and Ted Dudley, and the name Ilex ×wandoensis was proposed based on morphological characters. Ilex ×wandoensis has intermediate characters, like serrated leaf margins, while I. cornuta has spiny leaf margins and I. integra has entire leaf margins. However, the leaves of Ilex ×wandoensis are variable. Whether Ilex ×wandoensis is a natural hybrid or simply a variety of one of these other species has not been investigated employing molecular techniques. Based on the intermediate morphological characters, I. ×wandoensis was initially described as a putative natural hybrid between I. cornuta and I. integra. Using molecular markers generated from random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR), hybridization and introgression in natural populations of the I. ×wandoensis complex collected from Wando Island and Jeju-Do Province of Korea was revealed. Several marker bands of the putative parent taxa were also found in some populations of I. ×wandoensis, suggesting that I. ×wandoensis is a hybrid between I. cornuta and I. integra. Cluster analyses showed that I. ×wandoensis was more closely related to I. cornuta than to I. integra, suggesting that I. ×wandoensis has backcrossed more with I. cornuta than with I. integra.

Technical Abstract: Based on the intermediate morphological characters such as serrated leaf margins and female flowers, Ilex ×wandoensis was initially described as a putative natural hybrid between I. cornuta and I. integra by Miller and Dudley in 1985, and eventually described as a new hybrid species, I. ×wandoensis C. F. Mill., and M. Kim. Using molecular markers generated from random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR), hybridization and introgression in natural populations of the I. ×wandoensis complex collected from Wando Island (Wando) and Jeju-Do Province (Jeju-Do) of Korea was revealed. Several marker bands of the putative parent taxa were also found in some populations of I. ×wandoensis, suggesting that I. ×wandoensis is a natural hybrid between I. cornuta and I. integra. Other ISSR taxon-specific private markers (private markers) possessed only by I. ×wandoensis suggested that this hybrid arose from a pattern of ancient hybridization. This was supported by the significant morphological and genetic variations observed within and among populations of I. ×wandoensis. Although the three taxa were separated into three clades in the UPGMA dendrograms generated for RAPD and ISSR, some accessions identified using morphological characters did not cluster with other members of their assigned taxa on the dendrograms, which could be the result of introgressive hybridization. But dendrograms showed that I. ×wandoensis was more closely related to I. cornuta than to I. integra, suggesting that I. ×wandoensis has backcrossed more with I. cornuta than with I. integra. ISSR is more variable and informative in this group of Ilex than RAPD based on the number of total, private, and shared bands, and percent of polymorphic bands.

Last Modified: 9/10/2014
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