J Syst Evol ›› 2017, Vol. 55 ›› Issue (1): 25-33.DOI: 10.1111/jse.12217

• Research Articles • Previous Articles     Next Articles

Natural hybridization between Torreya jackii and T. grandis (Taxaceae) in southeast China

Yi-Xuan Kou1, Kun Xiao2, Xiao-Rong Lai1, Yu-Jin Wang3, and Zhi-Yong Zhang1*   

  1. 1Laboratory of Subtropical Biodiversity, Jiangxi Agricultural University, Nanchang 330045, China
    2College of Life Sciences, Jiangxi Normal University, Nanchang 330022, China
    3State Key Laboratory of Grassland Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
  • Received:2016-03-21 Published:2017-01-12

Abstract: The recognition of natural hybridization can help to understand the origin and maintenance of biodiversity. Based on intermediate morphology and overlapped distribution, Torreya grandis var. jiulongshanensis Z. Y. Li, Z. C. Tang & N. Kang was regarded as a putative natural hybrid between T. jackii Chun and T. grandis Fort. ex Lindl. in southeast China. This study tested the hybridization origin of T. grandis var. jiulongshanensis using nuclear internal transcribed spacer (ITS) and cytoplasm (chloroplast rbcL and rpl16 and mitochondrial rps3) DNA sequences. The results showed that most heterozygous sites of nuclear ITS sequences in T. grandis var. jiulongshanensis showed additivity between T. jackii and T. grandis. Cloned ITS sequences of T. grandis var. jiulongshanensis separately clustered withT. jackii and T. grandis in the phylogenetic analyses. Meanwhile, all of chloroplast and mitochondrial haplotypes of T. grandis var. jiulongshanensis were identical to those of T. jackii, not T. grandis. On the chloroplast DNA phylogenetic trees, T. grandis var. jiulongshanensis were grouped into the clade of T. jackii. These results suggest that T. grandis var. jiulongshanensis is a natural hybrid between T. jackii (maternal parent) and T. grandis (paternal parent). This study also implies that T. grandis should be cultivated with caution near the sites of T. jackii, because the endangered status of the latter might be deteriorated due to hybridization.

Key words: cytoplasm DNA, ITS, natural hybridization, southeast China, Torreya