AFLP and ISSR analysis reveals high genetic variation and inter-population differentiation in fragmented populations of the endangered Litsea szemaois (Lauraceae) from Southwest China

• Published in: Plant systematics and evolution 2008-07, Vol.273 (3/4), p.237-246
• Main Authors: Ci, Xiu-qin, Chen, Jun-qiu, Li, Qiao-ming, Li, Jie
• Format: Article
• Language: English
• Subjects: Amplified fragment length polymorphism; Biodiversity; Biodiversity conservation; Biomedical and Life Sciences; Conservation; Cultivation; Differentiation; Endangered & extinct species; Endangered populations; Endangered species; Endemic species; Evolutionary genetics; Genetic analysis; Genetic diversity; Genetic variation; Habitat conservation; Habitat fragmentation; Heterozygosity; Insects; Lauraceae; Life Sciences; Litsea; Markers; Original Article; Outbreeding; Plant Anatomy/Development; Plant Ecology; Plant Sciences; Plant Systematics/Taxonomy/Biogeography; Plants; Pollination; Population; Population decline; Population differentiation; Population genetics; Population number; Population size; Population structure; Populations; Rainforests; Rubber; Seedlings; Species diversity; Tropical forests; Tropical plants; Wildlife conservation
• ISSN: 0378-2697; 1615-6110; 2199-6881
• DOI: 10.1007/s00606-008-0012-4

Litsea szemaois (Lauraceae) is an endemic and endangered species from the tropical rain forests of Xishuangbanna, southern Yunnan, SW China, but habitat fragmentation, especially exacerbated by rubber planting, has caused a decline in population size of the species. AFLP and ISSR were used to investigate the genetic diversity and population structure of eight populations from across its known distribution. Three AFLP and ten ISSR primer combinations produced a total of 203 and 77 unambiguous and repeatable bands respectively, of which 164 (80.8%) and 67 (87.0%) were polymorphic for the two markers. These two markers showed that Litsea szemaois exhibits comparatively high genetic diversity at species level (heterozygosity (hs) = 0.2109) relative to some other Lauraceae. Most of the genetic variation was partitioned within populations, but genetic differentiation between populations was significant and relatively high (Φst = 0.2420, θB = 0.1986) compared with other tropical plants. The genetic characteristics of L. szemaois may be related to its outbreeding system, insect pollination and fragmented distribution. Because L. szemaois is dioecious and slow to mature, ex situ conservation across its genetic diversity is unlikely to succeed, although seedlings grow well under cultivation. Thus, in situ conservation is very important for this endangered species, especially as only 133 adult individuals are known in the wild. In particular, the Nabanhe and Mandian populations should be given a high conservation priority due to their higher genetic diversity, larger population size and better field condition, but wider sampling is required across all populations to determine additional areas with significant genetic conservation value.