ABSTRACT
Natural and man-made landscape features are effective geographical
barriers resulting inpopulation differentiation of plant species.
Taihang Mountains in China possess complexly geographical topology and
specific landscape characteristics. Opisopappus taihangensis andO. longilobus , two closely related syntopic Opisthopappusspecies, mainly distribute in the south and north of Taihang Mountains,
respectively. How the landscape of Taihang Mountains affects the
migration / gene exchange between these two species still unclear.
Combined SNP data from restriction-site associated DNA sequencing
(RAD-seq) and recently developed landscape genetic methods (EEMS,
Samβada, LFMM), we conducted a landscape genetic analysis of these two
species. It found that the diversity of O. longilobus was higher
than that of O. taihangensis , the gene flow was mostly from north
to south along Taihang Mountains. However, a general north–south gene
exchange barrier between O. longilobus and O. taihangensiswas detected. Among the landscape factors of Taihang Mountains, eight
was found to be the important ones, including average precipitation in
August, October, and November, solar radiation in August, soil PH,
built-up land, rain-fed cultivated land, and workability. And these
eight factors were closely related to the occurred barriers, indicating
that climatic conditions and human activities rather than geographical
environment resulted in these barriers. Twenty-nine selected SNPs were
identified to be significant correlated with the eight factors,
especially average precipitation in November. Thus, the average
precipitation in November could be regarded as an ecological indicator
for O. longilobus and O. taihangensis . The results
revealed the effect of landscape features on two species and the
adaption on the landscape environment of Taihang Mountains during the
long-term evolution.