Speciation in the genus Stevia of Mexico and Brazil
Grant-in-Aid for Scientific Research (B)
|Allocation Type||Single-year Grants|
|Research Institution||KYUSHU UNIVERSITY|
YAHARA Tetsukazu Kyushu University, Faculty of Science, Professor, 大学院・理学研究院, 教授 (90158048)
WATANASBE Kuniaki Kobe University, Faculty of Science, Professor, 理学部, 教授 (80031376)
KAWAHARA Takayuki Forestry & Forest Product Research Institute, Project leader, 札幌支所, 研究室長(研究職) (90221902)
MISHIMA Misako Kyushu University, University Museum, Research Associate, 総合研究博物館, 助手 (30346770)
HIRAMATSU Michikazu Kyushu University, Faculty of Agriculture, Research Associate, 大学院・農学研究院, 助手 (30264104)
SOEJIMA Akiko Osaka Prefecture University, College of Integrated Arts and Sciences, Research Associate, 総合科学部, 助手 (00244674)
小林 史郎 九州大学, 大学院・理学研究院, 学術振興会特別研究員
|Project Period (FY)
2002 – 2003
Completed(Fiscal Year 2003)
|Budget Amount *help
¥14,800,000 (Direct Cost : ¥14,800,000)
Fiscal Year 2003 : ¥7,100,000 (Direct Cost : ¥7,100,000)
Fiscal Year 2002 : ¥7,700,000 (Direct Cost : ¥7,700,000)
|Keywords||Mexico / Brazil / Sexual reproduction / Asexual reproduction / Polyploidy / AFLP analysis / Speciation / ステビア属 / AFLP / 進化速度|
An interesting challenge in modem plant systematics is to establish a synthetic case study for a particular group of plants that shows conspicuous adaptive divergence by reconstructing a phylogenetic relationship among almost all species of the group. The genus Stevia (Asteraceae; Eupatorieae) provides a good opportunity for such study because it contains extremely high divergence in life histry traits and reproductive systems.
We already studied phylogenetic relationship among Mexican species, but the following questions remain unanswered. The purpose of this project was to collect materials for answering these questions by carrying out a series of field expecitions in Mexico and Brazil.
(1)Whether an extremely polymorphic species Stevia origanoides is a single biological species or a complex of some cryptic species?
(2)Is there any agamospermous polyploidy in Brazil?
(3)How Mexican and Brazilian species are related to each other?
To answer the question (1), we carried out field surveys in
Durango, Jalisco, Michoacan, Guerrero and Oaxaca states of Mexico. As a results, co-occurrence of more than two cryptic diploid species was observed in five different areas. AFLP analysis showed that of two pairs of cryptic species were recently diverged as a result of adaptation to different environmental conditions of rocky habitats while two cryptic species in distinct ecological habitats were diverged at the base of phylogeny. These findings suggest that Stevia origanoides sensu lato continued to diverge to different environmental conditions since its origin.
To answer the question (2), we carried out field surveys in Sao Paulo, Santa Catarina, and Rio Grande do Sul states of Brazil. Cytological examinations of the materials collected revealed that all species of Stevia in Brazil were sexual diploids
To answer the question (3), we constructed a phylogenetic tree of Mexican and Brazilian species of Stevia by using ITS sequences. The results showed that Brazilian species is a branch of Mexican Stevia. Less
Research Products (9results)