Molecular phylogenetics and the evolution of fruit and leaf morphology of Dichaea (Orchidaceae: Zygopetalinae).
نویسندگان
چکیده
BACKGROUND AND AIMS The orchid genus Dichaea, with over 100 species found throughout the neotropics, is easily recognized by distichous leaves on long stems without pseudobulbs and flowers with infrastigmatic ligules. The genus has previously been divided into four sections based primarily on presence of ovary bristles and a foliar abscission layer. The aim of this work is to use DNA sequence data to estimate phylogenetic relationships within Dichaea and map the distribution of major morphological characters that have been used to delimit subgenera/sections. METHODS Sequence data for the nuclear ribosomal internal transcribed spacers and plastid matK, trnL intron, trnL-F spacer and ycf1 for 67 ingroup and seven outgroup operational taxonomic units were used to estimate phylogenetic relationships within Dichaea. Taxa from each of the four sections were sampled, with the greatest representation from section Dichaea, the most diverse and taxonomically puzzling group. KEY RESULTS Molecular data and morphology support monophyly of Dichaea. Results indicate that section Dichaeopsis is polyphyletic and based on symplesiomorphies, including deciduous leaves and smooth ovaries that are widespread in Zygopetalinae. There are at least three well-supported clades within section Dichaeopsis. Section Pseudodichaea is monophyletic and defined by setose ovaries and leaves with an abscission layer. Sections Dichaea and Dichaeastrum are monophyletic and defined by pendent habit and persistent leaves. Section Dichaeastrum, distinguished from section Dichaea primarily by a glabrous ovary, is potentially polyphyletic. CONCLUSIONS The leaf abscission layer was lost once, occurring only in the derived sections Dichaea and Dichaeastrum. The setose fruit is a more homoplasious character with several losses and gains within the genus. We propose an informal division of the genus based upon five well-supported clades.
منابع مشابه
Comparative labellar micromorphology of Zygopetalinae (Orchidaceae).
BACKGROUND AND AIMS Molecular evidence indicates that the Neotropical sub-tribe Zygopetalinae is sister to Maxillariinae. Most members of the latter sub-tribe have deceit pollination strategies, but some species produce rewards such as nectar, pseudopollen, resin and wax, and are pollinated by a range of pollinators that include stingless bees (Meliponini), wasps and hummingbirds. By contrast, ...
متن کاملMolecular genetic control of leaf lifespan in plants - A review
Leaf senescence constitutes the last stage of leaf development in plants and proceeds through a highly regulated program in order to redistribution of micro- and macro-nutrients from the senescing leaves to the developing/growing plant organs. Initiation and progression of leaf senescence is accompanied by massive sequential alterations at various levels of leaf biology including leaf morpholog...
متن کاملHigher level phylogeny and evolutionary trends in Campanulaceae subfam. Lobelioideae: molecular signal overshadows morphology.
Relationships within the subfamily Lobelioideae in Campanulaceae are inferred from DNA sequence variation in the rbcL and ndhF genes, and the trnL-F region including the trnL intron and the trnL-F intergenic spacer. Results derived from Bayesian and parsimony analyses provide evidence for the long-suspected paraphyly of the genus Lobelia, comprising over 400 species as presently circumscribed. ...
متن کاملEvolution of Mexican Bursera (Burseraceae) inferred from ITS, ETS, and 5S nuclear ribosomal DNA sequences.
I reconstructed a phylogeny of 66 species and varieties of Bursera and 9 outgroup species using sequences of the internal transcribed spacer region (ITS), the 5S non-transcribed region (5S-NTS), and the external transcribed region (ETS) of nuclear ribosomal DNA. This study extends a previously proposed parsimony-based phylogenetic study that used the ITS sequences of 57 Bursera species and five...
متن کاملMolecular evolution of rbcL in the mycoheterotrophic coralroot orchids (Corallorhiza Gagnebin, Orchidaceae).
The RuBisCO large subunit gene (rbcL) has been the focus of numerous plant phylogenetic studies and studies on molecular evolution in parasitic plants. However, there has been a lack of investigation of photosynthesis gene molecular evolution in fully mycoheterotrophic plants. These plants invade pre-existing mutualistic associations between ectomycorrhizal trees and fungi, from which they obta...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Annals of botany
دوره 104 3 شماره
صفحات -
تاریخ انتشار 2009