Molecular Evolution of the Internal Transcribed Spacers (ITS1 and ITS2) and Phylogenetic Relationships among Species of the Family Cucurbitaceae (original) (raw)
Related papers
Zeitschrift für Naturforschung C, 1989
The use o f intergenic spacer (IG S) fragments o f plant ribosomal D N A (rD N A) for the differ entiation betw een genera and species is tested by cross-hybridization experim ents with different IGS probes o f two Cucurbitaceae, Cucurbita pepo (zucchini) and Cucumis sativus (cucum ber). Hybridization with cloned fragments o f different parts o f the IGS of ribosomal D N A exhibit a different degree o f conservation within and between the Cucurbitaceae genera. In general, Cucur bita species seem to be closer related to each other than the Cucumis species. A repetitive elem ent o f the external transcribed spacer (E T S) shows a more genus-specific pattern, reacting only with the respective genera; the region preceding the ETS is conserved between the Cucurbita species but also cross-hybridizes w eakly with the Cucumis species. A GC-rich elem ent o f the Cucumis sativus IGS ("C fo-cluster") is present in small amounts in Cucumis melo (m elon) and even less represented in other genera o f the Cucurbitaceae.
Molecular evolution of the intergenic spacer in the nuclear ribosomal RNA genes of Cucurbitaceae
Journal of Molecular Evolution, 1993
The intergenic spacer (IGS) of a 10-kbp repeat (clone pRZ7D) of the nuclear 18S, 5.8S, and 25S ribosomal RNA genes ofCucurbita pepo (zucchini) was sequenced and compared to the IGS sequences of two other Cucurbitaceae.Cucurbita maxima (squash), andCucumis sativus (cucumber). The nucleotide sequence and the structural organization of the IGS ofC. pepo andC. maxima are rather similar (between 75 and 100% sequence similarity depending on the region compared). The IGS are mainly composed of three different repeated elements interspersed into unique sequences: GC-rich clusters, a 422-bp AT-rich element including the transcription initiation site (TIS) for RNA polymerase I, and 260-bp repeats in the 5′ external transcribed spacer (D repeats). The TIS is duplicated in the 10-kbp repeat class ofC. pepo, as it is also described for the 11.5-kbp rDNA repeat ofC. maxima. The IGS ofCucumis sativus is also composed of different repeated elements; however, obvious sequence identity to theCucurbita species only occurs around the TIS and the preceding AT-rich region. GC-rich clusters with different primary sequences are present in the IGS of all three plants. Remarkably, the repeated elements in the 5′ETS accumulate TpG and TpNpG motifs, whereas CpG and CpNpG motifs less frequently occur. This accumulation might be caused by the transition of methylated cytosines (inmCpG ormCpNpG motifs) into thymidine via deamination in a previously GC-rich ancestor. The following singular region exhibits 50% G + C inC. pepo, 53% G + C inC. maxima, and 63% G + C inC. sativus. A model for a common ancestor of the 3′IGS for these Cucurbitaceae is proposed.
Plant Systematics and Evolution, 2004
The phylogenetic relationships within the genus Cucumis (a total of 25 accessions belonging to 17 species) were studied using the nuclear ribosomal DNA internal transcribed spacer (ITS) region. The analysis included commercially important species such as melon (C. melo L.) and cucumber (C. sativus). Two additional cucurbit species, watermelon and zucchini, were also included as outgroups. The data obtained reflected the clustering of Cucumis species in four main groups, comprising accessions from cucumber, melon, C. metuliferus and the wild African species. Some of the species clustered in different positions from those reported in classifications previously described by other authors. The data obtained clearly identify a division between the 2n=2x = 14 species (C. sativus) and the 2n = 2x = 24 ones (C. melo and wild species). Within the wild species we identified a subgroup that included C. sagittatus and C. globosus. Oreosyce africana, also classified as Cucumis membranifolius, was shown to be nested within Cucumis. Three accessions previously classified as independent species were shown to be genotypes of Cucumis melo. A set of melon and cucumber SSRs were also used to analyse the Cucumis species and the results were compared with the ITS data. The differential amplification of the SSRs among the accessions made it possible to distinguish three main groups: melon, cucumber and the wild species, though with less detail than applying ITS. Some SSRs were shown to be specific for melon, but other SSRs were useful for producing PCR fragments in all species of the genus.
Proceedings of the National Academy of Sciences, 2002
We have investigated the phylogenetic relationships among six wild and six domesticated taxa of Cucurbita using as a marker an intron region from the mitochondrial nad1 gene. Our study represents one of the first successful uses of a mtDNA gene in resolving inter-and intraspecific taxonomic relationships in Angiosperms and yields several important insights into the origins of domesticated Cucurbita. First, our data suggest at least six independent domestication events from distinct wild ancestors. Second, Cucurbita argyrosperma likely was domesticated from a wild Mexican gourd, Cucurbita sororia, probably in the same region of southwest Mexico that gave rise to maize. Third, the wild ancestor of Cucurbita moschata is still unknown, but mtDNA data combined with other sources of information suggest that it will probably be found in lowland northern South America. Fourth, Cucurbita andreana is supported as the wild progenitor of Cucurbita maxima, but humid lowland regions of Bolivia in addition to warmer temperate zones in South America from where C. andreana was originally described should possibly be considered as an area of origin for C. maxima. Fifth, our data support other molecular results that indicate two separate domestications in the Cucurbita pepo complex. The potential zone of domestication for one of the domesticated subspecies, C. pepo subsp. ovifera, includes eastern North America and should be extended to northeastern Mexico. The wild ancestor of the other domesticated subspecies, C. pepo subsp. pepo, is undiscovered but is closely related to C. pepo subsp. fraterna and possibly will be found in southern Mexico.
Journal of Molecular Evolution, 1995
Two different satellite DNAs exist in the genus Cucurbita which are different with respect to repeat length (350 bp and 170 bp), array size, and sequence homogenization. Whereas the 350-bp satellite DNA is prominent and very homogeneous in all species investigated except for C. maxima and C. lundelliana, the 170bp satellite is rather evenly distributed in all species. In C. maxima and C. lundelliana the 350-bp satellite is present only in small amounts, but detectable by the sensitive PCR method. These repeats are also very homogeneous, reflecting a silent stage of satellite DNA. In contrast, the 170-bp satellite DNA is intra-and interspeciflcally heterogeneous. It is striking that the species with no detectable amount of 350-bp satellite contain 170-bp satellite DNA clusters with the highest degree of homogeneity. The evolution of satellite DNA repeats within cultivated and wild species in the genus Cucurbita is elucidated using the sequence data of both satellite DNAs from all species investigated. The value of satellite DNA for phylogenetic analysis between closely related species is discussed.
2015
Inter Simple Sequence Repeat (ISSR) markers were employed to study the genetic diversity among 30 indigenous species of Iranian cucurbit from five different genera of Cucurbitaceae. Eleven out of seventeen studied primers amplified a total of 283 bands, out of which 263 (92.93%) were polymorphic. The mean Polymorphism Information Content (PIC) was estimated at 0.327. Among the primers, ISSR15 exhibited the highest polymorphic bands and PIC value and was recognized as the most appropriate and discriminating primer to investigate genetic diversity. The results of clustering analysis showed that the least distance was observed between two species of Cucumis L. genus from Mashhad and Sabzevar with a genetic similarity value of 68.34%, while the highest genetic distance was observed between two species of Cucumis L. and Cucurbita L. genera from Dastgerd and Hamadan with a genetic similarity value of 20.71%. Although Cucurbita maxima and Cucurbita maschata were genetically similar, they w...
HAYATI Journal of Biosciences, 2021
Cucurbitaceae is one of the largest family in Angiosperm in which the most member of this family is important fruit crops in Indonesia such as Cucumber, Melon, Watermelon, and Apple Cucumber. In particular, Apple Cucumber, currently attracts attention to many researchers due to its phylogeneticand taxonomic problem. In term of its appearance, the fruit looks like an apple but the taste is melon. The purpose of this study was to elucidatephylogenetic relationship between Apple Cucumber and other species of Cucurbitaceae based on variation of DNA sequences derived from internal transcribed spacer (ITS) region. As many as six individuals of Apple Cucumber collected from Karawang, Jember, and Aceh were examined. The ITS sequences of some species of family Cucurbitaceae were retrieved from GenBank, and put them in the analysis. Phylogenetic analysis based on parsimony method with using Begoniaas outgroup reveals that Apple Cucumber are nested in the same clade as Melon (Cucumis melo) wit...
PHYLOGENY OF SUBFAMILY NHANDIROBOIDEAE (CUCURBITACEAE) BASED ON DNA SEQUENCE DATA: A REVIEW
The subfamily Nhandiroboideae (Cucurbitaceae) comprises 19 genera and 60 species. Morphologically, the subfamily is characterized by free style, pendulous ovules, and small pollen grains with a striate exine. In recent years, cpDNA, mitochondrial and nuclear markers have been used to infer phylogeny of Nhandiroboideae. The molecular data support the paraphyly of Nhandiroboideae as one of its genera Alsomitra is sister to all other Cucurbitaceae members. Within Nhandiroboideae, subtribes Gomphogyninae and Zanoniinae are polyphyletic, while Sicydiinae appears to be monophyletic.
Inter-genus variation analysis in few members ofCucurbitaceaebased on ISSR markers
Biotechnology & Biotechnological Equipment, 2015
Genetic diversity fosters the quintessence of speciation and species acclimatization of plants in their in situ environment. Members of Cucurbitaceae, an edible and economically vital crop family, have spread across the world, dominating the tropical regions. Thus, a study of the genetic relationships among cucurbit cultivars would throw light onto the extent of diversification among these vegetal crops. The present study endeavours to understand the phylogenetic patterns and relatedness among selected species of cucurbits, using inter simple sequence repeat (ISSR) markers, which are quick, reliable and produce sufficient polymorphisms for large-scale DNA fingerprinting purposes. A total of 117 bands, of which 57 were polymorphic, were amplified by five primers. The phylogram generated on the basis of Jacquards' similarity coefficient revealed a close genetic relationship between C. maderaspatanus and C. melo, while C. sativus, a member of the same genus, was placed as a distant relative from both species, thereby demonstrating remarkable diversification among members of the same genus.