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Resin glycoside is a type of secondary metabolite isolated commonly from the Convolvulaceae family. It consists of oligosaccharides conjugated to organic acids with a larger percentage having a macrocyclic structure. The resin glycosides reported in this review is classified mostly based on the number of sugar units constructing the structure, which is correlated to the biological properties of the compounds. According to preliminary reviews, the protocols to isolate the compounds are not straightforward and require a special technique. Additionally, the structural determination of the isolated compounds needs to minimize the structure for the elucidation to become easier. Even though resin glycosides have a complicated structural skeleton, several total syntheses of the compounds have been reported in articles published from 2010 to date. This review is an update on the prior studies of the resin glycosides reported in 2010 and 2017. The review includes the classification, isolation techniques, structural determination, biological properties, and total synthesis of the resin glycosides.

Parasitic lifestyle can often relax the constraint on the plastome, leading to gene pseudogenization and loss, and resulting in diverse genomic structures and rampant genome degradation. Although several plastomes of parasitic Cuscuta have been reported, the evolution of parasitism in the family Convolvulaceae which is linked to structural variations and reduction of plastome has not been well investigated. In this study, we assembled and collected 40 plastid genomes belonging to 23 species representing four subgenera of Cuscuta and ten species of autotrophic Convolvulaceae. Our findings revealed nine types of structural variations and six types of inverted repeat (IR) boundary variations in the plastome of Convolvulaceae spp. These structural variations were associated with the shift of parasitic lifestyle, and IR boundary shift, as well as the abundance of long repeats. Overall, the degradation of Cuscuta plastome proceeded gradually, with one clade exhibiting an accelerated degradation rate. We observed five stages of gene loss in Cuscuta, including NAD(P)H complex → PEP complex → Photosynthesis-related → Ribosomal protein subunits → ATP synthase complex. Based on our results, we speculated that the shift of parasitic lifestyle in early divergent time promoted relaxed selection on plastomes, leading to the accumulation of microvariations, which ultimately resulted in the plastome reduction. This study provides new evidence towards a better understanding of plastomic evolution, variation, and reduction in the genus Cuscuta.Key messageThe gain of parasitism in Cuscuta does trigger structural variations of the plastome, and it may initiate the relaxed selection in plastid genes, which leads to accumulation of microvariations, subsequent plastome reduction and gene loss.

We studied seeds from a set of plant species from the Convolvulaceae family. Seeds collected from natural populations and infested with beetles of genus Megacerus were monitored until the beetle emergence. We analyze the relationship between body weight of beetles and seed weight of host plants, and its connection with between-species differences and sexual dimorphism. The results show that differences in the scaling of body weight of beetles are associated with sexual dimorphism. For the same species of beetle, the females tend to have heavier bodies than the males. Differences between host plants species in the weight of seeds are related to differences in the body weight Megacerus species, resulting in a distinctive pattern of seed infestation across hosts. Small-sized (lighter) species of beetles tended to infest small-sized (lighter) seed species and, correspondingly, heavier beetles species tended to do it in heavier seed species. Mechanisms of female oviposition preferences may be involved to generate that pattern. In general, the beetle weight showed an asymptotic relation with the host seed weight. The greater the weight of the seed, the greater the weight of adult beetle was. However, the proportion in weights reaches an asymptotic value probably because beetles reached the maximum possible weight for their species. We conclude that the process of specialization in the seed-beetle assemblage studied is influenced by intrinsic traits of the species involved in the interaction (beetles and seeds) and by differences between sexes in their sexual-allocation paths.

New genes often evolve when one gene is duplicated, and one or both of the copies evolve new functions. Many studies have explored the mechanism behind this evolution, primarily thought to be the processes of neo-functionalization and escape from adaptive conflict. This paper proposes tests to distinguish between these two processes and argues that the latter has occurred much more often than previously thought. New genes often evolve when one gene is duplicated, and one or both of the copies evolve new functions. Many studies have explored the mechanism behind this evolution, primarily thought to be the processes of neo-functionalization and escape from adaptive conflict. This paper proposes tests to distinguish between these two processes and argues that the latter has occurred much more often than previously thought. Gene duplications have been recognized as an important source of evolutionary innovation and adaptation since at least Haldane 1 , and their varying fates may partly explain the vast disparity in observed genome sizes 2 . The expected fates of most gene duplications involve primarily non-adaptive substitutions leading to either non-functionalization of one duplicate copy or subfunctionalization 3 , neither of which yields novel function. A significant evolutionary problem is thus elucidating the mechanisms of adaptive evolutionary change leading to evolutionary novelty. Currently, the most widely recognized adaptive process involving gene duplication is neo-functionalization (NEO-F), in which one copy undergoes directional selection to perform a novel function after duplication 4 . An alternative, but understudied, adaptive fate that has been proposed is escape from adaptive conflict (EAC), in which a single-copy gene is selected to perform a novel function while maintaining its ancestral function 5 , 6 . This gene is constrained from improving either novel or ancestral function because of detrimental pleiotropic effects on the other function. After duplication, one copy is free to improve novel function, whereas the other is selected to improve ancestral function. Here we first present two criteria that can be used to distinguish NEO-F from EAC. Using both tests for positive selection and assays of enzyme function, we then demonstrate that adaptive evolutionary change in a duplicated gene of the anthocyanin biosynthetic pathway in morning glories ( Ipomoea ) is best interpreted as EAC. Finally, we argue that this phenomenon likely occurs more often than has been previously believed and may thus represent an important mechanism in generating evolutionary novelty.

Amarasekara, K.; Perera, C.; Yatawara, M., and Jayasiri, H.B., 2024. Lesser-known species (Ipomoea imperati) from the Convolvulaceae family: First record from the Manalkaadu sand dunes of Jaffna, Sri Lanka. Journal of Coastal Research, 40(4), 803–808. Charlotte (North Carolina), ISSN 0749-0208. Coastal sand dunes are dynamic and fragile ecosystems found along some sandy shorelines. They are typically supported by a wide variety of specialized floral and faunal life. Coastal sand dunes are especially common in temperate coastal areas but are less abundant in tropical or subtropical coasts. A comprehensive study of flora in the Manalkaadu sand dune ecosystem was completed from August 2022 to May 2023, using 50-m × 5-m belt transects. The study area was divided into nine distinct locations for systematic sampling. Ipomoea imperati (Vahl) Griseb., a dicotyledonous flowering plant commonly known as fiddle-leaf morning-glory of the Convolvulaceae family, was recorded for the first time in the Manalkaadu sand dunes of the Northern Province in Sri Lanka during the study. Ipomoea imperati has smooth trailing stems that are covered with alternately arranged lanceolate, fleshy dark green leaves with a notched apex. Ipomoea imperati bloomed from September 2022 to March 2023 in the study area, and the funnel-shaped flowers were fused with white petals and yellow centers. In the area where it was discovered, the species withstood high substrate temperatures (about 29°C to 35°C), sand scouring, and moderate burial by accreted sand. Out of nine sampling locations, I. imperati was found in five locations. The plant density (two to six), plant percentage frequency (40% to 60%), Shannon Wiener diversity index (0.54 to 1.43), species evenness (0.50 to 0.90), and richness (2 to 5) were also analyzed. Thus, the density of I. imperati in five sampling locations was considered to be moderate, whereas the diversity was very low. It is designated as endangered in the National Red List 2020—Conservation Status of the Flora of Sri Lanka.

Dodders ( Cuscuta spp., Convolvulaceae) are root- and leafless parasitic plants. The physiology, ecology, and evolution of these obligate parasites are poorly understood. A high-quality reference genome of Cuscuta australis was assembled. Our analyses reveal that Cuscuta experienced accelerated molecular evolution, and Cuscuta and the convolvulaceous morning glory ( Ipomoea ) shared a common whole-genome triplication event before their divergence. C. australis genome harbors 19,671 protein-coding genes, and importantly, 11.7% of the conserved orthologs in autotrophic plants are lost in C. australis . Many of these gene loss events likely result from its parasitic lifestyle and the massive changes of its body plan. Moreover, comparison of the gene expression patterns in Cuscuta prehaustoria/haustoria and various tissues of closely related autotrophic plants suggests that Cuscuta haustorium formation requires mostly genes normally involved in root development. The C. australis genome provides important resources for studying the evolution of parasitism, regressive evolution, and evo-devo in plant parasites. Dodders ( Cuscuta spp., Convolvulaceae) are root- and leafless parasitic plants. Here, the authors sequence the genome of Cuscuta australis and find remarkable gene loss associated with parasitic lifestyle and large changes in body plan.

Phylogenetic studies have demonstrated the largest morning glory genus, Ipomoea, is not monophyletic, and nine other segregate genera are derived from within Ipomoea. Therefore, systematic research is focused on the monophyletic tribe Ipomoeeae (c. 650-900 species). We used whole plastid genomes to infer relationships among exemplar species distributed across Ipomoeeae. Whole plastomes were sequenced, assembled and annotated for twenty-eight morning glory species, representing major Ipomoeeae lineages. Phylogenies were estimated for twenty-eight species sequenced here and one published plastome using alignments of: (a) eighty-two chloroplast genes and (b) whole plastomes. In addition, divergence times were estimated to date key divergence events within the Ipomoeeae. Two nodes were calibrated with fossil pollen for molecular dating analyses. Phylogenies estimated from the two plastome datasets had identical topologies. Phylogenetic results are generally consistent with prior phylogenetic analyses of morning glories. Two major clades, previously named Astripomoeinae and Argyreiinae, are well-supported. There also is support for the monophyly of Ipomoea subgenus Quamoclit. Higher-level relationships with weak support in previous analyses were recovered in this analysis with strong support. Results from the molecular dating analysis suggest a middle Eocene divergence time for the Ipomoeeae. Furthermore, the Argyreiinae clade was found to have diversified before the Astripomoeinae; however, error bars overlap between divergence time estimates of these two clades. Phylogenetic results presented here provide greater confidence in relationships among major lineages of the Ipomoeeae, and divergence time estimation results provide a temporal context for the diversification of this fascinating group of angiosperms.

Periglandula ipomoeae and P. turbinae (Ascomycota, Clavicipitaceae) are recently described fungi that form symbiotic associations with the morning glories (Convolvulaceae) Ipomoea asarifolia and Turbina corymbosa, respectively. These Periglandula species are vertically transmitted and produce bioactive ergot alkaloids in seeds of infected plants and ephemeral mycelia on the adaxial surface of young leaves. Whether other morning glories that contain ergot alkaloids also are infected by Periglandula fungi is a central question. Here we report on a survey of eight species of Convolvulaceae (Argyreia nervosa, I. amnicola, I. argillicola, I. gracilis, I. hildebrandtii, I. leptophylla, I. muelleri, I. pes-caprae) for ergot alkaloids in seeds and associated clavicipitaceous fungi potentially responsible for their production. All host species contained ergot alkaloids in four distinct chemotypes with concentrations of 15.8-3223.0 μg/g. Each chemotype was a combination of four or five ergot alkaloids out of seven alkaloids detected across all hosts. In addition, each host species exhibited characteristic epiphytic mycelia on adaxial surfaces of young leaves with considerable interspecific differences in mycelial density. We sequenced three loci from fungi infecting each host: the nuclear rDNA internal transcribed spacer region (ITS), introns of the translation factor 1-α gene (tefA) and the dimethylallyl-tryptophan synthase gene (dmaW), which codes for the enzyme that catalyzes the first step in ergot alkaloid biosynthesis. Phylogenetic analyses confirmed that these fungi are in the family Clavicipitaceae and form a monophyletic group with the two described Periglandula species. This study is the first to report Periglandula spp. from Asian, Australian, African and North American species of Convolvulaceae, including host species with a shrub growth form and host species occurring outside of the tropics. This study demonstrates that ergot alkaloids in morning glories always co-occur with Periglandula spp. and that closely related Periglandula spp. produce alkaloid chemotypes more similar than more distantly related species.

Ipomoea cairica is a perennial creeper that has been widely introduced as a garden ornamental across tropical, subtropical, and temperate regions. Because it grows extremely fast and spreads easily, it has been listed as an invasive species in many countries. Here, we constructed the chromosome-level reference genome of Ipomoea cairica by Pacific Biosciences HiFi and Hi-C sequencing, with the assembly size of 733.0 Mb, the contig N50 of 43.8 Mb, the scaffold N50 of 45.7 Mb, and the Benchmarking Universal Single-Copy Orthologs complete rate of 98.0%. Hi-C scaffolding assigned 97.9% of the contigs to 15 pseudo-chromosomes. Telomeric repeat analysis reveals that 7 of the 15 pseudo-chromosomes are gapless and telomere to telomere. The transposable element content of Ipomoea cairica is 73.4%, obviously higher than that of other Ipomoea species. A total of 38,115 protein-coding genes were predicted, with the Benchmarking Universal Single-Copy Orthologs complete rate of 98.5%, comparable to that of the genome assembly, and 92.6% of genes were functional annotated. In addition, we identified 3,039 tRNA genes and 2,403 rRNA genes in the assembled genome. Phylogenetic analysis showed that Ipomoea cairica formed a clade with Ipomoea aquatica, and they diverged from each other 8.1 million years ago. Through comparative genome analysis, we reconfirmed that a whole genome triplication event occurred specific to Convolvulaceae family and in the ancestor of the genus Ipomoea and Cuscuta. This high-quality reference genome of Ipomoea cairica will greatly facilitate the studies on the molecular mechanisms of its rapid growth and invasiveness.