Molecular phylogeny of the genus Corchorus(Grewioideae,Malvaceae s.l.) based on nuclear rDNA ITS sequences

A molecular phylogenetic analysis of the genus Corchorus(Grewioideae,Malvaceae s.l.)is presented,based on sequences of the nuclear ribosomal DNA internal transcribed spacer(ITS)region for 144 accessions representing 47 species.Several other genera from the subfamily Grewioideae,namely Pseudocorchorus,Triumfetta,Sparrmannia,Entelea,and Grewia,were included as outgroups.The monophyly of the genus was well supported by all phylogenetic analyses(maximum likelihood,Bayesian approaches,and parsimony),and Corchorus was divided into four major clades.The majority of African species formed a statistically highly supported and distinct clade separated from the other pantropically distributed species.Several endemic species from Australia,New Caledonia,and tropical America were nested within this distinct clade,indicating dispersal from Africa to the rest of the pantropics.Based on the taxa included in this study,the two cultivated species(C.olitorius and C.capsularis)shared a common ancestry with wild species of C.africanus,C.brevicornatus,C.pseudocapsularis,C.pseudo-olitorius,C.urticifolius,C.pilosus,C.orinocensis,and C.cunninghamii.Pseudocorchorus,previously considered an accepted genus,was nested within the genus Corchorus and shared a common ancestry especially with C.depressus and C.siliquosus.Based on morphological and anatomical similarity as well as the results of the present molecular findings,inclusion of the six Pseudocorchorus species into Corchorus is proposed,with Pseudocorchorus as a synonym of Corchorus.Of the included outgroup taxa,Triumfetta is the closest sister to Corchorus,while the common ancestor of Corchorus/Pseudocorchorus,Triumfetta,Sparrmannia,and Entelea is Grewia.A further phylogenetic study with more taxa mainly from Australia,together with additional molecular markers and morphological investigation,would help to test the hypothesis on the biogeography and growth form evolution of the genus Corchorus.

Taxonomic Studies on Some Members of the Genus <i>Abutilon</i>Mill. (Malvaceae)

The relationship between six Abutilon species was examined using different taxonomic investigation tools. The investigation was carried out using morphological and numerical studies. Fresh materials of Abutilon species were collected from different localities in Saudi Arabia during 2018 and 2019. Numerical analysis was based on the Principle Coordinates, the Principle Component and the Unweighted Pair Group Method with Arithmetic Algorithm Clustering. The results indicated that there were significant differences based on the morphological characters especially in the leaves, fruits and flowers features. Morphometric studies revealed that the six species of Abutilon clearly separated in all different analysis.

A Malvaceae-specific miRNA targeting the newly duplicated GaZIP1L to regulate Zn^(2+)ion transporter capacity in cotton ovules

MicroRNAs(miRNAs)play critical roles in regulating gene expression in plants,yet their functions underlying cultivated diploid Gossypium arboreum cotton ovule development are largely unknown.Here,we acquired small RNA profiles from G.arboreum ovules and fibers collected at different growth stages,and identified 46 novel miRNAs that accounted for 23.7%of all miRNAs in G.arboreum reported in the latest plant sRNA database.Through analysis of 84(including 38 conserved)differentially expressed G.arboreum miRNAs,we detected 215 putative protein-coding genes in 26 biological processes as their potential targets.A Malvaceae-specific novel miRNA named gar-miRN44 was found to likely regulate cotton ovule growth by targeting to a newly duplicated Zn^(2+)ion transporter gene GaZIP1L.During cotton ovule development,gar-miRN44 transcript level decreased sharply after 10 to 15 days post-anthesis(DPA),while that of the GaZIP1L increased significantly,with a concomitant increase of Zn^(2+)ion concentration in late ovule developmental stages.Molecular dynamics simulation and ion absorption analysis showed that GaZIP1L has stronger Zn2+ion binding ability than the original GaZIP1,indicating that the newly evolved GaZIP1L may be more suitable for maintaining high Zn2+ion transport capacity that is likely required for cotton ovule growth via enhanced cellulose synthase activities.Our systematic miRNA profiling in G.arboreum and characterization of gar-miRN44 not only contribute to the understanding of miRNA function in cotton,but also provide potential targets for plant breeding.

Genetic diversity and population structure of Hibiscus aridicola, an endangered ornamental species in dry-hot valleys of Jinsha River

Hibiscus aridicola is an endangered ornamental shrub of the family Malvaceae that is endemic to the dryhot valleys of Jinsha River in southwestern China.This species is a typical plant species with extremely small populations(PSESP).To support and monitor future conservation,develop management measures,and genotype this species,we performed extensive field studies together with genetic analyses.Specifically,we screened eleven microsatellite loci of 69 individuals of H.aridicola from four accessions.The population genetics analyses indicated that H.aridicola possesses high genetic diversity at both the population(0.6962-0.7293)and species level(0.7837)compared to other endemic/endangered species in China.The low differentiation of populations(Fst=0.0971)and the high gene flow between populations of H.aridicola(Nm=2.3236)could be due to its distribution along rivers in the hot-valleys of the Jinsha River and the wind-mediated dispersal of its seeds.Furthermore,the genetic diversity of H.aridicola is slightly positively correlated with geographic distance.Two populations are undergoing a genetic bottleneck,and require more specific attention from conservationists.Additionally,our analyses of the population genetics of H.aridicola demonstrate that the declines in populations are not the result of the internal genetics of these populations but due to external human activities over the past decades.

Fossil fruits of Firmiana and Tilia from the middle Miocene of South Korea and the efficacy of the Bering land bridge for the migration of mesothermal plants

Determining whether the high-latitude Bering land bridge(BLB)was ecologically suitable for the migration of mesothermal plants is significant for Holarctic phytogeographic inferences.Paleobotanical studies provide a critical source of data on the latitudinal positions of different plant lineages at different times,permitting assessment of the efficacy of the BLB for migration.Here we report exceptionally preserved fossils of Firmiana and Tilia endochrysea from the middle Miocene of South Korea.This represents a new reliable record of Firmiana and the first discovery of the T.endochrysea lineage in the fossil record of Asia.The occurrence of these fossils in South Korea indicates that the two lineages had a distribution that extended much farther north during the middle Miocene,but they were still geographically remote from the BLB.In light of the broader fossil record of Asia,our study shows that,in the middle Miocene,some mesothermal plants apparently inhabited the territory adjacent to the BLB and thus they were possibly capable of utilizing the BLB as a migratory corridor.Some other mesothermal plants,such as Firmiana and the T.endochrysea lineages,however,are restricted to more southern regions relative to the BLB based on current fossil evidence.These lineages may have been ecologically unable to traverse the BLB,which raises questions about the efficacy of the BLB as a universal exchange route for mesothermal plants between Asia and North America during the middle Miocene.

Pharmacognostic standardization of stems of Thespesia lampas(Cav.)Dalz & Gibs

Objective:To establish the standardization parameters for complete pharmacoguoslic evaluation of stems of Tlespesia lampas(T.lampas)(Cav.) Dalz & Gibs(Malvaceae),an important planl in the Indian system of medicine.Methods:Morphological,microscopical,physico-chemical evaluations,florescence analysis of T.lampas stems were investigated and preliminary phytochemical analysis,GO-MS analysis and HPTLC fingerprinting were carried out for qualitative phytochemical evaluation of various extracts of stems of T.lampas.Results:Chemomieroscopy revealed the presence of lignin.starch grains and calcium oxalate crystals.Physicochemical evaluation used to detennine numerical slandards showed a result with total ash(9.03± 0.05)%w/w,acid insoluble ash(1.50±0.01)%w/w,water soluble ash(2.51±0.02)%w/w,sulphated ash(7.50+0.01)%w/w,ethanol soluble extractive(0.24±0.02)%w/w,water soluble extractive(0.08 ±0.01)<7,w/w,moisture content(6.03±0.05)%w/w and total crude fibre content of stem powder(47.36±0.32)%w/w.Behavior characteristics of the stem powder showed presence of steroids, starch,alkaloid,flavonoids and proteins.Preliminary phytochemical analysis revealed presence of glycosides,phenolic compounds,tannins,steroids,saponins,flavonoids,carbohydrates and proteins.GC-MS analysis showed the presence of fatty acids such as dodecanoic acid, lelraclecanoic acid,n-hexadecanoic acid,9-lelradecenal and HPTLC fingerprinting revealed the presence of β-sitosterol and quercetin in stems of T.lampas.Conclusions:The pharmacognostic standardization of T.lampas is useful towards establishing standards for quality, purity and sample identification.

Cytochemical localization of H_2O_2 in pigment glands of cotton(Gossypium hirsutum L.)

Programmed cel death （PCD） plays a critical role in the development of plant pigment glands, while H2O2, which is a kind of reactive oxygen species （ROS） produced by the aerobic metabolism of cels, acts as an important signal in this process. Here, we investigated the temporal and spatial dynamics of accumulated H2O2 in pigment glands ofGossypium hirsutum L. with 3,3-diaminobenzidine （DAB） staining, 2’,7’-dichlorodihydrolfuorescein diacetate （DCFH2）-DA lfuorescent labeling and CeCl3 cytochemical localization techniques. The results showed that thepigment glandsofG. hirsutum could generate H2O2, and the amount and localization of H2O2 variedat different developmental stages. At the early developmental stage, a smal amount of H2O2 accumulated in the vacuole membrane of pigment gland cels. At the intermediate stage, a large number of H2O2 appeared in the vacuole membrane, while cel wals started to accumulate a smal amount of H2O2. When pigment gland cel degraded, H2O2 mainly accumulated on the chloroplast envelope membrane of inner sheath cels. With the degradation of the sheath cels, H2O2was detected in cel wal and the membrane of secretory vesicles which contains the preliminary contents of pigment gland. With the pigment glands completely maturation, H2O2 would disappeared. The accumulation sites of H2O2are consistent with the process of PCD of individual gland cels, which started from the degra-dation of intracelular membrane and ended with the degradation of cel wals. Thus H2O2 probably plays an important role in the development of pigment glands. In addition, the development of pigment glands and the generation of H2O2 are not associated with the light, and no H2O2 was detected in the secretions of pigment glands.

Vegetative Compatibility and Virulence Diversity of Verticillium dahliae from Okra (Abelmoschus esculentus) Plantations in Turkey and Evaluation of Okra Landraces for Resistance to V. dahliae

Forty-four V.dahliae isolates were collected from symptomatic vascular tissues of okra plants each from a different field in eight provinces located in the eastern Mediterranean and western Anatolia regions of Turkey during 2006-2009.Nitrate-nonutilizing(nit)mutants of V.dahliae from okra were used to determine heterokaryosis and genetic relatedness among isolates.All isolates from okra plants were grouped into two vegetative compatibility groups(VCGs)(1 and 2)and three subgroups as 1A(13.6%,6/44),2A(20.5%,9/44)and 2B(65.9%,29/44)according to international criteria.Pathogenicity tests were performed on a susceptible local okra(A.esculentus)landrace in greenhouse conditions.All isolates from VCG1A and VCG2B induced defoliation(D)and partial defoliation(PD)symptoms,respectively.Other isolates from VCG2A gave rise to typical leaf chlorosis symptoms without defoliation.The obtained data showed that the virulence level of V.dahliae isolates from okra was related to their VCG belongings.Eighteen okra landraces from diverse geographical origins were screened for resistance to VCG2B and VCG1A of V.dahliae.The results indicated that all landraces were more susceptible to highly virulent VCG1A-D pathotype displaying D or PD symptoms depending on their susceptibility levels with a mean disease severity index of 3.52 than to less virulent VCG2B-PD pathotype of V.dahliae displaying PD and ND symptoms with a mean disease severity index of 2.52.Significant differences were observed among the landraces;however,none of them exhibited a level of resistance.Okra landraces;Çorum,Hatay Has and Sanlıurfa displayed the lowest level of susceptibility or little tolerance to both D and PD pathotypes.VCG2B of PD was prevailing in the surveyed areas and VCG1A of D was the most virulent of the VCGs identified.Introduction of resistant genotypes to Turkish okra germplasm from different sources and breeding new resistant okra cultivars are critical for the sustainability of okra production.

Flavonoid Glycosides from the Leaves of Glyphaea brevis

A new flavonoid, acacetin-7-O-β-D-glucopyranosyl-(1 → 2)-β-D-glucuronopyranoside (1), together with four known flavonoids, apigenin-7-O-β-D-glucopyranosyl-(1 → 2)-β-D-glucuronopyranoside (2), acacetin (3), acacetin-7-O-β-D-glucuronide (4) and genkwanin-5-O-primveroside (5) were isolated from the leaves of Glyphaea brevis. Their structures were elucidated by spectroscopic techniques. The isolated compounds (1 - 5) were tested for their antioxidant activity using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. The tested compounds showed slight negative antioxidant activities against DPPH radicals.

Upgraded durian genome reveals the role of chromosome reshuffling during ancestral karyotype evolution,lignin biosynthesis regulation,and stress tolerance

Durian(Durio zibethinus)is a tropical fruit that has a unique flavor and aroma.It occupies a significant phylogenetic position within the Malvaceae family.Extant core-eudicot plants are reported to share seven ancestral karyotypes that have undergone reshuffling,resulting in an abundant genomic diversity.However,the ancestral karyotypes of the Malvaceae family,as well as the evolution trajectory leading to the28 chromosomes in durian,remain poorly understood.Here,we report the high-quality assembly of the durian genome with comprehensive comparative genomic analyses.By analyzing the collinear blocks between cacao and durian,we inferred 11 Malvaceae ancestral karyotypes.These blocks were present in a single-copy form in cacao and mainly in triplicates in durian,possibly resulting from a recent whole genome triplication(WGT)event that led to hexaploidization of the durian genome around 20(17–24)million years ago.A large proportion of the duplicated genes in durian,such as those involved in the lignin biosynthesis module for phenylpropane biosynthesis,are derived directly from whole genome duplication,which makes it an important force in reshaping its genomic architecture.Transcriptome studies have revealed that genes involved in feruloyl-Co A formations were highly preferentially expressed in fruit peels,indicating that the thorns produced on durian fruit may comprise guaiacyl and syringyl lignins.Among all the analyzed transcription factors(TFs),members of the heat shock factor family(HSF)were the most significantly upregulated under heat stress.All subfamilies of genes encoding heat shock proteins(HSPs)in the durian genome appear to have undergone expansion.The potential interactions between HSF Dzi05.397 and HSPs were examined and experimentally verified.Our study provides a high-quality durian genome and reveals the reshuffling mechanism of ancestral Malvaceae chromosomes to produce the durian genome.We also provide insights into the mechanism underlying lignin biosynthesis and heat stress tolerance.

Tetracyclic triterpenoids isolated from semi-mangrove plant Hibiscus tiliaceus

A continuing phytochemical study on the semi-mangrove plant Hibiscus tiliaceus yielded two new tetracyclic triterpenoids （3β,24S）-19（10→9）-abeo-8α,9β,10α-eupha-5,25（26）-dien-3,24-diol （tiliacol A, 1 ）, and （3β,23Z）-19（10→9）-abeo-8α,9β,10α-tircalla-5,23-dien-3,25-diol （tiliacol B, 3）, together with one known analog （2）. Their structures were elucidated on the basis of extensive spectral analyses （MS, IR, 1D NMR and 2D NMR） and comparison with literature compounds. Compound 2 showed potent cytotoxicity against both P388 and HeLa cells with ICon values of 11.2 μmol/L and 11.5 μmol/L, resoectively.