Setaria Species Research Articles

Impact of propagule type and burial depth on knotroot foxtail (Setaria parviflora) emergence and plant development, and comparison with other Setaria species

Abstract Knotroot foxtail [Setaria parviflora (Poir.) Kerguélen], a perennial Setaria species, is becoming more problematic in forage and grazing systems across the southeastern United States. Knotroot foxtail reproduces through the production of rhizomes and seeds, further complicating management strategies. Significant knowledge gaps exist regarding the biology and control of this species. This research aimed to understand the influence of burial depth on S. parviflora propagules and the physiological differences between it and other Setaria species. Experiments were conducted between October 2019 and February 2021 in Clarke County, GA, to investigate the influence of burial depth (1, 2, 4, 8, and 16 cm) on the emergence and growth of knotroot foxtail rhizomes and seeds. Zero emergence was estimated at 8.7, 10.8. and 11.2 cm for small rhizomes, large rhizomes, and seeds, respectively. Therefore, producers could implement tillage events to a depth of 11.2 cm or greater to control knotroot foxtail. A separate study compared knotroot foxtail, yellow foxtail [Setaria pumila (Poir.) Roem. & Schult.], green foxtail [Setaria viridis (L.) P. Beauv.], and giant foxtail (Setaria faberi Herrm.) plant morphology. Despite similar appearances aboveground, yellow, and knotroot foxtail had different total and belowground biomass two to five months after emergence, which suggest differences in root formation and perennialization of knotroot foxtail. The present research determined that burying propagules using tillage could be included in management recommendations concerning knotroot foxtail; however, it should be complemented with herbicide applications during the growing season to assist in controlling foxtail plants produced by seeds.

Lemma and palea micromorphological study of Setaria species (Poaceae) in Iran

Setaria (Poaceae, Paniceae, Cenchrinae) comprises 136 species worldwide and 3 species in Iran. This weedy grass is distributed in various parts of the world. In this study, the characters of the lemma and palea of 9 populations of Setaria were studied micromorphologically using a scanning electron microscope (SEM) to identify diagnostic characters for the delimitation of the studied species. A total of 18 qualitative and quantitative characters of the lemma and palea surfaces were considered. Different shapes of microhairs, epicuticular wax, and the occurrence of cork cells and silica cells were evident in the studied taxa. The results of this study revealed the taxonomic value of floret micromorphological characters in Setaria species.

Pottery Impressions Reveal Earlier Westward Dispersal of Foxtail Millet in Inner Asian Mountain Corridor

The Inner Asian Mountain Corridor (IAMC) has been identified as a major pathway for the westward dispersal of millet from Northern China, where it was initially cultivated. Cross-disciplinary investigations are necessary to distinguish cultivated millet taxa from their wild relatives and to clarify the social context underlying millet adoption in novel environments. Despite the ambiguity in distinguishing Setaria italica from Panicum miliaceum or other Setaria species using conventional analysis of charred macro remains, recent attention has focused on the time gap between the introduction of S. italica to IAMC following P. miliaceum. Here, we employed a pottery impression casting method on materials from four Bronze Age sites in eastern/southeastern Kazakhstan to investigate the surface textures of grain impressions on the surface of pottery containers. We successfully identified both millets (Setaeria and Panicum) from three of the sites, Begash, Tasbas, and Dali in the IAMC. Based on our findings, two species of millet were introduced to the region within a much shorter range of time than previously estimated. In addition, the current evidence supports the premise that these cereals were likely utilized for human consumption.

Seasonal Food Preference of Cheetal (Axis axis) and Sambar Deer (Cervus unicolor) In Corbett National Park, Uttarakhand

This study is based on two years field study by direct observation and questionnaire method in Bijrani and Jhirna zones of Corbett National Park. Cheetal (Axis axis) and Sambar deer (Cervus unicolor) are found with their sympatric species Barking deer in Corbett Park. The population of Cheetal and Sambar in different vegetative areas of Corbett varies according to the availability of their favourite food (seasonal). This study reveals that Cheetal preferred new sprouting of Cynadon dactylon, green Desmostachya bipinnata, Eulaliopsis binata, Setaria species, Heteropogon species, Imperata cylindrica, Saccharum bengalensis, and Saccharum narenga in grassland. In dense shrub area, Cheetal preferred green tender leaves of Murraya koenegi, Glycosmis arbores, and fruits of Ziziphus mauritiana, Emblica officinalis, and Solanum nigrum. In Sal-mixed forest Cheetal preferred green fallen leaves of Shorea robusta, Adena cordifolia, Mallotus philippensis and leaves & fruits of Syzigium cumini, Agle marmels, Ficus racemosa, Diospyras tomentosa, flowers of Bombax ceiba (calyx), Cassia fistula etc. In the water-side area Cheetal preferred Dalbergia sissoo, S. munja, Phragmites roxburghii and Acacia catechu etc. Sambar is mostly found in dense shrub area and preferred leaves of M. koenegi, G. arbores, E. officinalis, Justicia adhatoda, Z. mauritiana. In Sal-mixed forest, Sambar preferred leaves of S. robusta, A. cordifolia, A. marmeles, Dendrocalamus strictus, and flowers of B. ceiba etc. In grassland, Sambar preferred S. munja, I. cylindrica, D. bipinnata, E. binata. In water-side Sambar preferred A. arabica, P. roxburghii, and D. sissoo on a priority basis. Sambar generally preferred course food like rough leaves, bark, seeds, flowers, soft twigs, and large grasses.

An Update of the Cenchrinae (Poaceae, Panicoideae, Paniceae) and a New Genus for the Subtribe to Clarify the Dubious Position of a Species of Panicum L.

Subtribe Cenchrinae, so-called as the "bristle clade", is a monophyletic group of panicoid grasses characterized by having sterile branches or bristles on the inflorescences in most of its species. Within this subtribe is also placed Panicum antidotale Retz., an "incertae sedis" species of Panicum L. which lacks bristles along the inflorescence. In this study, we present an update of the subtribe Cenchrinae based on molecular, morphological, and anatomical evidence to clarify the systematic position of P. antidotale in the Cenchrinae, excluding it from Panicum and establishing it in a new genus (i.e., Janochloa Zuloaga & Delfini); the morphological features distinguishing the new genus from other closely related taxa are properly discussed and an identification key to the 24 genera recognized within Cenchrinae is presented. We also add American Setaria species, not tested before, of subgenera Paurochaetium and Reverchoniae, discussing the position of these taxa in actual phylogeny of the genus as well as defining placements in the tree of Setaria species that were imprecisely located in previous analyses. A comparison with the results from other studies, comments on Stenotaphrum Trin. and a brief discussion on conflicting placements in Cenchrus and related taxa, and of Acritochaete Pilg. are also included.

Molecular genetic and taxonomical relationship among selected Setaria species using inter simple sequence repeat (ISSR’s) and microsatellite (SSRs) markers

Foxtail millet is small diploid (2n = 2x = 18), one of the oldest domesticated, self-compatible, C4 Panicoid cereal grains in Eurasia. Change in climatic conditions, ecological degradation, overexploitaion, and commercial cultivation has led to the genetic loss of landraces as well wild relatives of cultivated crops. Established genetic relations among the species are prerequisites for their future breeding programs to improve cultivars. Therefore, there is an urgent need to conserve plant genetic resources for sustainable agriculture. Keeping in view, we collected seven different species of Setaria that include S. italica, S. viridis, S. sphacelata, S. pumila, S. glauca, S. verticillata, and S. intermedia from Andhra Pradesh, India. The specimens were examined for species identification and taxonomically described. In the present study, the trait “awn” was used as a key taxonomic character for the differentiation of two species viz., S. verticillata and S. intermedia. Earlier S. intermedia was merged in S. verticillata. We observed tremendous variation in phenotypic traits among weedy, wild, landrace, and cultivars of Setaria germplasm, indicating potential genotypic variation. To confirm the genetic variation, the selected Setaria sps were genotyped through ISSR and SSR genetic markers. The average number of amplicons amplified for ISSR and SSR markers was 3.75 and 2.45 alleles per locus, respectively. The Polymorphic information content and Shannon information index (I) for ISSR and SSR markers had an average value of 0.34, 0.34, and 0.46, 0.58, respectively. Gene flow among seven Setaria species was relatively high (Nm > − 1.0). Two-way cluster analysis separated 12 accessions into two significant clusters using combined marker systems and agreed with Principal coordinate analysis. An Analysis of molecular variance confirms that a substantial genetic variation among seven Setaria species. Morphological cluster analysis was almost similar to molecular cluster analysis.

Complete chloroplast genome sequences of two Alloteropsis species (Poaceae) from China

Alloteropsis is a widely-distributed genus with C3 and C4 photosynthetic species belonging to the Poaceae family. This study characterized the complete chloroplast genomes of two Alloteropsis species from Chinese mainland, i.e. Alloteropsis semialata with C4 photosynthetic type and Alloteropsis cimicina with C3 photosynthetic type. The chloroplast genomes of A. semialata and A. cimicina are 138,188 bp and 139,335 bp in length, with 38.48% and 38.59% GC contents, respectively. These two chloroplast genomes contain the same number of genes, i.e. 107 unique genes including 27 tRNA, 4 rRNA, and 76 protein-coding genes. Phylogenomic analysis confirmed the species identity of A. semialata and A. cimicina and supported a close relationship of Alloteropsis with species of Setaria and Panicum in grass family.

Germination response of three Setaria species (S. viridis, S. verticillata, and S. glauca) to water potential and temperature using non-linear regression and hydrothermal time models

Understanding factors influencing the time of weed seedling establishment can contribute to developing predictive models for control measures at early growth stages. Non-linear regression models (Dent-like and Quadratic polynomial) and hydrothermal time models were considered for estimating cardinal temperature and predicting the emergence time of the Setaria species (S. viridis, S. verticillata, and S. glauca) at different constant temperatures and water potentials. Field experiments were also conducted, in which seeds of the species were sown and seedling emergence was recorded daily. The optimum temperature for germination was 27.7, 30.2, and 30.5 °C as estimated by a Dent-like model at 0 MPa water potential for S. glauca, S. viridis and S. verticillata, respectively. According to the hydrotime model, the minimum amount of base water potential (Ψb) was observed at the optimum temperatures, while it reached its highest value at temperatures exceeding the optimum. Overall, at sub-optimal temperatures, with the decrease in water potential, the thermal time (TT) constant increased linearly until − 0.6 MPa, but this trend was downward at supra-optimal temperatures. The hydrothermal time constant (θHT) was 213.5, 228.8, and 318.8 MPa °C h for S. viridis, S. verticillata, and S. glauca, respectively. Non-linear regression and hydrothermal models showed that S. glauca can emerge earlier than other species because of lower base temperature and a higher hydrothermal time constant. Setaria species did not show a significant difference in their tolerance to water stress by similar base water potential (Ψb(50) ~ − 0.5).

Morphological and molecular characterization of Setaria equina in donkeys

BackgroundAdult worms of Setaria equina mainly found in the peritoneal cavity of equine. They were nonpathogenic but might induce varied degrees of peritonitis and might migrate to the eye, brain, lung, and scrotum causing lacrimation, blindness, paraplegia, locomotor, and neurological disturbances. Identification by light microscopy is insufficient to differentiate Setaria species, and so scanning electron microscopy (SEM) is required to observe their ultrastructures. The study was performed on 80 donkeys from May 2018 to January 2019 for the detection of microfilaria in blood and the adult worms in the peritoneal cavity. The blood samples were either stained with Giemsa stain or examined by modified Knott’s technique for the detection of microfilariae. Adult worms were morphologically characterized based on light microscope and scanning electron microscopy (SEM). PCR was performed targeting the 12S rRNA gene followed by sequencing and phylogenetic analysis.ResultsThe current study recorded 21.6% and 16.2% prevalence rates for adult worms and microfilariae, respectively. By using SEM, this study was able to clarify the detailed structure of amphids, predeirids, vulva, arrangement, and number of male caudal papillae. PCR amplified products for 12S rRNA gene (408 bp) for adult worm and microfilaria. Sequence and phylogenetic analysis revealed that S. equina isolated in the current study from donkeys in Egypt (accession no., MH345965) shared 100% identity with isolates from horse and man in Italy and Iran, respectively and clustered in the same clade with S. digitata, S. tundra and S. labiatopapillosa.ConclusionsIdentification with light microscopy lacked the ability to characterize different Setaria species, and so using scanning electron microscopy is considered a good choice to distinguish the ultrastructures. In addition, performing the phylogenetic analysis was necessary to detect relationships between different filarial worms, which could not detect by the morphological characterization of adult worms.

Robust and Reproducible Agrobacterium-Mediated Transformation System of the C4 Genetic Model Species Setaria viridis.

Setaria viridis (green foxtail) has been identified as a potential experimental model system to genetically and molecularly characterise the C4 monocotyledonous grasses due to its small physical size, short generation time and prolific seed production, together with a sequenced and annotated genome. Setaria viridis is the wild ancestor of the cropping species, foxtail millet (Setaria italica), with both Setaria species sharing a close evolutionary relationship with the agronomically important species, maize, sorghum, and sugarcane, as well as the bioenergy feedstocks, switchgrass, and Miscanthus. However, an efficient and reproducible transformation protocol is required to further advance the use of S. viridis to study the molecular genetics of C4 monocotyledonous grasses. An efficient and reproducible protocol was established for Agrobacterium tumefaciens-mediated transformation of S. viridis (Accession A10) regenerable callus material derived from mature seeds, a protocol that returned an average transformation efficiency of 6.3%. The efficiency of this protocol was the result of the: (i) use of mature embryo derived callus material; (ii) age of the seed used to induce callus formation; (iii) composition of the callus induction media, including the addition of the ethylene inhibitor, silver nitrate; (iv) use of a co-cultivation approach, and; (v) concentration of the selective agent. Our protocol furthers the use of S. viridis as an experimental model system to study the molecular genetics of C4 monocotyledonous grasses for the potential future development of improved C4 cropping species.

Ultrastructural and molecular characteristics of Setaria species based on sequence analysis of genomic and mitochondrial gene markers in cattle (Bos taurus) and buffaloes (Bubalus bubalis) from Iran

The aim of the present study was to investigate the ultrastructural characteristics and genetic diversity of Setaria parasites from cattle (n=696) and buffalo (n= 522) from Khuzestan province of Iran and to compare them with available data from other countries/regions by sequences analysis of the 12S Rdna and the mitochondrial cytochrome C oxidase subunit I (cox1) genes. Based on SEM (Scanning Electron Micrographs) and light microscopy, all the isolated worms were identified as Setaria labiatopapillosa. Our results showed that 12.3% of cattle were infected with Setaria spp., while no infection was found in buffaloes. The maximal prevalence was observed in cattle younger than one year old. The prevalence rate was not influenced by the season of the year or gender. Comparison of the obtained sequences from Setaria with sequences of Setaria spp. from GenBank confirmed that all samples belong to the species S. labiatopapillosa. The phylogenetic tree constructed using cox1 and 12S rDNA genes of several other filarial nematodes showed that the Khuzestan isolates share a common branch with S. labiatopapillosa from other regions. Intra-specific variation was observed in 12S rDNA but not in cox1. In conclusion, our results indicating that S. labiatopapillosa is the main species involved in the spread of setarial infection in south-west of Iran and the identified worms corresponded mostly to worms that reported previously throughout other continents.

Examination of commercially available bird feed for weed seed contaminants

AbstractIn 2016 and 2017, 98 separate commercially available bird feed mixes were examined for the presence of weed seed. All weed seed contaminants were counted and identified by species. Amaranthus species were present in 94 of the 98 bags of bird feed. Amaranthus species present in bird feed mixes included waterhemp [Amaranthus tuberculatus (Moq.) Sauer], redroot pigweed (Amaranthus retroflexus L.), Palmer amaranth (Amaranthus palmeri S. Watson), smooth pigweed (Amaranthus hybridus L.), and tumble pigweed (Amaranthus albus L.). Amaranthus palmeri was present in 27 of the 98 mixes. Seed of common ragweed (Ambrosia artemisiifolia L.), kochia [Bassia scoparia (L.) A.J. Scott], grain sorghum [Sorghum bicolor (L.) Moench], wild buckwheat (Fallopia convolvulus L., syn: Polygonum convolvulus), common lambsquarters (Chenopodium album L.), large crabgrass [Digitaria sanguinalis (L.) Scop.], and Setaria species were also present in bird feed mixes. A greenhouse assay to determine Amaranthus species seed germinability and resistance to glyphosate revealed that approximately 19% of Amaranthus seed in bird feed mixes are readily germinable, and five mixes contained A. tuberculatus and A. palmeri seed that were resistant to glyphosate. Results from linear regression and t-test analysis indicate that when proso millet (Panicum miliaceum L.), grain sorghum, and corn (Zea mays L.) were present in feed mixes, Amaranthus seed contamination was increased. The presence of proso millet and grain sorghum also increased contamination of grass weed species, while sunflower (Helianthus annuus L.) increased A. artemisiifolia contamination and safflower (Carthamus tinctorius L.) increased contamination of Bassia scoparia.

Effect of Physical Treatments on the Promotion of Seed Germination in Green and Giant Foxtails

The difficulty of breaking seed dormancy in Setaria (foxtail) species presents a problem in using them as model plants. In the present study, we observed the structure of the seed coat surface of two Setaria species, the green foxtail (Setaria viridis) and the giant foxtail (Setaria faberi), using an electron microscope. In addition, we tested the effects of physical treatment on Setaria seeds using four treatments: (1) Removing the outer seed coat, (2) removing the outer seed coat + mechanical scarification of the inner seed coat (the seeds were scarified using sand-paper with grit 350-2000), (3) removing the outer and inner seed coat and (4) No treatment (control). During the observation using electron microscope, we found a structure that was supposed to repel water (which is called the ‘lotus effect’). We found that seed germination in Setaria species can be induced by removing the outer seed coat along with mechanical scarification of the inner seed coat (second treatment) as well as by removing the outer and inner seed coat (third treatment), whereas seed germination was not observed after removing only the outer seed coat and no treatment.

Effect of Physical Treatments on the Promotion of Seed Germination in Green and Giant Foxtails

The difficulty of breaking seed dormancy in Setaria (foxtail) species presents a problem in using them as model plants. In the present study, we observed the structure of the seed coat surface of two Setaria species, the green foxtail (Setaria viridis) and the giant foxtail (Setaria faberi), using an electron microscope. In addition, we tested the effects of physical treatment on Setaria seeds using four treatments: (1) Removing the outer seed coat, (2) removing the outer seed coat + mechanical scarification of the inner seed coat (the seeds were scarified using sand-paper with grit 350-2000), (3) removing the outer and inner seed coat and (4) No treatment (control). During the observation using electron microscope, we found a structure that was supposed to repel water (which is called the ‘lotus effect’). We found that seed germination in Setaria species can be induced by removing the outer seed coat along with mechanical scarification of the inner seed coat (second treatment) as well as by removing the outer and inner seed coat (third treatment), whereas seed germination was not observed after removing only the outer seed coat and no treatment.

New findings of Setaria tundra and Setaria cervi in the red deer (Cervus elaphus) in Poland.

Our study aimed at examining the phylogenetic position of the newly-found Setaria nematodes obtained from the red deer (Cervus elaphus) based on sequences of the mitochondrial cytochrome c oxidase subunit 1 (COX-1). Alignment and phylogenetic analyses, as well as SEM microscopic analysis, revealed the presence of two Setaria species: S. cervi and S. tundra. Setaria tundra was noted in only one individual, a calf of the red deer, while S. cervi was observed in three stages, two hinds and one calf of the red deer. According to our knowledge, it is the first case of S. cervi in the red deer in Poland confirmed in molecular studies and also the first case of S. tundra infection in the red deer.

Roots and Panicles of the C4 Model Grasses Setaria viridis (L). and S. pumila Host Distinct Bacterial Assemblages With Core Taxa Conserved Across Host Genotypes and Sampling Sites.

Virtually all studied plant tissues are internally inhabited by endophytes. Due to their relevance for plant growth and health, bacterial microbiota of crop plants have been broadly studied. In plant microbiome research the root is the most frequently addressed environment, whereas the ecology of microbiota associated with reproductive organs still demands investigation. In this work, we chose the model grasses Setaria viridis and Setaria pumila to better understand the drivers shaping bacterial communities associated with panicles (representing a reproductive organ) as compared to those associated with roots. We collected wild individuals of both grass species from 20 different locations across Austria and investigated the bacterial assemblages within roots and ripe grain-harboring panicles by 16S rRNA gene-based Illumina sequencing. Furthermore, plant samples were subjected to genotyping by genetic diversity-focused Genotyping by Sequencing. Overall, roots hosted more diverse microbiota than panicles. Both the plant organ and sampling site significantly shaped the root and panicle-associated microbiota, whereas the host genotype only affected root communities. In terms of community structure, root-specific assemblages were highly diverse and consisted of conserved bacterial taxa. In contrast, panicle-specific communities were governed by Gammaproteobacteria, were less diverse and highly origin-dependent. Among OTUs found in both plant tissues, relative abundances of Gammaproteobacteria were higher in panicles, whereas Rhizobiales dominated root communities. We further identified core and non-core taxa within samples of both Setaria species. Non-core taxa included members of the Saccharibacteria and Legionelalles, while core communities encompassed eleven OTUs of seven bacterial orders, together with a set of ten panicle-enriched OTUs. These communities were widespread across root and panicle samples from all locations, hinting toward an evolved form of mutualism through potential vertical transmission of these taxa within Setaria species.

Archaeobotanical data from an ‘agglomerated cells’ type site: Plant macro-remains from Arteni-1 (Armenia)

So-called ‘agglomerated cells’ and “desert kites” are usually neighbouring archaeological stone-walled constructions mostly found in desert or mountainous areas of the Middle East and Southwest Asia. Various functions, almost always related with the funnelling of wild or domestic animals, are ascribed to the “kite” constructions - mostly V-shape converging long and low stone walls. Meanwhile, the functions of the ‘agglomerated cells’ are less clear and archaeobotanical data can provide some hints for interpretation. As far as we know, there are not currently any other archaeobotanical studies of ‘agglomerated cells’ type sites. The visible part of the Arteni-1 site discussed in this article represents an ‘agglomerated cells’ type construction neighbouring a “desert kite.” Excavations (2016–2017) and further archaeobotanical investigations of the Middle Bronze Age layers of the Arteni-1 site revealed coprolite, seeds, some charcoal fragments and other macroscopic organic remains. The presence, abundance and spread of coprolite in almost all studied contexts suggest that those constructions were mostly or frequently used as pens for animals. Morphologically identifiable parts of the coprolites recovered from the site resemble droppings of sheep and goat. The recovered findings of seeds, including remains of cultivated cereals, are an indirect evidence of domestic use of the area. Hulled and naked (free-threshing) barley (Hordeum vulgare), naked wheat (possibly bread wheat, Triticum cf. aestivum) and emmer (Triticum dicoccum) recorded for the site, presumably are remains of food. There are also seeds remains of several wild and weedy taxa (species of Setaria, Hordeum, Lolium, Galium, Buglossoides, Salsola, Chenopodium, Vaccaria, Thymelea, etc.).

Taxonomic Demarcation of Setaria pumila (Poir.) Roem. & Schult., S. verticillata (L.) P. Beauv., and S. viridis (L.) P. Beauv. (Cenchrinae, Paniceae, Panicoideae, Poaceae) From Phytolith Signatures.

Background and Aims: The role and significance of phytoliths in taxonomic diagnosis of grass species has been well documented with a focus on the types found in foliar epidermis and the synflorescence. The present paper is an attempt to broaden the scope of phytoliths in species diagnosis of grasses by developing phytolith signatures of some species of the foxtail genus Setaria P. Beauv. through in situ location and physico-chemical analysis of various phytolith morphotypes in different parts of the plant body.Methods: Clearing solution and dry ashing extraction methods were employed for in situ location and isolation of phytolith morphotypes respectively. Ultrastructural details were worked out by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy. Morphometric and frequency data of phytolith morphotypes were also recorded. Biochemical architecture of various phytolith types was worked out through SEM-EDX, XRD, and FTIR analysis. Data were analyzed through Principal Component Analysis and Cluster Analysis.Key Results: In situ location of phytoliths revealed species specific epidermal patterns. The presence of cystoliths (calcium oxalate crystals) in the costal regions of adaxial leaf surface of S. verticillata (L.) P. Beauv. is the first report for the genus Setaria. Our results revealed marked variations in epidermal ornamentation and undulation patterns with a novel “Λ” (Lamda) type of undulated ornamentation reported in S. verticillata. Dry ashing method revealed species specific clusters of phytolith morphotypes.Conclusions: The study revealed that phytoliths can play a significant role in resolution of taxonomic identity of three species of Setaria. Each species was marked out by a unique assemblage of phytolith morphotypes from various parts of the plant body. Apart from in situ location and epidermal patterning, diagnostic shapes, frequency distribution, size dimensions, and biochemical architecture emerged as complementary traits that help in developing robust phytolith signatures for plant species.

Gene mapping and functional analysis of the novel leaf color gene SiYGL1 in foxtail millet [Setaria italica (L.) P. Beauv

Setaria italica and its wild ancestor Setaria viridis are emerging as model systems for genetics and functional genomics research. However, few systematic gene mapping or functional analyses have been reported in these promising C4 models. We herein isolated the yellow-green leaf mutant (siygl1) in S. italica using forward genetics approaches. Map-based cloning revealed that SiYGL1, which is a recessive nuclear gene encoding a magnesium-chelatase D subunit (CHLD), is responsible for the mutant phenotype. A single Phe to Leu amino acid change occurring near the ATPase-conserved domain resulted in decreased chlorophyll (Chl) accumulation and modified chloroplast ultrastructure. However, the mutation enhanced the light-use efficiency of the siygl1 mutant, suggesting that the mutated CHLD protein does not completely lose its original activity, but instead, gains novel features. A transcriptional analysis of Chl a oxygenase revealed that there is a strong negative feedback control of Chl b biosynthesis in S. italica. The SiYGL1 mRNA was expressed in all examined tissues, with higher expression observed in the leaves. Comparison of gene expression profiles in wild-type and siygl1 mutant plants indicated that SiYGL1 regulates a subset of genes involved in photosynthesis (rbcL and LHCB1), thylakoid development (DEG2) and chloroplast signaling (SRP54CP). These results provide information regarding the mutant phenotype at the transcriptional level. This study demonstrated that the genetic material of a Setaria species could be ideal for gene discovery investigations using forward genetics approaches and may help to explain the molecular mechanisms associated with leaf color variation.

Morphology and leaf anatomy of Setaria s.l. (Poaceae: Panicoideae: Paniceae) and its taxonomic significance

Setaria is numerically one of the largest and most taxonomically complex genera of the tribe Paniceae. The currently published phylogenies of Setaria are not fully resolved and some of the resulting clades reveal more geographical signals than morphological affinities. Therefore, external similarities among species of Setaria do not generally indicate relationships, morphology appears to be highly labile, and few inferences can be made regarding the taxonomy of the genus. In the present study we analyze the variation of the foliar anatomy through a cluster analysis including morphological characters used traditionally to delimit subgenera, sections and species. The aim of this study is to examine whether foliar anatomy, a source of evidence not previously utilized, provides useful information and can be predictive for recognizing homogenous groups of species within Setaria. The significance of the characters is evaluated to identify species groups. These groups were compared with infrageneric taxa and monophyletic clades established in previously published molecular phylogenies. Additionally, some foliar anatomical characters associated with the photosynthetic pathway are also discussed and compared with other members of the tribes Paniceae and Paspaleae.