<Emphasis Type="Italic">Sporidiobolus johnsonii</Emphasis> and <Emphasis Type="Italic">Sporidiobolus salmonicolor</Emphasis> revisited

The relationship between Sporidiobolus johnsonii and S. salmonicolor was investigated using rDNA sequence data. Two statistically well-supported clades were obtained. One clade included the type strain of S. johnsonii and the other included the type strain of S. salmonicolor. However, some mating strains of S. salmonicolor were found in the S. johnsonii group. These strains belonged to mating type A2 and were sexually compatible with mating type A1 strains from the S. salmonicolor group. DNA–DNA reassociation values were high within each clade and moderate between the two clades. In the re-investigation of teliospore germination, we observed that the basidia of S. salmonicolor were two-celled. In S. johnsonii, basidia were not formed and teliospore germination resulted in direct formation of yeast cells. We hypothesize that the S. johnsonii clade is becoming genetically isolated from the S. salmonicolor group and that a speciation process is presently going on. We suspect that the observed sexual compatibility between strains of the S. johnsonii and S. salmonicolor groups and the possible genetic flow between the two species has little biological relevance because distinct phenotypes have been fixed in the two taxa and intermediate (hybrid) sequences for LSU and ITS rDNAs have not been detected.     

Molecular phylogeny of pectinase genes <Emphasis Type="Italic">PGU</Emphasis> in the yeast genus <Emphasis Type="Italic">Saccharomyces</Emphasis>

Using yeast genome databases and literature data, phylogenetic analysis of pectinase PGU genes from 112 Saccharomyces strains assigned to the biological species S. arboricola, S. bayanus (var. uvarum), S. cariocanus, S. cerevisiae, S. kudriavzevii, S. mikatae, S. paradoxus, and the hybrid taxon S. pastorianus (syn. S. carlsbergensis) was carried out. A superfamily of divergent PGU genes was found. Natural interspecies transfer of the PGU gene both from S. cerevisiae to S. bayanus and from S. paradoxus to S. cerevisiae may, however, occur. Within the Saccharomyces species, identity of the PGU nucleotide sequences was 98.8–100% for S. cerevisiae, 86.1–95.7% for S. bayanus (var. uvarum), 94–98.3% for S. kudriavzevii, and 96.8–100% for S. paradoxus/S. cariocanus. For the first time, a family of polymeric PGU1b, PGU2b, PGU3b and PGU4b genes is documented for the yeast S. bayanus var. uvarum, a variety important for winemaking.     

Interactions between the grass shrimp <Emphasis Type="Italic">Palaemonetes pugio</Emphasis> and the salt marsh grasses <Emphasis Type="Italic">Phragmites australis</Emphasis> and <Emphasis Type="Italic">Spartina alterniflora</Emphasis>

The grass shrimp Palaemonetes pugio, a species common to Spartina alterniflora-dominated marshes, may be sensitive to the invasion of the common reed Phragmites australis in northeastern US salt marshes. We examined two questions: (1) Do grass shrimp have a preference for the native plant over the non-native plant? (2) Are grass shrimp more effective foragers on P. australis? We tested the first hypothesis by comparing the amount of time shrimp spend in physical contact with the plant types over a 1-h period. Shrimp were observed under different arrangements of vegetation to control for differences in conspicuous structural features. Additionally, the amount of time shrimp spent foraging on S. alterniflora and P. australis shoots was compared to determine if shrimp graze more often on S. alterniflora. Shrimp spent significantly more time in contact with S. alterniflora only when plant types were grouped at opposite ends of aquaria, but did not exhibit a foraging preference for this plant type. To address our second question, we investigated the effects of shrimp foraging on stem epifauna, an assemblage of semi-aquatic invertebrates associated with macrophyte shoots. Previous research showed that P. australis supports a lower density of stem-dwelling epifauna relative to S. alterniflora. We hypothesized that the primary grazer of this community, P. pugio, can forage on P. australis stems more effectively due to structural differences between the two plants, causing the lower abundance of epifauna through top-down effects. We exposed individual shoots inhabited by epifauna to shrimp and compared faunal densities on exposed shoots to densities on control shoots after 18 h. The reduction of epifauna by predation was proportional on the two plant types. Therefore, top-down effects can be ruled out as an explanation for the patchy distribution of epifauna observed in P. australis–S. alterniflora marshes.     

Biotic resistance of impact: a native predator (<Emphasis Type="Italic">Chaoborus</Emphasis>) influences the impact of an invasive predator (<Emphasis Type="Italic">Bythotrephes</Emphasis>) in temperate lakes

Introduced predators have caused some of the largest documented impacts of non-native species. Interactions among predators can have complex effects, leading to both synergistic and antagonistic outcomes. Complex interactions with native predators could play an important role in mediating the impact of non-native predators. We explore the role of the native predator context on the effect of the introduced predatory cladoceran Bythotrephes longimanus. While post-invasion impacts have been well described, studies have largely ignored the role of native predators. We used a field mesocosm experiment to determine whether Bythotrephes’ impact on prey communities is influenced by the presence of the ubiquitous native predatory insect larvae Chaoborus. The two predators exhibited niche complementarity as no change in total zooplankton prey abundance was detected across predator treatments. Rather, copepod abundances increased with decreasing abundances of Chaoborus, while cladocerans decreased with increasing abundances of Bythotrephes. Thus, the replacement of Chaoborus with Bythotrephes led to changes in the overall community structure of the zooplankton prey, but had little effect on prey total abundance. More interestingly, we found evidence of biotic resistance of impact, that is, the impact of Bythotrephes on the cladoceran community was altered when the two predators co-occurred. Specifically, the predation effect of Bythotrephes was more restricted to the shallower regions of the water column in the presence of Chaoborus, leading to a reduced impact on deeper dwelling prey taxa. Overall, our results demonstrate that the native predator context is important when trying to understand the effect of non-native predators and that variation in native predator abundances and assemblages could explain variation in impact across invaded habitats.     

Molecular evidence for hybridization between invasive <Emphasis Type="Italic">Solidago canadensis</Emphasis> and native <Emphasis Type="Italic">S</Emphasis>. <Emphasis Type="Italic">virgaurea</Emphasis>

Hybridization between alien and native species is biologically very important and could lead to genetic erosion of native taxa. Solidago × niederederi was discovered over a century ago in Austria and described by Khek as a natural hybrid between the alien (nowadays regarded also as invasive) S. canadensis and native S. virgaurea. Although interspecific hybridization in the genus Solidago is considered to be relatively common, hybrid nature of S. × niederederi has not been independently proven using molecular tools, to date. Because proper identification of the parentage for the hybrid Solidago individuals solely based on morphological features can be misleading, in this paper we report an additive polymorphism pattern expressed in the ITS sequences obtained from individuals representing S. × niederederi, and confirm the previous hypothesis that the parental species of this hybrid are S. canadensis and S. virgaurea. Additionally, based on variability at the cpDNA rpl32-trnL locus, we showed that in natural populations hybridization occurs in both directions.     

A functional response evaluation of pre-infestation with <Emphasis Type="Italic">Bemisia tabaci</Emphasis> cryptic species MEAM1 on predation by <Emphasis Type="Italic">Propylea japonica</Emphasis> of <Emphasis Type="Italic">Myzus persicae</Emphasis> on host plant tomatoes

Herbivore feeding on host plants may induce defense responses of the plant which influence other herbivores and interacting species in the vicinity, such as natural enemies. The present work evaluated the impact of pre-infestation with the tobacco whitefly Bemisia tabaci cryptic species MEAM 1, on the predation ability of the ladybird Propylea japonica, to the green peach aphid Myzus persicae, on tomato plants. The results show that B. tabaci pre-infestation density, duration, and leaf position, can impact prey consumed by P. japonica under various aphid densities. The aphids consumed by P. japonica in each treatment were fit using the Holling type II functional response equation. The predatory efficiency (a/T _h) of P. japonica was the highest in the treatment with 60 aphids and 48-h infestation directly on damaged leaves. The predatory efficiencies of P. japonica decreased with a reduction of pre-infestation density and duration. We also observed that pre-infestation on young and undamaged leaves increased predation by P. japonica.     

<Emphasis Type="Italic">Rhizobium</Emphasis> strains in the biological control of the phytopathogenic fungi <Emphasis Type="Italic">Sclerotium</Emphasis> (<Emphasis Type="Italic">Athelia</Emphasis>) <Emphasis Type="Italic">rolfsii</Emphasis> on the common bean

Aims

To identify Rhizobium strains’ ability to biocontrol Sclerotium rolfsii, a fungus that causes serious damage to the common bean and other important crops, 78 previously isolated rhizobia from common bean were assessed.

Methods

Dual cultures, volatiles, indole-acetic acid (IAA), siderophore production and 16S rRNA sequencing were employed to select strains for pot and field experiments.

Results

Thirty-three antagonistic strains were detected in dual cultures, 16 of which were able to inhibit ≥84% fungus mycelial growth. Antagonistic strains produced up to 36.5 μg mL^?1 of IAA, and a direct correlation was verified between IAA production and mycelium inhibition. SEMIA 460 inhibited 45% of mycelial growth through volatile compounds. 16S rRNA sequences confirmed strains as Rhizobium species. In pot condition, common bean plants grown on S. rolfsii-infested soil and inoculated with SEMIA 4032, 4077, 4088, 4080, 4085, or 439 presented less or no disease symptoms. The most efficient strains under field conditions, SEMIA 439 and 4088, decreased disease incidence by 18.3 and 14.5% of the S. rolfsii-infested control.

Conclusions

Rhizobium strains could be strong antagonists towards S. rolfsii growth. SEMIA 4032, 4077, 4088, 4080, 4085, and 439 are effective in the biological control of the collar rot of the common bean.

     

<Emphasis Type="Italic">In vitro</Emphasis> fertilization and preimplantation development in the primate

Nonhuman primates represent a strong model for examining the chromosomal, biochemical, and temporal normality of embryos produced byin vitro fertilization. Morein vitro fertilized embryos from the squirrel monkey(Saimiri sciureus) have been produced and examined than with all other primate species combined. In studies over a 13 year period a fertilization rate approximating 60 % has been developed in this species with 30% of these embryos proceeding to the two cell stage and 50% of these to the three-four cell stage. Chromosomal abnormalities (primarily missing or extra chromosomes) at a level of nine to 16% have been found, a value corresponding to that found inin vivo mating andin vitro fertilization in other species. An incidence of triploidy of 16.7% was observed. RNA and protein synthetic rates appear comparable with those of laboratory species subjected toin vitro fertilization and indicate the initial stages of metabolic activity of the newly formed embryo. Similarly, increases in estrogen incorporation appear after fertilization but no effect is observed in progesterone incorporation. Utilizing 2-deoxy-glucose and insulin, it was determined that the glucose requirement as an energy source for early preimplantationin vitro fertilized primate embryos is very low.Of very great importance is the temporal relationship of the development ofin vitro fertilized squirrel monkey embryos compared with similar development in other primates (including humans) afterin vivo andin vitro fertilization. An analysis of over a decade of work with the squirrel monkey embryos demonstrates a pattern of temporal development that is comparable with all other primate species that have been examined (including the human) and comparable with development afterin vivo fertilization.     

A New Subspecies of <Emphasis Type="Italic">Saguinus fuscicollis</Emphasis> (Primates,Callitrichidae)

Saddleback tamarins (Saguinus fuscicollis, S. melanoleucus, and S. tripartitus) occur in the upper Amazon, west of the rios Madeira and Mamoré–Guaporé to the Andes. They currently comprise 13 species and subspecies in Bolivia, Brazil, Colombia, Ecuador, and Peru. Here we report on a previously undescribed subspecies of Saguinus fuscicollis from the interfluvium of the lower rios Madeira and Purus in the central Amazon of Brazil. It is a distinct form with a very pronounced mottling on the back giving the appearance of a saddle, a characteristic shared by the 3 species, and the reason for their collective common name. The lack of a white superciliary chevron and its highly mottled ochraceous-dark brown to black saddle that extends from the scapular region to the base of the tail distinguish the new taxon from Saguinus fuscicollis weddelli. The latter characteristic also distinguishes it from another saddleback tamarin (Saguinus fuscicollis ssp.) that has been reported immediately to the south of its range in the same interfluvium. We compare pelage coloration, external characters and craniometric measurements with its geographically closest relatives, Saguinus fuscicollis weddelli and S. f. avilapiresi, and indicate its probable geographic distribution in a small area between the rios Madeira and Purus, just south of the Rio Amazonas.     

Incidence of <Emphasis Type="Italic">Fusarium</Emphasis> spp. on the invasive <Emphasis Type="Italic">Spartina alterniflora</Emphasis> on Chongming Island,Shanghai, China

Fusarium palustre is an endophyte/pathogen of Spartina alterniflora, a saltmarsh grass native to North America that has been associated in the USA with a saltmarsh decline known as Sudden Vegetation Dieback (SVD). Since the intentional introduction of S. alterniflora to stabilize mud flats on Chongming Island, Shanghai, China, S. alterniflora has become invasive, but shows no symptoms of dieback even though F. palustre can be isolated from the plant. When declining S. alterniflora from SVD sites in the northeastern USA were assayed for Fusarium species, an average of 8 % of tissues sampled gave rise to a species of Fusarium of these, 64 % were F. palustre and 16 % were F. incarnatum, a nonpathogenic species. To determine if low densities of F. palustre could explain the lack of dieback symptoms on S. alterniflora from Chongming Island, we assessed the incidence and distribution of Fusarium spp. on S. alterniflora from 12 sites on Chongming Island. On average, 26 % of the stem and root tissues sampled were colonized by a Fusarium species. Of 196 isolates recovered from S. alterniflora, 44 % were F. incarnatum and 41 % were F. palustre. Species determinations were confirmed for a subset of these isolates using a phylogenetic analysis of partial sequences of the translation elongation factor (tef) gene. The observation that Fusarium incidence on S. alterniflora was much greater on Chongming Island than in the USA survey raises the question as to why S. alterniflora on Chongming Island is showing no dieback. Other factors, such as predator release, enhanced nutritional, edaphic and/or other unidentified environmental constraints on Chongming Island may afford S. alterniflora protection from dieback.     

<Emphasis Type="Italic">Bactrocera oleae</Emphasis> pupae predation by <Emphasis Type="Italic">Ocypus olens</Emphasis> detected by molecular gut content analysis

The pupae of Bactrocera oleae (Diptera: Tephritidae) complete their development during autumn and winter in the soil, rather than in the drupe, resulting susceptible to edaphic predators. Environmentally friendly methods to control this olive pest involve the identification of its natural enemies. This study evaluated the role of Ocypus olens (Coleoptera: Staphylinidae) in the predation of B. oleae pupae, by means of molecular gut content analysis. Modified dry pitfall traps were used to collect live specimens from low-input olive orchards in Tuscany (Italy). Sampling was fine-tuned with a degree-day model estimating the presence of pest pupae in the soil. PCR analyses carried out on field-collected specimens demonstrated that O. olens is a predator of B. oleae, at least during autumn. These results are consistent with predictions of the degree-day model. Knowledge on species composition, traits and complementarity of the natural enemies of B. oleae pupae needs further investigation to advance conservation biological control strategies.     

Identification of <Emphasis Type="Italic">Bacillus</Emphasis> Probiotics Isolated from Soil Rhizosphere Using 16S rRNA, <Emphasis Type="Italic">recA</Emphasis>, <Emphasis Type="Italic">rpoB</Emphasis> Gene Sequencing and RAPD-PCR

Some Bacillus species, especially Bacillus subtilis and Bacillus pumilus groups, have highly similar 16S rRNA gene sequences, which are hard to identify based on 16S rDNA sequence analysis. To conquer this drawback, rpoB, recA sequence analysis along with randomly amplified polymorphic (RAPD) fingerprinting was examined as an alternative method for differentiating Bacillus species. The 16S rRNA, rpoB and recA genes were amplified via a polymerase chain reaction using their specific primers. The resulted PCR amplicons were sequenced, and phylogenetic analysis was employed by MEGA 6 software. Identification based on 16S rRNA gene sequencing was underpinned by rpoB and recA gene sequencing as well as RAPD-PCR technique. Subsequently, concatenation and phylogenetic analysis showed that extent of diversity and similarity were better obtained by rpoB and recA primers, which are also reinforced by RAPD-PCR methods. However, in one case, these approaches failed to identify one isolate, which in combination with the phenotypical method offsets this issue. Overall, RAPD fingerprinting, rpoB and recA along with concatenated genes sequence analysis discriminated closely related Bacillus species, which highlights the significance of the multigenic method in more precisely distinguishing Bacillus strains. This research emphasizes the benefit of RAPD fingerprinting, rpoB and recA sequence analysis superior to 16S rRNA gene sequence analysis for suitable and effective identification of Bacillus species as recommended for probiotic products.     

Clavicipitaceous entomopathogens: new species in <Emphasis Type="Italic">Metarhizium</Emphasis> and a new genus <Emphasis Type="Italic">Nigelia</Emphasis>

In several surveys in the tropical forests in Thailand, specimens that looked morphologically similar to Metarhizium martiale and Cordyceps variegata, as well as other Metarhizium species were collected and cultured in vitro. A combined phylogeny of several genes including the small (18S) and large (28S) subunits of the ribosomal DNA, elongation factor 1-α (TEF), RNA polymerase II subunits 1 and 2 (RPB1, RPB2) genes has shown these to be new taxa in the Clavicipitaceae. Nigelia is described as a new genus closely related to Metarhizium, to the scale insect pathogens Aschersonia (Hypocrella), Samuelsia and Moelleriella, and to plant pathogens in Claviceps and Balansia, and other relatives. Nigelia comprises M. martiale and a new species Nigelia aurantiaca, which has been found infecting lepidopteran larvae and which produces pseudoimmersed, obliquely arranged, obpyriform perithecia with curved or bent ostioles and with whole (non-separating) cylindric ascospores. Metarhizium chaiyaphumense, M. kalasinense, M. prachinense, M. samlanense, and M. takense are described as new species of Metarhizium. Metarhizium martiale is transferred to Nigelia, and Paecilomyces reniformis is transferred to Metarhizium.     

Revision of the <Emphasis Type="Italic">Serrulati</Emphasis> species of <Emphasis Type="Italic">Penstemon</Emphasis> section <Emphasis Type="Italic">Saccanthera</Emphasis> subsection <Emphasis Type="Italic">Serrulati</Emphasis>

A revision of Penstemon sect. Saccanthera subsect. Serrulati includes a new species (P. salmonensis), a new variety (P. triphyllus var. infernalis), and the elevation of a subspecies to species (P. curtiflorus), bringing the total number of species to eight, which are keyed and described, complete with nomenclature and type citations.     

Parasitism rates and parasitoid complexes of the wheat midges, <Emphasis Type="Italic">Sitodiplosis mosellana</Emphasis>, <Emphasis Type="Italic">Contarinia tritici</Emphasis> and <Emphasis Type="Italic">Haplodiplosis marginata</Emphasis>

Three species of cecidomyiid midges (Diptera: Cecidomyiidae), whose larvae overwinter in the soil, can cause significant yield losses on wheat in Europe: the orange wheat blossom midge, Sitodiplosis mosellana (Géhin), the yellow wheat blossom midge, Contarinia tritici (Kirby), and the saddle gall midge, Haplodiplosis marginata (von Roser). The biological control of wheat midges by their parasitoids can contribute to reduce the midge populations. Soil samples were collected in several fields in Belgium in 2012–2014 in order to characterize the parasitism rates and parasitoid complexes in overwintering larvae. The parasitism rates varied greatly between the sampled fields: 3–100, 0–100 and 2% for S. mosellana, H. marginata and C. tritici, respectively. The parasitism rate was not related to the larval density of wheat midge. The three wheat midges have totally distinct parasitoid complexes in Belgium. Eight species (Hymenoptera: Pteromalidae and Platygastridae) were found as parasitoid of S. mosellana: Macroglenes penetrans (Kirby), Amblypasis tritici (Walker), Euxestonotus error (Fitch), Euxestonutus sp. Fouts, Leptacis sp. Foerster, Platygaster gracilipes (Huggert), Platygaster nisus Walker, and Platygaster tuberosula (Kieffer). According to their abundance, M. penetrans, E. error and P. tuberosula appeared as the main parasitoids of S. mosellana in Belgium. For the two other wheat midges, only one species of the family Platygastridae was found for each midge: Platygaster equestris (Spittler) for H. marginata and Synopeas myles (Walker) for C. tritici.     

Stable,fertile somatic hybrids between <Emphasis Type="Italic">Sinapis alba</Emphasis> and <Emphasis Type="Italic">Brassica juncea</Emphasis> show resistance to <Emphasis Type="Italic">Alternaria brassicae</Emphasis> and heat stress

Wild relatives of Brassica are a rich reservoir of genes that are invaluable for the improvement of cultivated species. Sinapis alba is a close relative of crop Brassicas that possesses several desirable traits such as tolerance to Alternaria black spot disease, heat stress, insect pests and nematodes. This study is aimed at developing and characterizing hybrids between Brassica juncea and S. alba with the ultimate goal of transferring genes for tolerance to Alternaria brassicae and heat stress, the traits that are lacking in cultivated Brassica. We generated three hybrids between B. juncea and S. alba through protoplast fusion. The hybridity was confirmed through cytology and molecular markers. While two of the hybrids were symmetric, the third one was asymmetric and had greater resemblance to B. juncea. Hybrids showed some characteristic features of the parents and were fully male and female fertile and also set seeds upon back crossing with the parent species. In vitro leaf assay and field inoculation studies revealed that the hybrids are highly resistant to A. brassicae. Besides, hybrids set seeds at temperature of >?38 °C when parents failed to produce seeds indicating that hybrids possess heat tolerance. These stable hybrids provide a reliable genetic resource for transfer of genes from S. alba into cultivated Brassica species.