Fungi from leaves of lotus (<Emphasis Type="Italic">Nelumbo nucifera</Emphasis>)

In spite of the self-cleaning property of its leaves called the lotus effect, leaves of lotus (Nelumbo nucifera) provide a habitat for an unknown fungal diversity. The aim of this study was to detect and identify fungi from leaves of N. nucifera, including ectophytic, parasitic and endophytic fungi, in Taiwan using different collection strategies, as well as morphological and diverse molecular markers established in the different systematic groups of fungi. Among ectophytic and parasitic fungi, a new species of Dissoconium and of Pseudocercospora are described, respectively. Phyllosticta nelumbonis Sawada is transferred to Diaporthe. Among plant parasitic fungi, Erysiphe takamatsui and Ps. nymphaeacea are recorded in Taiwan for the first time. Euryale is recorded as a new host genus for Ps. nymphaeacea. The basidiomycetous yeast Fereydounia khargensis is recorded for the first time from living plants and in East Asia. Endophytic fungi from lotus were studied for the first time. From 1002 plant segments, 476 endophytic isolates were produced in culture, comprising 33 typical terrestrial species mainly belonging to the genera Colletotrichum (mainly C. siamense), Diaporthe (D. tulliensis and D. ueckerae) and Fusarium (F. solani species 6, hitherto known from clinical samples), as well as to Xylariaceae, but no Ingoldian fungi. Most isolates were from leaf laminas (71%) compared to those from petioles (29%). From this observation, we conclude that the fungi of the aquatic lotus plant appear to have terrestrial origin and, after dispersal by wind and in spite of the lotus effect, may enter the plant from the lamina. Only three species isolated as endophytes were also found as ectophytic or parasitic fungi.     

Evidence for diversification of <Emphasis Type="Italic">Calophyllum</Emphasis> L. (Calophyllaceae) in the Neogene Siwalik forests of eastern Himalaya

Here, we report fossil leaves, woods, and pollen grains comparable to Calophyllum L. (mainly to Calophyllum inophyllum L. and Calophyllum polyanthum Wall. ex Choisy) of Calophyllaceae from the upper (Kimin Formation, late Pliocene-early Pleistocene), middle (Subansiri Formation, Pliocene) Siwalik sediments of the Arunachal sub-Himalaya, and lower (Gish Clay Formation of Sevok Group; middle to late Miocene) Siwalik sediments of the Darjeeling foothills, eastern Himalaya. Their presence indicates a warm and humid tropical environment in the region during the period of Siwalik sedimentation. Considering all records of Calophyllum, it is suggested that Calophyllum was a frequent forest element throughout the period of Siwalik sedimentation during the Neogene (Miocene time). At present, C. polyanthum grows in the eastern Himalaya, but C. inophyllum is totally absent from north-eastern regions suggesting differential adaptability of these taxa to changing ecoclimatic conditions. Distinct climate change in the area, possibly related to the Himalayan Orogeny during Miocene–Pleistocene times, might have caused the disappearance of C. inophyllum from the entire eastern Himalaya and north-east Indian plains and a move to littoral/coastal and swampy forests of India and other adjoining south-east Asian regions, Polynesia, and the east coast of Africa. The past global distribution of Calophyllum is also discussed, and it is suggested that India may have been its primary centre of origin. This is the first time Cenozoic fossil leaves Calophyllum siwalikum Khan, R.A.Spicer & Bera, sp. nov. comparable to C. inophyllum are described using the both macro- and micromorphological characters.     

A Model for the Spread of an Invasive Weed, <Emphasis Type="Italic">Tradescantia fluminensis</Emphasis>

Tradescantia fluminensis is an invasive weed and a serious threat to native forests in eastern Australia and New Zealand. Current methods of eradication are often ineffective, so understanding the growth mechanisms of Tradescantia is important in formulating better control strategies. We present a partial differential equation (PDE) model for Tradescantia growth and spatial proliferation that accounts for Tradescantia’s particular creeping and branching morphology, and the impact of self-shading on plant growth. This is the first PDE model to represent a weed that spreads via a creeping growth habit rather than by seed dispersal. We use a travelling wave analysis to investigate how Tradescantia extends to colonise new territory. Numerical simulations and analysis show that the model provides a good qualitative representation of the behaviour of this plant. This model provides a foundation for assessing different control and eradication strategies for Tradescantia.     

Analysis of genetic diversity and population structure in <Emphasis Type="Italic">Capsicum</Emphasis> landraces from North Eastern India using TE-AFLP markers

North eastern (NE) India harbours a precious germplasm repository of Capsicum in the form of various landraces. The present study was undertaken to characterise the extent of genetic variation present in different Capsicum landraces from north eastern India. A set of 171 Capsicum accessions were characterised using three-endonuclease amplified fragment length polymorphism (AFLP) markers. Out of 416 bands obtained from six primer combinations, 254 (61 %) were polymorphic. The pairwise genetic dissimilarity among accessions ranged from 0.03 to 0.97. Cluster analysis based on neighbour joining showed two major clusters. Cluster I contained most of the bhut jolokia accessions whereas cluster II contained all of the Capsicum annuum genotypes. Similar grouping was observed with population STRUCTURE analysis as well as principle coordinate analysis. Analysis of molecular variance (AMOVA) revealed 45 and 54 % variation among and within populations, respectively. This information on population structure analysis and molecular characterisation will be helpful for effective utilisation of this germplasm in Capsicum improvement programs.     

Marker-assisted pyramiding of <Emphasis Type="BoldItalic">Thinopyrum-</Emphasis>derived leaf rust resistance genes <Emphasis Type="BoldItalic">Lr19</Emphasis> and <Emphasis Type="BoldItalic">Lr24</Emphasis> in bread wheat variety HD2733

This study was undertaken to pyramid two effective leaf rust resistance genes (Lr19 and Lr24) derived from Thinopyrum (syn. Agropyron), in the susceptible, but agronomically superior wheat cultivar HD2733 using marker-assisted selection. In the year 2001, HD2733 was released for irrigated timely sown conditions of the north eastern plains zone (NEPZ) of India became susceptible to leaf rust, a major disease of the region. Background selection helped in developing near-isogenic lines (NILs) of HD2733 with Lr19 and Lr24 with 97.27 and \(98.94\%\), respectively, of genomic similarity with the parent cultivar, after two backcrossing and one generation of selfing. NILs were intercrossed to combine the genes Lr19 and Lr24. The combination of these two genes in the cultivar HD2733 is expected to provide durable leaf rust resistance in farmers’ fields.     

Vetch aphid, <Emphasis Type="Italic">Megoura crassicauda</Emphasis> (Hemiptera: Aphididae), parasitism does not reduce the bean production of narrow-leaved vetch, <Emphasis Type="Italic">Vicia sativa</Emphasis> subsp. <Emphasis Type="Italic">nigra</Emphasis> (Fabaceae)

Megoura crassicauda Mordvilko (Hemiptera: Aphididae) is a dominant aphid species found on Vicia sativa subsp. nigra (L.) Ehrh. (Fabaceae) in the spring. Worker ants of Formica japonica, the dominant ant species attracted to the extrafloral nectaries of V. s. nigra, often attack ladybirds (Coccinella septempunctata), which are aphid enemies. However, the workers of F. japonica do not attack or exclude M. crassicauda, the non-myrmecophilous aphid. It appears that the “bodyguard” retained by the plant guards the plant’s herbivore by attacking the herbivores’ enemies, rather than guarding the plant itself. The relationship between V. s. nigra and M. crassicauda was observed in the field to examine and evaluate the cost of parasitism. Parasitism by M. crassicauda delayed flower bud formation markedly in V. s. nigra but did not kill the plants. V. s. nigra plants that were parasitized showed a net bean production similar to that of the non-parasitized controls. The parasitism rate of M. crassicauda increased when extrafloral nectaries were used by F. japonica. These results may indicate that M. crassicauda provides V. s. nigra with benefits by preventing other serious disadvantages.     

<Emphasis Type="Italic">chr</Emphasis> genes from adaptive replicons are responsible for chromate resistance by <Emphasis Type="Italic">Burkholderia xenovorans</Emphasis> LB400

The chromate ion transporter (CHR) superfamily includes proteins that confer chromate resistance by extruding toxic chromate ions from cytoplasm. Burkholderia xenovorans strain LB400 encodes six CHR homologues in its multireplicon genome and has been reported as highly chromate-resistant. The objective of this work was to analyze the involvement of chr redundant genes in chromate resistance by LB400. It was found that B. xenovorans plant rhizosphere strains lacking the megaplasmid are chromate-sensitive, suggesting that the chr gene present in this replicon is responsible for the chromate-resistance phenotype of the LB400 strain. Transformation of a chromate-sensitive B. xenovorans strain with each of the six cloned LB400 chr genes showed that genes from ‘adaptive replicons’ (chrA1b and chr1NCb from chromosome 2 and chrA2 from the megaplasmid) conferred higher chromate resistance levels than chr genes from ‘central’ chromosome 1 (chrA1a, chrA6, and chr1NCa). An LB400 insertion mutant affected in the chrA2 gene displayed a chromate-sensitive phenotype, which was fully reverted by transferring the chrA2 wild-type gene, and partially reverted by chrA1b or chr1NCb genes. These data indicate that chr genes from adaptive replicons, mainly chrA2 from the megaplasmid, are responsible for the B. xenovorans LB400 chromate-resistance phenotype.     

Detection of pea wilt pathogen <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> f. sp. <Emphasis Type="Italic">pisi</Emphasis> using DNA-based markers

Identification of the fungus Fusarium oxysporum f. sp. pisi (Fop), the causal organism of wilt disease of pea, is a time consuming and arduous task. Diagnosis of Fop by traditional means requires more than 2 months and involves two steps, identification of species using morphological characters and formae specialis ‘pisi’ using pathogenicity assays. The ambiguous morphological differences between F. solani and F. oxysporum further complicate the diagnosis of F. oxysporum. A polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) based method was developed to detect Fop from India. A PCR–RFLP marker, HPACAPS1₃₈₀, generated after restriction of 28S rDNA region with enzyme MvaI, detected accurately the Fop among several other fungi with detection sensitivity of 5 fg of Fop genomic DNA. In a mixture of Fop and pea DNA, the sensitivity was 500 pg of Fop DNA in 50 ng of pea DNA. The assay was further refined to detect the Fop from infected tissues and infested soil. The current assay can detect Fop from culture, plant tissues and soil in a considerably shorter period of time compared to traditional methods.     

Reduced ant defenses in <Emphasis Type="Italic">Macaranga</Emphasis> myrmecophytes (Euphorbiaceae) infested with a winged phasmid <Emphasis Type="Italic">Orthomeria cuprinus</Emphasis>

Macaranga is a tree genus that includes many species of myrmecophytes, which are plants that harbor ant colonies within hollow structures known as domatia. The symbiotic ants (plant–ants) protect their host plants against herbivores; this defense mechanism is called ‘ant defense’. A Bornean phasmid species Orthomeria cuprinus feeds on two myrmecophytic Macaranga species, Macaranga beccariana and Macaranga hypoleuca, which are obligately associated with Crematogaster ant species. The phasmids elude the ant defense using specialized behavior. However, the mechanisms used by the phasmid to overcome ant defenses have been insufficiently elucidated. We hypothesized that O. cuprinus only feeds on individual plants with weakened ant defenses. To test the hypothesis, we compared the ant defense intensity in phasmid-infested and non-infested M. beccariana trees. The number of plant–ants on the plant surface, the ratio of plant–ant biomass to tree biomass, and the aggressiveness of plant–ants towards experimentally introduced herbivores were significantly lower on the phasmid-infested trees than on the non-infested trees. The phasmid nymphs experimentally introduced into non-infested trees, compared with those experimentally introduced into phasmid-infested trees, were more active on the plant surface, avoiding the plant–ants. These results support the hypothesis and suggest that ant defenses on non-infested trees effectively prevent the phasmids from remaining on the plants. Thus, we suggest that O. cuprinus feeds only on the individual M. beccariana trees having decreased ant defenses, although the factors that reduce the intensity of the ant defenses remain unclear.     

A new <Emphasis Type="Italic">Gephyraulus</Emphasis> species (Diptera: Cecidomyiidae) inducing flower bud galls on the European sea rocket <Emphasis Type="Italic">Cakile maritima</Emphasis> Scop. (Brassicaceae)

The European sea rocket Cakile maritima Scop. (Brassicaceae) is a common herb growing on sandy coastlines worldwide and is considered a useful plant because of its medicinal importance, its edibility, and potential as an oilseed crop. However, C. maritima is an invasive plant over a wide range, e.g., eastern South America, North America, northern Iran, Australia and New Zealand, and has a limited number of associated herbivorous insects. During investigations on gall midges (Diptera: Cecidomyiidae) in Egypt, we found a gall midge inducing flower bud galls on C. maritima and preventing fruit production, which suggested that this gall midge is a potential pest of this plant. In this paper, we describe this gall midge species, Gephyraulus zewaili Elsayed and Tokuda sp. nov., as new to science by comparing its morphology with that of close congeners. Partial sequence data of the mitochondrial DNA cytochrome oxidase subunit I gene are also provided.     

Expression of an endochitinase gene from <Emphasis Type="Italic">Trichoderma virens</Emphasis> confers enhanced tolerance to <Emphasis Type="Italic">Alternaria</Emphasis> blight in transgenic <Emphasis Type="Italic">Brassica juncea</Emphasis> (L.) czern and coss lines

An endochitinase gene ‘ech42’ from the biocontrol fungus ‘Trichoderma virens’ was introduced to Brassica juncea (L). Czern and Coss via Agrobaterium tumefaciens mediated genetic transformation method. Integration and expression of the ‘ech42’ gene in transgenic lines were confirmed by PCR, RT-PCR and Southern hybridization. Transgenic lines (T₁) showed expected 3:1 Mendelian segregation ratio when segregation analysis for inheritance of transgene ‘hpt’ was carried out. Fluorimetric analysis of transgenic lines (T₀ and T₁) showed 7 fold higher endochitinase activity than the non-transformed plant. Fluorimetric zymogram showed presence of endochitinase (42 kDa) in crude protein extract of transgenic lines. In detached leaf bioassay with fungi Alternaria brassicae and Alternaria brassicicola, transgenic lines (T₀ and T₁) showed delayed onset of lesions as well as 30–73 % reduction in infected leaf area compared to non-transformed plant.     

Silencing of <Emphasis Type="Italic">GbANS</Emphasis> reduces cotton resistance to <Emphasis Type="Italic">Verticillium dahliae</Emphasis> through decreased ROS scavenging during the pathogen invasion process

Anthocyanins are secondary metabolites that play important roles in plant adaption to adverse environments. The anthocyanin biosynthetic pathway is conserved in high plants. Previous studies revealed the significant role of anthocyanins in natural-colorized cotton. However, little is known about the involvement of anthocyanins in the interaction of cotton and pathogen. In this study, a pathogen-induced gene was isolated from Gossypium barbadense that encodes an anthocyanidin synthase protein (GbANS) with dioxygenase structures. GbANS was preferentially expressed in colored tissue. Silencing of GbANS significantly reduced the production of anthocyanins, as well as the cotton’s resistance to Verticillium dahliae. Biochemical studies revealed that GbANS-silenced cotton accumulated more hydrogen peroxide compared to control plants during the V. dahliae invasion process. This accumulation of hydrogen peroxide corresponded with increased cell death around the invasion sites, which in turn accelerated the V. dahliae infection. Taken together, we found that GbANS contributes to the biosynthesis of anthocyanins in cotton and anthocyanins positively regulate cotton’s resistance to V. dahliae.     

New ideas on the system of the Permian <Emphasis Type="Italic">Inoceramus</Emphasis>-like bivalves of the eastern Boreal zone

New concepts of systematics and phylogeny of the Permian Inoceramus-like bivalve mollusks of the eastern part of the Boreal zone are discussed based on analysis of the group’s historical development. All taxa studied are referred to the family Kolymiidae Kusnezov, which is divided into two subfamilies, Kolymiinae and Atomodesmatinae. In the subfamily Kolymiinae, two new genera are described: Praekolymia with the type species P. archboldi sp. nov. and P. urbajtisae sp. nov., and Taimyrokolymia with the type species T. ustritskyi sp. nov. In the subfamily Atomodesmatinae, two new genera, Costatoaphanaia and Okhotodesma, are described. The development of the group is shown to be generally autochthonous with some invasions (genus Atomodesma and, probably, Trabeculatia) from extraboreal regions.     

Diversity of root-endophytic <Emphasis Type="Italic">Trichoderma</Emphasis> from Malaysian Borneo

Trichoderma species form endophytic associations with plant roots and may provide a range of benefits to their hosts. However, few studies have systematically examined the diversity of Trichoderma species associated with plant roots in tropical regions. During the evaluation of Trichoderma isolates for use as biocontrol agents, root samples were collected from more than 58 genera in 35 plant families from a range of habitats in Malaysian Borneo. Trichoderma species were isolated from surface-sterilised roots and identified following analysis of partial translation elongation factor-1α (tef1) sequences. Species present included Trichoderma afroharzianum, Trichoderma asperelloides, Trichoderma asperellum, Trichoderma guizhouense, Trichoderma reesei, Trichoderma strigosum and Trichoderma virens. Trichoderma asperellum/T. asperelloides, Trichoderma harzianum s.l. and T. virens were the most frequently isolated taxa. tef1 sequence data supported the recognition of undescribed species related to the T. harzianum complex. The results suggest that tropical plants may be a useful source of novel root-associated Trichoderma for biotechnological applications.     

New species of the buprestid genus <Emphasis Type="Italic">Endelus</Emphasis> Deyrolle (Coleoptera,Buprestidae) from China,India, and Laos

Endelus (Kubaniellus) indicus sp. n. from India, E. (K.) lao sp. n. and E. (K.) khnzoriani sp. n. from Laos, E. (s. str.) sausai sp. n. from China, and E. (s. str.) dembickyi sp. n. from India are described, the two latter species are included in the Endelus bicarinatus Théry, 1932 species-group recently established by the author. E. collinus Obenberger, 1922 is included in this group; lectotype of this species is designated. Keys to species of the subgenus Kubaniellus and of the E. collinus group are provided. E. (K.) kareni Kalashian is for the first time recorded for Shaanxi Prov., E. pacholatkoi Kalashian, E. smaragdinus Desc. et Vill., and E collinus Obenb., for Laos (the latter species, also for Myanmar).     

The expression level of anthocyanidin synthase determines the anthocyanin content of crabapple (<Emphasis Type="Italic">Malus</Emphasis> sp.) petals

In addition to contributing to the coloration of plant organs and their defense against herbivores, the consumption of anthocyanins in the human diet has a number of health benefits. Crabapple (Malus sp.) represents a valuable experimental model system to research the mechanisms and regulation of anthocyanin accumulation, in part due to the often vivid and varied petal and leaf coloration that is exhibited by various cultivars. The enzyme anthocyanidin synthase (ANS) plays a pivotal role in anthocyanin biosynthesis; however, the relationship between ANS expression and petal pigmentation has yet to be established in crabapple. To illuminate the mechanism of anthocyanin accumulation in crabapple petals, we evaluated the expression of two crabapple ANS allelic genes (McANS-1 and McANS-2) and the levels of anthocyanins in petals from cultivars with dark red (‘Royalty’) and white (‘Flame’) petals, as well as another (‘Radiant’) whose petals have an intermediate pink color. We determined that the expression of McANS in the three cultivars correlated with the variation of anthocyanin accumulation during different petal developmental stages. Furthermore, transgenic tobacco plants constitutively overexpressing one of the two McANS genes, McANS-1, had showed elevated anthocyanin accumulation and a deeper red coloration in their petals than those from untransformed control lines. In conclusion, we propose that McANS are responsible for anthocyanin accumulation during petal coloration in different crabapple cultivars.     

Natural variation of potato <Emphasis Type="Italic">allene oxide synthase 2</Emphasis> causes differential levels of jasmonates and pathogen resistance in <Emphasis Type="Italic">Arabidopsis</Emphasis>

Natural variation of plant pathogen resistance is often quantitative. This type of resistance can be genetically dissected in quantitative resistance loci (QRL). To unravel the molecular basis of QRL in potato (Solanum tuberosum), we employed the model plant Arabidopsis thaliana for functional analysis of natural variants of potato allene oxide synthase 2 (StAOS2). StAOS2 is a candidate gene for QRL on potato chromosome XI against the oömycete Phytophthora infestans causing late blight, and the bacterium Erwinia carotovora ssp. atroseptica causing stem black leg and tuber soft rot, both devastating diseases in potato cultivation. StAOS2 encodes a cytochrome P450 enzyme that is essential for biosynthesis of the defense signaling molecule jasmonic acid. Allele non-specific dsRNAi-mediated silencing of StAOS2 in potato drastically reduced jasmonic acid production and compromised quantitative late blight resistance. Five natural StAOS2 alleles were expressed in the null Arabidopsis aos mutant under control of the Arabidopsis AOS promoter and tested for differential complementation phenotypes. The aos mutant phenotypes evaluated were lack of jasmonates, male sterility and susceptibility to Erwinia carotovora ssp. carotovora. StAOS2 alleles that were associated with increased disease resistance in potato complemented all aos mutant phenotypes better than StAOS2 alleles associated with increased susceptibility. First structure models of ‘quantitative resistant’ versus ‘quantitative susceptible’ StAOS2 alleles suggested potential mechanisms for their differential activity. Our results demonstrate how a candidate gene approach in combination with using the homologous Arabidopsis mutant as functional reporter can help to dissect the molecular basis of complex traits in non model crop plants.