The responses of an early (<Emphasis Type="Italic">Rhynchospora alba</Emphasis>) and a late (<Emphasis Type="Italic">Molinia japonica</Emphasis>) colonizer to solar radiation in a boreal wetland after peat mining

The responses of seedlings to solar radiation, including ultraviolet (UV), were investigated for Rhynchospora alba, an early colonizer, and Molinia japonica, a late colonizer, in a mined peatland in northern Japan. The solar radiation and rainfall were, respectively, higher and lower in 2008 than in 2009 during the field surveys. The seedlings were transplanted to bare ground, and measurements were made of the biomass, the allocation of biomass to shoots and roots, the absorbance of ultraviolet A and ultraviolet B, and the concentrations of anthocyanin and chlorophyll. R. alba did not change its biomass in response to any solar radiation treatment in 2008 and decreased shoot biomass with low UV and decreased root biomass with shade in 2009. Additionally, M. japonica did not change its biomass in 2008 but decreased its root biomass with low UV in 2009. The chlorophyll concentration of R. alba did not change in 2008 or 2009, whereas the chlorophyll concentration of M. japonica increased with decreased solar radiation, including UV. The UV absorbance of R. alba decreased under shade and with high peat moisture. In contrast, the content of UV-absorbing substances remained unchanged in M. japonica. Therefore, R. alba, the early colonizer, adapted more to strong solar radiation by changing its shoot-root allometry and producing UV-absorbing substances, whereas M. japonica, the late colonizer, tended to respond more to peat moisture. These differing responses to solar radiation and peat moisture may explain the temporal patterns of species replacement from early to late colonizers.     

Engineering of the carotenoid pathway in <Emphasis Type="Italic">Xanthophyllomyces dendrorhous</Emphasis> leading to the synthesis of zeaxanthin

Zeaxanthin is an essential nutrient for prevention of macular degeneration. However, it is limited in our diet. For the production of zeaxanthin, we have engineered zeaxanthin synthesis into a carotenoid mutant of Xanthophyllomyces dendrorhous which is blocked in astaxanthin synthesis and accumulates β-carotene instead. Two strategies were followed to reach high-yield zeaxanthin synthesis. Total carotenoid synthesis was increased by over-expression of genes HMGR, crtE, and crtYB encoding for limiting enzymes in the pathway leading to and into carotenoid biosynthesis. Then bacterial genes crtZ were used to extend the pathway from β-carotene to zeaxanthin in this mutant. The increase of total carotenoids and the formation of zeaxanthin is dependent on the number of gene copies of crtYB and crtZ integrated into the X. dendrorhous upon transformation. The highest zeaxanthin content around 500 μg/g dw was reached by shaking flask cultures after codon optimization of crtZ for Xanthophyllomyces. Stabilization of carotenoid and zeaxanthin formation in the final transformant in the absence of selection agents was achieved after passing through a sexual cycle and germination of basidiospores. The values for the transformant before and after stabilization were very similar resembling about 70 % of total carotenoids and corresponding to a conversion rate of 80 % for hydroxylation of β-carotene to zeaxanthin. The stabilized transformant allowed experimental small-scale fermentation yielding X. dendrorhous cells with a zeaxanthin content similar to the shaking flask cultures. Our result demonstrates the potential of X. dendrorhous for its development as a zeaxanthin producer and its suitability for large-scale fermentation.     

<Emphasis Type="Italic">Rf5</Emphasis> is able to partially restore fertility to Honglian-type cytoplasmic male sterile <Emphasis Type="Italic">japonica</Emphasis> rice (<Emphasis Type="Italic">Oryza sativa</Emphasis>) lines

Three-line japonica hybrids have been developed mainly on Chinsurah Boro II (BT)-type cytoplasmic male sterile (CMS) lines of Oryza sativa L., but the unstable sterility of some BT-type CMS lines, and the threat of genetic vulnerability when using a single cytoplasm source, have inhibited their use in rice cultivation. Previously, the sterility of Honglian (HL)-type japonica CMS lines derived from common red-awned wild rice (Oryza rufipogon) has been proven to be more stable than that of BT-type japonica CMS lines. Here, we genetically characterized HL-type japonica CMS lines and the restorer-of-fertility (Rf) gene for breeding HL-type japonica hybrids. HL-type japonica CMS lines displayed stained abortive pollen grains, unlike HL-type indica CMS lines. The BT-type japonica restorer lines, which contain Rf, had different capabilities to restore HL-LiuqianxinA (HL-LqxA), an HL-type japonica CMS line, and the restorers for the HL-type japonica CMS lines could be selected from the preexisting BT-type japonica restorers in rice production. A genetic analysis showed that the restoration of normal fertility to HL-LqxA was controlled by a major gene and was affected by minor effector genes and/or modifiers. The major Rf in SiR2982, a BT-type japonica restorer, was mapped to a ~100-kb physical region on chromosome 10, and was demonstrated to be Rf5 (Rf1a) by sequencing. Furthermore, Rf5 partially restored fertility and had a dosage effect on HL-type japonica CMS lines. These results will be helpful for the development of HL-type japonica hybrids.     

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.     

Genetic mapping of ovary colour and quantitative trait loci for carotenoid content in the fruit of <Emphasis Type="Italic">Cucurbita maxima</Emphasis> Duchesne

The high content of carotenoids, sugars, dry matter, vitamins and minerals makes the fruit of winter squash (Cucurbita maxima Duchesne) a valuable fresh-market vegetable and an interesting material for the food industry. Due to their nutritional value, long shelf-life and health protective properties, winter squash fruits have gained increased interest from researchers in recent years. Despite these advantages, the genetic and genomic resources available for C. maxima are still limited. The aim of this study was to use the genetic mapping approach to map the ovary colour locus and to identify the quantitative trait loci (QTLs) for high carotenoid content and flesh colour. An F₆ recombinant inbred line (RIL) mapping population was developed and used for evaluations of ovary colour, carotenoid content and fruit flesh colour. SSR markers and DArTseq genotyping-by-sequencing were used to construct an advanced genetic map that consisted of 1824 molecular markers distributed across linkage groups corresponding to 20 chromosomes of C. maxima. Total map length was 2208 cM and the average distance between markers was 1.21 cM. The locus affecting ovary colour was mapped at the end of chromosome 14. The identified QTLs for carotenoid content in the fruit and fruit flesh colour shared locations on chromosomes 2, 4 and 14. QTLs on chromosomes 2 and 4 were the most meaningful. A correlation was clearly confirmed between fruit flesh colour as described by the chroma value and carotenoid content in the fruit. A high-density genetic map of C. maxima with mapped loci for important fruit quality traits is a valuable resource for winter squash improvement programmes.     

Hair growth effects of <Emphasis Type="Italic">Laminaria japonica</Emphasis> extract and growth factor mixture on a C57BL/6 mouse model

To develop a drug to treat hair loss, we evaluated the effects of Laminaria japonica extract mixed with growth factor. After topical application of the L. japonica growth factor mixture to a six-week-old C57BL/6 mouse model, analysis of hair re-growth was determined using a high-resolution hair analysis system, as well as, photographic and histologic analysis. Depilated areas were completely covered with fully-grown hair in all study groups (control group, L. japonica extract group, and L. japonica extract mixed with growth factor group) and the hair re-growth score was the highest in the group treated with L. japonica supplemented with insulin-like growth factor-1 (IGF-1). The width and length of the hair follicles showed a significant increase in the groups treated with L. japonica mixed with IGF-1, compared to the control groups. Groups treated with L. japonica mixed with growth factor showed significantly increased gene expression of IGF-1 and decreased expression of transforming growth factor (TGF)-β, compared to the control groups. We confirmed that IGF-1 was more effective in promoting hair growth than vascular endothelial growth factor (VEGF). Therefore, we suggest that L. japonica mixed with IGF-1 could successfully be used to treat patients with alopecia; however, clinical trials and additional studies on the side effects of the mixture are necessary.     

Temperature-dependent QTLs in <Emphasis Type="Italic">indica</Emphasis> alleles for improving grain quality in rice: increased prominence of QTLs responsible for reduced chalkiness under high-temperature conditions

Quantitative trait loci (QTLs) for the apparent quality of brown rice under high temperatures during ripening were analyzed using chromosomal segment substitution lines. Segments from the indica cultivar Habataki were substituted into a japonica cultivar with a Sasanishiki background. We found the following two QTLs for increasing grain quality in the Habataki allele on chromosome 3: (1) qTW3-2, located near the marker RM14702, decreased the percentage of total white immature (TWI) grains, and (2) qRG3-2, located near RM3766, increased the percentage of regular grains. The effects of these two QTLs were more obvious under high-temperature ripening conditions; hence, these loci are considered QTLs not only for reducing TWI grains but also for increasing high-temperature tolerance. Additionally, we found two QTLs, i.e., qTW3-1 and qRG3-1, responsible for reduced grain quality near RM14314 on chromosome 3. Although the QTL for narrow grains in the Habataki allele qNG3 was genetically linked to qTW3-2, the effect was only slightly significant, and the length/width ratio of qNG3-carrying grains was within the range observed in widely grown japonica cultivars. Incorporating the Habataki region, including qRG3-2 and qTW3-2 but not qTW3-1 and qRG3-1, in addition to previously reported grain quality QTLs in breeding japonica cultivars will improve high-temperature tolerance and grain quality.     

Species,community, and ecosystem-level responses following the invasion of the red alga <Emphasis Type="Italic">Dasysiphonia japonica</Emphasis> to the western North Atlantic Ocean

Species invasions have been increasing in frequency worldwide, yet critical gaps remain in our understanding of how invaders affect community structure and ecosystem functioning, particularly during the initial stages of invasion. Even less is known about changes in the invader that may take place immediately following an invasion. This study examined the recent invasion of the red macroalga Dasysiphonia (formerly, Heterosiphonia) japonica to the western North Atlantic Ocean with the aim of filling in gaps in our understanding of the impacts that invasive seaweeds have at the species, community and ecosystem levels immediately following their establishment. Within 5 years of invasion, community composition had changed and biodiversity had decreased to nearly half of pre-invasion levels. In addition, the relative proportion of Dasysiphonia decreased by 35% over our four-year study from initially high levels shortly after establishment. We found evidence that functional traits of this initially aggressive invader changed over time, as it ultimately became a less aggressive, co-inhabiting member of the local algal community, particularly with respect to nutrient uptake and relative abundances, although native diversity remained low relative to pre-invasion levels. Using these realistic changes in community structure, including decreases in biodiversity, we also showed that nutrient uptake of algal assemblages changed over time, suggesting changes in the functional characteristics of invaded communities, with implications for ecosystem-level processes such as nutrient fluxes. This study provides rare empirical evidence about the successional stages occurring at the individual, community, and ecosystem levels during the first 5 years of an invasion.     

Cloning,characterization and function analysis of <Emphasis Type="Italic">DAX1</Emphasis> in Chinese loach (<Emphasis Type="Italic">Paramisgurnus dabryanus</Emphasis>)

The mechanisms of sex determination and differentiation have not been elucidated in most fish species. In this study, the full-length cDNAs of DAX1 was cloned and characterized in aquaculture fish Chinese loach (Paramisgurnus dabryanus), designated as Pd-DAX1. The cDNA sequence of Pd-DAX1 was 1261 bp, including 795 bp open reading frame (ORF) encoding 264 amino acids. Pd-DAX1 shares highly identical sequence with DAX1 homologues from different species. The expression profiles of Pd-DAX1 in different developmental stages and diverse adult tissues were analyzed by quantitative real-time RT-PCR and in situ hybridization (ISH). Pd-DAX1 was continuously expressed during embryogenesis, with the extensive distribution in the development of the central nervous system. Tissue distribution analysis revealed that Pd-DAX1 expressed widely in adult tissues, with the highest expression level found in testis, moderate level in ovary, showing a sex-dimorphic expression pattern. Pd-DAX1 mainly located in spermatogonia cells, spermatocytes, primary oocytes and previtellogenic oocyte cells, implying that Pd-DAX1 may involve in gametogenesis. These preliminary findings suggest that Pd-DAX1 gene is highly conserved during vertebrate evolution and involved in a wide range of developmental processes including embryogenesis, central nervous system development and gonad development.     

Tandem duplications of receptor-like kinase genes reshaped the homologous chromosome 1 regions in <Emphasis Type="Italic">Oryza sativa</Emphasis> ssp. <Emphasis Type="Italic">indica</Emphasis> and <Emphasis Type="Italic">japonica</Emphasis> and their possible ancestral genomes

Plant receptor-like kinase (Rlk) genes form a large family, each encoding a protein with a signal motif, a single transmembrane region, and a cytoplasmic kinase domain. Various gene duplications have contributed to the establishment and expansion of the family. Here, we characterized the formation and evolution of the Rlk gene family in cultivated rice and their possible progenitors. Using wheat Rlk gene sequences, we identified orthologs from the genomes of domesticated rice subspecies Oryza sativa ssp. japonica and ssp. indica and their putative progenitors O. glaberrima and O. rufipogon. The four chromosome 1 orthologous regions ranged from 103 to 281 kb comprising 181 syntenic blocks with 75 to 100% sequence identity. These regions contained 11–19 Triticum aestivum kinases (Taks) and 10–15 Lr10 receptor-like kinases (Lrks) organized in clusters and 3–12 transposable elements (TEs). Dot plot analyses showed that the 4 regions had 21–37 conserved catalytic domains, mainly in protein kinases (PKs) and tyrosine kinases (TyrKs) in coupling state. Over 50% of the sequences of glaberrima/rufipogon and japonica/indica pairs were colinear, while japonica/indica displayed a marked sequence expansion with duplicated genes and TEs. A total of 2312 single nucleotide polymorphisms (SNPs) and insertion-deletions (INDELs) were identified between japonica and indica. Duplication of the Rlk genes in O. glaberrima and O. rufipogon occurred after the grass species radiation and before the divergence of O. rufipogon from O. glaberrima; the orthologous Rlk genes from O. japonica and O. indica duplicated after O. sativa separated from O. rufipogon; paralogs, obtained through extensive duplication, happened after the separation of rice from maize. Tandem duplication was the major factor contributing to the gene copy number variation and genome size expansion.     

The dual role of phytoene synthase genes in carotenogenesis in carrot roots and leaves

Carrot (Daucus carota L.) is an important food crop and is useful for studying carotenogenesis due to the quantity and diversity of carotenoids in its roots. Phytoene synthase catalyzes the first committed step in the carotenoid biosynthesis pathway, and its overexpression is the main driving force in the orange phenotype. At present, we lack fundamental knowledge of the role of these genes and their effects on carotenoid accumulation in leaves. In the present study, three backcross inbred lines (BC2S4) with different colored roots derived from a cross between the orange inbred line (Af) and related wild species were used to investigate the role of the duplicated DcPSY genes in root carotenogenesis. Promoter analysis showed that DcPSY genes have diverged substantially in their regulatory sequences after gene duplication. Expression levels of DcPSY1 and DcPSY2 were generally positively correlated with carotenoid content during root development. In mature leaves, total carotenoid content was higher than that in the roots, DcPSY1 expression increased extremely higher than DcPSY2 expression compared with roots, and DcPSY1 was more sensitive than DcPSY2 during leaf de-etiolation under sunlight. These results suggest that DcPSY1 seems to make an important contribution to carotenoid accumulation in the leaves and is important for photosynthesis and photoprotection, but they are not the determining factors of root color. This expands our understanding of the regulation of carotenoid biosynthesis in carrot.     

The effect of galling aphids feeding on photosynthesis photochemistry of elm trees (<Emphasis Type="Italic">Ulmus</Emphasis> sp.)

Changes of chlorophyll (Chl) a fluorescence and photosynthetic pigment contents were analysed in galled leaves (visibly damaged and undamaged parts) and intact leaves. The values of minimal fluorescence of the dark-adapted state, maximal quantum yield of PSII photochemistry, effective quantum yield of PSII photochemical conversion, and photochemical quenching coefficient decreased in Ulmus pumila L. leaves galled by Tetraneura ulmi (L.) and in U. glabra Huds. galled by Eriosoma ulmi (L.). Colopha compressa (Koch.) feeding affected these parameters only in damaged parts of U. laevis Pall. galled leaves. The increasing number of T. ulmi galls progressively decreased photosynthetic performance. In gall tissues of all analysed aphid species, the lowest photosynthetic pigment content was found, indicating that the photosynthetic capacity must have been low in galls. Significant reduction of Chl and carotenoid contents were observed in damaged and undamaged portions of galled leaves only in the case of T. ulmi feeding.     

<Emphasis Type="Italic">Cacopsylla biwa</Emphasis> sp. nov. (Hemiptera: Psyllidae): a new pest of loquat <Emphasis Type="Italic">Eriobotrya japonica</Emphasis> (Rosaceae) in Japan

A new psyllid species, Cacopsylla biwa Inoue, sp. nov., is described from Tokushima Prefecture, Shikoku, Japan. This new species develops only on Eriobotrya japonica (Thunb.) Lindl. (Rosaceae), causing severe damage to its fruits and flowers. It is strongly suspected that C. biwa is an alien species. Morphological similarities and host-plant relationships indicate that C. biwa is most closely related to Cacopsylla eriobotryae (Yang) comb. nov. (transferred from Edentatipsylla Li), which occurs in Taiwan and feeds on Eriobotrya deflexa (Hemsl.) Nakai. Morphological diagnostic characteristics of C. biwa and differences from the other congeners are discussed. Information is provided on the biology and life cycle of the new species.     

Knockout of <Emphasis Type="Italic">pprM</Emphasis> Decreases Resistance to Desiccation and Oxidation in <Emphasis Type="Italic">Deinococcus radiodurans</Emphasis>

Deinococcus radiodurans has attracted a great interest in the past decades due to its extraordinary resistance to ionizing radiation and highly efficient DNA repair system. Recent studies indicated that pprM is a putative pleiotropic gene in D. radiodurans and plays an important role in radioresistance and antioxidation, but its underlying mechanisms are poorly elucidated. In this study, pprM mutation was generated to investigate resistance to desiccation and oxidative stress. The result showed that the survival of pprM mutant under desiccation was markedly retarded compared to the wild strain from day 7–28. Furthermore, knockout of pprM increases the intercellular accumulation of ROS and the sensibility to H₂O₂ stress in the bacterial growth inhibition assay. The absorbance spectrum experiment for detecting the carotenoid showed that deinoxanthin, a carotenoid that peculiarly exists in Deinococcus, was reduced in the pprM mutant in the pprM mutant. Quantitative real time PCR showed decreased expression of three genes viz. CrtI (DR0861, 50%),CrtB (DR0862, 40%) and CrtO (DR0093, 50%), which are involved in deinoxanthin synthesis, and of Dps (DNA protection during starving) gene (DRB0092) relevant to ion combining and DNA protection in cells. Our results suggest that pprM may affect antioxidative ability of D. radiodurans by regulating the synthesis of deinoxanthin and the concentration of metal ions. This may provide new clues for the treatment of antioxidants.