<Emphasis Type="Italic">Ty</Emphasis>1<Emphasis Type="Italic">/copia</Emphasis>- and <Emphasis Type="Italic">Ty</Emphasis>3<Emphasis Type="Italic">/gypsy</Emphasis>-like DNA sequences in <Emphasis Type="Italic">Helianthus </Emphasis>species

Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes.     

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.     

<Emphasis Type="Italic">In vitro</Emphasis> culture of <Emphasis Type="Italic">Chrysanthemum</Emphasis> plantlets using light-emitting diodes

Effects of illumination spectrum on the morphogenesis of chrysanthemum plantlets (Chrysanthemum morifolium Ramat. ‘Ellen’) grown in vitro were studied using an illumination system consisting of four groups of light-emitting diodes (LEDs) in the following spectral regions: blue (450nm), red (640nm), red (660nm), and far-red (735nm). Taking into account all differences in shoot height, root length, and fresh and dry weight (FW and DW, respectively), observed while changing the total photon flux density (PFD), the optimal total PFD for growth of chrysanthemum plantlets in vitro was estimated. For 16 h photoperiod and typical fractions of the spectral components (14%, 50%, 28%, and 8%, respectively), the optimal total PFD was found to be 40 μmol m⁻² s⁻¹. Our study shows that the blue component in the illumination spectrum inhibits the plantlet extension and formation of roots and simultaneously increases the DW to FW ratio and content of photosynthetic pigments. We demonstrate photomorphogenetic effects in the blue region and its interaction with the fractional PFD of the far-red spectral component. Under constant fractional PFD of the blue component, the root number, length of roots and stems, and fresh weight of the plantlets have a correlated nonmonotonous dependence on the fractional PFD of the far-red component.     

Comparative genomic analysis of CIPK gene family in <Emphasis Type="Italic">Arabidopsis</Emphasis> and <Emphasis Type="Italic">Populus</Emphasis>

Calcium serves as a second messenger in various signal transduction pathways in plants. CBL-interacting protein kinases (CIPKs), which have a variety of functions, are involved in calcium signal transduction. Previous, the studies on CIPK family members focused on Arabidopsis and rice. Here, we present a comparative genomic analysis of the CIPK gene family in Arabidopsis and poplar, a model tree species. Twenty-seven potential CIPKs were identified from poplar using genome-wide analysis. Like the CIPK gene family from Arabidopsis, CIPK genes from poplar were also divided into intron-free and intron-harboring groups. In the intron-harboring group, the intron distribution of CIPKs is rather conserved during the genome evolutionary process. Many homologous gene pairs were found in the CIPK gene family, indicating duplication events might contribute to the amplification of this gene family. The phylogenetic comparison of CIPKs in combination with intron distribution analysis revealed that CIPK genes from both Arabidopsis and poplar might have an ancient origin, which formed earlier than the separation of these two eudicot species. Our genomic and bioinformatic analysis will provide an important foundation for further functional dissection of the CBL-CIPK signaling network in poplars. Electronic Supplementary Material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Overexpression of <Emphasis Type="Italic">AP1-</Emphasis>like genes from <Emphasis Type="Italic">Asteraceae</Emphasis> induces early-flowering in transgenic <Emphasis Type="Italic">Chrysanthemum</Emphasis> plants

Chrysanthemum is one of the most important commercial cut flowers in the world. Early-flowering cultivars are required to produce quality chrysanthemum flowers with a lower cost of production. To shorten the vegetative growth phase of chrysanthemum, three AP1-like genes from Asteraceae were constitutively overexpressed in 80 independent transgenic chrysanthemum lines. All lines were characterized by PCR and RT-PCR and demonstrated that overexpression of compositae AP1-homologs in transgenic chrysanthemum under long-day conditions had no effect on plant development compared to non-transgenic controls. Conversely, under short-day conditions, transgenic plants commenced bud initiation 2 wk earlier than non-transgenic chrysanthemum plants. Subsequently, transgenic chrysanthemum flowers showed color earlier and resulted in full opening of inflorescences 3 wk prior to non-transgenic control plants. These results open new possibilities for genetic improvement and breeding of chrysanthemum cultivars.     

Evolution of nematode-resistant <Emphasis Type="Italic">Mi</Emphasis>-<Emphasis Type="Italic">1</Emphasis> gene homologs in three species of <Emphasis Type="Italic">Solanum</Emphasis>

Plants have evolved several defense mechanisms, including resistance genes. Resistance to the root-knot nematode Meloidogyne incognita has been found in wild plant species. The molecular basis for this resistance has been best studied in the wild tomato Solanum peruvianum and it is based on a single dominant gene, Mi-1.2, which is found in a cluster of seven genes. This nematode attacks fiercely several crops, including potatoes. The genomic arrangement, number of copies, function and evolution of Mi-1 homologs in potatoes remain unknown. In this study, we analyzed partial genome sequences of the cultivated potato species S. tuberosum and S. phureja and identified 59 Mi-1 homologs. Mi-1 homologs in S. tuberosum seem to be arranged in clusters and located on chromosome 6 of the potato genome. Previous studies have suggested that Mi-1 genes in tomato evolved rapidly by frequent sequence exchanges among gene copies within the same cluster, losing orthologous relationships. In contrast, Mi-1 homologs from cultivated potato species (S. tuberosum and S. phureja) seem to have evolved by a birth-and-death process, in which genes evolve mostly by mutations and interallelic recombinations in addition to sequence exchanges.     

Expression patterns of <Emphasis Type="Italic">engrailed</Emphasis> and <Emphasis Type="Italic">dpp</Emphasis> in the gastropod <Emphasis Type="Italic">Lymnaea stagnalis</Emphasis>

We isolated the full-length cDNAs of engrailed and dpp-BMP2/4 orthologues from the pond snail Lymnaea stagnalis and examined their expression patterns during development by the whole mount in situ hybridization. At the gastrula and trochophore stages, engrailed is expressed in the peripheral ectoderm of the presumptive and invaginating shell gland, corroborating its role in the shell formation that is widely conserved among molluscs. At the same stages, dpp-BMP2/4 is expressed in the right-hand side ectoderm of the shell gland and in the invaginating stomodaeum. Unlike in the gastropod Patella vulgata, our results suggested that dpp-BMP2/4 has a role in the shell formation, rather than in the regional specification and that it could be involved in the specification pathway of the left–right asymmetry of the developing shell in L. stagnalis.     

Polyhydroxybutyrate in <Emphasis Type="Italic">Rhizobium</Emphasis> and <Emphasis Type="Italic">Bradyrhizobium</Emphasis>: quantification and <Emphasis Type="Italic">phbC</Emphasis> gene expression

Polyhydroxyalkanoates (PHAs) are hydroxyalkanoate polymers that are produced and accumulate by many kinds of bacteria. These polymers act as an energy store for bacteria. Polyhydroxybutyrate (PHB) is the most studied polymer in the PHA family. These polymers have awakened interest in the environmental and industrial research areas because they are biodegradable and have thermoplastic qualities, like polypropylene. In this work, we analyzed the PHB production in Bradyrhizobium sp., Rhizobium leguminosarum bv. phaseoli, and Rhizobium huautlense cultured with two different carbon sources. We did biochemical quantification of PHB production during the three phases of growth. Moreover, these samples were used for RNA extraction and phbC gene expression analysis via real-time PCR. The bacteria showed different manner of growth, PHB accumulation and phbC gene expression when different quantity and quality of carbon sources were used. These results showed that under different growth media conditions, the growth and metabolism of different species of bacteria were influenced. These differences reflect the increase or decrease in PHB accumulation.     

Prevalence,intensity and associated factor analysis of <Emphasis Type="Italic">Tropilaelaps</Emphasis><Emphasis Type="Italic">mercedesae</Emphasis> infesting <Emphasis Type="Italic">Apis</Emphasis><Emphasis Type="Italic">mellifera</Emphasis> in China

Tropilaelaps mercedesae is a serious ectoparasite of Apis mellifera in China. The aim of this study was to investigate the infestation rates and intensity of T. mercedesae in A. mellifera in China, and to explore the relative importance of climate, district, management practices and beekeeper characteristics that are assumed to be associated with the intensity of T. mercedesae. Of the 410 participating apiaries, 379 apiaries were included in analyses of seasonal infestation rates and 352 apiaries were included in multivariable regression analysis. The highest infestation rate (86.3%) of T. mercedesae was encountered in autumn, followed by summer (66.5%), spring (17.2%) and winter (14.8%). In autumn, 28.9% (93) of the infested apiaries were in the north (including the northeast and northwest of China), 71.1% (229) were in the central and south (including east, southeast and southwest China), and 306 apiaries (82.9%) were co-infested by both T. mercedesae and Varroa. Multivariable regression analysis showed that geographical location, season, royal jelly collection and Varroa infestation were the factors that influence the intensity of T. mercedesae. The influence of beekeeper’s education, time of beekeeping, operation size, and hive migration on the intensity of T. mercedesa was not statistically significant. This study provided information about the establishment of the linkage of the environment and the parasite and could lead to better timing and methods of control.     

<Emphasis Type="Italic">Galleria</Emphasis><Emphasis Type="Italic">mellonella</Emphasis> are Resistant to <Emphasis Type="Italic">Pneumocystis</Emphasis><Emphasis Type="Italic">murina</Emphasis> Infection

Studying Pneumocystis has proven to be a challenge from the perspective of propagating a significant amount of the pathogen in a facile manner. The study of several fungal pathogens has been aided by the use of invertebrate model hosts. Our efforts to infect the invertebrate larvae Galleria mellonella with Pneumocystis proved futile since P. murina neither caused disease nor was able to proliferate within G. mellonella. It did, however, show that the pathogen could be rapidly cleared from the host.     

<Emphasis Type="Italic">In vitro</Emphasis> bud regeneration of <Emphasis Type="Italic">Carthamus tinctorius</Emphasis> and wild <Emphasis Type="Italic">Carthamus</Emphasis> species from leaf explants and axillary buds

The organogenic competence of leaf explants of eleven Carthamus species including C. tinctorius on Murashige and Skoog (MS) medium supplemented with different concentrations of thidiazuron (TDZ) + α-naphthaleneacetic acid (NAA) and 6-benzyladenine (BA) + NAA was investigated. Highly prolific adventitious shoot regeneration was observed in C. tinctorius and C. arborescens on both growth regulator combinations and the shoot regeneration frequency was higher on medium supplemented with TDZ + NAA. Nodal culture of nine Carthamus species on media supplemented with BA and kinetin (KIN) individually revealed the superiority of media supplemented with BA over that of KIN in facilitating a higher shoot proliferation index. Proliferating shoots from axillary buds and leaf explants were transferred to medium supplemented with 1.0 mg dm⁻³ KIN or 0.5 mg dm⁻³ BA for shoot elongation. Elongated shoots were rooted on half-strength MS medium supplemented with 1.0 mg dm⁻³ each of indole-butyric acid (IBA) and phloroglucinol. The plantlets thus obtained were hardened and transferred to soil.     

<Emphasis Type="Italic">Agrobacterium</Emphasis><Emphasis Type="Italic">tumefaciens</Emphasis>-mediated transformation of callus cells of <Emphasis Type="Italic">Crataegus</Emphasis><Emphasis Type="Italic">aronia</Emphasis>

A genetic transformation system has been developed for callus cells of Crataegus aronia using Agrobacterium tumefaciens. Callus culture was established from internodal stem segments incubated on Murashige and Skoog (MS) medium supplemented with 5 mg l⁻¹ Indole-3-butyric acid (IBA) and 0.5 mg l⁻¹ 6-benzyladenine (BA). In order to optimize the callus culture system with respect to callus growth and coloration, different types and concentrations of plant growth regulators were tested. Results indicated that the best average fresh weight of red colored callus was obtained on MS medium supplemented with 2 mg l⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.5 mg l⁻¹ kinetin (Kin) (callus maintenance medium). Callus cells were co-cultivated with Agrobacterium harboring the binary plasmid pCAMBIA1302 carrying the mgfp5 and hygromycin phosphotransferase (hptII) genes conferring green fluorescent protein (GFP) activity and hygromycin resistance, respectively. Putative transgenic calli were obtained 4 weeks after incubation of the co-cultivated explants onto maintenance medium supplemented with 50 mg l⁻¹ hygromycin. Molecular analysis confirmed the integration of the transgenes in transformed callus. To our knowledge, this is the first time to report an Agrobacterium-mediated transformation system in Crataegus aronia.