<Emphasis Type="Italic">Xanthium italicum</Emphasis>, <Emphasis Type="Italic">Xanthium strumarium</Emphasis> and <Emphasis Type="Italic">Arctium lappa</Emphasis> as new hosts for <Emphasis Type="Italic">Diaporthe helianthi</Emphasis>

Sunflower (Helianthus annuus) stem canker caused by Diaporthe helianthi is one of the most important sunflower diseases in Croatia. Until recently, sunflower was the only known host for D. helianthi. In our research carried out in the area of Eastern Croatia, isolates of Diaporthe/Phomospis were collected from Xanthium italicum, X. strumarium and Arctium lappa. Using morphological, cultural and molecular ITS rDNA data, isolates from these weeds were identified as D. helianthi. The following isolates were used in the pathogenicity test: one isolate originated from sunflower (Su5/04), three from X. italicum (Xa2, Xa3 and Xa5), two from X. strumarium (Xa9 and Xa12), one from Xanthium sp. (Xa13) and one from A. lappa (Ar3). According to the results, it was determined that isolate Xa5 (originated from X. italicum) was the most pathogenic to sunflower stems. The average length of the lesion was 11.3 cm. The lowest level of pathogenicity was found in Xa9 (isolated from X. strumarium). The length of the lesion was 0.1 cm.     

<Emphasis Type="Italic">Piriformospora indica</Emphasis>-mediated salinity tolerance in <Emphasis Type="Italic">Aloe vera</Emphasis> plantlets

Piriformospora indica, a root endophytic fungus, has been reported to promote growth of many plants under normal condition and allow the plants to survive under stress conditions. However, its impact on an important medicinal plant Aloe vera L. has not been well studied. Therefore, this study was undertaken to investigate the effect of P. indica on salinity stress tolerance of A. vera plant. P. indica inoculated and non-inoculated A. vera plantlets were subjected to four levels of salinity treatment- 0, 100, 200 and 300 mM NaCl. The salinity stress decreased the ability of the fungus to colonize roots of A. vera but the interaction of A. vera with P. indica resulted in an overall increase in plant biomass and greater shoot and root length as well as number of shoots and roots. The photosynthetic pigment (Chl a, Chl b and total Chl) and gel content were significantly higher for the fungus inoculated A. vera plantlets, at respective salinity concentrations. Furthermore, the inoculated plantlets had higher phenol, flavonoid, flavonol, aloin contents and radical scavenging activity at all salinity concentrations. The higher phenolic and flavonoid content may help the plants ameliorate oxidative stress resulting from high salinity.     

Growth promotion of <Emphasis Type="Italic">Xanthium italicum</Emphasis> by application of rhizobacterial isolates of <Emphasis Type="Italic">Bacillus aryabhattai</Emphasis> in microcosm soil

This study was conducted using rhizobacteria, which are able to exert beneficial effects upon plant growth in the infertile soil collected from barren lakeside areas. Four strains of plant growth promoting bacteria were isolated from the rhizosphere of a common wild plant, Erigeron canadensis. Isolated strains LS9, LS11, LS12, and LS15 were identified as Bacillus aryabhattai by 16S rDNA sequence analysis. B. aryabhattai LS9, LS11, LS12, and LS15 could solubilize 577.9, 676.8, 623.6, and 581.3 mg/L of 0.5% insoluble calcium phosphate within 2 days of incubation. Production of indole acetic acid, a typical growth promoting phytohormone auxin, by strain LS15 was 471.3 mg/L in 2 days with the addition of auxin precursor L-tryptophan. All the strains also produced other phytohormones such as indole butyric acid, gibberellins, and abscisic acid, and strain LS15 showed the highest production rate of gibberellin (GA₃), 119.0 μg/mg protein. Isolated bacteria were used in a microcosm test for growth of wild plant Xanthium italicum, which can be utilized as a pioneer plant in barren lands. Seed germination was facilitated, and the lengths of roots, and shoots and the dry weights of germinated seedlings after 16 days were higher than those of the uninoculated control plants. Root lengths of seedlings of X. italicum increased by 121.1% in LS11-treated samples after 16 days. This plant growth-promoting capability of B. aryabhattai strains may be utilized as an environmentally friendly means of revegetating barren lands, especially sensitive areas such as lakeside lands.     

A <Emphasis Type="Italic">Vitis vinifera</Emphasis> xanthine dehydrogenase gene, <Emphasis Type="Italic">VvXDH</Emphasis>, enhances salinity tolerance in transgenic <Emphasis Type="Italic">Arabidopsis</Emphasis>

Xanthine dehydrogenase (EC1.1.1.204; XDH) plays an important role in purine catabolism that catalyzes the oxidative hydroxylation of hypoxanthine to xanthine and of xanthine to uric acid. Long attributed to its role in recycling and remobilization of nitrogen, recently, XDH is implicated in plant stress responses and acclimation, such research efforts, however, have thus far been restricted to Arabidopsis XDH-knockdown/knockout studies. This study, using an ectopic overexpression approach, is expected to provide novel findings. In this study, a XDH gene from Vitis vinifera, named VvXDH, was synthesized and overexpressed in Arabidopsis, the transgenic Arabidopsis showed enhanced salt tolerance. The VvXDH gene was investigated and the results demonstrated the explicit role of VvXDH in conferring salt stress by increasing allantoin accumulation and activating ABA signaling pathway, enhancing ROS scavenging in transgenic Arabidopsis. In addition, the water loss and chlorophyll content loss were reduced in transgenic plants; the transgenic plants showed higher proline level and lower MDA content than that of wild-type Arabidopsis, respectively. In conclusion, the VvXDH gene has the potential to be applied in increasing allantoin accumulation and enhancing the tolerance to abiotic stresses in Arabidopsis and other plants.     

<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">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">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.     

The <Emphasis Type="Italic">Caenorhabditis</Emphasis><Emphasis Type="Italic">briggsae</Emphasis> genome contains active <Emphasis Type="Italic">CbmaT1</Emphasis> and <Emphasis Type="Italic">Tcb1</Emphasis> transposons

The maT clade of transposons is a group of transposable elements intermediate in sequence and predicted protein structure to mariner and Tc transposons, with a distribution thus far limited to a few invertebrate species. We present evidence, based on searches of publicly available databases, that the nematode Caenorhabditis briggsae has several maT-like transposons, which we have designated as CbmaT elements, dispersed throughout its genome. We also describe two additional transposon sequences that probably share their evolutionary history with the CbmaT transposons. One resembles a fold back variant of a CbmaT element, with long (380-bp) inverted terminal repeats (ITRs) that show a high degree (71%) of identity to CbmaT1. The other, which shares only the 26-bp ITR sequences with one of the CbmaT variants, is present in eight nearly identical copies, but does not have a transposase gene and may therefore be cross mobilised by a CbmaT transposase. Using PCR-based mobility assays, we show that CbmaT1 transposons are capable of excising from the C. briggsae genome. CbmaT1 excised approximately 500 times less frequently than Tcb1 in the reference strain AF16, but both CbmaT1 and Tcb1 excised at extremely high frequencies in the HK105 strain. The HK105 strain also exhibited a high frequency of spontaneous induction of unc-22 mutants, suggesting that it may be a mutator strain of C. briggsae.     

New combinations and typifications in <Emphasis Type="Italic">Bistorta</Emphasis>, <Emphasis Type="Italic">Persicaria</Emphasis>, <Emphasis Type="Italic">Polygonum,</Emphasis> and <Emphasis Type="Italic">Rumex</Emphasis> (Polygonaceae)

New combinations are proposed in anticipation of the Polygonaceae treatment in the forthcoming volume of Intermountain Flora: Polygonum kelloggii var. esotericum, P. kelloggii var. watsonii , Rumex densiflorus var. pycnanthus , R. salicifolius var. utahensis, and R. occidentalis var. tomentellus. Typifications are proposed to facilitate ongoing studies in Polygonaceae and to maintain current usage.     

Ectopic expression of cucumber (<Emphasis Type="Italic">Cucumis sativus</Emphasis> L.) <Emphasis Type="Italic">CsTIR</Emphasis>/<Emphasis Type="Italic">AFB</Emphasis> genes enhance salt tolerance in transgenic <Emphasis Type="Italic">Arabidopsis</Emphasis>

Auxin receptors TIR1/AFBs play an essential role in a series of signaling network cascades. These F-box proteins have also been identified to participate in different stress responses via the auxin signaling pathway in Arabidopsis. Cucumber (Cucumis sativus L.) is one of the most important crops worldwide, which is also a model plant for research. In the study herein, two cucumber homologous auxin receptor F-box genes CsTIR and CsAFB were cloned and studied for the first time. The deduced amino acid sequences showed a 78% identity between CsTIR and AtTIR1 and 76% between CsAFB and AtAFB2. All these proteins share similar characteristics of an F-box domain near the N-terminus, and several Leucine-rich repeat regions in the middle. Arabidopsis plants ectopically overexpressing CsTIR or CsAFB were obtained and verified. Shorter primary roots and more lateral roots were found in these transgenic lines with auxin signaling amplified. Results showed that expression of CsTIR/AFB genes in Arabidopsis could lead to higher seeds germination rates and plant survival rates than wild-type under salt stress. The enhanced salt tolerance in transgenic plants is probably caused by maintaining root growth and controlling water loss in seedlings, and by stabilizing life-sustaining substances as well as accumulating endogenous osmoregulation substances. We proposed that CsTIR/AFB-involved auxin signal regulation might trigger auxin mediated stress adaptation response and enhance the plant salt stress resistance by osmoregulation.     

Enhanced salinity tolerance and improved yield properties in Bangladeshi rice Binnatoa through <Emphasis Type="Italic">Agrobacterium-</Emphasis>mediated transformation of <Emphasis Type="Italic">PgNHX1</Emphasis> from <Emphasis Type="Italic">Pennisetum glaucum</Emphasis>

Rice yield is severely affected by high-salt concentration in the vicinity of the plant. In an effort to engineer rice for improved salt tolerance Agrobacterium-mediated transformation of rice cv. Binnatoa was accomplished with the Pennisetum glaucum vacuolar Na⁺/H⁺ antiporter gene (PgNHX1) under the constitutive CaMV35S promoter. For the molecular analysis of putative transgenic plants, PCR and RT-PCR were performed. Transgenic rice plants expressing PgNHX1 showed better physiological status and completed their life cycle by setting flowers and seeds in salt stress, while wild-type plants exhibited rapid chlorosis and growth inhibition. Moreover, transgenic rice plants produced higher grain yields than wild-type plants under salt stress. Assessment of the salinity tolerance of the transgenic plants at seedling and reproductive stages demonstrated the potential of PgNHX1 for imparting enhanced salt tolerance capabilities and improved yield.     

Salt tolerance of two aquatic macrophytes, <Emphasis Type="Italic">Pistia stratiotes</Emphasis> and <Emphasis Type="Italic">Salvinia molesta</Emphasis>

The physiological responses to NaCl salinity were investigated in two floating aquatic macrophytes, Pistia stratiotes L. and Salvinia molesta L. With the increasing NaCl concentration a decrease in chlorophyll and carotenoid contents was recorded in Salvinia as compared to Pistia. Also a greater increase in H₂O₂ accumulation and lipid peroxidation was observed in the shoot and root tissues of Salvinia as compared to Pistia. The superoxide dismutase, glutathione reductase, catalase and guaiacol peroxidase activities, and ascorbate and glutathione contents increased in Salvinia and Pistia shoot and root tissues in response to NaCl.     

Quantitative study of interactions between <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> and <Emphasis Type="Italic">Oenococcus </Emphasis><Emphasis Type="Italic">oeni</Emphasis> strains

This study examines the interactions that occur between Saccharomyces cerevisiae and Oenococcus oeni strains during the process of winemaking. Various yeast/bacteria pairs were studied by applying a sequential fermentation strategy which simulated the natural winemaking process. First, four yeast strains were tested in the presence of one bacterial strain leading to the inhibition of the bacterial component. The extent of inhibition varied widely from one pair to another and closely depended on the specific yeast strain chosen. Inhibition was correlated to weak bacterial growth rather than a reduction in the bacterial malolactic activity. Three of the four yeast strains were then grown with another bacteria strain. Contrary to the first results, this led to the bacterial stimulation, thus highlighting the importance of the bacteria strain. The biochemical profile of the four yeast fermented media exhibited slight variations in ethanol, SO(2) and fatty acids produced as well as assimilable consumed nitrogen. These parameters were not the only factors responsible for the malolactic fermentation inhibition observed with the first bacteria strain. The stimulation of the second has not been reported before in such conditions and remains unexplained.     

Ectomycorrhizae of <Emphasis Type="Italic">Tuber huidongense</Emphasis> and <Emphasis Type="Italic">T. liyuanum</Emphasis> with <Emphasis Type="Italic">Castanea mollissima</Emphasis> and <Emphasis Type="Italic">Pinus armandii</Emphasis>

Tuber huidongense and T. liyuanum are common commercial white truffles in China that belong to the Rufum and Puberulum groups of the genus Tuber, respectively. Their mycorrhizae were successfully synthesized with two native trees—Castanea mollissima and Pinus armandii—under greenhouse conditions. The identities of the mycorrhizae were confirmed through internal transcribed spacer (ITS) sequence analyses, and their morphological characteristics were described. All of the obtained mycorrhizae have an interlocking pseudoparenchymatous mantle, which is a typical feature of truffle mycorrhizae. The mycorrhizae of T. huidongense on the two trees have hyaline branched emanating hyphae, similar to the documented mycorrhizae of the Rufum group. The unramified, spiky, and hyaline cystidia on the mycorrhizae of T. liyuanum with both C. mollissima and P. armandii further confirmed that this characteristic is constant for the mycorrhizae of the Puberulum group. The successful mycorrhizal syntheses on the two nut-producing trees will be of economic importance in the cultivation of the two truffles.     

In planta transformation of <Emphasis Type="Italic">Notocactus scopa</Emphasis> cv. <Emphasis Type="Italic">Soonjung</Emphasis> by <Emphasis Type="Italic">Agrobacterium </Emphasis><Emphasis Type="Italic">tumefaciens</Emphasis>

Notocactus scopa cv. Soonjung was subjected to in planta Agrobacterium tumefaciens-mediated transformation with vacuum infiltration, pin-pricking, and a combination of the two methods. The pin-pricking combined with vacuum infiltration (20-30 cmHg for 15 min) resulted in a transformation efficiency of 67-100%, and the expression of the uidA and nptII genes was detected in transformed cactus. The established in planta transformation technique generated a transgenic cactus with higher transformation efficiency, shortened selection process, and stable gene expression via asexual reproduction. All of the results showed that the in planta transformation method utilized in the current study provided an efficient and time-saving procedure for the delivery of genes into the cactus genome, and that this technique can be applied to other asexually reproducing succulent plant species.