A single-base deletion mutation in <Emphasis Type="Italic">SlIAA9</Emphasis> gene causes tomato (<Emphasis Type="Italic">Solanum lycopersicum</Emphasis>) <Emphasis Type="Italic">entire</Emphasis> mutant

The entire (e) locus of tomato (Solanum lycopersicum L.) controls leaf morphology. Dominant E and recessive e allele of the locus produce pinnate compound and complex reduced leaves. Previous research had indicated that SlIAA9, an Aux/IAA gene, was involved in tomato leaf morphology. Down-regulation of SlIAA9 gene by antisense transgenic method decreased the leaf complex of tomato and converted tomato compound leaves to simple leaves. The leaf morphology of these transgenic lines was similar with leaf morphology of tomato entire mutant. In this paper, we report that a single-base deletion mutation in the coding region of SlIAA9 gene results in tomato entire mutant phenotypes.     

<Emphasis Type="Italic">Dunaliella salina</Emphasis> exopolysaccharides: a promising biostimulant for salt stress tolerance in tomato (<Emphasis Type="Italic">Solanum lycopersicum</Emphasis>)

Microalgal exopolysaccharides represent a potential sustainable alternative for the enhancement and protection of agricultural crops including management of both biotic and abiotic stress. In the present study, we investigated the potential of Dunaliella salina exopolysaccharides (PS) to attenuate the effect of salt stress on growth of Solanum lycopersicum, which was grown under different salinity levels (3 and 6 g L^?1 NaCl). The effects of PS treatment on plant growth, osmoprotectant molecules, protein content, and antioxidant enzymes activities of tomato plants under salt stress were analyzed. A metabolomics study showed that the exopolysaccharides released by D. salina contained sulfated moiety along with carbohydrates and uronic acids. The application of sulfated exopolysaccharides on tomato plants alleviated the salt stress and mitigated the decrease in length and dry weight of the plant’s shoot and root systems, as well as that of potassium (K⁺), and K⁺/Na⁺ ratio. Furthermore, the increase in proline, phenolic compounds, Na⁺, and antioxidant enzymes (CAT, POD, SOD) activities caused by salt stress were attenuated after the exopolysaccharide treatment. GC-MS metabolomics analysis showed that PS treatment allowed the activation and/or inhibition of various metabolic pathways involved in the plant’s tolerance to stress such as jasmonic acid-dependent pathways. This study shows the potential of microalgal exopolysaccharides for enhancing tomato tolerance to salt stress and highlights the possibility of their use as plant growth biostimulants under harsh environmental conditions.     

Identification of novel small RNAs in tomato (<Emphasis Type="Italic">Solanum lycopersicum</Emphasis>)

To date, the majority of plant small RNAs (sRNA) have been identified in rice, poplar and Arabidopsis. To identify novel tomato sRNAs potentially involved in tomato specific processes such as fruit development and/or ripening, we cloned 4,018 sRNAs from tomato fruit tissue at the mature green stage. From this pool of sRNAs, we detected tomato homologues of nine known miRNAs, including miR482; a poplar miRNA not conserved in Arabidopsis or rice. We identified three novel putative miRNAs with flanking sequence that could be folded into a stem-loop precursor structure and which accumulated as 19-24nt RNA. One of these putative miRNAs (Put-miRNA3) exhibited significantly higher expression in fruit compared with leaf tissues, indicating a specific role in fruit development processes. We also identified nine sRNAs that accumulated as 19–24nt RNA species in tomato but genome sequence was not available for these loci. None of the nine sRNAs or three putative miRNAs possessed a homologue in Arabidopsis that had a precursor with a predicted stem-loop structure or that accumulated as a sRNA species, suggesting that the 12 sRNAs we have identified in tomato may have a species specific role in this model fruit species. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Reactive oxygen species (ROS) and antioxidative enzyme status in <Emphasis Type="Italic">Solanum lycopersicum</Emphasis> on priming with fluorescent <Emphasis Type="Italic">Pseudomonas</Emphasis> spp. against <Emphasis Type="Italic">Fusarium oxysporum</Emphasis>

In plants, ROS signaling and increase in activities of antioxidants are among defense responses. The present study describes the oxidative stress profiling in model host plant tomato (Solanum lycopersicum L.), during an invasion of the wilt pathogen Fusarium oxysporum f. sp. lycopersici with or without seed priming with Pseudomonas isolates M80, M96 and T109. Tomato seeds were primed with known Pseudomonas isolates M80, M96 and T109 and the forty-day- old plants were challenged with spores of F. oxysporum under greenhouse conditions. Leaf samples were collected at 0, 24, 48 72 and 96 h post fungal challenge and analysed for systemic level of oxidative stress parameters including total phenolics, proline, hydrogen peroxide, lipid peroxidation and enzymatic antioxidants. Disease incidence in the plants under greenhouse conditions was also calculated. Results revealed that priming with Pseudomonas isolates resulted in reduced oxidative stress in the host, during pathogen invasion. M80-priming showed highest antioxidative protection to the host plants during F. oxysporum invasion. The observed reduction in hydrogen peroxide and lipid peroxidation in primed plants was in agreement with the increased activities of the corresponding antioxidant enzymes. Greenhouse results showed that the highest wilt disease symptoms were with M80-priming followed by M96 and T109. The present study gives substantial evidences on the oxidative stress mitigation in response to Pseudomonas-priming on the model tomato-Fusarium interaction system.     

Endogenous pararetroviral sequences in tomato (<Emphasis Type="Italic">Solanum lycopersicum</Emphasis>) and related species

Background  

Endogenous pararetroviral sequences (EPRVs) are a recently discovered class of repetitive sequences that is broadly distributed in the plant kingdom. The potential contribution of EPRVs to plant pathogenicity or, conversely, to virus resistance is just beginning to be explored. Some members of the family Solanaceae are particularly rich in EPRVs. In previous work, EPRVs have been characterized molecularly in various species of Nicotiana including N.tabacum (tobacco) and Solanum tuberosum (potato). Here we describe a family of EPRVs in cultivated tomato (Solanum lycopersicum L.) and a wild relative (S.habrochaites).     

24-Epibrassinolide reduces stress in nematode-infected tomato (<Emphasis Type="Italic">Solanum lycopersicum</Emphasis> L.) plants cultured <Emphasis Type="Italic">in vitro</Emphasis>

24-Epibrassinolide (EBL) is considered the most probable brassinosteroid (BR) candidate that could be used for practical application in agriculture. EBL-induced stress-protective properties were evaluated in in vitro-grown tomato (Solanum lycopersicum L.) varieties Pusa Ruby (susceptible to nematodes) and PNR-7 (resistant to nematodes) during nematode pathogenesis. Sterilized tomato seeds treated with 10^?11, 10^?9, or 10^?7 M EBL and germinated in vitro were inoculated with second-stage juveniles of Meloidogyne incognita [(Kofoid and White) Chitwood]. Whole plant analyses of morphological and biochemical parameters 7 d after inoculation showed significant improvements in plant growth and development for both varieties and a highly significant reduction in the number of galls in the susceptible variety. Increased specific activities of antioxidative enzymes (catalase, ascorbate peroxidase, glutathione reductase, glutathione peroxidase, guaiacol peroxidase, and superoxide dismutase) were observed in EBL-treated seedlings of both varieties, but increases were higher in the resistant variety. A highly significant increase in antioxidants (ascorbic acid content, total flavonoid content, total glutathione content, and total phenolic content) was observed in EBL-treated Pusa Ruby seedlings, whereas in PNR-7, significant increases were found except for total flavonoid content, which increased non-significantly. Confocal microscopic images showed amelioration of stress in roots of EBL-treated seedlings as indicated by the decrease in level of green fluorescence in them as compared to untreated and nematode-inoculated roots.     

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.     

Flight behavior and oviposition of <Emphasis Type="Italic">Tuta absoluta</Emphasis> on susceptible and resistant genotypes of <Emphasis Type="Italic">Solanum lycopersicum</Emphasis>

Plants produce volatile chemical compounds that can negatively affect the preference (antixenosis) or the performance (antibiosis) of herbivorous insects. It is thought that these volatile compounds are used as cues by herbivorous insects to determine the suitability of the plant for egg deposition and, hence, offspring performance. Here, we investigated whether volatiles produced by tomato plants play a role in modulating the flight and oviposition behavior of mated Tuta absoluta females. We found that the behavioral steps displayed by mated females did not differ when they flew toward resistant or susceptible tomato genotypes, but they reached the susceptible genotypes faster than the resistant ones. Moreover, females landed more often and laid more eggs on the most susceptible genotype, the Santa Clara variety. Because this variety is known to be of high quality for the development of T. absoluta larvae, the female’s decision to land and lay more eggs on this genotype seems to be mainly to maximize offspring performance. However, this is not so straightforward because the proportion of landings and eggs laid by T. absoluta on another susceptible genotype tested in this study was not significantly higher than on the resistant genotypes. Finally, although future studies are still needed, considering the antixenotic and antibiotic traits of the resistant genotypes studied here, they are likely to succeed if used in integrated pest management.     

<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.     

Fine mapping of the nematode resistance gene <Emphasis Type="Italic">Mi-3</Emphasis> in <Emphasis Type="Italic">Solanum peruvianum</Emphasis> and construction of a <Emphasis Type="Italic">S. lycopersicum</Emphasis> DNA contig spanning the locus

Currently, the only genetic resistance against root-knot nematodes in the cultivated tomato Solanum lycopersicum (Lycopersicon esculentum) is due to the gene Mi-1. Another resistance gene, Mi-3, identified in the related wild species Solanum peruvianum (Lycopersicon peruvianum) confers resistance to nematodes that are virulent on tomato lines that carry Mi-1, and is effective at temperatures at which Mi-1 is not effective (above 30°C). Two S. peruvianum populations segregating for Mi-3 were used to develop a high-resolution map of the Mi-3 region of chromosome 12. S. lycopersicum BACs carrying flanking markers were identified and used to construct a contig spanning the Mi-3 region. Markers generated from BAC-end sequences were mapped in S. peruvianum plants in which recombination events had occurred near Mi-3. Comparison of the S. peruvianum genetic map with the physical map of S. lycopersicum indicated that marker order is conserved between S. lycopersicum and S. peruvianum. The 600 kb contig between Mi-3-flanking markers TG180 and NR18 corresponds to a genetic distance of about 7.2 cM in S. peruvianum. We have identified a marker that completely cosegregates with Mi-3, as well as flanking markers within 0.25 cM of the gene. These markers can be used to introduce Mi-3 into cultivated tomato, either by conventional breeding or cloning strategies.     

Pedogamy in <Emphasis Type="Italic">Neidium</Emphasis> (<Emphasis Type="Italic">Bacillariophyceae</Emphasis>)

Single (unpaired) vegetative cells of freshwater pennate diatom Neidium cf. ampliatum differentiated into gametangia and produced a single zygote (auxospore) via a pedogamic process. The gametic nuclei fused after auxospore expansion had begun. The auxospore expanded in parallel to the apical axis of the gametangium.     

New species in <Emphasis Type="Italic">Barleria</Emphasis> sect. <Emphasis Type="Italic">Stellatohirta</Emphasis> (<Emphasis Type="Italic">Acanthaceae</Emphasis>) from Africa

Summary  Three new species are described in Barleria L. sect. Stellatohirta M. Balkwill from tropical Africa: B. aristata from south-central Tanzania, B. aenea from south-western Tanzania and northeast Zambia, and B. purpureotincta from south-western Zambia. Their affinities and conservation status are discussed.     

<Emphasis Type="Italic">In silico</Emphasis> and <Emphasis Type="Italic">in situ</Emphasis> characterization of the zebrafish (<Emphasis Type="Italic">Danio rerio</Emphasis>) <Emphasis Type="Italic">gnrh3</Emphasis> (sGnRH) gene

Background

Gonadotropin releasing hormone (GnRH) is responsible for stimulation of gonadotropic hormone (GtH) in the hypothalamus-pituitary-gonadal axis (HPG). The regulatory mechanisms responsible for brain specificity make the promoter attractive for in silico analysis and reporter gene studies in zebrafish (Danio rerio).

Results

We have characterized a zebrafish [Trp⁷, Leu⁸] or salmon (s) GnRH variant, gnrh 3. The gene includes a 1.6 Kb upstream regulatory region and displays the conserved structure of 4 exons and 3 introns, as seen in other species. An in silico defined enhancer at -976 in the zebrafish promoter, containing adjacent binding sites for Oct-1, CREB and Sp1, was predicted in 2 mammalian and 5 teleost GnRH promoters. Reporter gene studies confirmed the importance of this enhancer for cell specific expression in zebrafish. Interestingly the promoter of human GnRH-I, known as mammalian GnRH (mGnRH), was shown capable of driving cell specific reporter gene expression in transgenic zebrafish.

Conclusions

The characterized zebrafish Gnrh3 decapeptide exhibits complete homology to the Atlantic salmon (Salmo salar) GnRH-III variant. In silico analysis of mammalian and teleost GnRH promoters revealed a conserved enhancer possessing binding sites for Oct-1, CREB and Sp1. Transgenic and transient reporter gene expression in zebrafish larvae, confirmed the importance of the in silico defined zebrafish enhancer at -976. The capability of the human GnRH-I promoter of directing cell specific reporter gene expression in zebrafish supports orthology between GnRH-I and GnRH-III.

     

Floral development and systematic position of <Emphasis Type="Italic">Arillastrum</Emphasis>, <Emphasis Type="Italic">Allosyncarpia</Emphasis>, <Emphasis Type="Italic">Stockwellia</Emphasis> and <Emphasis Type="Italic">Eucalyptopsis</Emphasis> (Myrtaceae)

We have investigated the floral ontogeny of Arillastrum, Allosyncarpia, Stockwellia and Eucalyptopsis (of the eucalypt group, Myrtaceae) using scanning electron microscopy and light microscopy. Several critical characters for establishing relationships between these genera and to the eucalypts have been determined. The absence of compound petaline primordia in Arillastrum, Allosyncarpia, Stockwellia and Eucalyptopsis excludes these taxa from the eucalypt clade. Post-anthesis circumscissile abscission of the hypanthium above the ovary in Stockwellia, Eucalyptopsis and Allosyncarpia is evidence that these three taxa form a monophyletic group; undifferentiated perianth parts and elongated fusiform buds are characters that unite Stockwellia and Eucalyptopsis as sister taxa. No floral characters clearly associate Arillastrum with either the eucalypt clade or the clade of Stockwellia, Eucalyptopsis and Allosyncarpia.We gratefully acknowledge Clyde Dunlop and Bob Harwood (Northern Territory Herbarium) for collecting specimens of Allosyncarpia, and Bruce Gray (Atherton) for collecting specimens of Stockwellia. The Australian National Herbarium (CANB) kindly lent herbarium specimens of Eucalyptopsis for examination. This research was supported by a University of Melbourne Research Development Grant to Andrew Drinnan.     

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">Quinua</Emphasis> and Relatives (<Emphasis Type="Italic">Chenopodium</Emphasis> sect.<Emphasis Type="Italic">Chenopodium</Emphasis> subsect.<Emphasis Type="Italic">Celluloid</Emphasis>)

Traditionally viewed as an Andean grain crop,Chenopodium quinoa Willd. includes domesticated populations that are not Andean, and Andean populations that are not domesticated. Comparative analysis of leaf morphology and allozyme frequencies have demonstrated that Andean populations, both domesticated(quinua) and free-living(ajara), represent an exceptionally homogeneous unit that is well differentiated from allied domesticates of coastal Chile(quingua) and freeliving populations of the Argentine lowlands(C. hircinum). This pattern of relationships indicates that Andean populations represent a monophyletic crop/weed system that has possibly developed through cyclic differentiation (natural vs. human selection) and introgressive hybridization. Relative levels of variation suggest that this complex originated in the southern Andes, possibly from wild types allied withC. hircinum, with subsequent dispersal north to Colombia and south to the Chilean coast. Coastal populations were apparently isolated from post-dispersal differentiation and homogenization that occurred in the Andes. Other data point toward a center of origin in the northern Andes with secondary centers of genetic diversity subsequently developing in the southern Andes and the plains of Argentina. Comparative linkage of South American taxa, all tetraploid, with North American tetraploids of the subsection will eventually clarify this problem. While the possibility of a direct phyletic connection betweenC. quinoa and the Mexican domesticate(C. berlandieri subsp. nuttalliae,) cannot be excluded, available evidence indicates that the latter represents an autonomous lineage that is associated with the basal tetraploid, C. b. subsp.berlandieri, through var.sinuatum, whereas South American taxa show possible affinities to either var. zschackei or var.berlandieri. An extinct domesticate of eastern North America,C. b. subsp.jonesianum, represents either another instance of independent domestication, possibly from subsp. b. var.zschackei, or a northeastern outlier of subsp.nuttalliae.     

New species of <Emphasis Type="Italic">Chalybea</Emphasis> and <Emphasis Type="Italic">Huilaea</Emphasis> (Melastomataceae)

One new species each is proposed in Chalybea and Huilaea (Melastomataceae: Blakeeae). Chalybea peruviana has elliptic, 5-plinerved leaves with entire, revolute margins, inflorescences with 33–39 flowers, and is endemic to Peru. Huilaea calyptrata has inflorescences with 15–17, irregularly calyptrate flowers, anthers with a warty connective in the shape of an inverted hand fan, and is endemic to Ecuador. A key to the eight species of Huilaea is provided.