Gene amplification of the Hps locus in Glycine max

Background  

Hydrophobic protein from soybean (HPS) is an 8 kD cysteine-rich polypeptide that causes asthma in persons allergic to soybean dust. HPS is synthesized in the pod endocarp and deposited on the seed surface during development. Past evidence suggests that the protein may mediate the adherence or dehiscence of endocarp tissues during maturation and affect the lustre, or glossiness of the seed surface.     

Comparative morphology and physiology of fruit and seed development in the two shrubs Rhus aromatica and R. glabra (Anacardiaceae)

Morphology and physiology of fruit and seed development were compared in Rhus aromatica and R. glabra (Anacardiaceae), both of which produce drupes with water-impermeable endocarps. Phenology of flowering/fruiting of the two species at the study site was separated by ∼2 mo. However, they were similar in the timetable and pattern of fruit and seed development; it took ∼2 mo and ∼1.5 mo for flowers of Rhus aromatica and R. glabra, respectively, to develop into mature drupes. The single sigmoidal growth curve for increase in fruit size and in dry mass of these two species differs from the double-sigmoidal one described for typical commercial drupes such as peach and plum. Order of attainment of maximum size was fruit and endocarp (same time), seed coat, and embryo. By the time fruits turned red, the embryo had reached full size and become germinable; moisture content of seed plus endocarp had decreased to ∼40%. The endocarp was the last fruit component to reach physiological maturity, which coincided with development of its impermeability and a seed plus endocarp moisture content of <10%. At this time, ∼50, 37, and 13% of the dry mass of the drupe was allocated to the exocarp plus mesocarp unit, endocarp, and seed, respectively. The time course of fruit and seed development in these two species is much faster than that reported for other Anacardiaceae, including Rhus lancea, Protorhus, and Pistacia.     

Seed‐swallowing Toucans are Less Effective Dispersers of Guettarda viburnoides (Rubiaceae) than Pulp‐feeding Jays

For many tropical plants, birds are the most important seed dispersers. Not all birds, however, will provide equally effective dispersal services. Behavioral differences, during and after feeding, can result in different establishment probabilities of new individuals. During 3 yr, we examined species‐specific quantitative and qualitative aspects of Guettarda viburnoides seed dispersal by avian frugivores, focusing on how these aspects modify seed dispersal effectiveness. Fruits of G. viburnoides were consumed by ten species of birds, two of which, Cyanocorax cyanomelas and Pteroglossus castanotis, removed 80 percent of the fruits. These two species differ in qualitative aspects of seed dispersal. First, they select for fruits of different sizes; C. cyanomelas feeds on larger fruits than P. castanotis, which results in the former dispersing larger endocarps than the latter. Second, they differ in their fruit handling treatment; C. cyanomelas are pulp consumers, whereas P. castanotis swallow the fruit whole, and are thus traditionally considered ‘legitimate’ dispersers. The probability of seedling emergence, the temporal pattern of emergence, the number of emerged seedlings per endocarp, and the probability of post‐dispersal seed predation differs between endocarps dispersed by C. cyanomelas and P. castanotis; endocarps dispersed by the former have higher emergence probabilities, higher number of seedlings, faster emergence times, and lower predation probabilities than those dispersed by the latter. Finally, these birds differ in their landscape patterns of endocarp deposition; C. cyanomelas disperses endocarps to habitats with higher recruitment probabilities. Ultimately, the pulp consumer C. cyanomelas is a more effective disperser of G. viburnoides than P. castanotis.     

Anatomical structure of <Emphasis Type="Italic">Camellia oleifera</Emphasis> shell

The main product of Camellia oleifera is edible oil made from the seeds, but huge quantities of agro-waste are produced in the form of shells. The primary components of C. oleifera fruit shell are cellulose, hemicellulose, and lignin, which probably make it a good eco-friendly non-wood material. Understanding the structure of the shell is however a prerequisite to making full use of it. The anatomical structure of C. oleifera fruit shells was investigated from macroscopic to ultrastructural scale by stereoscopic, optical, and scanning electron microscopy. The main cell morphology in the different parts of the shell was observed and measured using the tissue segregation method. The density of the cross section of the shell was also obtained using an X-ray CT scanner to check the change in texture. The C. oleifera fruit pericarp was made up of exocarp, mesocarp, and endocarp. The main types of exocarp cells were stone cells, spiral vessels, and parenchyma cells. The mesocarp accounted for most of the shell and consisted of parenchyma, tracheids, and some stone cells. The endocarp was basically made up of cells with a thickened cell wall that were modified tracheid or parenchyma cells with secondary wall thickening. The most important ultrastructure in these cells was the pits in the cell wall of stone and vessel cells that give the shell a conducting, mechanical, and protective role. The density of the shell gradually decreased from exocarp to endocarp. Tracheid cells are one of the main cell types in the shell, but their low slenderness (length to width) ratio makes them unsuitable for the manufacture of paper. Further research should be conducted on composite shell-plastic panels (or other reinforced materials) to make better use of this agro-waste.     

The <Emphasis Type="Italic">defH9-iaaM</Emphasis> auxin-synthesizing gene increases plant fecundity and fruit production in strawberry and raspberry

Background  

The DefH9-iaaM gene fusion which is expressed specifically in placenta/ovules and promotes auxin-synthesis confers parthenocarpic fruit development to eggplant, tomato and tobacco. Transgenic DefH9-iaaM eggplants and tomatoes show increased fruit production due mainly to an improved fruit set. However, the weight of the fruits is also frequently increased.     

Role of small rodents in the seed dispersal process: Microcavia australis consuming Prosopis flexuosa fruits

Understanding the functional role of animal species in seed dispersal is central to determining how biotic interactions could be affected by anthropogenic drivers. In the Monte Desert, mammals play different functional roles in Prosopis flexuosa seed dispersal, acting as opportunistic frugivores (endozoochorous medium‐sized and large mammals) or seed hoarders (some small sigmodontine rodents). Our objective was assessing the functional role of Microcavia australis, a small hystricognathi rodent, in the fruit removal and seed deposition stages of P. flexuosa seed dispersal, compared to sympatric sigmodontine rodents. In situ, we quantified fruit removal by small rodents during non‐fruiting and fruiting periods, and determined the distance seeds were transported, particularly by M. australis. In laboratory experiments, we analysed how M. australis stores seeds (through scatter‐ or larder‐hoarding) and how many seeds are left in caches as living seeds, relative to previous data on sigmodontine rodents. To conduct field studies, we established sampling stations under randomly chosen P. flexuosa trees at the Ñacuñán Man and Biosphere Reserve. We analysed fruit removal by small rodents and seed dispersal distance by M. australis using camera traps focused on P. flexuosa fruits covered with wire screen, which only allowed entry of small animals. In laboratory trials, we provided animals with a known number of fruits and assessed seed conditions after removal. Small rodents removed 75.7% of fruit supplied during the non‐fruiting period and 53.2% during the fruiting period. Microcavia australis and Graomys griseoflavus were the main fruit removers. Microcavia australis transported seeds to a mean distance of 462 cm and cached seeds mainly in scatter‐hoards, similarly as Eligmodontia typus. All transported seeds were left in fruit segments or covered only by the endocarp, never as predated seeds. Microcavia australis disperses P. flexuosa seeds by carrying fruits away from a source to consume them and then by scatter‐hoarding fruits and seeds.     

A transcriptomic approach highlights induction of secondary metabolism in citrus fruit in response to <Emphasis Type="Italic">Penicillium digitatum</Emphasis>infection

Background  

Postharvest losses of citrus fruit due to green mold decay, caused by the fungus Penicillium digitaum, have a considerable economic impact. However, little is known about the molecular processes underlying the response of citrus fruit to P. digitatum.     

Multiplex real‐time PCR assays for detection of four seedborne spinach pathogens

Aims

To develop multiplex TaqMan real‐time PCR assays for detection of spinach seedborne pathogens that cause economically important diseases on spinach.

Methods and Results

Primers and probes were designed from conserved sequences of the internal transcribed spacer (for Peronospora farinosa f. sp. spinaciae and Stemphylium botryosum), the intergenic spacer (for Verticillium dahliae) and the elongation factor 1 alpha (for Cladosporium variabile) regions of DNA. The TaqMan assays were tested on DNA extracted from numerous isolates of the four target pathogens, as well as a wide range of nontarget, related fungi or oomycetes and numerous saprophytes commonly found on spinach seed. Multiplex real‐time PCR assays were evaluated by detecting two or three target pathogens simultaneously. Singular and multiplex real‐time PCR assays were also applied to DNA extracted from bulked seed and single spinach seed.

Conclusions

The real‐time PCR assays were species‐specific and sensitive. Singular or multiplex real‐time PCR assays could detect target pathogens from both bulked seed samples as well as single spinach seed.

Significance and Impact of the Study

The freeze‐blotter assay that is currently routinely used in the spinach seed industry to detect and quantify three fungal seedborne pathogens of spinach (C. variabile, S. botryosum and V. dahliae) is quite laborious and takes several weeks to process. The real‐time PCR assays developed in this study are more sensitive and can be completed in a single day. As the assays can be applied easily for routine seed inspections, these tools could be very useful to the spinach seed industry.     

Cytoplasmic- and extracellular-proteome analysis of <Emphasis Type="Italic">Diplodia seriata</Emphasis>: a phytopathogenic fungus involved in grapevine decline

Background  

The phytopathogenic fungus Diplodia seriata, whose genome remains unsequenced, produces severe infections in fruit trees (fruit blight) and grapevines. In this crop is recognized as one of the most prominent pathogens involved in grapevine trunk disease (or grapevine decline). This pathology can result in the death of adult plants and therefore it produces severe economical losses all around the world. To date no genes or proteins have been characterized in D. seriata that are involved in the pathogenicity process. In an effort to help identify potential gene products associated with pathogenicity and to gain a better understanding of the biology of D. seriata, we initiated a proteome-level study of the fungal mycelia and secretome.     

Seed production,dispersal and germination in Cryptostegia grandiflora and Ziziphus mauritiana,two invasive shrubs in tropical woodlands of northern Australia

Abstract Cryptostegia grandiflora and Ziziphus mauritiana are exotic shrubs that are invading tropical woodlands of northern Australia. Although they are widespread, they currently occupy only small proportions of their respective potential ranges. Large C. grandiflora can produce more than 8000 wind-dispersed seeds in a single reproductive episode and can set seed at least twice per year. More than 90% of seeds will germinate within 10 days of moisture becoming available. Few, if any, seeds survive for more than 12 months in the soil. Large Z. mauritiana can produce more than 5000 fruits per year. The fruit is a drupe that contains a single seed (sometimes two) enclosed in a woody endocarp. Less than 10% of fresh seeds will germinate without removal of the endocarp. Removal of the endocarp increased germination to 56%. Less than 10% of seeds of Z. mauritiana remain viable after burial in the soil for 12 months. Seeds of Z. mauritiana are dispersed by several mammalian vectors, including wallabies and feral pigs, but domestic cattle are probably the major means by which large numbers of seeds reach new sites. Propagules pass intact through the digestive tract of cattle, feral pigs and wallabies and contain viable seeds that germinate more readily than seed in fresh intact fruits. Controlling movement of cattle that have had recent access to mature fruit of Z. mauritiana could significantly reduce the likelihood of new infestations. For both species, management that reduces seed production will be important for containing spread.     

The mericarp of the halophyte <Emphasis Type="Italic">Crithmum maritimum</Emphasis> (Apiaceae): structural features,germination, and salt distribution

At maturation and during seed fall and dispersal, halophyte seeds may be subjected to invasion by salt ions. How these seeds remain viable in such hostile environments is however still unclear, depending for instance on the species and the family. In the Apiaceae, the mericarp (fruit) shows a wide range of morphological and anatomical modifications, many of which may enhance the adaptation to severe environmental conditions. Therefore, structural features, ion accumulation, and long-term floating capacity were investigated in the fruit (mericarp) of the halophyte Crithmum maritimum L. The mericarp was composed of a spongy outer coat, a secretory envelope, a thin endocarp reduced to a unicellular layer delimiting the endosperm, and an embryo. Both of the secretory canals and the endocarp adhered after complete ripening of the mericarp, while the epicarp and much of the mesocarp formed the spongy coat. Assessing long-term floating ability of the fruit under laboratory conditions revealed that even after 60 d, more than 98% of C. maritimum L. mericarps still floated over seawater. Seed germination was delayed and reduced by the spongy coat. The X-ray microanalysis revealed that the spongy coat and the secretory canals contained essentially Cl and Na, while seeds, i.e. endosperm and embryo, accumulated mostly Mg, K and P. In a subsequent experiment designed to simulate salt leaching by rain, most of the salt accumulated in the spongy coat and seeds was released after 2 h imbibition in distilled water. Taken together, these results highlight the protective role of the mericarp and the likely involvement of this structure in the seed dispersal of C. maritimum L. This may ultimately have eco-physiological implications explaining the successful establishment of this halophyte in its native saline biotopes.     

<Emphasis Type="Italic">Arabidopsis thaliana</Emphasis> outer ovule integument morphogenesis: Ectopic expression of <Emphasis Type="Italic">KNAT1</Emphasis>reveals a compensation mechanism

Background  

The Arabidopsis outer ovule integument is a simple two-cell layered structure that grows around the developing embryo and develops into the outer layer of the seed coat. As one of the functions of the seed coat is the protection of the plant embryo, the outer ovule integument is an example for a plant organ whose morphogenesis has to be precisely regulated.     

Morphological and histological impacts of the laurina mutation on fructification and seed characteristics in Coffea arabica L.

Key message

The comparison between the cultivar Bourbon and its mutant, the Bourbon pointu, of Coffea arabica led to five novel findings on fruit development and three main impacts of the mutation.

Abstract

Coffea arabica ‘Laurina’ (Bourbon pointu) is a natural mutant of Coffea arabica ‘Bourbon’. Relative to the ‘Bourbon’ cultivar, it is characterized by internode dwarfism, a Christmas tree shape, and lower caffeine content. The effects of the laurina mutation on fructification over time, the fruit structure and seed characteristics were studied here. Fruits of ‘Bourbon’ and ‘Bourbon pointu’ were monitored. The trees were grown in the same plot and flowered on the same day. Harvesting was done every 2 weeks from the 6th to the 26th week after flowering. Histological observations were carried out using multiphoton and conventional microscopes. The measurements concerned the fruit, parchment and seed. Five novel findings on fructification development were obtained: (1) a sigmoid model and non-linear regression efficiently described the phenomenon; (2) a precise relationship was defined between the qualitative stages of fructification and quantitative observations, thus revealing key weeks in this process; (3) the parchment had a mesocarpic origin; (4) a meristematic zone was present close to the parchment; and (5) an endocarp with three cell layers was visible in young fruits. Three effects of the laurina mutation were highlighted: (1) fruit growth ended 1 week earlier in ‘Bourbon’, but without difference in fruit length. In contrast, fruits were wider on average in ‘Bourbon’; (2) the parchment of narrow seeds in ‘Bourbon pointu’ was thicker than in other ‘Bourbon pointu’ and ‘Bourbon’ seeds; and (3) the narrow seed frequency in ‘Bourbon pointu’ depended on environmental conditions.     

Analysis of cDNA libraries from developing seeds of guar (<Emphasis Type="Italic">Cyamopsis tetragonoloba</Emphasis>(L.) Taub)

Background  

Guar, Cyamopsis tetragonoloba (L.) Taub, is a member of the Leguminosae (Fabaceae) family and is economically the most important of the four species in the genus. The endosperm of guar seed is a rich source of mucilage or gum, which forms a viscous gel in cold water, and is used as an emulsifier, thickener and stabilizer in a wide range of foods and industrial applications. Guar gum is a galactomannan, consisting of a linear (1→4)-β-linked D-mannan backbone with single-unit, (1→6)-linked, α-D-galactopyranosyl side chains. To better understand regulation of guar seed development and galactomannan metabolism we created cDNA libraries and a resulting EST dataset from different developmental stages of guar seeds.     

Berry and phenology-related traits in grapevine (<Emphasis Type="Italic">Vitis vinifera</Emphasis>L.): From Quantitative Trait Loci to underlying genes

Background  

The timing of grape ripening initiation, length of maturation period, berry size and seed content are target traits in viticulture. The availability of early and late ripening varieties is desirable for staggering harvest along growing season, expanding production towards periods when the fruit gets a higher value in the market and ensuring an optimal plant adaptation to climatic and geographic conditions. Berry size determines grape productivity; seedlessness is especially demanded in the table grape market and is negatively correlated to fruit size. These traits result from complex developmental processes modified by genetic, physiological and environmental factors. In order to elucidate their genetic determinism we carried out a quantitative analysis in a 163 individuals-F₁ segregating progeny obtained by crossing two table grape cultivars.     

Development of ovule,fruit and seed of Xyris (Xyridaceae,Poales) and taxonomic considerations

The development of the ovule, fruit and seed of Xyris spp. was studied to assess the embryological characteristics of potential taxonomic usefulness. All of the studied species have (1) orthotropous, bitegmic and tenuinucellate ovules, with a micropyle formed by both the endostoma and exostoma; (2) a cuticle in the ovules and seeds between the nucellus/endosperm and the inner integument and between the inner and outer integuments; (3) helobial, starchy endosperm; (4) a reduced, campanulate and undifferentiated embryo; (5) a seed coat formed by a tanniferous endotegmen, endotesta with thick‐walled cells and exotesta with thin‐walled cells; and (6) a micropylar operculum formed from inner and outer integuments. The pericarp is composed of a mesocarp with cells containing starch grains and an endocarp and exocarp formed by cells with U‐shaped thickened walls. The studied species differ in the embryo sac development, which can be of the Polygonum or Allium type, and in the pericarp, which can have larger cells in either endocarp or exocarp. The Allium‐type embryo sac development was observed only in Xyris spp. within Xyridaceae. Xyris also differs from the other genera of Xyridaceae by the presence of orthotropous ovules and a seed coat formed by endotegmen, endotesta and exotesta, in agreement with the division of the family into Xyridoideae and Abolbodoideae. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 177 , 619–628.     

Identification and characterization of NAGNAG alternative splicing in the moss <Emphasis Type="Italic">Physcomitrella patens</Emphasis>

Background  

Alternative splicing (AS) involving tandem acceptors that are separated by three nucleotides (NAGNAG) is an evolutionarily widespread class of AS, which is well studied in Homo sapiens (human) and Mus musculus (mouse). It has also been shown to be common in the model seed plants Arabidopsis thaliana and Oryza sativa (rice). In one of the first studies involving sequence-based prediction of AS in plants, we performed a genome-wide identification and characterization of NAGNAG AS in the model plant Physcomitrella patens, a moss.     

Fruit structure and systematics of Monimiaceae s.s. (Laurales)

Fruit structure (anatomy) was studied in 27 species of 15 genera of Monimiaceae s.s. Almost all have apocarpous gynoecia, with the carpels more or less surrounded by a floral cup. The fruitlets are presented on the opened floral cup, which, depending on its pre‐ and post‐floral development, differentially contributes to the attractive part of the mature fruit. Morphologically similar fruits may differ conspicuously in anatomical structure. Based on anatomical characters two different fruit forms were found: drupe(let)s (with compact sclerenchymatic endocarp forming a stone: putamen) and berry(let)s (with parenchymatic endocarp, and mesocarp parenchyma containing isolated sclereid nests). Four types of drupelets differing by the endocarp structure were tentatively distinguished: (1) the Monimia‐type has a many‐cell‐layered putamen of large isodiametric sclereids, interrupted on the ventral side by few radial rows of small sclereids; (2) the Hortonia‐type has a few‐cell‐layered putamen of isodiametric, especially thick‐walled sclereids – it may be composed of two lateral halves, i.e. with the sclerenchyma partially interrupted on the ventral and dorsal sides (but without rows of small sclereids); (3) the Mollinedia‐type has a few‐cell‐layered putamen, with more or less radially elongate sclereids with wavy cell walls; and (4) the Hedycarya‐type has a one‐cell‐layered putamen of pronouncedly radially elongate sclereids with wavy cell walls. Drupelets of some taxa with a single‐cell‐layered endocarp with only weakly thickened cell walls may represent a transition from drupelets to berrylets. The fruit structure supports three major clades recognized earlier by morphological studies and by molecular phylogenetic analyses: (1) Monimioideae (Monimia‐type drupelets), (2) Hortonieae of Mollinedioideae (Hortonia‐type drupelets), and (3) the remainder of Mollinedioideae (Hedycarya‐ and Mollinedia‐types) and berrylets. Fruit structure also supports the close relationship of Monimiaceae and Lauraceae. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 153 , 265–285.     

The draft genome and transcriptome of <Emphasis Type="Italic">Cannabis sativa</Emphasis>

Background  

Cannabis sativa has been cultivated throughout human history as a source of fiber, oil and food, and for its medicinal and intoxicating properties. Selective breeding has produced cannabis plants for specific uses, including high-potency marijuana strains and hemp cultivars for fiber and seed production. The molecular biology underlying cannabinoid biosynthesis and other traits of interest is largely unexplored.