Changes in the Flower and Leaf Proteome of Common Buckwheat (Fagopyrum esculentum Moench) under High Temperature

Common buckwheat (Fagopyrum esculentum Moench), a pseudocereal crop, produces a large number of flowers, but this does not guarantee high seed yields. This species demonstrates strong abortion of flowers and embryos. High temperatures during the generative growth phase result in an increase in the degeneration of embryo sacs. The aim of this study was to investigate proteomic changes in flowers and leaves of two common buckwheat accessions with different degrees of heat tolerance, Panda and PA15. Two-dimensional gel electrophoresis and mass spectrometry techniques were used to analyze the proteome profiles. Analyses were conducted for flower buds, open flowers capable of fertilization, and wilted flowers, as well as donor leaves, i.e., those growing closest to the inflorescences. High temperature up-regulated the expression of 182 proteins. The proteomic response to heat stress differed between the accessions and among their organs. In the Panda accession, we observed a change in abundance of 17, 13, 28, and 11 proteins, in buds, open and wilted flowers, and leaves, respectively. However, in the PA15 accession there were 34, 21, 63, and 21 such proteins, respectively. Fifteen heat-affected proteins were common to both accessions. The indole-3-glycerol phosphate synthase chloroplastic-like isoform X2 accumulated in the open flowers of the heat-sensitive cultivar Panda in response to high temperature, and may be a candidate protein as a marker of heat sensitivity in buckwheat plants.     

Patterns and Consequences of Benzyl Acetone Floral Emissions from Nicotiana attenuata Plants

The emission of a single compound, benzyl acetone (BA, 4-phenyl-2-butanone), is barely detectable during the day in the headspace of flowers of the self-compatible disturbance species Nicotiana attenuata, but it increases dramatically (50×) in the evening, becoming the dominant component in the floral headspace. This striking temporal pattern of emission may be sculpted by its potential ecological roles (e.g., synomonal and kairomonal), which we examine here. We measured the nightly BA emissions from individual flowers at six different branch positions on plants receiving either self-pollen or pollen from another genotype and calculated the nightly whole-plant emission. The first flowers produced on a branch have a lower rate of emission than flowers produced later on the same branch; however, cross pollination did not influence the quantity of BA emitted from subsequently produced flowers. Informed by these measures of whole-plant emission, we constructed a device that released BA at a constant rate equivalent to that of a plant with 240 open flowers (an approximate 10× increase in emissions). This device and a control device were attached to 50 matched pairs of plants growing in a native population in Utah to estimate the fitness consequences of enhanced, constant BA emission. Plants with elevated BA emissions in the field were browsed more frequently than control plants and produced fewer capsules, so that lifetime seed production was reduced by 3.1%. However, both treatment and control plants were heavily attacked by negro bugs (Cormelina spp.) and produced light seeds with low viabilities, representing 47% and 23% of the mass per seed and viability, respectively, of unmanipulated plants, which flowered two weeks later in the same population. From glasshouse experiments, we estimated the consequences of out-crossing and attack by negro bugs on seed production. Out-crossing did not significantly affect seed production, seed mass or viability. In contrast, negro bug infestation dramatically decreased seed mass and viability. We conclude that while the phenological variation in attack rates might have obscured our ability to estimate the fitness consequences of enhanced BA emission, the effects are likely to be dominated by kairomonal rather than synomonal interactions for this self-compatible species.     

Isolation of chemically induced mutants in borage (Borago officinalis L.)

γ-Linolenic acid (GLA, 18:3 Δ6,9,12) has been reported to be helpful in the treatment of a wide range of disorders. Borage (Borago officinalis L.) is an annual plant of renewed interest because the seeds are an important source of GLA. The failure to retain mature seeds until harvest limits the total seed and GLA yield per plant and is the major limiting factor for the commercial production of borage. In the course of a mutagenesis program, an agronomically good line of white-flowered borage (RG-001) was treated with ethyl methane sulfonate. As a result of this program, several types of mutants were identified in the M2 generation of plants: a chlorotic mutant (type A); a mutant with increased number of sepals, petals, and ovules but reduced fertility (type B); and mutants with closed flowers (type C1) or partially opened flowers (type C2) that had increased seed retention. The type C mutants are the first reported borage plants with a nonshattering habit. After crossing type B plants with normal plants, a new mutant (type B1) was obtained with higher fertility and higher seed production per flower than those from normal plants. These mutants could be used to develop borage lines that would be superior to those currently available as a source of GLA.     

Jasmonate-Induced Responses of Nicotiana sylvestris Results in Fitness Costs Due to Impaired Competitive Ability for Nitrogen

We present the first evidence for a fitness cost of an inducible response that is detectable in a nitrogen (N) currency. Nicotine is an induced defense in Nicotiana sylvestris that can utilize 5–8% of the plant's total N, an investment that apparently cannot be recouped by metabolism. Induced nicotine production is endogenously regulated by jasmonic acid (JA), and we treated leaves with the methyl ester of this wound hormone (MeJA) in quantities (0, 25, 250 g) known to elicit changes in endogenous JA and subsequent nicotine responses comparable to those elicited by mechanical wounding and herbivory in this species. We grew plants in competition chambers (CCs) in which three same-sized plants could compete for a communal but fixed pool of ¹⁵NO₃ to quantify the outcome of competition for this fitness-limiting resource that is used both in defense and seed production. Competition profoundly increased all measures of growth and reproductive performance measured per milligram of N acquired. While plants acquired all the N supplied to them in the hydroponic solution, plants grown in CCs (as compared those grown in individual chambers—ICs) retained more of this N and produced more biomass, had larger nicotine contents, allocated less of their N to nicotine, produced larger floral stalks with more flowers, aborted fewer flowers, matured more capsules, and produced a greater mass of seed. Plants grown in ICs produced heavier seed, but this difference did not translate into a difference in seed viability.MeJA treatment increased nicotine concentrations in proportion to the amount applied and significantly reduced growth (13–23%) and reproductive (31–44%) performance for plants grown with uninduced competitors, reflecting a large opportunity cost of induction. The effects of MeJA treatment on growth and reproduction were significantly less pronounced for plants grown in ICs. MeJA treatment significantly reduced the ability of plants to compete for [¹⁵N]KNO₃ (reducing uptake by 9.5% and 23.7% for 25- and 250-g MeJA-treated plants, respectively); no reductions in N acquisition were found in IC grown plants treated with MeJA. This impairment of competitive ability could account for 41–47% of the jasmonate-induced reductions in biomass by the day 15 harvest and 12–20% of the reductions in seed set and, in addition, created by "opportunity benefit" for neighboring uninduced plants, which grew larger, aborted fewer flowers, and matured more seed (a 28% increase) than did uninduced plants competing with similarly uninduced plants.Competition dramatically increased plant growth and reproductive performance, and MeJA treatment of these high-performing plants significantly reduced their competitive ability, which translated into opportunity costs for induced plants and opportunity benefits for neighboring uninduced plants. Induced plants minimized these fitness costs by reducing their use of recently acquired N for nicotine biosynthesis when growing with competitors. MeJA treatments also altered stalk length, flower production, flower abortion, and allocation to seed mass. In spite of all this plasticity, induced responses incur large fitness costs, costs that could be in part attributed to reductions in competitive ability for N. We conclude that inducibility functions to minimize these costs.     

Calendula and Coriandrum – New Potential Oilcrops for Industrial Uses

In a two years' field test Calendula officinalis and Coriandrum sativum were shown to be promising candidates for new crops for industrial oil productions. In Calendula seed oil the main fatty acid is calendic acid containing three conjugated double bonds. The mean oil content is 19.4%, and 62.8% of all fatty acids are calendic acid. Seed yield potential of C. officinalis proved to be excellent, but seed shedding is a major problem. Within the species a wide variation was established for genetic differences in, e.g. date of flowering, flower heads per plant, ray and disk flowers and different achene types. For sowing and harvest common farm machinery can be used. In Coriandrum sativum the main fatty acid is petroselinic acid, an isomer of the oleic acid. The agronomic potential of C. sativum appeared to be very good and no special breeding efforts are necessary to initiate first productions. The oil content was 17.1%, and 82% of all fatty acids consisted of oleic and petroselinic acid. In a 2 ha field trial with C. sativum the seed yield was as high as 25 dt/ha. Further breeding work should be directed to increase the oil content of the fruit and to possibly improve disease resistance.     

Carbon Nanotube-Mediated Plasmid DNA Delivery in Rice Leaves and Seeds

CRISPR-Cas gene editing technologies offer the potential to modify crops precisely; however, in vitro plant transformation and regeneration techniques present a bottleneck due to the lengthy and genotype-specific tissue culture process. Ideally, in planta transformation can bypass tissue culture and directly lead to transformed plants, but efficient in planta delivery and transformation remains a challenge. This study investigates transformation methods that have the potential to directly alter germline cells, eliminating the challenge of in vitro plant regeneration. Recent studies have demonstrated that carbon nanotubes (CNTs) loaded with plasmid DNA can diffuse through plant cell walls, facilitating transient expression of foreign genetic elements in plant tissues. To test if this approach is a viable technique for in planta transformation, CNT-mediated plasmid DNA delivery into rice tissues was performed using leaf and excised-embryo infiltration with reporter genes. Quantitative and qualitative data indicate that CNTs facilitate plasmid DNA delivery in rice leaf and embryo tissues, resulting in transient GFP, YFP, and GUS expression. Experiments were also initiated with CRISPR-Cas vectors targeting the phytoene desaturase (PDS) gene for CNT delivery into mature embryos to create heritable genetic edits. Overall, the results suggest that CNT-based delivery of plasmid DNA appears promising for in planta transformation, and further optimization can enable high-throughput gene editing to accelerate functional genomics and crop improvement activities.     

The Rab Geranylgeranyl Transferase Beta Subunit Is Essential for Embryo and Seed Development in Arabidopsis thaliana

Auxin is a key regulator of plant development affecting the formation and maturation of reproductive structures. The apoplastic route of auxin transport engages influx and efflux facilitators from the PIN, AUX and ABCB families. The polar localization of these proteins and constant recycling from the plasma membrane to endosomes is dependent on Rab-mediated vesicular traffic. Rab proteins are anchored to membranes via posttranslational addition of two geranylgeranyl moieties by the Rab Geranylgeranyl Transferase enzyme (RGT), which consists of RGTA, RGTB and REP subunits. Here, we present data showing that seed development in the rgtb1 mutant, with decreased vesicular transport capacity, is disturbed. Both pre- and post-fertilization events are affected, leading to a decrease in seed yield. Pollen tube recognition at the stigma and its guidance to the micropyle is compromised and the seed coat forms incorrectly. Excess auxin in the sporophytic tissues of the ovule in the rgtb1 plants leads to an increased tendency of autonomous endosperm formation in unfertilized ovules and influences embryo development in a maternal sporophytic manner. The results show the importance of vesicular traffic for sexual reproduction in flowering plants, and highlight RGTB1 as a key component of sporophytic-filial signaling.     

Folivory Affects Composition of Nectar,Floral Odor and Modifies Pollinator Behavior

Herbivory induces changes in plants that influence the associated insect community. The present study addresses the potential trade-off between plant phytochemical responses to insect herbivory and interactions with pollinators. We used a multidisciplinary approach and have combined field and greenhouse experiments to investigate effects of herbivory in plant volatile emission, nectar production, and pollinator behavior, when Pieris brassicae caterpillars were allowed to feed only on the leaves of Brassica nigra plants. Interestingly, volatile emission by flowers changed upon feeding by herbivores on the leaves, whereas, remarkably, volatile emission by leaves did not significantly differ between infested and non-infested flowering plants. The frequency of flower visits by pollinators was generally not influenced by herbivory, but the duration of visits by honeybees and butterflies was negatively affected by herbivore damage to leaves. Shorter duration of pollinator visits could be beneficial for a plant, because it sustains pollen transfer between flowers while reducing nectar consumption per visit. Thus, no trade-off between herbivore-induced plant responses and pollination was evident. The effects of herbivore-induced plant responses on pollinator behavior underpin the importance of including ecological factors, such as herbivore infestation, in studies of the ecology of plant pollination.     

Buckwheat in Tissue Culture Research: Current Status and Future Perspectives

Buckwheat is a member of a genus of 23 species, where the two most common species are Fagopyrum esculentum (common buckwheat) and Fagopyrum tataricum (Tartary buckwheat). This pseudocereal is a source of micro and macro nutrients, such as gluten-free proteins and amino acids, fatty acids, bioactive compounds, dietary fibre, fagopyrins, vitamins and minerals. It is gaining increasing attention due to its health-promoting properties. Buckwheat is widely susceptible to in vitro conditions which are used to study plantlet regeneration, callus induction, organogenesis, somatic embryogenesis, and the synthesis of phenolic compounds. This review summarises the development of buckwheat in in vitro culture and describes protocols for the regeneration of plantlets from various explants and differing concentrations of plant growth regulators. It also describes callus induction protocols as well as the role of calli in plantlet regeneration. Protocols for establishing hairy root cultures with the use of Agrobacterium rhizogens are useful in the synthesis of secondary metabolites, as well as protocols used for transgenic plants. The review also focuses on the future prospects of buckwheat in tissue culture and the challenges researchers are addressing.     

Molecular Genetic Understanding of Photoperiodic Regulation of Flowering Time in Arabidopsis and Soybean

The developmental switch from a vegetative phase to reproduction (flowering) is essential for reproduction success in flowering plants, and the timing of the floral transition is regulated by various environmental factors, among which seasonal day-length changes play a critical role to induce flowering at a season favorable for seed production. The photoperiod pathways are well known to regulate flowering time in diverse plants. Here, we summarize recent progresses on molecular mechanisms underlying the photoperiod control of flowering in the long-day plant Arabidopsis as well as the short-day plant soybean; furthermore, the conservation and diversification of photoperiodic regulation of flowering in these two species are discussed.     

Arbuscular Mycorrhizal Fungi and Plant Growth-Promoting Pseudomonads Increases Anthocyanin Concentration in Strawberry Fruits (Fragaria x ananassa var. Selva) in Conditions of Reduced Fertilization

Anthocyanins are a group of common phenolic compounds in plants. They are mainly detected in flowers and fruits, are believed to play different important roles such as in the attraction of animals and seed dispersal, and also in the increase of the antioxidant response in tissues directly or indirectly affected by biotic or abiotic stress factors. As a major group of secondary metabolites in plants commonly consumed as food, they are of importance in both the food industry and human nutrition. It is known that arbuscular mycorrhizal (AM) fungi can influence the plant secondary metabolic pathways such as the synthesis of essential oils in aromatic plants, of secondary metabolites in roots, and increase flavonoid concentration. Plant Growth-Promoting Bacteria (PGPB) are able to increase plant growth, improving plant nutrition and supporting plant development under natural or stressed conditions. Various studies confirmed that a number of bacterial species living on and inside the root system are beneficial for plant growth, yield and crop quality. In this work it is shown that inoculation with AM fungi and/or with selected and tested Pseudomonas strains, under conditions of reduced fertilization, increases anthocyanin concentration in the fruits of strawberry.     

Oil content and fatty acid composition of seed oil from guayule plants with different chromosome numbers

Guayule, a perennial desert plant, is being developed for domestic production of natural rubber, a strategic commodity for which the United States presently depends totally on foreign sources. At present, rubber alone is not sufficient to make guayule a commercial crop, and additional revenues are being sought from by-products. Because guayule flowers profusely during several years of growth before it is harvested for rubber, seed may also contribute to the economics of guayule production. Seed from 120 plants, including 20 genotypes with 36, 37, 54 and 72 chromosomes, were analyzed for oil content and fatty acid composition. Oil content ranged from 17.1 to 30.5%. On average, seed from diploid and aneuploid plants (with 36 and 37 chromosomes) contained 40.4% more oil than the seed from polyploid plants. The oil consisted of four fatty acids—palmitic (8.7–11.5%), stearic (3.7–6.2%), oleic (6.5–13.9%) and linoleic (69.1–80.2%)—at all ploidy levels. Guayule seed oil was similar to the seed oil from high-linoleic safflower varieties. The use of genetic variation to increase seed yield and seed oil will depend on the absence of negative correlation between oil and rubber production.     

"绿生源"高效植物营养液的研制及其应用

通过对蔬菜和花卉的试验表明,“绿生源”高效植物营养液对促进作物生长发育、增强光合作用、提高植株的抗逆性等方面,均有明显作用。     

Quantitative and qualitative characteristics of jojoba seed

Data are presented on the composition of jojoba seed harvested from randomly selected individual plants (175 in 1973, 139 in 1974) of the native population at Aguanga, CA. Except for seed yield per plant, which was 2.7 times higher in 1974, wax, protein, and hull content of the seed, as well as fatty acid and alcohol composition of the wax, were not very different in the 2 years. A significant (P<0.01) positive correlation was found between seed wt and wax content of the seed. Highly significant (P<0.01) correlations were found in pairs of fatty acids and alcohols except where fatty acid 20∶1 was included. Comparison of data from 22 plants of known identity for the 2 years also showed no significant change in wax content and composition of the seed. By contrast, correlations for seed wt, protein, hull percent, and yield per plant for the same period were all nonsignificant.     

Cuphea a rich source of medium chain triglycerides: Fatty acid composition and oil diversity in Cuphea procumbens

The phenological characteristics, oil content, and fatty acid composition of 34 selections of Cuphea procumbens have been studied. The mean seed yield per plant was 9.7 ± 0.43 g. Maximum seed yield (16.7 g) was noticed in NBC‐27, while the average number of fruits per plant was 124.9 ± 10.7. The oil content in the seeds ranged from 16.7—28.7%, maximum being in NBC‐34. The fatty acid composition revealed the presence of capric acid (C10:0) in all the selections of C. procumbens as the major constituent of the oil ranging from 87.7—94.6%. C. procumbens showed its novelty as an alternative source of capric acid and may be utilized as a renewable resource in the production of plasticizers and lubricants which wholly depend on petrochemical import. Researches are in progress in order to obtain tolerant cultivars against wild plant characteristics and some delayed seed shattering plants have been identified.     

The maximum yield potential of subterranean clover swards achieved from superphosphate applications is influenced by the maturity and the plant density of the swards

In two field experiments, one conducted in 1987 and the other in 1988, the effect of maturity grading (days from emergence of seedlings to appearance of first flowers) of four clover cultivars (Trifolium subterraneum cvv. Northam, Dalkeith, Junee and Karridale) on the relationship between yield (herbage and seed) and the level of superphosphate applied was measured for dense (170 kg seed ha^–1), single-strain, undefoliated swards. In another two field experiments, one conducted in 1987 and the other in 1988, the effect of the density of clover plants, produced by sowing 1, 10, 100 and 1,000 kg seed ha^–1 ofT. subterraneum cv. Karridale in 1987 and cv. Junee in 1988, on the relationship between yield (herbage and seed) and the level of superphosphate applied was measured for single-strain, undefoliated swards. In all experiments, phosphorus concentration in dried herbage or seed (tissue test for P) were related to plant yields.For herbage production, the maturity of the clover cultivar largely affected the maximum yields (i.e. yield plateaux) achieved for the relationship between yield and the level of phosphorus (P) applied. The P requirements of the different cultivars were similar. For seed production, however, the different cultivars achieved different maximum yields and the P requirement of the clover cultivars were different. The later-maturing cultivars would have experienced greater water stress whilst producing seed which may have affected the P requirements of the different cultivars for seed production.For herbage production in the two plant density experiments, as the density of clover plants in the swards was increased, then the maximum herbage yields for the relationship between yield and the level of P applied increased markedly. The P requirements of the different density swards was in most cases not greatly affected. By contrast, the maximum seed yields tended to decrease drastically with increasing plant density. The 10 kg seed ha^–1 sowing rate produced the largest maximum seed yields. Swards with larger plant densities produced greater herbage yields which presumably increased water stress during seed production thus reducing the maximum seed yields for the relationship between yield and the level of P applied.When tissue test for P values were related to absolute yields, foreach harvest, different relationship between yield and tissue test for P values were required for different clover cultivars or for swards with different plant densities. However, expressing yield as a percentage of the maximum yield for the relationship between yield and tissue test for P values reduced differences foreach harvest due to different clover cultivars or different plant densities. But regardless of whether absolute yield or percentage of the maximum yield were used, different relationships between yield and tissue test for P values were required fordifferent harvest, both in the same or different years.     

Jojoba seed: Phenotypic within plant variability in wax content and composition

Data are presented on the wax content and composition and seed weight of 7 individual plants in Aguanga, California. Mean wax content was 48.5% and average range 17.6 percent units. Mean seed weight was 0.38 g and mean range 0.43 g. The range in seed weight wax content and composition among seeds within single plants was comparable in magnitude to that found among single plant means. It appears that most of that variability is due to environmental factors. Thus, selection for these traits should be based on single plant performance; propagation should not be based on analyses of single seeds harvested in bulk from several plants. Correlations between fatty acids and alcohols among seeds within plants were the same as those found among single plant samples. Seeds of jojoba can be cut in half transversely without impairing germination of the basal half including the embryo axis. The upper half can be used to obtain a wax sample for single-seed analyses.     

Ontogeny Constrains Systemic Protease Inhibitor Response in Nicotiana attenuata

Protease inhibitors (PIs) are plant compounds that can inhibit proteases of mammal, insect, or pathogen origin and are frequently induced by mechanical wounding, insect feeding, or pathogen infection. Nicotiana attenuata is a species that induces nicotine, volatiles, and phenolics in response to damage. Here we examine the distribution of PIs in N. attenuata to determine if they are part of the induced response in this species and if this response is ontogenetically constrained. We found that N. attenuata shoot extracts inhibited trypsin (Tryp) and chymotrypsin (Chym) activities, while root extracts inhibited Tryp, Chym, and the bacterial protease subtilisin (Sub). The highest TrypPI levels were found at midday in the source-sink transition leaf, while older or younger leaves contained lower TrypPI levels and did not show significant diurnal fluctuations. Rosette plants, bolting plants, and flowering plants all contained TrypPIs in leaves, stems, and flowers, while seed capsules, seeds, and young seedlings did not contain any PIs. PIs in N. attenuata rosette plants were induced by Manduca sexta larval feeding, methyl jasmonate (MeJA) treatment, wounding, and application of M. sexta oral secretion and regurgitant. The response to MeJA application was stronger and longer lasting than to mechanical wounding. The direction and magnitude of the systemic response to mechanical wounding or larval damage depended on the age of the leaf that was damaged and the frequency of wounding. The systemic signal for TrypPI induction appears to follow source-sink relations in the plant and to be regulated by the octadecanoid pathway. Interestingly, by the time plants reach the flowering stage, they had lost the ability to increase PI levels after MeJA treatment. We concluded that plant ontogeny constrains both constitutive and inducible PI production in N. attenuata.