Extensive metabolic cross-talk in melon fruit revealed by spatial and developmental combinatorial metabolomics

? Variations in tissue development and spatial composition have a major impact on the nutritional and organoleptic qualities of ripe fleshy fruit, including melon (Cucumis melo). To gain a deeper insight into the mechanisms involved in these changes, we identified key metabolites for rational food quality design. ? The metabolome, volatiles and mineral elements were profiled employing an unprecedented range of complementary analytical technologies. Fruits were followed at a number of time points during the final ripening process and tissues were collected across the fruit flesh from rind to seed cavity. Approximately 2000 metabolite signatures and 15 mineral elements were determined in an assessment of temporal and spatial melon fruit development. ? This study design enabled the identification of: coregulated hubs (including aspartic acid, 2-isopropylmalic acid, β-carotene, phytoene and dihydropseudoionone) in metabolic association networks; global patterns of coordinated compositional changes; and links of primary and secondary metabolism to key mineral and volatile fruit complements. ? The results reveal the extent of metabolic interactions relevant to ripe fruit quality and thus have enabled the identification of essential candidate metabolites for the high-throughput screening of melon breeding populations for targeted breeding programmes aimed at nutrition and flavour improvement.     

Early anther ablation triggers parthenocarpic fruit development in tomato

Fruit set and fruit development in tomato is largely affected by changes in environmental conditions, therefore autonomous fruit set independent of fertilization is a highly desirable trait in tomato. Here, we report the production and characterization of male‐sterile transgenic plants that produce parthenocarpic fruits in two tomato cultivars (Micro‐Tom and Moneymaker). We generated male‐sterility using the cytotoxic gene barnase targeted to the anthers with the PsEND1 anther‐specific promoter. The ovaries of these plants grew in the absence of fertilization producing seedless, parthenocarpic fruits. Early anther ablation is essential to trigger the developing of the transgenic ovaries into fruits, in the absence of the signals usually generated during pollination and fertilization. Ovaries are fully functional and can be manually pollinated to obtain seeds. The transgenic plants obtained in the commercial cultivar Moneymaker show that the parthenocarpic development of the fruit does not have negative consequences in fruit quality. Throughout metabolomic analyses of the tomato fruits, we have identified two elite lines which showed increased levels of several health promoting metabolites and volatile compounds. Thus, early anther ablation can be considered a useful tool to promote fruit set and to obtain seedless and good quality fruits in tomato plants. These plants are also useful parental lines to be used in hybrid breeding approaches.     

Breeding and biotechnology for improving berry nutritional quality

Breeding and biotechnological approaches are currently used to increase the content of specific bioactive components of plants, but the manipulation of plant metabolism is still not easy to address. There is an increasing awareness that multiple genetic and environmental factors affect production and accumulation of bioactive compounds, but these factors are rarely taken into account when fruit is marketed. Rigorous and unprejudiced evaluation of scientific evidence requires a defined set of criteria and methods of evaluation, particularly when breeding and biotech programs are aimed of producing new varieties with improved nutritional values combined with high plant production efficiency and fruit quality. In order to develop new genotypes and commercial cultivars the availability of new sources of Quality Attributes (QA) and Nutritional Attributes (NA) should be explored. In the strawberry, wild species such as F. virginiana glauca and F. vesca are good sources of bioactive compounds, but in raspberries the introduction of the wild germplasm (R. parvifolium) did not improve the nutritional quality of fruit. The methods available for detecting fruit TAC, combined with TPH and other quality parameters such as sugars, total acidity and fruit color, can be proposed as excellent tools for developing a fast and reliable program for screening large breeding populations for high nutritional quality genotypes. Furthermore, NA can represent a useful tool to facilitate analysis of "substantial equivalence" of transgenic and control derived fruit.     

Reproductive Biology ofDalbergia miscolobiumBenth. (Leguminosae-Papilionoideae) in SE Brazil: The Effects of Pistillate Sorting on Fruit-set

The breeding system ofDalbergia miscolobiumBenth. was investigatedby means of controlled pollinations and studies of post-pollinationevents in pistils. This species does not have homomorphic self-incompatibility,but crossed flowers always have higher fruit set than selfs,despite the fact that embryo development may be initiated inselfed pistils. It is suggested that deleterious recessive alleles,which lead to abortion of most selfed seeds, together with somematernal resource limitation, result in low fruiting success.Copyright1998 Annals of Botany Company Dalbergia miscolobiumBenth., Leguminosae, breeding system, pistillate sorting, fruiting success, seed set.     

Answering biological questions by analysis of the strawberry metabolome

Background

The qualitative and quantitative analysis of all low molecular weight metabolites within a biological sample, known as the metabolome, provides powerful insights into their roles in biological systems and processes. The study of all the chemical structures, concentrations, and interactions of the thousands of metabolites is called metabolomics. However present state of the art methods and equipment can only analyse a small portion of the numerous, structurally diverse groups of chemical substances found in biological samples, especially with respect to samples of plant origin with their huge diversity of secondary metabolites. Nevertheless, metabolite profiling and fingerprinting techniques have been applied to the analysis of the strawberry metabolome since their early beginnings.

Aim

The application of metabolomics and metabolite profiling approaches within strawberry research was last reviewed in 2011. Here, we aim to summarize the latest results from research of the strawberry metabolome since its last review with a special emphasis on studies that address specific biological questions.

Key scientific concepts

Analysis of strawberry, and other fruits, requires a plethora of analytical methods and approaches encompassing the analysis of primary and secondary metabolites, as well as capturing and quantifying volatile compounds that are related to aroma as well as fruit development, function and plant-to-plant communication. The success and longevity of metabolite and volatile profiling approaches in fruit breeding relies upon the ability of the approach to uncover biologically meaningful insights. The key concepts that must be addressed and are reviewed include: gene function analysis and genotype comparison, analysis of environmental effects and plant protection, screening for bioactive compounds for food and non-food uses, fruit development and physiology as well as fruit sensorial quality. In future, the results will facilitate fruit breeding due to the identification of metabolic QTLs and candidate genes for fruit quality and consumer preference.

     

Negative indirect effects of an avian insectivore on the fruit set of an insect-pollinated herb

Though an abundance of research has focused on direct interactions between birds and plants, relatively few studies have reported on indirect interactions. Of those reports, all have focused on positive indirect effects of birds on plants through predation of plant natural enemies. We conducted an observational study along the Middle Rio Grande in New Mexico to determine if avian aerial insectivores had a negative, indirect impact on insect-pollinated plants through predation of insect pollinators. We found considerable taxonomic overlap, at the order and family level, between insects visiting sweet clover ( Melilotus officinalis ) and those eaten by cliff swallows ( Hirundo pyrrhonota ). We found a significant negative relationship between proximity of sweet clover to cliff swallow breeding colonies and sweet clover fruit set during the cliff swallow nestling period. The apparent effect of cliff swallows was strongest within 200 m of breeding colonies (approximately 50% reduction in fruit set) and decreased nonlinearly to a distance of approximately 400 m. Finally, we found that the clover fruit set gradient disappeared after the nestling period, when chicks had fledged and the colony was abandoned.     

Effects of Flowering Period on Nectar Secretion and Fruit Set of Epimedium wushanense (Berberidaceae)

The effect of flowering time on nectar secretion, effective pollinators activities and fruit set in Epimedium wushanense were revealed by One way ANOVA. Among the three stage of flowering, the differences in nectar standing crop and sugar content of E.wushanense were very remarkable. In this three populations, the nectar standing crop in the initial stage was higher than that in other stages, but the sugar content of nectar was higher in the last stage. The results indicated that the activities of effective pollinators were influenced by the flowering time significantly. During a day, the activities of effective pollinators were mainly concentrated in the noon. At the same time the visiting frequency of effective pollinators in last stage was higher than that in the initial and middle stage. It was also indicated that the fruit set, the seed number and percentage of seed abortion per fruit of E.wushanense were influenced by the flowering time significantly. During the initial and the middle stage of flowering, the fruit set and the seed number per fruit were bigger than that in the last stage of flowering. But the percentage of seed abortion per fruit was higher in the last stage. So, in order to make work more effective, we should choose the fruits of E.wushanense in the initial of flowering stage for experiments and breeding, and pay attention to the flowering regulation in artificial cultivation.     

AN UNUSUAL KIND OF DISTYLY IN QUINCHAMALIUM CHILENSE (SANTALACEAE) ON VOLCÁN CASABLANCA,SOUTHERN CHILE

In mature flowers of the southern Andean parasitic herb, Quinchamalium chilense (Santalaceae), the stigmas and anthers are closer together in the pin morph than in the thrum morph. While the stigmas and anthers of the two morphs are in reciprocal positions as the flowers open, such reciprocity is lost as the result of post-anthesis allometric growth of the styles and stamens. Experimental pollinations reveal that both morphs of Q. chilense are self-compatible. Natural fruit set is higher on the pin morph. The latter is also statistically under-represented in natural populations with respect to a 1:1 ratio for pins and thrums. Pin flowers produce larger numbers of pollen grains than thrum flowers and pollen of pin flowers is smaller in size than that of thrum flowers. Higher fruit set on the pin morph is consistent with some tendency towards subdioecious breeding behavior, although an expected excess of geitonogamous pollinations on the pin morph might also be contributing to the difference in fruit set on the two morphs. The unusual floral morphology of Q. chilense could have evolved as a result of selection for larger flowers by certain pollinator groups less likely to effect geitonogamous pollination. Alternatively, extended development of post-anthesis flowers might be a reflection of selection for an array of flower sizes on individual inflorescences, producing a target effect for pollinator attraction. The evolution of such inflorescence morphology would have been facilitated by the fact that a trend in the direction of subdioecious breeding behavior accrues the same outcrossing advantages as strict distyly. Precise information on periods of stigma receptivity is required to further our understanding of the floral morphology of Q. chilense.     

果树胚挽救技术育种研究进展

胚挽救技术在果树育种上的应用研究进展作了综述,并对应用中可能出现的问题,如胚龄、培养基和培养条件等进行了分析,初步提出了胚挽救技术培育果树新种质应用方面的不足和研究热点。     

Pollination biology and breeding system of Acacia senegal

Phenology, pollination biology and breeding system were investigated in three populations of Acacia senegal located in Delhi and Rajasthan. Flowers emit a mild fragrance and produce a minute quantity of nectar. The stigma is wet non-papillate, cup-shaped and generally accommodates one polyad with 16 pollen grains. The style is solid. The mass effect created by the brush type of blossoms attracts a wide variety of insects, of which the giant Asian honeybee, Apis dorsata , is the effective pollinator. Manual in vivo pollination studies have shown that the species is self-incompatible. Self-incompatibility appears to operate inside the embryo sac. Under natural conditions fruit set is as low as 0.36%. Insufficient pollination is the main cause of low fruit set. Manual xenogamous pollinations substantially improve fruit set to 30%     

Annuario della societa botanica italiana 1934

Apple research has undergone great improvements in the last years, in both quantitative and qualitative terms. Huge amount of data are now available, especially as far as the early development and the ripening phase are concerned. Moreover, the recent release of the apple genome sequence is significantly speeding up research, allowing on one hand to shed light on the most critical aspects of fruit development with almost immediate practical implications and, on the other hand, to identify new molecular markers that will improve the future breeding programs. In this context, apple is being increasingly considered as a model for fruit development studies, although many gaps still exist in apple research. These gaps are being filled by coupling the next generation high-throughput technologies with new physiological approaches, aimed at achieving both new basic knowledge and innovative tools to improve the final quality of the fruit. In this review, the available information on the regulatory aspects of apple fruit development will be reported and discussed in the light of the future perspectives of apple research.     

Identification and characterisation of the tomato parthenocarpic mutant high fruit set under stress (hfs) exhibiting high productivity under heat and salt stress

Pollination and therefore fruit set in tomato (Solanum lycopersicum) is very sensitive to temperature. Parthenocarpy can be a very useful trait in tomato breeding in sustainable agriculture faced with global warming. Within a collection of Moneymaker tomato mutants a monogenic and recessive mutant with high fruit number was identified in heat stress conditions and named high fruit set under stress (hfs). No morphological alterations in vegetative and reproductive organs were observed except the bigger size of ovary. hfs is parthenocarpic, pollination not being required for fruit set, although this trait was not absolute since it produced some under‐seeded fruit. When plants were grown under extreme temperatures (higher than 35°C), hfs exhibits higher fruit yield than wild‐type (WT) due to increased fruit number. Another very interesting characteristic of hfs is its improved fruit quality under heat stress, exhibiting a better sweetness/acidity balance than WT. Interestingly, hfs was also tolerant to the combination of heat and salt stress, and the positive effect on production was due to both components of yield, fruit number and fruit weight. The generation of mostly seedless fruit and the high productivity and fruit quality under extreme temperatures make hfs a very interesting mutant to obtain new breeding high‐yield lines in adverse environmental conditions.     

Parthenocarpic fruit development in tomato

Abstract: Parthenocarpic fruit development is a very attractive trait for growers and consumers. In tomato, three main sources of facultative parthenocarpy, pat, pat-2, pat-3/pat-4, are known to have potential applications in agriculture. The parthenocarpic fruit development in these lines is triggered by a deregulation of the hormonal balance in some specific tissues. Auxins and gibberellins are considered as the key elements in parthenocarpic fruit development of those lines. An increased level of these hormones in the ovary can substitute for pollination and trigger fruit development. This has opened up genetic engineering approaches for parthenocarpy that have given promising results, both in quality and quantity of seedless fruit production.     

A DNA test for routine prediction in breeding of peach blush,Ppe-R<Subscript>f</Subscript>-SSR

Blush, the proportion of red overcolor on the skin surface of fruit, is highly variable in peach breeding germplasm and is important in the marketing of peach fruit. The fresh market peach industry demands a high level of blush to entice consumers, while the processing peach industry requires minimal blush. Therefore, blush is a major selection criterion in breeding programs. The use of DNA-based information could improve breeding efficiency and accuracy for fruit blush coverage, but a predictive DNA test is required. The objective of this study was to develop a DNA test for the prediction of blush coverage by targeting the major locus, R _f , associated with blush variation. Initially, haplotypes were developed based on five SNP markers associated with variation in blush coverage. To convert the 5-SNP haplotype test into a single, simple PCR-based assay, 11 simple sequence repeat markers were designed and used to screen individuals representing all SNP haplotypes. The most informative assay, named Ppe-R_f-SSR, was chosen to screen 200 individuals of the RosBREED peach reference germplasm set that incorporated germplasm from four breeding programs. Ppe-R_f-SSR accurately differentiated individuals with high-, medium-, and low-blush coverage in most lineages. Outcomes highlighted that DNA tests can be quite predictive for some breeding programs or specific germplasm sets, while for others the predictiveness can falter. Therefore, the confirmation of genotype effects for any DNA test is recommended in new germplasm before routine use. The prediction accuracy and breeding utility of Ppe-R_f-SSR in the University of Arkansas breeding program were subsequently confirmed by screening 443 seedlings, independent of the initial DNA test development process, derived from 18 cross-combinations of 28 parents. Ppe-R_f-SSR can be used to efficiently and accurately predict fruit blush coverage, especially in fresh market germplasm, and has been deployed for routine use in the University of Arkansas peach breeding program.