QTL-seq analysis of the seed size trait in grape provides new molecular insights on seedlessness

Seedlessness in grape(Vitis vinifera)is an important commercial trait for both the fresh and drying markets.However,despite numerous studies,the mechanisms and key genes regulating grape seedlessness are mostly unknown.In this study,we sequenced the genomes of the V.vinifera seeded cultivar‘Red Globe’,the seedless cultivar‘Centennial Seedless’,and the derived hybrids.Nonsynonymous single nucleotide polymorphisms(SNPs)were identified by genome sequencing and analyzed using published transcriptome data.Nonsynonymous SNPs occurred in genes related to seed development,which were identified as protein kinases,transcription factors,and cytochrome P450 s and showed differential expression during ovule development in both seeded and seedless grapes.These nonsynonymous SNP-associated genes were mainly involved in biological processes such as hormone balance,seed coat and endosperm development,reproductive organ development,oxidation and reduction,senescence and cell death.A potential quantitative trait locus(QTL)region associated with seed size was characterized based on the SNP-index,and expression analysis of candidate genes in the QTL region during ovule development in multiple seeded and seedless grape cultivars were conducted.Three SNPs were further subjected to SNa Pshot analysis and one SNP in G8 showed 67.5%efficiency in the grape progeny validation.Overall,the data obtained in this study shed light on the differences in seed development between seeded and seedless progeny at the genomic level,which provides valuable resources for future functional studies and grape breeding.

Development and application of KASP marker for high throughput detection of the seedless trait in grapevine

Molecular marker-assisted selection(MAS) can significantly accelerate and improve the efficiency of the breeding process in seedless grape cultivars. In this study, we developed the KASP_VviAGL11 and VviAGL11_410 markers based on a single nucleotide polymorphism(SNP) site(Chr18: 26889437(A/C)) of the VviAGL11 gene, and compared them with previously reported SSR markers p3_VvAGL11 and 5U_VviAGL11 by testing 101 cultivars and 81 F1 hybrid progenies. The results showed that both of the proposed markers obtained 100% accuracy rates in detecting allele A, which was closely associated with the seedless trait in grapes, while p3_VvAGL11 and 5U_VviAGL11 had lower accuracy rates due to their tendency to produce false positives. After careful evaluation of the technical advantages and disadvantages associated with these markers, we concluded that KASP_VviAGL11 was superior in terms of simplicity,cost-effectiveness, efficiency, and accuracy. Thus, we optimized the process of molecular MAS for seedless grapes,focusing on the KASP_VviAGL11 marker as a central component, to provide key technical support for the development of new seedless grape cultivars.

Screening Test of Small Seedless Watermelon Varieties in Beijing Area

[Objectives]This study was conducted to select small seedless watermelon varieties with excellent quality and high yield suitable for planting in Beijing.[Methods]Under the conditions of facility cultivation in Beijing,a screening test was conducted on seven small seedless watermelon varieties for growth process,field traits,yield traits,fruit quality,and disease resistance.[Results]Varieties Mitong,Motong and Tianbao Xiaowuzi had a short growth period and relatively stable growth,and bore fruit easily,and their female flowers were closely spaced.Their yields exceeded 60000 kg/hm~2,ranking in the top three among all varieties.The fruit had a thin skin,a bright red flesh color,and a high mass fraction of soluble solids in the center.The flesh was tight or crispy,and tasted good.They also showed good disease resistance.Overall,they showed excellent comprehensive agronomic traits,and are thus suitable for facility cultivation in Beijing and its surrounding areas.[Conclusions]This study provides a theoretical basis for the upgrading of varieties and the increase in production and farmers'income in the suburbs of Beijing.

Effects of Different Concentrations of Paclobutrazol on Seedling Quality of Small Seedless Watermelon in Autumn

[Objectives]The paper was to explore the effects of different concentrations of paclobutrazol on seedling quality of small seedless watermelon in autumn.[Methods]The leaves of watermelon seedlings were sprayed with 30,50,80 and 120 mg/L paclobutrazol at cotyledon expansion stage,and those sprayed with tap water were used as control.[Results]All the treatments of paclobutrazol effectively inhibited the excessive growth of watermelon at seedling stage,significantly enhanced the leaf quality of watermelon seedlings and promoted root growth.The seedlings treated by 50 mg/L paclobutrazol had the best performance compared with the control:a decrease of hypocotyl by 37.9%,an increase of plant dry weight by 46.55%,significantly increased seedling strength index,deep green leaf color,thick leaves,an increase of specific leaf weight by 28.13%,and significantly heavier root weight and longer length.[Conclusions]The results will provide a reference for strong seedling cultivation of small seedless watermelon.

Influence of Gamma Irradiation on Seedless Citrus Production: Pollen Germination and Fruit Quality

Seedlessness is a desirable characteristic in citrus fruits sold for fresh consumption. Gamma irradiation is widely used to obtain seedless citrus fruits. Here, different clones of the self-incompatible parthenocarpic ‘Moncada’ mandarin, obtained by gamma irradiation, were studied to assess seedlessness, pollen germination, fruit characteristics and qua- lity attributes. Findings indicate that irradiation altered aspects other than seedlessness, such as pollen germination, and some of the clones presented different weight, size, acidity and maturity index. Fruit quality and nutritional bio- components were affected differently;some clones presented no changes compared to the control ‘Moncada’ man-darin, while other clones showed significant differences. In general, all clones examined presented low seed numbers and re- duced pollen viability. Some of these clones, which ripen late in the season and whose fruit quality is maintained or improved, are in the process of registration.

Rapid Seedless Synthesis of Gold Nanoplates with Microscaled Edge Length in a High Yield and Their Application in SERS

We report a facile and reproducible approach toward rapid seedless synthesis of single crystalline gold nanoplates with edge length on the order of microns.The reaction is carried out by reducing gold ions with ascorbic acid in the presence of cetyltrimethylammonium bromide(CTAB).Reaction temperature and molar ratio of CTAB/Au are critical for the formation of gold nanoplates in a high yield,which are,respectively,optimized to be 85 °C and 6.The highest yield that can be achieved is 60 % at the optimized condition.The synthesis to achieve the microscaled gold nanoplates can be finished in less than 1 h under proper reaction conditions.Therefore,the reported synthesis approach is a time-and costeffective one.The gold nanoplates were further employed as the surface-enhanced Raman scattering substrates and investigated individually.Interestingly,only those adsorbed with gold nanoparticles exhibit pronounced Raman signals of probe molecules,where a maximum enhancement factor of 1.7 9 10~7 was obtained.The obtained Raman enhancement can be ascribed to the plasmon coupling between the gold nanoplate and the nanoparticle adsorbed onto it.

Immature Embryo Rescue and in Vitro Development Evaluation of Intraspecific Hybrids from Brazilian Seedless Grapevine“Superior×Thompson”Clones

The fruit production for export is an economically significant activity in the Valley of S?o Francisco River, especially in the irrigated lands of Petrolina-PE/Juazeiro-BA, Brazil. The development of new genetic material most suitable to the tropical climate and the demands of the consumer market have led to the selection of new seedless grapes cultivars. In this case, the use of the embryo rescue technique has produced satisfactory results for obtaining such materials, especially in the semiarid region. This study aimed to evaluate the in vitro development of intraspecific hybrids of grapevine (Vitis vinifera L.), derived from the rescue of immature embryos resultant from the crossing of “Superior Seedless” and “Thompson Seedless” Brazilian clones. To establish and develop the cultivation, the culture media was supplemented with 30 g/L sucrose, 0.1 g/L myo-inositol, 0.002 g/L glycine, 0.1 mg/L indoleacetic acid (IAA), 6.5 g/L of agar, adjusted pH to 5.7. The experiment was evaluated after 90 days. The variables measured were: number of nodes, number of leaves, plant height (cm), number of roots and length (cm) of the root system and internodes. The period of 60 days of in vitro culture of ovules resulted in the highest values of embryos (about 50%), as well as better characterized developmental stages with higher germination (47.3%). The three types of hybrid grapes evaluated in micropropagation showed very similar values of the measured parameters, even having originated from embryos of different developmental stages.

Seedless synthesis of gold nanorods with tunable plasmonic peaks beyond 1300 nm

Gold nanorods(AuNRs),as relatively common materials used in biomedical areas,have been synthesized by means of many methods.However,the conventional seed-mediated method is limited by complex operations and low yield.Besides,for further applications of AuNRs,well monodispersed AuNRs and tun-able longitudinal surface plasmon resonance(LSPR)remain to be improved.Herein,we report a one-pot method for synthesizing AuNRs without seeding agents.In this method,we use phenols as reducing agents and hydrochloric acid and nitric acid are used to regulate the pH of the growth solution.AuNRs with the longest LSPR peak position reaching 1340 nm are prepared.Furthermore,by systematically op-timizing concentrations of the reagents involved in the growth solution,different aspect ratios of AuNRs are synthesized.The facile synthesis,controllability aspect ratio,and long LSPR peak make our method promising for wider applications of AuNRs.

Effects of dehydration speed on the metabolism of membrane lipids and its relation to the browning of the Thompson seedless grape

Xinjiang is the main producing area of raisins and the largest green raisins production base in China.The browning of Thompson seedless grape raisin is extremely serious during the drying process,and has become the key issue in the development of Xinjiang raisin industry.Previous studies have shown that dehydration speed has a great impact on the browning of Thompson seedless grape,but few relevant mechanisms have been studied.Here,we demonstrate the effect of dehydration speed on lipid metabolism and its relation to the browning of the Thompson seedless grape during drying.Compared to slow dehydration treatment,rapid dehydration treatment of the Thompson seedless grape exhibited a lower degree of browning and activities of lipoxygenase(LOX),a higher index of unsaturated fatty acids and degree of unsaturated fatty acid.Moreover,the Thompson seedless grape treated with rapid dehydration resulted in a lower rate of superoxide anion production,hydrogen peroxide content,membrane permeability,and malondialdehyde content.These findings demonstrate that rapid dehydration inhibiting the browning of Thompson seedless grapes might be due to the inhibiting activities of LOX and the lower accumulation of reactive oxygen species.These activities can inhibit lipid peroxidation and slow the decomposition of unsaturated fatty acid in the membrane in Thompson seedless grapes,protecting the cellular membrane structural integrity,which may result in less contact of polyphenol oxidase with phenolic substrates and less enzymatic browning during drying.The results provide a theoretical basis for the application of rapid dehydration in drying Thompson seedless grapes.