The Low Potential of Teff (<Emphasis Type="Italic">Eragrostis tef</Emphasis>) as an Inoculum Source for <Emphasis Type="Italic">Verticillium dahliae</Emphasis>

Teff (Eragrostis tef) is a fine stemmed annual grass and gluten free small grain that is of interest as a forage, cover, or a rotation crop. Little is known about the susceptibility of teff to many diseases. Teff could be grown in rotation with potato in the northwestern United States provided teff cultivation is economical and does not increase soil populations for pathogens affecting rotation crops such as Verticillium dahliae. Verticillium dahliae infects a wide range of dicotyledonous plants, making it one of the most important fungal pathogens of crop plants in North America, including potato. The objective of this study was to quantify the susceptibility of teff to eight V. dahliae isolates and compare the susceptibility of teff to eggplant. Teff was confirmed as a host for V. dahliae, as indicated by the presence of microsclerotia in teff stems and roots after artificial inoculation in two years of greenhouse studies. The number of microsclerotia produced in teff did not differ between mint and potato pathotypes of V. dahliae. No V. dahliae isolate produced significantly greater numbers of microsclerotia than any of the seven other isolates tested in a two-year study. Microsclerotia production of V. dahliae in teff was consistently less than in susceptible eggplant cv. Night shadow in both greenhouse experiments (P?<?0.02). It is unlikely that teff infected by V. dahliae will proliferate microsclerotia of mint or potato-aggressive pathotypes, especially when compared to susceptible eggplant cultivars.     

Potato Stem Cuttings to Study <Emphasis Type="Italic">Verticillium dahliae</Emphasis> Infection for Resistance Breeding and ‘omics’ Studies

Consistent and effective methods for early discrimination of pathogen resistance, and selection of times for tissue sampling, are important for experiments using global gene expression and metabolomics. Assays for resistance to the vascular pathogen Verticillium dahliae (Vd), the causal agent of Verticillium wilt (VW), are particularly difficult because escapes are common in field assays. Seedling dip assays offer a potential solution, but homogeneous populations are not typically available. As an alternative strategy, we have developed a protocol for studying spatiotemporal infection dynamics of Vd using potato stem cuttings. The protocol was validated using genotypes varying in resistance/susceptibility to Vd. Although there were no visual symptoms in the plants, stem sections were infested with Vd as early as 7 dpi. Symptoms were first observed in the most susceptible genotype at 10 dpi and became apparent on all test subjects at 14 dpi. The protocol has potential applications in resistance breeding and ‘omics’ studies where populations derived from true seeds are not available.     

The Effect of Alfalfa Residue Incorporation on Soil Bacterial Communities and the Quantity of <Emphasis Type="Italic">Verticillium dahliae</Emphasis> Microsclerotia in Potato Fields in the Columbia Basin of Washington State,USA

Verticillium wilt, caused by the soil-borne fungus Verticillium dahliae, is one of the most important diseases of potato in North America. Soil incorporation of alfalfa residues prior to planting potato could be a nonchemical Verticillium wilt management tactic by reducing the number of viable microsclerotia in field soil. Verticillium dahliae microsclerotia were quantified in field soils where organic material from alfalfa was incorporated, and numbers of microsclerotia were compared to fields where alfalfa residue was not incorporated. In addition, bacterial metagenomics was utilized to characterize soils where organic material from alfalfa was or was not incorporated to determine if alfalfa residue incorporation facilitates the formation of soils that suppress or kill V. dahliae microsclerotia. The number of V. dahliae microsclerotia in soil was greater (P = 0.0003) in fields where crop residue was incorporated than fields without incorporation when chloropicrin was used as a fumigant. Conversely, the number of V. dahliae microsclerotia observed in potato plants did not differ (P = 0.4020) between fields where residues were or were not incorporated if chloropicrin was used. Alfalfa residue incorporation did not significantly alter the soil bacterial metagenome compared to fields not subject to residue incorporation in both years of study. Despite these conclusions, the method can be employed to analyze the effect of grower practices with the intent of linking a field practice to increasing soil bacterial diversity and decreasing Verticillium wilt severity on potato.     

Rooting Characteristics of <Emphasis Type="Italic">Solanum chacoense</Emphasis> and <Emphasis Type="Italic">Solanum tuberosum in Vitro</Emphasis>

The precise level of environmental control in vitro may aid in identifying genetically superior plant germplasm for rooting characteristics (RC) linked to increased foraging for plant nitrogen (N). The objectives of this research were to determine the phenotypic variation in root morphological responses of 49 Solanum chacoense (chc), 30 Solanum tuberosum Group Phureja – Solanum tuberosum Group Stenotomum (phu-stn), and three Solanum tuberosum (tbr) genotypes to 1.0 and 0.5 N rate in vitro for 28 d, and identify genotypes with superior RC. The 0.5 N significantly increased density of root length, surface area, and tips. All RC were significantly greater in chc than in either phu-stn or tbr. Based upon clustering on root length, surface area, and volume, the cluster with the greatest rooting values consisted of eight chc genotypes that may be utilized to initiate a breeding program to improve RC in potato.     

The Effects of <Emphasis Type="Italic">Pimpinella anisum</Emphasis> Essential Oils on Young Larvae <Emphasis Type="Italic">Leptinotarsa decemlineata</Emphasis> Say (Coleoptera: Chrysomelidae)

The effect of essential oil (EO) from anise (Pimpinellia anisum) on the mortality of young larvae of Colorado potato beetles has been studied. In our bioassays, P. anisum EO significantly increased the mortality of the second instar larvae of L. decemlineata. Significantly different values of LD₅₀ and LD₉₀ were established for acute (LD₅₀ = 1.76, and LD₉₀ = 8.29) as well as chronic toxicity (LD₅₀ = 0.45, and LD₉₀ = 1.01). Decrease of both values over experimental period was evident, which showed that the larval mortality was slow and cumulative. The composition of EO used for biological experiments was also assessed. The main component detected in EO from P. anisum was anethole (79.87%), followed by anisaldehyde (7.74%), estragole (5.88%) and β-linalool (1.07%). Within five days, residual concentration of EO decreased from 3.87 mg/g of dry weight immediately after foliar applications to 0.9 mg per g of dry weight. The effect of this slow evaporation could be explained by dominant presence of anethole or by the type of formulation and the addition of oil and tween. Results of our study demonstrate that EO from P. anisum has insecticidal properties that may lead to the development of new organic products for the control of Colorado potato beetles.     

Effects of Different Soil Treatments on the Development of <Emphasis Type="Italic">Spongospora subterranea</Emphasis> f. sp. <Emphasis Type="Italic">subterranea</Emphasis> in Potato Roots and Tubers in the Greenhouse

Powdery scab caused by Spongospora subterranea f. sp. subterranea (Sss) causes extensive losses in potato production systems globally. Two pot experiments were established in the greenhouse in summer 2013 and winter 2014 to evaluate the effectiveness of different soil chemicals, fumigant, amendments and biological control agents (BCAs) against Sss in the rhizospheric soil, potato roots and tubers. The study used visual assessment methods to assess the effect of treatments on root galling and zoosporangia production, and qPCR to measure Sss concentration in the soil and in the potato roots and tubers. All six soil treatments, namely metam sodium, fluazinam, ZincMax, calcium cyanamide, Biocult and a combination of Bacillus subtilis and Trichoderma asperellum recorded significantly (P < 0.05) lower numbers of zoosporangia in the roots compared to the untreated control. The same effect was observed on the concentration of Sss DNA in the roots at tuber initiation. A more diverse picture was obtained when root gall scores at tuber initiation and Sss DNA in the rhizospheric soil at tuber initiation and harvesting were compared. Significant differences (P < 0.05) were also noted in disease severity, disease incidence, and tuber yield between metam sodium, fluazinam, ZincMax, calcium cyanamide and the untreated control. Calcium cyanamide gave the highest tuber yield. The study demonstrated the potential of soil treatments such as metam sodium, fluazinam, ZincMax and calcium cyanamide in managing Sss in potatoes by reducing the pathogen both in the rhizospheric soil and the roots of the potato plant.     

Effective Management of the <Emphasis Type="Italic">Phthorimaea operculella</Emphasis> (Zeller) Using PVA Nanofibers Loaded with <Emphasis Type="Italic">Cinnamomum zeylanicum</Emphasis> Essential Oil

Phthorimaea operculella (Zeller) is one of the most common insect pests of cultivated potato in tropical and subtropical regions. In this research, a potential strategy to improve the insecticidal activity of plant essential oils for the effective management of P. operculella was studied. The insecticidal and residual effects of nanofiber oil (NFO) and pure essential oil (PEO) of Cinnamomum zeylanicum were assessed on PTM under laboratory conditions. The nanofibers were made by the electrospinning method using polyvinyl alcohol (PVA) polymer. The morphological characteristics of the nanofibers were evaluated by scanning electron microscopy and Fourier transform infrared spectroscopy. The chemical constituents of cinnamon essential oil (EO) were detected by GC/MS. Fumigant toxicity of NFO and PEO were evaluated on different growth stages (egg, male and female adults) of P. operculella. SEM and FTIR analyses confirmed the presence of EO on the nanofiber structure. The yield of the EO from C. zelanicum on the nanofibers was 1.86%. GC/MS analysis showed that cinnamaldehyde was the primary constituent (69.88%) of cinnamon EO. LC₅₀ values of C. zelanicum EO and NFO were 4.92 and 1.76 μl/l air for eggs, 0.444 and 0.212 μl/l air for female adults, and 0.424 and 0.192 μl/l air for male adults, respectively. Fumigant bioassays revealed that NFO was more toxic than C. zeylanicum oil against at all stages of P. operculella. The residual effect of PEO and NFO was evaluated against the egg stage of the P. operculella. NFO lost insecticidal effectiveness 47 days after application, while the efficacy of PEO decreased 15 days after application. Our results suggest that NFO of C. zeylanicum can be used as an effective new tool for the management of P. operculella.     

<Emphasis Type="Italic">Lupinus albus</Emphasis> Conglutin Gamma Modifies the Gene Expressions of Enzymes Involved in Glucose Hepatic Production <Emphasis Type="Italic">In Vivo</Emphasis>

Lupinus albus seeds contain conglutin gamma (Cγ) protein, which exerts a hypoglycemic effect and positively modifies proteins involved in glucose homeostasis. Cγ could potentially be used to manage patients with impaired glucose metabolism, but there remains a need to evaluate its effects on hepatic glucose production. The present study aimed to analyze G6pc, Fbp1, and Pck1 gene expressions in two experimental animal models of impaired glucose metabolism. We also evaluated hepatic and renal tissue integrity following Cγ treatment. To generate an insulin resistance model, male Wistar rats were provided 30% sucrose solution ad libitum for 20 weeks. To generate a type 2 diabetes model (STZ), five-day-old rats were intraperitoneally injected with streptozotocin (150 mg/kg). Each animal model was randomized into three subgroups that received the following oral treatments daily for one week: 0.9% w/v NaCl (vehicle; IR-Ctrl and STZ-Ctrl); metformin 300 mg/kg (IR-Met and STZ-Met); and Cγ 150 mg/kg (IR-Cγ and STZ-Cγ). Biochemical parameters were assessed pre- and post-treatment using colorimetric or enzymatic methods. We also performed histological analysis of hepatic and renal tissue. G6pc, Fbp1, and Pck1 gene expressions were quantified using real-time PCR. No histological changes were observed in any group. Post-treatment G6pc gene expression was decreased in the IR-Cγ and STZ-Cγ groups. Post-treatment Fbp1 and Pck1 gene expressions were reduced in the IR-Cγ group but increased in STZ-Cγ animals. Overall, these findings suggest that Cγ is involved in reducing hepatic glucose production, mainly through G6pc inhibition in impaired glucose metabolism disorders.     

Marker assisted pyramiding of <Emphasis Type="Italic">Bph6</Emphasis> and <Emphasis Type="Italic">Bph9</Emphasis> into elite restorer line 93–11 and development of functional marker for <Emphasis Type="Italic">Bph9</Emphasis>

Background

The brown planthopper (BPH) has become the most destructive and a serious threat to the rice production in Asia. Breeding the resistant varieties with improved host resistance is the most effective and ecosystem-friendly strategy of BPH biological management. As host resistance was always broken down by the presence of the upgrading BPH biotype, the more resistant varieties with novel resistance genes or pyramiding known identified BPH resistance genes would be needed urgently for higher resistant level and more durability of resistance.

Results

Here, we developed near isogenic lines of Bph9 (NIL-Bph9) by backcrossing elite cultivar 93–11 with Pokkali (harboring Bph9) using marker-assisted selection (MAS). Subsequently, we pyramided Bph6 and Bph9 in 93–11 genetic background through MAS. The resulting Bph6 and Bph9 pyramided line LuoYang69 had stronger antixenotic and antibiosis effects on BPH and exhibited significantly enhanced resistance to BPH than near isogenic lines NIL-Bph6 and NIL-Bph9. LuoYang69 derived hybrids, harboring heterozygous Bph6 and Bph9 genes, also conferred high level of resistance to BPH. Furthermore, LuoYang69 did not affect the elite agronomic traits and rice grain quality of 93–11. The current study also developed functional markers for Bph9. Using functional dominant marker, we screened and evaluated worldwide accessions of rice germplasm. Of the 673 varieties tested, 8 cultivars were identified to harbor functional Bph9 gene.

Conclusion

The development of Bph6 and Bph9 pyramided line LuoYang69 provides valuable resource to develop hybrid rice with highly and durable BPH resistance. The development of functional markers will promote MAS of Bph9. The identified Bph9 containing cultivars can be used as new sources for BPH resistance breeding programs.

     

Amplification of the <Emphasis Type="Italic">Phytophthora infestans</Emphasis> RG57 loci Facilitates <Emphasis Type="Italic">in planta</Emphasis> T-RFLP Identification of Late Blight Genotypes

Late blight, caused by the oomycete Phytophthora infestans (Mont.) de Bary, is a devastating disease in potato and tomato and causes yield and quality losses worldwide. The disease first emerged in central America and has since spread in North America including the United States and Canada. Several new genotypes of P. infestans have recently emerged, including US-22, US-23 and US-24. Due to significant economic and environmental impacts, there has been an increasing interest in the rapid identification of P. infestans genotypes. In addition to providing details regarding the various phenotypic characteristics such as fungicide resistance, host preference, and pathogenicity associated with various P. infestans genotypes, information related to pathogen movement and potential recombination may also be determined from the genetic analyses. Restriction fragment length polymorphism (RFLP) analysis with the RG57 loci is one of the most reliable procedures used to genotype P. infestans. However, the RFLP procedure requires propagation and isolation of the pathogen and relatively large amounts of DNA. Isolation of the late blight pathogen is sometimes impossible due to the poor condition of the infected tissues or the presence of fungicide residues. In this study, we describe a procedure to identify P. infestans at the molecular level in planta using terminal restriction fragment length polymorphism (T-RFLP) of the RG57 loci. This T-RFLP assay is sufficiently sensitive to detect and differentiate P. infestans genotypes directly in planta without propagation and isolation of the pathogen, to facilitate the timely implementation of best management practices.     

Tuber Resistance and Slow-Rotting Characteristics of Potato Clones Associated with the Solanaceae Coordinated Agricultural Project to the US-24 Clonal Lineage of <Emphasis Type="Italic">Phytophthora infestans</Emphasis>

Late blight, caused by Phytophthora infestans, is a devastating disease on potato worldwide and new lineages of the pathogen continue to develop in the U.S. Breeding for resistance is important for economic and environmental purposes. The Solanaceae Coordinated Agricultural Project (SolCAP) focuses on linking allelic variation in genes to valuable traits in elite cultivated potato germplasm. This research assessed the SolCAP diversity panel (206 clones in Washington and 213 clones in Wisconsin) for tuber resistance to the US-24 clonal lineage of P. infestans after potatoes were harvested from fields in Washington and Wisconsin in 2011. This is the first time this germplasm has been evaluated for tuber resistance to P. infestans using a non-intrusive zoospore inoculation technique. Clones with a percent incidence of 30% or less were considered resistant and only eight clones (Palisade Russet, AWN86514–2, MSL268-D, MSM171-A, MSM182–1, MSN230-1RY, Patagonia and Yukon Gem) were characterized as resistant at both locations. These clones have previously demonstrated high to moderate partial foliar resistance to isolates of P.infestans and therefore represent germplasm with both foliar and tuber resistance. Nine clones (AWN86514–2, F66041, MN 18747, MSM 182–1, MSN230-1RY, Modoc, Ama-Rosa, Patagonia and Purple Majesty), were characterized as slow-rotting at both locations with a mean percent internal rot of 75% or less after 33 days of storage. Two clones, MN 18747 and Modoc, are considered to have the highest risk of being a carrier for P. infestans of all the clones evaluated in the SolCAP collection. Not a single clone demonstrated complete tuber resistance to the US-24 strain at both locations.     

Association of Potato Psyllid (<Emphasis Type="Italic">Bactericera cockerelli</Emphasis>; Hemiptera: Triozidae) with <Emphasis Type="Italic">Lycium</Emphasis> spp. (Solanaceae) in Potato Growing Regions of Washington,Idaho, and Oregon

Potato psyllid, Bactericera cockerelli (?ulc), causes economic damage to potato crops throughout the major potato growing regions of western North America. When cultivated crops are not available, potato psyllid often occurs on non-crop hosts. In the southern U.S. and northern Mexico, native species of Lycium (Solanaceae) are important non-crop hosts for the psyllid. We determined whether Old World species of Lycium now widespread in the Pacific Northwest are reservoirs of potato psyllid in this growing region. We examined Lycium spp. across a wide geographic region in Washington, Oregon, and Idaho at irregular intervals during three growing seasons. Potato psyllids were present at all locations. To determine whether Lycium is also a host during intervals of the year in which the potato crop is not available, we monitored a subset of these sites over the entire year. Six sites were monitored at 1- to 3-week intervals from June 2014 to June 2016. Psyllids were present on Lycium throughout the year at all sites, including during winter, indicating that Lycium is also a host when the potato crop is seasonally not available. Psyllid populations included a mixture of Northwestern and Western haplotypes. We observed well-defined spring and fall peaks in adult numbers, with peaks separated by long intervals in which psyllid numbers were very low. Seasonal patterns in psyllid numbers on these non-native Lycium hosts were very similar to what has been observed on native Lycium in the desert southwest region of the U.S. Our findings demonstrate that potato psyllid associates with Lycium across a broad geographic region within the Pacific Northwest. These results will assist in predicting sources of potato psyllid colonizing potatoes in this important growing region.     

Draft Genome Sequence of Potato Dry Rot Pathogen <Emphasis Type="Italic">Fusarium sambucinum</Emphasis> Fckl. F-4

Fusarium sambucinum is one of the most important causal agents that not only cause the dry rot disease of potato tubers in fields and stores worldwide but also capable of producing secondary metabolites toxic for people and animals. Here we present the first draft genome sequence of the strain (F-4) estimated to be around appx. 42.0 Mb. The genome has 12,845 protein coding genes with more than 35,900 exons and gene density of 3.13 per 10Kb. F. sambucinum is evolutionary more close to the F. graminearum among the Fusarium species complex. The genome sequence represents a valuable resource for understanding the pathogenecity and virulence factors, and their evolution within the complex and highly plastic genus Fusarium.     

Hypolipidemic Activity of <Emphasis Type="Italic">Camellia euphlebia</Emphasis> Flower Extract in High–fat-fed Mice

Camellia euphlebia (family, Theaceae) has been used for the prevention and treatment of cardiovascular diseases in Southern China. However, there has been no report on the hypolipidemic activity of Camellia euphlebia flower. This study evaluated the hypolipidemic activity of different preparation of Camellia euphlebia flower extracts using in vivo models. Mice intragastrically administered aqueous extract at 400 mg/kg dose or ethanol extract at 100 and 400 mg/kg doses of Camellia euphlebia flower for 28 days exhibited significant decreases in the levels of total cholesterol, triglycerides and low-density lipoprotein cholesterol, while displaying increased level of high-density lipoprotein cholesterol in the serum. The Camellia euphlebia flower extracts also improved the antioxidant ability of hyperlipidemic mice as well as protecting the animals against liver damage by lowering the level of glutamic-pyruvic transaminase activity. Furthermore, 400 mg/kg ethanol extract effectively down-regulated the mRNA levels of fatty acid synthase, 3-hydroxy-3-methylglutaryl CoA reductase and glycerol-3-phosphate acyl transferase, suggesting that Camellia euphlebia flower extract may potentially inhibit lipid accumulation in the liver by regulating the expression of fatty acid synthase, 3-hydroxy-3-methylglutaryl CoA reductase and glycerol-3-phosphate acyl transferase. These results provided support for the potential hypolipidemic activity of Camellia euphlebia flower and could partly explain the basis of using Camellia euphlebia for the treatment of hyperlipidemia.     

Identification and fine mapping of a new gene, <Emphasis Type="Italic">BPH31</Emphasis> conferring resistance to brown planthopper biotype 4 of India to improve rice, <Emphasis Type="Italic">Oryza sativa</Emphasis> L

Background

Rice (Oryza sativa L.) is the staple food for more than 3.5 billion people, mainly in Asia. Brown planthopper (BPH) is one of the most destructive insect pests of rice that limits rice production. Host-plant resistance is one of the most efficient ways to overcome BPH damage to the rice crop.

Results

BPH bioassay studies from 2009 to 2015 conducted in India and at the International Rice Research Institute (IRRI), Philippines, revealed that the cultivar CR2711–76 developed at the National Rice Research Institute (NRRI), Cuttack, India, showed stable and broad-spectrum resistance to several BPH populations of the Philippines and BPH biotype 4 of India. Genetic analysis and fine mapping confirmed the presence of a single dominant gene, BPH31, in CR2711–76 conferring BPH resistance. The BPH31 gene was located on the long arm of chromosome 3 within an interval of 475 kb between the markers PA26 and RM2334. Bioassay analysis of the BPH31 gene in CR2711–76 was carried out against BPH populations of the Philippines. The results from bioassay revealed that CR2711–76 possesses three different mechanisms of resistance: antibiosis, antixenosis, and tolerance. The effectiveness of flanking markers was tested in a segregating population and the InDel type markers PA26 and RM2334 showed high co-segregation with the resistance phenotype. Foreground and background analysis by tightly linked markers as well as using the Infinium 6 K SNP chip respectively were applied for transferring the BPH31 gene into an indica variety, Jaya. The improved BPH31-derived Jaya lines showed strong resistance to BPH biotypes of India and the Philippines.

Conclusion

The new BPH31 gene can be used in BPH resistance breeding programs on the Indian subcontinent. The tightly linked DNA markers identified in the study have proved their effectiveness and can be utilized in BPH resistance breeding in rice.

     

Chloropicrin Soil Fumigation Reduces <Emphasis Type="Italic">Spongospora subterranea</Emphasis> Soil Inoculum Levels but Does Not Control Powdery Scab Disease on Roots and Tubers of Potato

The effect of chloropicrin fumigation on the soil populations of Spongospora subterranea and the development of powdery scab, formation of root galls and tuber yield was investigated in seven field trials conducted in Minnesota and North Dakota. Sixteen potato cultivars, with different levels of susceptibility to disease on roots and tubers, were planted in plots treated with chloropicrin at rates ranging from zero to 201.8 kg a.i. ha^?1. The amount of S. subterranea DNA in soil was determined using qPCR. Bioassays were conducted to further assess the effect of chloropicrin fumigation on root colonization by S. subterranea in two potato cultivars with contrasting disease susceptibility. In the field, chloropicrin applied at rates between 70.1 to 201.8 kg a.i. ha^?1 significantly decreased S. subterranea initial inoculum in soil but increased the amount of disease observed on roots and tubers of susceptible cultivars. The effect of increasing disease was confirmed in controlled conditions experiments. Although the amount of S. subterranea DNA in roots of bioassay plants increased with increasing chloropicrin rates, it remained similar among potato cultivars. Chloropicrin fumigation significantly increased tuber yield which in cultivars such as Shepody and Umatilla Russet were associated with the amount root galls (r = 0.30; P < 0.03). Results of these studies contradict earlier reports on the use of chloropicrin fumigation for the control of powdery scab. Factors other than inoculum level, such as environmental conditions that affect inoculum efficiency and host susceptibility, may be significant contributors to the development of powdery scab and root gall formation.     

Genetic and Pathogenic Diversity of <Emphasis Type="Italic">Ralstonia solanacearum</Emphasis> Causing Potato Brown Rot in China

Causing potato brown rot, Ralstonia solanacearum (R. solanacearum) strains are reported as one of the most destructive bacteria to potato (Solanum tuberosum L.) in China. In this study, 113 strains were isolated from potato, collected in the four major agroecological zones in China. The study showed that 102 strains belonged to the phylotype IIB sequevar 1 (race 3 biovar 2). The 11 remaining strains belonged to the phylotype I, sequevar 13, 17, 18, 16 or 14 M, a new sequevar closely related to sequevar 14. Thirty-four strains were further characterized according to their virulence at low temperature on three wild potato species. IIB-1 strains all belonged to high and moderate virulence, while others belonged to the low virulence group, which had limited pathogenicity.     

Effect of Inulin on the Viability of <Emphasis Type="Italic">L. plantarum</Emphasis> during Storage and <Emphasis Type="Italic">In Vitro</Emphasis> Digestion and on Composition Parameters of Vegetable Fermented Juices

The prebiotic effect of different concentrations of inulin (0, 1 and 2%) on the growth and survival of Lactobacillus plantarum (LP) CECT 220 in blended carrot and orange juices was investigated after 24 h of fermentation, during 30 days of storage at 4 °C and through the phases of gastrointestinal digestion after different storage periods. Microbiological and chemical determinations were also carried out in all juices. The lactic fermentation increased the shelf life of the fermented juices with inulin. The hygienic-sanitary quality in fermented juices was better than the control juices. During storage, the inulin improved the viability of LP and the monosaccharide concentration remained higher with respect to the juice without inulin (40% lower). At 30 days, the fermented juices with 2% inulin after in vitro digestion presented the highest survival of L. plantarum.     

<Emphasis Type="Italic">GNS4</Emphasis>, a novel allele of <Emphasis Type="Italic">DWARF11</Emphasis>, regulates grain number and grain size in a high-yield rice variety

Background

Rice plays an extremely important role in food safety because it feeds more than half of the world’s population. Rice grain yield depends on biomass and the harvest index. An important strategy to break through the rice grain yield ceiling is to increase the biological yield. Therefore, genes associated with organ size are important targets for rice breeding.

Results

We characterized a rice mutant gns4 (grain number and size on chromosome 4) with reduced organ size, fewer grains per panicle, and smaller grains compared with those of WT. Map-based cloning indicated that the GNS4 gene, encoding a cytochrome P450 protein, is a novel allele of DWARF11 (D11). A single nucleotide polymorphism (deletion) in the promoter region of GNS4 reduced its expression level in the mutant, leading to reduced grain number and smaller grains. Morphological and cellular analyses suggested that GNS4 positively regulates grain size by promoting cell elongation. Overexpression of GNS4 significantly increased organ size, 1000-grain weight, and panicle size, and subsequently enhanced grain yields in both the Nipponbare and Wuyunjing7 (a high-yielding cultivar) backgrounds. These results suggest that GNS4 is key target gene with possible applications in rice yield breeding.

Conclusion

GNS4 was identified as a positive regulator of grain number and grain size in rice. Increasing the expression level of this gene in a high-yielding rice variety enhanced grain yield. GNS4 can be targeted in breeding programs to increase yields.

     

Analysis of <Emphasis Type="Italic">Potato Mop-Top Virus</Emphasis> Survival Probability in Post-Harvest Storage

Potato mop top virus (PMTV) induced necrosis can cause tuber quality loss at harvest and storage. Stored potatoes help maintain a constant supply of potatoes to the market and processing industry. PMTV-induced necrosis continues to develop during storage and appropriate timelines are needed for growers to make marketing decisions of their potatoes before incurring any significant quality losses. Survival analysis was used to estimate the time to event occurrence (PMTV-induced necrosis) in four (red-, russet-, white-, and yellow-skinned) potato market types across six post-harvest assessments conducted over two years. At each assessment the presence and absence of PMTV-induced necrosis was recorded and probability of tuber survival was estimated. Survival curves were significantly different among the four market type potato cultivars (Log-Rank test, P < 0.0005). Red- and russet-market type cultivars showed low and high survival probability, respectively, demonstrating that red cultivars need priority marketing. The survival probabilities decreased with increased storage time during both years, indicating that PMTV-induced necrosis development is dependent on potato cultivar and post-harvest storage. The median (50% of tubers with symptoms) survival times were estimated as 167 and 214 days for red- and other market type potato cultivars. The information from this study could potentially help growers regulate storage times for their cultivars to minimize tuber quality loss due to PMTV-induced tuber necrosis.