Detection of QTL for Cold Tolerance at Bud Bursting Stage Using Chromosome Segment Substitution Lines in Rice (Oryza sativa)

The cold tolerance at the bud bursting stage (CTB) was evaluated at 5°C by using a set of 95 chromosome segment substitution lines (CSSLs) derived from an indica rice 9311 and a japonica rice Nipponbare with a genetic background of 9311. The result showed that six CSSLs had slightly stronger effect on CTB than 9311. Total four quantitative trait loci (QTLs) for CTB were preliminary mapped on chromosomes 5 and 7 by substitution mapping. qCTB-5-1, qCTB-5-2 and qCTB-5-3 were mapped in the region of RM267-RM1237, RM2422-RM6054 and RM3321-RM1054, which were 21.3 cM, 27.4 cM and 12.7 cM in genetic distance on rice chromosome 5, respectively. qCTB-7 was mapped in a 6.8-cM region of RM11-RM2752 on rice chromosome 7.     

利用染色体片段置换系定位水稻芽期耐冷性QTL

以籼稻品种9311为受体、粳稻品种日本晴为供体构建的95个染色体片段置换系为材料,在5℃低温条件下进行芽期耐冷性鉴定。结果表明,6个置换系低温处理后的成苗率与受体亲本9311有一定差异,其耐冷性略强于9311。利用代换作图法共鉴定出4个与芽期耐冷性相关的QTL,分别位于水稻第5和第7染色体上。其中qCTB-5-1、qCTB-5-2和qCTB-5-3分别被定位在第5染色体RM267与RM1237、RM2422与RM6054及RM3321与RM1054之间遗传距离分别为21.3cM、27.4cM和12.7cM的置换片段上;qCTB-7被定位在第7染色体RM11-RM2752区间遗传距离为6.8cM的置换片段上。     

Chromosome Segment Substitution Lines: A Powerful Tool for the Introgression of Valuable Genes from Oryza Wild Species into Cultivated Rice (O. sativa)

Wild species of rice (genus Oryza) contain many useful genes but a vast majority of these genes remain untapped to date because it is often difficult to transfer these genes into cultivated rice (Oryza sativa L.). Chromosome segment substitution lines (CSSLs) and backcross inbred lines (BILs) are powerful tools for identifying these naturally occurring, favorable alleles in unadapted germplasm. In this paper, we present an overview of the research involving CSSLs and BILs in the introgression of quantitative trait loci (QTLs) associated with the improved performance of rice including resistance to various biotic and abiotic stresses, and even high yield from wild relatives of rice and other unadapted germplasm into the genetic background of adapted rice cultivars. The CSSLs can be used to dissect quantitative traits into the component genetic factors and evaluate gene action as single factors (monogenic loci). CSSLs have the potential to uncover new alleles from the unadapted, non-productive wild rice accessions, develop genome-wide genetic stocks, and clone genes identified in QTL studies for functional genomics research. Recent development of high-density single-nucleotide polymorphism (SNP) arrays in rice and availability of custom-designed medium- and low-density SNP arrays will enhance the CSSL development process with smaller marker-defined segment introgressions from unadapted germplasm.     

Sucrose avoidance by American robins (Turdus migratorius): Implications for control of bird damage in fruit crops

Altering the relative sugar content in fruit is a potential alternative to chemical, aural and visual repellents to control bird damage to cultivated fruit crops. Some frugivorous birds, such as the American robin (Turdus migratorius), lack the digestive enzyme sucrase, and therefore cannot digest sucrose. It was predicted that robins would avoid consumption of foods that contain sucrose. When offered sweetened agar cubes that contained glucose, fructose, sucrose, or a hexose mixture, total consumption was significantly lower and faecal sugar concentration higher in the sucrose tests. In tests involving two sugars, mean total consumption was reduced when sucrose was eaten. Development of high-sucrose fruits warrants further investigation as a means to mitigate bird damage to certain fruit crops.     

Triterpene Glycosides from the Far Eastern Sea Cucumber Thyonidium (=Duasmodactyla) kurilensis (Levin): The Structures,Cytotoxicities, and Biogenesis of Kurilosides A3, D1, G,H, I,I1, J,K, and K1

Nine new mono-, di-, and trisulfated triterpene penta- and hexaosides, kurilosides A₃ (1), D₁ (2), G (3), H (4), I (5), I₁ (6), J (7), K (8), and K₁ (9) and two desulfated derivatives, DS-kuriloside L (10), having a trisaccharide branched chain, and DS-kuriloside M (11), having hexa-nor-lanostane aglycone with a 7(8)-double bond, have been isolated from the Far-Eastern deep-water sea cucumber Thyonidium (=Duasmodactyla) kurilensis (Levin) and their structures were elucidated based on 2D NMR spectroscopy and HR-ESI mass-spectrometry. Five earlier unknown carbohydrate chains and two aglycones (having a 16β,(20S)-dihydroxy-fragment and a 16β-acetoxy,(20S)-hydroxy fragment) were found in these glycosides. All the glycosides 1–9 have a sulfate group at C-6 Glc, attached to C-4 Xyl1, while the positions of the other sulfate groups vary in different groups of kurilosides. The analysis of the structural features of the aglycones and the carbohydrate chains of all the glycosides of T. kurilensis showed their biogenetic relationships. Cytotoxic activities of the compounds 1–9 against mouse neuroblastoma Neuro 2a, normal epithelial JB-6 cells, and erythrocytes were studied. The highest cytotoxicity in the series was demonstrated by trisulfated hexaoside kuriloside H (4), having acetoxy-groups at C(16) and C(20), the latter one obviously compensated the absence of a side chain, essential for the membranolytic action of the glycosides. Kuriloside I₁ (6), differing from 4 in the lacking of a terminal glucose residue in the bottom semi-chain, was slightly less active. The compounds 1–3, 5, and 8 did not demonstrate cytotoxic activity due to the presence of hydroxyl groups in their aglycones.     

Lipid Inhibitory Effect of (−)-loliolide Isolated from Sargassum horneri in 3T3-L1 Adipocytes: Inhibitory Mechanism of Adipose-Specific Proteins

Sargassum horneri (S. horneri) is a well-known brown seaweed widely distributed worldwide. Several biological activities of S. horneri have been reported. However, its effects on lipid metabolism and the underlying mechanisms remain elusive. In the present study, we examined the inhibitory effect of the active compound “(−)-loliolide ((6S,7aR)-6-hydroxy-4,4,7a-trimethyl-5,6,7,7a-tetrahydro-1-benzofuran-2(4H)-one (HTT))” from S. horneri extract on lipid accumulation in differentiated adipocytes. MTT assays demonstrated that (−)-loliolide is not toxic to 3T3-L1 adipocytes in a range of concentrations. (−)-loliolide significantly reduced intracellular lipid accumulation in the differentiated phase of 3T3-L1 adipocytes as shown by Oil Red O staining. Western blot analysis revealed that (−)-loliolide increased the expression of lipolytic protein phospho-hormone-sensitive lipase (p-HSL) and thermogenic protein peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1). Additionally, (−)-loliolide decreased expression of adipogenic and lipogenic proteins, including sterol regulatory element-binding protein-1 (SREBP-1), peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT/enhancer-binding protein-α (C/EBP-α), and fatty acid-binding protein 4 (FABP4) in 3T3-L1 adipocytes. These results indicate that (−)-loliolide from S. horneri could suppress lipid accumulation via regulation of antiadipogenic and prolipolytic mechanisms in 3T3-L1 cells. Considering the multifunctional effect of (−)-loliolide, it can be useful as a lipid-lowering agent in the management of patients who suffer from obesity.     

Evaluation of A1, A2, A3, A4(M), A4(G) and A4(VZM) cytoplasms in iso-nuclear backgrounds for grain mold resistance

Breeding for resistance to grain mold, an economically important disease of sorghum, has been only partially successful. Hybrid technology is well developed in sorghum due to availability of the cytoplasm male sterility (CMS) system and at present almost all commercial hybrids are based on the A₁ CMS system. To compare the available alternate CMS systems for grain mold resistance, 72 hybrids were produced by crossing 36 A-lines (six CMS systems; A₁, A₂, A₃, A_4(M), A_4(G), A_4(VZM) each in six nuclear backgrounds) with two common restorers, and were evaluated during the 2006 and 2007 rainy seasons in grain mold nursery at ICRISAT. Data analyses indicated influence of cytoplasm on the responses of hybrids to grain mold infection as measured by panicle grain mold resistance (PGMR) score. The A₁ cytoplasm seemed to contribute to grain mold resistance followed by A_4(VZM) and A₂ cytoplasms. The A_4(M) cytoplasm had superior general combining ability (GCA) effects while the A₁ and A_4(VZM) cytoplasm based hybrids had superior specific combining ability (SCA) effects on the PGMR score. Almost all hybrids had significant mid-parent heterosis. The A₁ cytoplasm is the best suited for the development of sorghum hybrids for the rainy season adaptation with grain mold resistance. However, use of alternate cytoplasms (A₂ and A_4(VZM)) for hybrid development will not increase susceptibility to grain mold in commercial grain production.     

Genotypic variation for grain and stover yield of dryland (rabi) sorghum in India: 1. Magnitude of genotype × environment interactions

Grain and stover yield are key traits for the improvement of rabi sorghum varieties and hybrids in India. Large genotype-by-environment interactions (GEI) were identified for both grain and stover yield based on 10 years’ data available from the All India Coordinated Sorghum Improvement Program (AICSIP) experiments conducted from 1986/87 to 1996/97. From the estimates of the genotypic, GEI and residual components of variance for the four traits, a multi-environment testing strategy based on 15–20 locations, 2–3 years, and two replicates per trial would be required to achieve estimates of repeatability of approximately 0.70 for grain yield, 0.45 for stover yield, 0.70 for flowering time, and 0.85 for plant height.     

Differential Spread of <Emphasis Type="Italic">Potato virus Y</Emphasis> (PVY) Strains O,N:O and NTN in the Field: Implications for the Rise of Recombinant PVY Strains in New Brunswick,Canada

Potato virus Y (PVY) is a major cause of yield and quality loss in potato crops worldwide. Recently, populations of PVY strains have shifted dramatically toward recombinant strains such as PVY^NTN and PVY^N:O. A 2010 to 2016 survey of PVY strains in commercial fields of New Brunswick (NB), Canada, and five field trials tracking PVY spread in NB and Manitoba, were conducted to study the current status of PVY strains and their relative rates of spread. In NB, PVY^O dropped from 82% of infections in 2010 to 14% in 2016, replaced mostly by PVY^NTN (64%) and PVY^N:O (22%).In field trials with Russet Burbank and Gold rush varieties, PVY^NTN spread most effectively compared to PVY^N:O and PVY^O. Strain-specific PVY spread varied with the potato variety, possibly due to selective PVY^O resistance in Goldrush, mostly expressed at the plant-to-plant transmission level with little difference in transduction to tubers in infected plants. Relevance of in-field differences in spread of strains to changes in regional PVY populations, and potential mechanisms responsible, are discussed.