Constitutive expression of <Emphasis Type="Italic">REL1</Emphasis> confers the rice response to drought stress and abscisic acid

Leaf rolling is one of the most significant symptoms of drought stress in plant. Previously, we identified a dominant negative mutant, termed rolled and erect 1 (hereafter referred to rel1-D), regulating leaf rolling and erectness in rice. However, the role of REL1 in drought response is still poorly understood. Here, our results indicated that rel1-D displayed higher tolerance to drought relative to wild type, and the activity of superoxide dismutase (SOD) and drought responsive genes were significantly up-regulated in rel1-D. Moreover, our results revealed that rel1-D was hypersensitive to ABA and the expression of ABA associated genes was significantly increased in rel1-D, suggesting that REL1 likely coordinates ABA to regulate drought response. Using the RNA-seq approach, we identified a large group of differentially expressed genes that regulate stimuli and stresses response. Consistently, we also found that constitutive expression of REL1 alters the expression of biotic and abiotic stress responsive genes by the isobaric tags for relative and absolute quantification (iTRAQ) analysis. Integrative analysis demonstrated that 8 genes/proteins identified by both RNA-seq and iTRAQ would be the potential targets in term of the REL1-mediated leaf morphology. Together, we proposed that leaf rolling and drought tolerance of rel1-D under normal condition might be caused by the endogenously perturbed homeostasis derived from continuous stressful dynamics.     

<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.     

Amphipathic Starch with Phosphate and Octenylsuccinate Substituents for Strong Adhesion to Cotton in Warp Sizing

The objectives of this work were to survey the effect of amphipathic modification of starch on the adhesion to cotton fibers for improving the adhesion of starch to cotton in warp sizing. The amphipathic starch (AS) with oleophilic octenylsuccinate and hydrophilic phosphate substituents was prepared by the phosphorylation with sodium tripolyphosphate (STP) followed by the octenylsuccinylation with 2-octenylsuccinic anhydride (OSA). Two series of AS samples with differential total degrees of substitution (DS_t) and substituent ratios of phosphates to octenylsuccinates were evaluated by fourier transform infrared (FTIR) analysis, degree of substitution, adhesion to cotton and surface tension. The adhesion of the starch to fibers was investigated using a legal method (FZ/T 15001-2008). The FTIR spectra revealed that octenylsuccinates and phosphates have been attached to the backbones of the starch. The amphipathic modification of starch with STP and OSA was an effective method to enhance the adhesion of corn starch to cotton. The strong adhesion of the AS to cotton was attributed to the reduced surface tension arisen from oleophilic octenylsuccinate and hydrophilic phosphate substituents and increased steric hindrance of the substituents introduced onto starch. The investigation showed that the improvement in the adhesion of the starch after amphipathic modification could be buttressed by the tensile strength of cotton yarns sized with AS. It was found that the AS was desizable and showed satisfactory desizing efficiency in oxidant desizing. Based on the adhesion, reaction efficiencies, and desizability, the AS with a total DS_t of 0.033 and a substituent ratio of DS_p0.014/DS_o0.032 showed potential for use in warp sizing.     

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 ATP-binding cassette (ABC) transporter OsABCG3 is essential for pollen development in rice

Background

The pollen wall, which protects male gametophyte against various stresses and facilitates pollination, is essential for successful reproduction in flowering plants. The pollen wall consists of gametophyte-derived intine and sporophyte-derived exine. From outside to inside of exine are tectum, bacula, nexine I and nexine II layers. How these structural layers are formed has been under extensive studies, but the molecular mechanisms remain obscure.

Results

Here we identified two osabcg3 allelic mutants and demonstrated that OsABCG3 was required for pollen development in rice. OsABCG3 encodes a half-size ABCG transporter localized on the plasma membrane. It was mainly expressed in anther when exine started to form. Loss-function of OsABCG3 caused abnormal degradation of the tapetum. The mutant pollen lacked the nexine II and intine layers, and shriveled without cytoplasm. The expression of some genes required for pollen wall formation was examined in osabcg3 mutants. The mutation did not alter the expression of the regulatory genes and lipid metabolism genes, but altered the expression of lipid transport genes.

Conclusions

Base on the genetic and cytological analyses, OsABCG3 was proposed to transport the tapetum-produced materials essential for pollen wall formation. This study provided a new perspective to the genetic regulation of pollen wall development.

     

Inclusion of Whole Flour from Latin-American Crops into Bread Formulations as Substitute of Wheat Delays Glucose Release and Uptake

Bakery formulations limiting glucose availability for uptake without compromising product quality are required. Herein, bread formulations containing whole flour from Amaranthus hypochondriacus (AB), Chenopodium quinoa (QB), Salvia hispanica L (ChB) or wheat (WWB) were compared to white bread (WB) for glycaemic index (GI) in fasted animals. The hepatic expression (mRNA) of PPAR-γ receptor as key regulator in substrate fractionation towards energy expenditure was monitored. GIs were associated to fluxes of glucose release (F_Gluc) and metabolic response (MTT assay) of HepG2 cells. ChB (19.7%) and AB (13.5%) decreased GI to a higher extent than QB (2.7%), but all increased expression of PPARγ in relation to WB. F_Gluc (AB>?>?ChB, WWB, WB?>?QB) showed a reciprocal relationship with the area under curve (AUC) in vivo, and decreased MTT conversion values (WB?>?WWB, ChB, AB, QB) by HepG2 cells. Thus, inclusion of latin-american crops (LAcs) reducing GI, without compromising bread quality, could help preventing metabolic diseases.     

Role and effects of winter buds and rhizome morphology on the survival and growth of common reed (Phragmites australis)

To confirm the role of winter buds and rhizome morphology on the winter survival and subsequent growth of common reed (Phragmites australis), rhizome fragments of varying sizes with and without winter buds from three different P. australis populations were transplanted to small pots in a greenhouse and wintered by exposing them to a dry atmospheric condition. Survival ratios of the rhizome fragments with winter buds were much greater than those without winter buds regardless of population type, supporting that winter buds play a role as the insulator of rhizome fragments from dry atmosphere during winter season. Most growth characteristics of surviving P. australis from the rhizome fragments were similar to those in natural wetlands, indicating preserved growth characteristics through the rhizomes, which is an asexual organ. The average number of rhizome fragment nodes showed negative relationships with the number of blades per culm (P < .05) and basal culm diameter (P < .05) of surviving P. australis. In contrast, the diameter of planted rhizome fragments had significant positive relationships with the final shoot height (P < .05), above-ground dry weight (P < .05), root DW (P < .01), and total DW (P < .05). Rhizome volume also showed a similar correlation with the rhizome diameter. Thicker and larger rhizome fragments particularly with winter buds, indicating the young age of rhizome, seemed likely to guarantee greater survival and higher subsequent shoot growth and biomass production as well.     

Identification of resistant germplasm containing novel resistance genes at or tightly linked to the <Emphasis Type="Italic">Pi2/9</Emphasis> locus conferring broad-spectrum resistance against rice blast

Background

The rice Pi2/9 locus harbors multiple resistance (R) genes each controlling broad-spectrum resistance against diverse isolates of Magnaporthe oryzae, a fungal pathogen causing devastating blast disease to rice. Identification of more resistance germplasm containing novel R genes at or tightly linked to the Pi2/9 locus would promote breeding of resistance rice cultivars.

Results

In this study, we aim to identify resistant germplasm containing novel R genes at or tightly linked to the Pi2/9 locus using a molecular marker, designated as Pi2/9-RH (Pi2/9 resistant haplotype), developed from the 5′ portion of the Pi2 sequence which was conserved only in the rice lines containing functional Pi2/9 alleles. DNA analysis using Pi2/9-RH identified 24 positive lines in 55 shortlisted landraces which showed resistance to 4 rice blast isolates. Analysis of partial sequences of the full-length cDNAs of Pi2/9 homologues resulted in the clustering of these 24 lines into 5 haplotypes each containing different Pi2/9 homologues which were designated as Pi2/9-A5, ?A15, ?A42, ?A53, and -A54. Interestingly, Pi2/9-A5 and Pi2/9-A54 are identical to Piz-t and Pi2, respectively. To validate the association of other three novel Pi2/9 homologues with the blast resistance, monogenic lines at BC₃F₃ generation were generated by marker assisted backcrossing (MABC). Resistance assessment of the derived monogenic lines in both the greenhouse and the field hotspot indicated that they all controlled broad-spectrum resistance against rice blast. Moreover, genetic analysis revealed that the blast resistance of these three monogenic lines was co-segregated with Pi2/9-RH, suggesting that the Pi2/9 locus or tightly linked loci could be responsible for the resistance.

Conclusion

The newly developed marker Pi2/9-RH could be used as a potentially diagnostic marker for the quick identification of resistant donors containing functional Pi2/9 alleles or unknown linked R genes. The three new monogenic lines containing the Pi2/9 introgression segment could be used as valuable materials for disease assessment and resistance donors in breeding program.

     

Antioxidant Properties of Extracts Obtained from Raw,Dry-roasted,and Oil-roasted US Peanuts of Commercial Importance

Raw, skinless peanut kernels from US commercial production lines were dry- and oil-roasted according to standard industrial practices. Eighty percent (v/v) methanolic extracts from the peanut cultivars were prepared and characterized by RP-HPLC: five predominant compounds were found comprising free p-coumaric acid and potential p-coumaric acid derivatives, as elucidated by DAD-UV spectra with comparisons to those of commercial standards. A Spanish high-oleic peanut possessed the greatest naturally-occurring level of p-coumaric acid and its derivatives, followed by a high-oleic Runner, a normal Runner, and a Virginia peanut. Upon thermal processing, p-coumaric acid was liberated at the expense of its derivatives according to the relationship: oil roasting > dry roasting > raw. A high-oleic Runner exhibited the greatest increase (～785%) in free p-coumaric acid levels after oil roasting. For many of the samples from the 2007 crop, processing increased the TPC and antioxidant capacities in the order of raw < dry roast < oil roast, but results were cultivar dependent. Oil-roasted peanuts were more effective at scavenging O₂ ^●- than their dry-roasted counterparts, as determined by a photochemiluminescence assay. Overall findings indicate that although thermal processing altered the composition of peanut kernel antioxidants, TPC values and radical-scavenging activities are preserved. Depending on peanut type, cultivar, and harvest date, enhanced antioxidant capacities can result.     

Identification and fine mapping of <Emphasis Type="Italic">Bph33</Emphasis>, a new brown planthopper resistance gene in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

Background

Host-plant resistance is the most desirable and economic way to overcome BPH damage to rice. As single-gene resistance is easily lost due to the evolution of new BPH biotypes, it is urgent to explore and identify new BPH resistance genes.

Results

In this study, using F_2:3 populations and near-isogenic lines (NILs) derived from crosses between two BPH-resistant Sri Lankan rice cultivars (KOLAYAL and POLIYAL) and a BPH-susceptible cultivar 9311, a new resistance gene Bph33 was fine mapped to a 60-kb region ranging 0.91–0.97 Mb on the short arm of chromosome 4 (4S), which was at least 4 Mb distant from those genes/QTLs (Bph12, Bph15, Bph3, Bph20, QBph4 and QBph4.2) reported before. Seven genes were predicted in this region. Based on sequence and expression analyses, a Leucine Rich Repeat (LRR) family gene (LOC_Os04g02520) was identified as the most possible candidate of Bph33. The gene exhibited continuous and stable resistance from seedling stage to tillering stage, showing both antixenosis and antibiosis effects on BPH.

Conclusion

The results of this study will facilitate map-based cloning and marker-assisted selection of the gene.

     

Implications of the Red Beet Ripening on the Colour and Betalain Composition Relationships

The evolution during ripening of Beta vulgaris (var. Pablo) on colour and betalain composition, not previously conducted in conjunction in red beets, has been examined. According to the results, it could be asserted that the ripening stage significantly (p?<?0.05) influenced on all the studied parameters. On the basis of the betalain content, the optimum ripening stage corresponded to a medium weigh-to-calibre ratio, in the light of the significantly (p?<?0.05) higher content of betalains, especially betanin and vulgaxanthin I. Moreover, colour attributes also differed during ripening, having the medium-ripened beetroots a significantly (p?<?0.05) more reddish hue (h_ab) and lower lightness (L*), probably due to the higher content of betaxanthins in this stage. The colour differences among red beets in the stage II and the rest of stages were visually appreciable (ΔE*_ab?>?3) and mainly qualitative. A new range of opportunities for diversification of colorant market, from a nutritional and colorimetric point of view, could be possible by employing red beets with different stages of ripening.     

The Suppression of Verticillium Wilt of Potato Using Corn as a Green Manure Crop

Field studies involving the effects of growing sweet corn (Zea mays var. Jubilee sweet corn and var. Jubilee super-sweet corn) as a green manure for 2 or 3 seasons demonstrated both suppression of verticillium wilt by 60–70% (Verticillium dahliae Kleb.) and increased potato yields. Although these treatments showed no direct effect on V. dahliae soil populations, the colonization of V. dahliae on potato feeder-roots and in potato tissue of stem apices were reduced. Feeder-root colonization by V. dahliae was positively correlated with verticillium wilt incidence (P?≤?0.05 to P?≤?0.01) and negatively correlated with yield (P?≤?0.05). Corn green manures additionally increased populations of several soilborne fungi which included Ulocladium, and Fusarium equiseti. Specific nutritional and microbial effects were secondary to the effects of cropping practices. When compared with the fallow treatments for 1994, 1995, and 1997, the percentage yield increases for 1994 were: +34% for total yield, +57% for U.S. #1’s, and +127% for tubers >280 g; for 1995 (a year of reduced degree-days and decreased verticillium incidence): +14% for total yields, +15% for U.S. #1 yields, and +21% for tubers >280 g; for 1997: +24% for yield totals, +74% for U.S. #1’s and +179% for tubers >280 g. For establishing these yield benefits, stalks with and without ears of corn were used as green manures. Corn varieties differed for effectiveness as a green manure, which could be accounted for by differences of biomass. When compared with the super-sweet corn, the sweet corn produced an increase (>2-fold) of biomass with less than half of the resulting wilt incidence. When potato was grown consecutively for 2 years, the benefits from green manures became mostly eliminated. However, following 2 consecutive years of potato, a single green manure of sweet corn was sufficient to return the potato crop to the original benefits of verticillium suppression and increased yields. This occurred even though soilborne V. dahliae inoculum levels had increased by >4-fold from 45 to 182 cfu g^?1 of soil. Results of this study demonstrate the importance of green manures and soil-ecology to the management of the Russet Burbank potato.     

Genome-wide association study and candidate gene analysis of rice cadmium accumulation in grain in a diverse rice collection

Background

Cadmium (Cd) accumulation in rice followed by transfer to the food chain causes severe health problems in humans. Breeding of low Cd accumulation varieties is one of the most economical ways to solve the problem. However, information on the identity of rice germplasm with low Cd accumulation is limited, particularly in indica, and the genetic basis of Cd accumulation in rice is not well understood.

Results

Screening of 312 diverse rice accessions revealed that the grain Cd concentrations of these rice accessions ranged from 0.12 to 1.23?mg/kg, with 24 accessions less than 0.20?mg/kg. Three of the 24 accessions belong to indica. Japonica accumulated significantly less Cd than indica (p < 0.001), while tropical japonica accumulated significantly less Cd than temperate japonica (p < 0.01). GWAS in all accessions identified 14 QTLs for Cd accumulation, with 7 identified in indica and 7 identified in japonica subpopulations. No common QTL was identified between indica and japonica. The previously identified genes (OsHMA3, OsNRAMP1, and OsNRAMP5) from japonica were colocalized with QTLs identified in japonica instead of indica. Expression analysis of OsNRAMP2, the candidate gene of the novel QTL (qCd3–2) identified in the present study, demonstrated that OsNRAMP2 was mainly induced in the shoots of high Cd accumulation accessions after Cd treatment. Four amino acid differences were found in the open reading frame of OsNRAMP2 between high and low Cd accumulation accessions. The allele from low Cd accumulation accessions significantly increased the Cd sensitivity and accumulation in yeast. Subcellular localization analysis demonstrated OsNRAMP2 expressed in the tonoplast of rice protoplast.

Conclusion

The results suggest that grain Cd concentrations are significantly different among subgroups, with Cd concentrations decreasing from indica to temperate japonica to tropical japonica. However, considerable variations exist within subgroups. The fact that no common QTL was identified between indica and japonica implies that there is a different genetic basis for determining Cd accumulation between indica and japonica, or that some QTLs for Cd accumulation in rice are subspecies-specific. Through further integrated analysis, it is speculated that OsNRAMP2 could be a novel functional gene associated with Cd accumulation in rice.

     

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.

     

Panicle blast 1 (Pb1) resistance is dependent on at least four QTLs in the rice genome

Background

Rice blast is the most serious disease afflicting rice and there is an urgent need for the use of disease resistance (R) genes in blast tolerance breeding programs. Pb1 is classified as a quantitative resistance gene and it does not have fungal specificity. Pb1-mediated resistance develops in the latter stages of growth. However, some cultivars, such as Kanto209 (K209), cultivar name Satojiman, despite possessing Pb1, do not exert resistance to rice blast during the reproductive stage.

Results

We found that the expression of WRKY45 gene downstream of Pb1 was weakly induced by rice blast inoculation at the full heading stage in K209. Genetic analysis using the SNP-based Golden Gate assay of K209 crossing with Koshihikari Aichi SBL (KASBL) found at least four regions related to the resistance in the rice genome (Chr8, Chr9, Chr7, Chr11). Mapping of QTL related to Chr7 confirmed the existence of factors that were required for the resistance of Pb1 in the 22 to 23 Mbp region of the rice genome.

Conclusion

We clarified how the K209 cultivar is vulnerable to the blast disease despite possessing Pb1 and found the DNA marker responsible for the quantitative resistance of Pb1. We identified the QTL loci required for Pb1-mediated resistance to rice panicle blast. Pb1 was negatively dependent on at least three QTLs, 7, 9 and 11, and positively dependent on one, QTL 8, in the K209 genome. This finding paves the way for creating a line to select optimal QTLs in order to make use of Pb1-mediated resistance more effectively.