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At least 109 records · Page 6Linked to original sources
PubMed2004

Proteomic analysis of pathogen-responsive proteins from rice leaves induced by rice blast fungus, Magnaporthe grisea.

Proteomic approaches using two-dimensional gel electrophoresis (2-DE) were adopted to identify proteins from rice leaf that are differentially expressed in response to the rice blast fungus, Magnaporthe grisea. Microscopic observation of inoculated leaf with M. grisea revealed that callose deposition and hypersensitive response was clearly visible in incompatible interactions but excessive invading hypha with branches were evident in compatible interactions. Proteins were extracted from leaves 24, 48, and 72 hours after rice blast fungus inoculation. Eight proteins resolved on the 2-DE gels were induced or increased in the inoculated leaf. Matrix-assisted laser desorption/ionization-time of flight analysis of these differentially displayed proteins showed them to be two receptor-like protein kinases (RLK), two beta-1.3-glucanases (Glu1, Glu2), thaumatin-like protein (TLP), peroxidase (POX 22.3), probenazole-inducible protein (PBZ1), and rice pathogenesis-related 10 (OsPR-10). Of these proteins, RLK, TLP, PBZ, and OsPR-10 proteins were induced more in the incompatible interactions than in compatible ones. A phytohormone, jasmonic acid also induced all eight proteins in leaves. To confirm whether the expression profile is equal to the 2-DE data, seven cDNA clones were used as probes in Northern hybridization experiments using total RNA from leaf tissues inoculated with incompatible and compatible rice blast fungal races. The genes encoding POX22.3, Glu1, Glu2, TLP, OsRLK, PBZ1, and OsPR-10 were activated in inoculated leaves, with TLP, OsRLK, PBZ1, and OsPR-10 being expressed earlier and more in incompatible than in compatible interactions. These results suggest that early and high induction of these genes may provide host plants with leading edges to defend themselves. The localization of two rice PR-10 proteins, PBZ1 and OsPR-10, was further examined by immunohistochemical analysis. PBZ1 accumulated highly in mesophyll cells under the attachment site of the appressorium. In contrast, OsPR-10 expression was mainly localized to vascular tissue.

Blotting, Northern↗
PubMed2005

Assessment of acetolactate synthase (ALS) tolerance to imazethapyr in red rice ecotypes (Oryza spp) and imidazolinone tolerant/ resistant rice (Oryza sativa) varieties.

Three red rice ecotypes (Oryza spp), including LA 5, MS 5 and TX 4, were evaluated for acetolactate synthase resistance/tolerance to imazethapyr. The red rice ecotypes were compared with a tolerant line (CL-121), a resistant line (CL-161) and a conventional rice variety (Cypress). Based on enzymatic activity, the mean I(50) values were 1.5, 1.1, 1.5, 1.6, 20.8 and 590.6 microM imazethapyr, respectively, for LA 5, MS 5, TX 4, Cypress, CL-121 and CL-161. CL-161 was 32 times more resistant than CL-121 and at least 420 times more resistant than the average of the red rice ecotypes and Cypress. Results from the acetolactate synthase (ALS) assay showed that red rice ecotypes and Cypress had high susceptibility to imazethapyr when compared with the tolerant CL-121 and the resistant CL-161. Measurable enzymatic tolerance to ALS-inhibiting herbicides has not yet developed in these red rice ecotypes.

Acetolactate Synthase↗
PubMed1993

Transient and stable expression of gusA fusions with rice genes in rice, barley and perennial ryegrass.

Transcriptional and translational fusions were made between the reading frame coding for beta-D-glucuronidase and sequences of either a constitutively expressed rice gene (GOS2) involved in initiation of translation or a light-inducible rice gene (GOS5). The transient expression of the fusions was studied via particle bombardment of seedling tissues of rice, perennial ryegrass and barley. Furthermore, the results of transient and stable expression were compared for cell suspensions of four rice varieties, one barley variety and one perennial ryegrass variety. The GOS2-gusA fusions were active in all three monocots studied. Best results were obtained for a construct having both a transcriptional and a translational fusion as well as intron and exon sequences (PORCEHyg). The level of GUS activity was in the range of activities as obtained by the 35S CaMV promoter transcriptionally fused to gusA. The gusA fusion with the light-inducible gene (GOS5) was active in green seedling tissues of all monocots studied. Also a weak expression compared to the GOS2 constructs was found in stably transformed rice callus. The gusA fusions with the mannopine synthase promoters 1' and 2' of the TR-DNA were transiently expressed at lower levels in cell suspensions than PORCEHyg. For stably transformed rice callus the expression of the GOS2-gusA fusion often decreased during prolonged subculture. This decrease in GUS activity and the various GUS-staining phenotypes of transgenic calli are explained by the presence of different cell types in the suspensions used and in the calli. It is presumed that the nature of the cells and their relative contribution in the calli change drastically upon further subculture.

Amino Acid Sequence↗
PubMed1993

Transient and stable expression of gusA fusions with rice genes in rice, barley and perennial ryegrass.

Transcriptional and translational fusions were made between the reading frame coding for beta-D-glucuronidase and sequences of either a constitutively expressed rice gene (GOS2) involved in initiation of translation or a light-inducible rice gene (GOS5). The transient expression of the fusions was studied via particle bombardment of seedling tissues of rice, perennial ryegrass and barley. Furthermore, the results of transient and stable expression were compared for cell suspensions of four rice varieties, one barley variety and one perennial ryegrass variety. The GOS2-gusA fusions were active in all three monocots studied. Best results were obtained for a construct having both a transcriptional and a translational fusion as well as intron and exon sequences (PORCEHyg). The level of GUS activity was in the range of activities as obtained by the 35S CaMV promoter transcriptionally fused to gusA. The gusA fusion with the light-inducible gene (GOS5) was active in green seedling tissues of all monocots studied. Also a weak expression compared to the GOS2 constructs was found in stably transformed rice callus. The gusA fusions with the mannopine synthase promoters 1' and 2' of the TR-DNA were transiently expressed at lower levels in cell suspensions than PORCEHyg. For stably transformed rice callus the expression of the GOS2-gusA fusion often decreased during prolonged subculture. This decrease in GUS activity and the various GUS-staining phenotypes of transgenic calli are explained by the presence of different cell types in the suspensions used and in the calli. It is presumed that the nature of the cells and their relative contribution in the calli change drastically upon further subculture.

Amino Acid Sequence↗
PubMed1995

Suitability of full fat and defatted rice brain obtained from Indian rice for use in food products.

The effect of blending different types of rice bran in wheat flour on the rheological, pasting and baking properties is reported. Dough development time and strength as measured through farinograph decreased with the blending of unstabilized full fat and defatted bran; whereas, blending of stabilized full fat and defatted bran improved the dough strength. Pasting properties revealed an increase in gelatinization temperature and decrease in paste viscosities and set-back values with the blending of various types of rice bran. Bread volume and cookie spread decreased with blending of different types of rice bran; however, the decrease was more pronounced with the defatted bran. Muffin volume improved with the blending of rice bran. Stabilized full fat rice bran up to 20% level and unstabilized full fat or stabilized defatted rice bran up to 10% was found suitable in various food products.

Dietary Fats↗
PubMed2002

Expression and inheritance of hypersensitive resistance to rice hoja blanca virus mediated by the viral nucleocapsid protein gene in transgenic rice.

Rice hoja blanca virus (RHBV) is a major virus disease of economic importance affecting rice in northern South America, Central America and the Caribbean. This is the first report of transgenic resistance to RHBV and the transformation of an indica rice variety from Latin America. Rice transformed with the RHBV nucleocapsid protein ( N) gene had a significant reduction in disease development. Several reactions were observed that ranged from susceptible to completely resistant plants (immunity). The resistant reactions were characterized by the production of local lesions like a hypersensitive reaction or a recovery phenotype with the emergence of symptom-less new leaves. These transgenic RHBV-resistant rice lines expressed the N gene RNA at low levels that were below the detection limit by Northern blots and only resolved by RT-PCR. The nucleocapsid protein could not be detected in any of the transgenic plants either by Western or ELISA tests. These results suggest that the resistance encoded by the N gene in these plants appears to be mediated by RNA. When challenged with RHBV, the resistant transgenic lines showed a significant increased performance for important agronomic traits including the number of tillers, the number of grains per plant and the yield as compared to the susceptible control. Furthermore, upon inoculation some of the most-resistant transgenic lines showed agronomic traits similar to the uninoculated non-transgenic Cica 8 control. Using both agronomic traits and disease severity as criteria, several of the most-resistant lines were followed through the R(4) generation and demonstrated that the N gene and RHBV resistance was inherited in a stable manner. These transgenic rice lines could become a new genetic resource in developing RHBV-resistant cultivars.

Capsid Proteins↗
PubMed2006

Molecular mapping of a novel gene, Grh5, conferring resistance to green rice leafhopper (Nephotettix cincticeps Uhler) in rice, Oryza sativa L.

The green rice leafhopper (GRH), Nephotettix cincticeps Uhler, is one of the most serious insect pests affecting cultivated rice (Oryza sativa L.) in temperate regions of East Asia. An accession of the wild rice species, Oryza rufipogon Griff. (W1962), was found to be highly resistant to GRH by an antibiosis test. To understand the genetic basis of the GRH resistance, a BC1F1 population derived from a cross between a susceptible Japonica variety, Taichung 65 (T65), and a highly resistant accession W1962 was analyzed by quantitative trait loci (QTL) mapping. A single major QTL for GRH resistance was detected on rice chromosome 8. A nearly isogenic population containing segments of the targeted QTL region derived from W1962 was then developed through advanced backcrossing with marker-assisted selection. Further molecular mapping using a BC4F2 population revealed that a new resistance gene, designated as Green rice leafhopper resistance 5 (Grh5), was located on the distal region of the long arm of chromosome 8 and tightly linked to the simple sequence repeat markers RM3754 and RM3761. A nearly isogenic line (NIL) carrying Grh5 was subsequently developed in the progeny of the mapping population. The resistance level of Grh5-NIL was compared with those of developed NILs for GRH resistance and was found to have the highest resistance. The DNA markers found to be closely linked to Grh5 would be useful for marker-assisted selection for the improvement of resistance to GRH in rice.

Animals↗
PubMed2006

Effects of lead contamination on soil enzymatic activities, microbial biomass, and rice physiological indices in soil-lead-rice (Oryza sativa L.) system.

The effect of lead (Pb) treatment on the soil enzymatic activities, soil microbial biomass, rice physiological indices and rice biomass were studied in a greenhouse pot experiment. Six levels of Pb viz. 0(CK), 100, 300, 500, 700, 900 mg/kg soil were applied in two types of paddy soils. The results showed that Pb treatment had a stimulating effect on soil enzymatic activities and microbial biomass carbon (Cmic) at low concentration and an inhibitory influence at higher concentration. The degree of influence on enzymatic activities and Cmic by Pb was related to the clay and organic matter contents of the soils. When the Pb treatment was raised to the level of 500 mg/kg, ecological risk appeared both to soil microorganisms and plants. The results also revealed a consistent trend of increased chlorophyll contents and rice biomass initially, maximum at a certain Pb treatment, and then decreased gradually with the increase in Pb concentration. Pb was effective in inducing proline accumulation and its toxicity causes oxidative stress in rice plants. Therefore, it was concluded that soil enzymatic activities, Cmic and rice physiological indices, could be sensitive indicators to reflect environmental stress in soil-lead-rice system.

Acid Phosphatase↗
PubMed2006

Uptake and translocation of Cd in different rice cultivars and the relation with Cd accumulation in rice grain.

The variations among six rice cultivars in cadmium (Cd) uptake and translocation were investigated with pot soil experiments. The results showed that only a very small portion (0.73%) of Cd absorbed by rice plant was transferred into grain. With regard to plant total Cd uptake, Cd concentrations and quantity accumulations in roots, stems and leaves, the differences among the cultivars (between the largest one and the smallest one) were less than one time. But for Cd concentrations and Cd quantity accumulations in the grains, the differences were more than five and eight times, respectively. With respect to Cd distribution portions in plant organs, the diversities among the cultivars were also small in roots, stems and leaves, but much larger in grains. Grain Cd concentrations correlated positively and significantly (P<0.01) with Cd quantity accumulations in plant, Cd distribution ratios to aboveground parts, and especially with Cd distribution ratios from aboveground parts to the grain. The results indicated that Cd concentration in rice grain was governed somewhat by plant Cd uptake and the transport of Cd from root to shoot, and in a greater extent, by the transport of Cd from shoot to grain. Cd was not distributed evenly in different products after rice grain processing. The average Cd concentration in cortex (embryo) was five times more than that in chaff and polished rice. With regard to Cd quantity accumulation in the products, near 40% in cortex (embryo), 45% in polished rice and 15% in chaff averagely.

Cadmium↗
PubMed2006

OsWRKY71, a rice transcription factor, is involved in rice defense response.

WRKY proteins are a large family of transcription factors that mainly participate in plant biotic stress responses. So far, one hundred and five OsWRKY genes have been predicted in the rice genome. To identify OsWRKY genes that might function in inducible defense responses, a phylogenetic tree including 184 WRKY proteins from Arabidopsis thaliana, rice, and other species was constructed. Based on the phylogenetic analysis, ten candidate OsWRKY genes that may be involved in defense responses were isolated from salicylic acid (SA)-treated rice seedlings. One of them, OsWRKY71, was up-regulated by several defense signaling molecules, such as SA, methyl jasmonate (MeJA), 1-aminocyclo-propane-1-carboxylic acid (ACC), as well as wounding and pathogen infection, suggesting that OsWRKY71 might function in rice biotic stress response. Transient expression of OsWRKY71:GFP fusion protein in onion epidermis cells revealed that OsWRKY71 was localized in the nucleus. Overexpression of OsWRKY71 gene in rice resulted in enhanced resistance to virulent bacterial pathogens Xanthomonas oryzae pv. oryzae (Xoo) 13751. Furthermore, two marker genes in defense signaling pathway, OsNPR1 and OsPR1b, were constitutively expressed in OsWRKY71-overexpressing transgenic plants. These results suggest that OsWRKY71 might function as a transcriptional regulator upstream of OsNPR1 and OsPR1b in rice defense signaling pathways.

Arabidopsis↗
PubMed1999

Sulfate-reducing bacteria in rice field soil and on rice roots.

Rice plants that were grown in flooded rice soil microcosms were examined for their ability to exhibit sulfate reducing activity. Washed excised rice roots showed sulfate reduction potential when incubated in anaerobic medium indicating the presence of sulfate-reducing bacteria. Rice plants, that were incubated in a double-chamber (phylloshpere and rhizosphere separated), showed potential sulfate reduction rates in the anoxic rhizosphere compartment. These rates decreased when oxygen was allowed to penetrate through the aerenchyma system of the plants into the anoxic root compartment, indicating that sulfate reducers on the roots were partially inhibited by oxygen or that sulfate was regenerated by oxidation of reduced S-compounds. The potential activity of sulfate reducers on rice roots was consistent with MPN enumerations showing that H2-utilizing sulfate-reducing bacteria were present in high numbers on the rhizoplane (4.1 x 10(7) g-1 root fresh weight) and in the adjacent rhizosperic soil (2.5 x 10(7) g-1 soil dry weight). Acetate-oxidizing sulfate reducers, on the other hand, showed highest numbers in the unplanted bulk soil (1.9 x 10(6) g-1 soil dry weight). Two sulfate reducing bacteria were isolated from the highest dilutions of the MPN series and were characterized physiologically and phylogenetically. Strain F1-7b which was isolated from the rhizoplane with H2 as electron donor was related to subgroup II of the family Desulfovibrionaceae. Strain EZ-2C2, isolated from the rhizoplane on acetate, grouped together with Desulforhabdus sp. and Syntrophobacter wolinii. Other strains of sulfate-reducing bacteria originated from bulk soil of rice soil microcosms and were isolated using different electron donors. From these isolates, strains R-AcA1, R-IbutA1, R-PimA1 and R-AcetonA170 were Gram-positive bacteria which were affiliated with the genus Desulfotomaculum. The other isolates were members of subgroup II of the Desulfovibrionaceae (R-SucA1 and R-LacA1), were related to Desulforhabdus sp. (strain BKA11), Desulfobulbus (R-PropA1), or culstered between Desulfobotulus sapovorans and Desulfosarcina variabilis (R-ButA1 and R-CaprA1).

Gram-Negative Anaerobic Straight, Curved, and Heli↗
PubMed2003

Hypolipidemic and anti-atherogenic effects of long-term Cholestin (Monascus purpureus-fermented rice, red yeast rice) in cholesterol fed rabbits.

Long-term effects of Cholestin (Monascus purpureus rice; red yeast rice) on serum lipids and severity of atherosclerosis were examined in rabbits fed for 200 days on a semi-purified diet containing 0.25% cholesterol. Serum total cholesterol was 25 and 40% lower, respectively, in rabbits fed 0.4 or 1.35 g/kg/day of Cholestin (Monascus purpureus rice; red yeast rice) compared to controls. This treatment also lowered serum LDL cholesterol. This 200-day treatment significantly reduced serum triglycerides and atherosclerotic index (ratio of non-HDL-cholesterol to HDL-cholesterol). Although similar reductions of total, LDL-cholesterol and triglycerides were observed, a parallel group of rabbits fed lovastatin (0.0024 g/kg/day) failed to reduce the index significantly. Apolipoprotein A(1) was increased and apolipoprotein B was reduced in all treatment groups. Severity of atherosclerosis was reduced significantly in all treatment groups. The sudanophilic area of involvement was 80.6% in controls, and reduced significantly; to 30.1% on the low dose of Cholestin (Monascus purpureus rice; red yeast rice), and 17.2% on the high dose. Lovastatin reduced severity of lesions by 89% (sudanophilia) and 84% (visual). Visual grading of lesion severity showed reduction by 38% and 68%.

Animals↗
PubMed2003

Co-expression of a modified maize ribosome-inactivating protein and a rice basic chitinase gene in transgenic rice plants confers enhanced resistance to sheath blight.

Chitinases, beta-1,3-glucanases, and ribosome-inactivating proteins are reported to have antifungal activity in plants. With the aim of producing fungus-resistant transgenic plants, we co-expressed a modified maize ribosome-inactivating protein gene, MOD1, and a rice basic chitinase gene, RCH10, in transgenic rice plants. A construct containing MOD1 and RCH10 under the control of the rice rbcS and Act1 promoters, respectively, was co-transformed with a plasmid containing the herbicide-resistance gene bar as a selection marker into rice by particle bombardment. Several transformants analyzed by genomic Southern-blot hybridization demonstrated integration of multiple copies of the foreign gene into rice chromosomes. Immunoblot experiments showed that MOD1 formed approximately 0.5% of the total soluble protein in transgenic leaves. RCH10 expression was examined using the native polyacrylamide-overlay gel method, and high RCH10 activity was observed in leaf tissues where endogenous RCH10 is not expressed. R1 plants were analyzed in a similar way, and the Southern-blot patterns and levels of transgene expression remained the same as in the parental line. Analysis of the response of R2 plants to three fungal pathogens of rice, Rhizoctonia solani, Bipolaris oryzae, and Magnaporthe grisea, indicated statistically significant symptom reduction only in the case of R. solani (sheath blight). The increased resistance co-segregated with herbicide tolerance, reflecting a correlation between the resistance phenotype and transgene expression.

Blotting, Southern↗
PubMed2006

Phylogeography of Asian wild rice, Oryza rufipogon, reveals multiple independent domestications of cultivated rice, Oryza sativa.

Cultivated rice, Oryza sativa L., represents the world's most important staple food crop, feeding more than half of the human population. Despite this essential role in world agriculture, the history of cultivated rice's domestication from its wild ancestor, Oryza rufipogon, remains unclear. In this study, DNA sequence variation in three gene regions is examined in a phylogeographic approach to investigate the domestication of cultivated rice. Results indicate that India and Indochina may represent the ancestral center of diversity for O. rufipogon. Additionally, the data suggest that cultivated rice was domesticated at least twice from different O. rufipogon populations and that the products of these two independent domestication events are the two major rice varieties, Oryza sativa indica and Oryza sativa japonica. Based on this geographical analysis, O. sativa indica was domesticated within a region south of the Himalaya mountain range, likely eastern India, Myanmar, and Thailand, whereas O. sativa japonica was domesticated from wild rice in southern China.

Asia↗
PubMed1984

Effect of rice and salty rice diets on the structure of mouse stomach.

The effect of rice and salty rice diets on stomach morphology was investigated in Swiss/ICR mice. Mice were fed rice, salty rice, or standard pellet diets for 3-12 months, starting when the mice were 4 weeks of age. Long-term maintenance on the rice or salty rice diet increased the dimension and wet weight of the forestomach and decreased the same parameters of the glandular stomach. Similar bidirectional changes of the forestomach (hypertrophy) and glandular stomach (atrophy) were produced by hydrocortisone treatment. Histological study showed that a reduction in the parietal cell population accounted for the regression of the glandular stomach in both cases. Evidence is presented to suggest that an excess of carbohydrate and sodium chloride combined with a deficiency of fat and protein produced steroidal disorders that in turn gave rise to hyperplasia of the forestomach and atrophy of the glandular stomach of the mice. Possible impact of the above findings on the genesis of human gastric cancer is discussed in relation to the metabolic competence of the host animals to synthesize vitamin C.

Animals↗
PubMed2004

Protein-enriched pea flour extract protects stored milled rice against the rice weevil, Sitophilus oryzae.

Studies were conducted to evaluate the effect of a protein-enriched pea (Pisum sativum var. Bonneville) flour extract against the rice weevil, Sitophilus oryzae in its repellency, toxicity, effect on fecundity, stability and sensory properties. Milled rice admixed with pea flour extract at 1% concentration significantly repelled S. oryzae. Mortality of S. oryzae was found to increase and fecundity was markedly suppressed, in rice treated with 1% pea flour extract. The toxicity and reproductive effects of the pea protein-enriched rice were found to be stable for a period of 5 months. The sensory characteristics of stored rice when eaten were not affected by the treatment with pea flour extract. This study indicates that the protein-enriched flour extract obtained from the Bonneville pea may be feasible to protect stored milled rice from insect attack.

Animals↗
PubMed1990

Colonization of rice fields by mosquitoes (Diptera: Culicidae) and larvivorous predators in asynchronous rice cultivation areas in the Philippines.

Colonization of rice fields by mosquitoes and larvivorous predators was studied in asynchronous rice cultivation areas in the Philippines. Dipper samples were taken from rice fields at six phases of maturity (fallow, ploughed, nursery, newly transplanted, after tillering, mature). All phases were present concurrently at each of two study sites. Abundance levels of the vishnui subgroup of Culex and of the genus Anopheles were high in ploughed fields, nurseries, and newly transplanted fields; this was primarily because of the concentration of Culex vishnui. Theobald and Anopheles vagus Doenitz in those fields with short, sparse vegetation. Dytiscidae, Anisoptera, and Zygoptera were more abundant in fallow or mature fields. The abundance of aquatic predators decreased at the onset of ploughing and then recovered slowly as rice plants grew. The abundance of surface predators showed a similar pattern, but less conspicuously. The abundance of nonpredators (other than mosquitoes) was relatively stable with regard to rice field phases. Alleviation of mortality by predation was considered to be a secondary cause of increased mosquito abundance in the fields under early phases of rice cultivation.

Animals↗
PubMed2005

Genome-wide identification of the rice calcium-dependent protein kinase and its closely related kinase gene families: comprehensive analysis of the CDPKs gene family in rice.

In plants, calcium acts as a universal second messenger in various signal transduction pathways. The plant-specific calcium-dependent protein kinases (CDPKs) play important roles regulating downstream components of calcium signaling. We conducted a genome-wide analysis of rice CDPKs and identified 29 CDPK genes and eight closely related kinase genes, including five CDPK-related kinases (CRKs), one calcium and calmodulin-dependent protein kinase (CCaMK) and two phosphoenolpyruvate (PEP) carboxylase kinase-related kinases (PEPRKs). The mRNA splicing sites of the rice CDPKs, CRKs and PEPRKs (but not OsCCaMK) are highly conserved, suggesting that these kinases are derived from a common ancestor. RNA gel blot analyses revealed that the majority of rice CDPK genes exhibited tissue-specific expression. Expression of OsCPK9 was elevated in seedlings infected by rice blast, indicating that this gene plays an important role in signaling in response to rice blast treatment. Our genomic and bioinformatic analyses will provide an important foundation for further functional dissection of the rice CDPK gene family.

Alternative Splicing↗