QTL mapping of protein content in rice using single chromosome segment substitution lines.

Protein content (PC) is an important component of rice nutritional quality. In order to better understand the genetic basis of this trait and increase related breeding efficiency, 21 single chromosome segment substitution (SCSS) lines grown in four sites over two growing seasons (regarded as eight environments) were used to associate PC with particular chromosome segments. Segments from 15 chromosomes were found to contain quantitative trait loci (QTLs) for PC in at least one environment.

[Analysis of the molecular motif for inducing response to jasmonic acid and ethylene in Pib promoter via rice transformation].

The expression of Pib gene in rice was induced by hormone, such as jasmonic acid and ethylene. In order to determine the necessary regions of sequence or motifs for response to jasmonic acid and ethylene in Pib promoter, the full length promoter of Pib (-3,572 approximately 2 bp) and three different 5' deletion fragments of Pib promoter (-2,692 approximately 2 bp, -1,335 approximately 2 bp, -761 approximately 2 bp) were synthesized by PCR and then were substituted for 35S upstream gus in a binary plasmid to construct re-combined plasmids of Pib promoter-gus fusions. Transgenic rice plants of the four recombined plasmids were produced by Agrobacterium-mediated transformation.

The distribution of japonica rice cultivars in the lower region of the Yangtze River valley is determined by its photoperiod-sensitivity and heading date genotypes.

There are generally four recognized classes of japonica rice cultivars grown in the lower region of the Yangtze River valley. The geographical distribution of the four classes is latitude-dependent. Variation for heading date (HD) among 29 japonica rice cultivars grown in the lower region of the Yangtze River valley and belonging to the four classes was characterized, and their sensitivity to variations in photoperiod and temperature was analyzed.

Identification and characterization of a novel Waxy allele from a Yunnan rice landrace.

Low amylose content (AC) is a desirable trait for rice (Oryza sativa L.) cooking quality and is selected in soft rice breeding. To gain a better understanding of the molecular mechanism controlling AC formation, we screened 83 Yunnan rice landraces in China and identified a rice variety, Haopi, with low AC.

[Current status and strategies for improvement of rice grain chalkiness].

This paper reviews the current status of correlation between rice chalkiness and other rice quality characters, formative mechanism, and classical and molecular genetics for rice chalkiness. The formation of rice chalkiness proves to be a complicated physiological process and tightly relate to "source-sink" of rice, dynamics of grain filing, biosynthesis and accumulation of starch in endosperm. Rice chalkiness is a complicated quantitative trait, which is controlled by maternal effects, endosperm effects, and cytoplasmic effects.

Identification of a new rice blast resistance gene, Pid3, by genomewide comparison of paired nucleotide-binding site--leucine-rich repeat genes and their pseudogene alleles between the two sequenced rice genomes.

Rice blast, caused by Magnaporthe oryzae, is one of the most devastating diseases. The two major subspecies of Asian cultivated rice (Oryza sativa L.), indica and japonica, have shown obvious differences in rice blast resistance, but the genomic basis that underlies the difference is not clear.

The distribution and identification of brown planthopper resistance genes in rice.

A collection of 515 rice landraces originating from Vietnam and China were screened for the reaction to brown planthopper (BPH) infestation. Most of the resistant landraces were indica types from Vietnam and the Guangxi province in China. An F(2) mapping population was created from the cross between a BPH resistant Vietnamese landrace Yagyaw and the susceptible cultivar Cpslo17.

The vacuolar processing enzyme OsVPE1 is required for efficient glutelin processing in rice.

Rice (Oryza sativa L.) accumulates prolamines and glutelins as its major storage proteins. Glutelins are synthesized on rough endoplasmic reticulum as 57-kDa precursors; they are then sorted into protein storage vacuoles where they are processed into acidic and basic subunits.

Fine mapping of the grain chalkiness QTL qPGWC-7 in rice (Oryza sativa L.).

Chalkiness of rice grain is an important quality component of rice, as it has a profound influence on eating and milling qualities. We has determined the inheritance of percentage of grain with chalkiness (PGWC) using a set of chromosome segment substitution lines, made from a cross between cv. PA64s and cv.

Isolation and initial characterization of GW5, a major QTL associated with rice grain width and weight.

Grain weight is a major determinant of crop grain yield and is controlled by naturally occurring quantitative trait loci (QTLs). We earlier identified a major QTL that controls rice grain width and weight, GW5, which was mapped to a recombination hotspot on rice chromosome 5. To gain a better understanding of how GW5 controls rice grain width, we conducted fine mapping of this locus and uncovered a 1 212-bp deletion associated with the increased grain width in the rice cultivar Asominori, in comparison with the slender grain rice IR24.

Relationship between leaf photosynthetic function at grain filling stage and yield in super high-yielding hybrid rice (Oryza sativa. L).

The characteristics of dry matter production before and after heading and the relationships between photosynthesis of flag leaves and dry matter accumulation in panicles were investigated on super high-yielding rice cv. Xieyou 9308 (the yield of up to 12 t/ha) with rice cv. Xieyou 63 as a control.

Effects on genome constitution and novel cell wall formation caused by the addition of 5RS rye chromosome to common wheat.

The cytological instability of common wheat-rye addition lines was investigated in the present study. The chromosome numbers of almost all addition lines were considerably stable, but those of CS + 5R were very variable. The rye chromosome added in this line was found to be much shorter than expected.

Brassinosteroids regulate grain filling in rice.

Genes controlling hormone levels have been used to increase grain yields in wheat (Triticum aestivum) and rice (Oryza sativa). We created transgenic rice plants expressing maize (Zea mays), rice, or Arabidopsis thaliana genes encoding sterol C-22 hydroxylases that control brassinosteroid (BR) hormone levels using a promoter that is active in only the stems, leaves, and roots. The transgenic plants produced more tillers and more seed than wild-type plants.

Quantitative trait loci (QTL) analysis for rice grain width and fine mapping of an identified QTL allele gw-5 in a recombination hotspot region on chromosome 5.

Rice grain width and shape play a crucial role in determining grain quality and yield. The genetic basis of rice grain width was dissected into six additive quantitative trait loci (QTL) and 11 pairs of epistatic QTL using an F(7) recombinant inbred line (RIL) population derived from a single cross between Asominori (japonica) and IR24 (indica). QTL by environment interactions were evaluated in four environments.

[Initial functional analysis of the promoter region and coding region of Pib gene in transgenic rice].

The promoter region and intact coding region of Pib gene (9.9 kb) was inserted into the downstream of CaMV 35S promoter in a binary vector pPZP2Ha3(+), resulting a plasmid pNAR701. And a fragment of Pib gene from 6 986 to 9 392 bp was placed into pPZP2Ha3(-) under the control of CaMV 35S promoter, producing an antisense expression vector pNAR703.

A novel lipoxygenase gene from developing rice seeds confers dual position specificity and responds to wounding and insect attack.

OsLOX1 is a novel full-length cDNA isolated from developing rice seeds. We have examined its biochemical properties and expression patterns. The protein has dual positional specificity, as it releases both C-9 and C-13 oxidized products in a 4:3 ratio.

Quantitative trait loci mapping of resistance to Laodelphax striatellus (Homoptera: Delphacidae) in rice using recombinant inbred lines.

Laodelphax striatellus Fallén (Homoptera: Delphacidae), is a serious pest in rice, Oryza sativa L., production. A mapping population consisting of 81 recombinant inbred lines (RILs), derived from a cross between japonica' Kinmaze' and indica' DV85' rice, was used to detect quantitative trait loci (QTLs) for the resistance to L.

Identification of quantitative trait loci associated with resistance to brown planthopper in the indica rice cultivar Col.5 Thailand.

The brown planthopper (BPH) is one of the most serious insect pests of rice throughout Asia. In this study, we constructed a linkage map to determine the locus for BPH resistance gene, using an F(2) population from a cross between a resistant indica cultivar, 'Col.5 Thailand', and a susceptible cultivar '02428'.

A chlorophyll-deficient rice mutant with impaired chlorophyllide esterification in chlorophyll biosynthesis.

Chlorophyll (Chl) synthase catalyzes esterification of chlorophyllide to complete the last step of Chl biosynthesis. Although the Chl synthases and the corresponding genes from various organisms have been well characterized, Chl synthase mutants have not yet been reported in higher plants. In this study, a rice (Oryza Sativa) Chl-deficient mutant, yellow-green leaf1 (ygl1), was isolated, which showed yellow-green leaves in young plants with decreased Chl synthesis, increased level of tetrapyrrole intermediates, and delayed chloroplast development.

The inheritance of early heading in the rice variety USSR5.

USSR5, a japonica rice variety from the former Soviet Union, is an extremely early maturing rice variety. To elucidate the genetic basis for its early heading, genetic analysis was carried out by crossing it with a set of major gene nearly isogenic lines (NIL) and QTL-isogenic lines. The early heading of USSR5 was attributed to the presence of photoperiod-insensitive alleles at E(1) and Se-1 gene, the photoperiod-sensitive inhibitor gene i-Se-1, and the dominant earliness gene Ef-1.

[Physiological function of the qPGWC-9 related to high percentage of rice grains with Chalkiness].

Percentage of grains with chalkiness (PGWC), one of the important traits assessing rice grain appearance quality, belonged to qualitative trait controlled by many genes. Our previous study identified a novel quantitative trait locus (QTL), namely qPGWC-9, related to high PGWC using chromosomal segment substitution line (CSSL) population. qPGWC-9 was shown to be expressed stably in eight environments.

Two novel loci for pollen sterility in hybrids between the weedy strain Ludao and the Japonica variety Akihikari of rice (Oryza sativa L.).

Partial pollen sterility has been observed in hybrid progeny derived from a japonica cultivar, Akihikari and a weedy strain, Ludao, which naturally grows in Jiangsu province of east China. Cytological and histological analyses revealed that pollen abortion occurred largely at the bicellular pollen stage, primarily due to the gradual disaggregation of generative and vegetative cells. A genome-wide analysis was further carried out in a backcross population of Akihikari //Ludao/Akihikari using a total of 118 simple sequence repeat (SSR) markers and an expressed sequence tag (EST) marker distributed on the entire rice linkage map.

Fine mapping of pss1, a pollen semi-sterile gene in rice (Oryza sativa L.).

During routine seed increase procedures in rice, semi-sterile plants are common; however, such semi-sterility mutants in rice varieties have been only rarely analyzed genetically. W207-2 is a semi-sterile selection from the japonica rice variety Nipponbare. In this report, we found the female gamete of W207-2 was normal, and its semi-sterility was unaffected by growth duration but was conditioned by a recessive nuclear gene whose action leads to pollen semi-sterility and anther indehiscence, and the gene was named as pss1 (pollen semi-sterile).