• The Plant Pathology Journal
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• 제19권6호
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• pp.301-304
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• 2003

Gamma-ray irradiation is known to induce various mutations in plants caused by chromosome alterations. This study investigated disease responses of selected gamma-ray induced rice mutants generated from seven Japonica-type rice cultivars against three plant diseases. Among the tested 22 mutants, three gain-of-function mutants and six loss-of-function mutants against rice blast were obtained, as well as three loss-of-function mutants against bacterial leaf blight (BLB). Two of the loss-of-function mutants were susceptible to both rice blast and BLB. Gain-of-function mutation has not been frequently observed in rice plants, thus, the mutants can be used to identify loci of novel genes for the regulation of disease resistant response.

• Current Research on Agriculture and Life Sciences
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• 제29권
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• pp.1-10
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• 2011

This study was conducted to determine the agronomic characteristics of low amylose lines which were derived from induced mutants by T-DNA insertion. The agronomic and physicochemical properties of the low amylose mutants were analyzed and compared with a donor cultivar 'Dongjin' and a low amylose cultivar 'Baekjinju'. The heading date of the low amylose mutants was similar to the donor cultivar 'Dongjin' and yield index of the mutants was 78~92% compared with 'Dongjin'. The amylose content of four mutants in brown rice was ranged from 16.1 to 16.7%. Among low amylose mutants, 'P50-4-4-5' was lower 3.6%(13.3%) than those of 'Dongjin'(16.9%) in amylose content of milled rice. The grain length of 'P50-4-4-5' was similar to the donor cultivar, however, thousand grain weight(18.9g) was lighter than those of 'Dongjin'. The score of alkali digestion in brown rice of 'P50-4-4-5'(5.5) was lower than that of 'Dongjin'(6.8) and similar to 'Baekjinju'(5.8). The gel consistency of 'P50-4-4-5'(84mm) in milled rice exhibited that was longer than 'Dongjin'(76mm) and 'Baekjinju'(81mm). The result of eating quality showed that 'P50-4-4-5'(78.8) was higher than those of 'Dongjin'(60.3) and 'Baekjinju'(67.2). Thus our data suggest that 'P50-4-4-5' will facilitate the development of a new cultivar with low amylose rice.

• Journal of Plant Biotechnology
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• 제30권3호
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• pp.227-232
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• 2003

Radiation technique has been used to develope mutant rice. Suwon 345 rice seeds were irradiated with 250 Gy gamma ray. Morphological characteristics of the variants in M$_{8}$ generation were observed and random amplified polymorphic DNA(RAPD) analysis was carried out. Plant height, panicle length, 1,000 grain weight and lodging were very different in mutants compared with donor cultivar. RAPD analysis showed that polymorphic bands were presented in several primers of the mutants. In comparison with original variety, variants were classified into four group through UPGMA analysis. A group has mutation trait in panicle length, B group in plant height and C group in 1,000 grain weight. Among mutants, no. 46 and 147 was ranked as salt tolerance and the malonaldehyde content of these mutants was more increased than that of original variety. Valuable mutants obtained will be useful for developing new cultivars and for studing gene function in molecular level.l.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.67.2-68
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• 2003

A rice cultivar, Taebaegbyeo, is highly resistant to rice blast and moderately resistant to bacterial leaf blight (BLB) caused by Magnaporthe grisea and Xanthomonas oryzae pv. oryzae, respectively. To study the rice disease resistance mechanism, we generated rice deletion M3 mutants by gamma-ray irradiation. Blast and BLB responses of 16,000 M3 mutants were screened by inoculating mixtures of 4 races (KJ-201, H-1113a, KI-313, KI-409) of M. grisea and 3 Korean races of X. oryzae pv. oryzae. We selected so far 21 M3 mutants of Taebaegbyeo showing high susceptibility to the diseases. One of the mutants, KCT-6417, was susceptible to KI-1113a race of M. grisea, suggesting the deletion of a race-specific blast resistance gene in the mutant. To isolate rice genes involved in blast resistance and defense response, we take a PCR-based suppression subtractive hybridization approach using cDNAs of blast-inoculated wild type and the KCT-6417 as a tester and a driver, respectively. Genes specifically expressed in the wild type will be presented. The selected genes would give us a clue to understand mechanism for the race specific resistance and defense responses against M. grisea H-1113a in Taebaegbyeo.

• Rapid Communication in Photoscience
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• 제3권3호
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• pp.53-55
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• 2014

The shade avoidance syndrome is a morphological and physiological response when plants are exposed to shade. Recent work in Arabidopsis had begun to define the molecular components of the shade avoidance syndrome in dicotyledonous model plant. However, little is known about the shade avoidance response networks in agriculturally important monocotyledon crops such as rice. Here, we found that the degree of bending at the lamina joint is inversely proportional to the R:FR ratio. To elucidate which phytochrome is involved in this response, we did lamina joint inclination assay with the rice phytochrome-deficient mutants (osphyA, osphyB, and osphyC) and the wild type plants. Whereas the osphyA and osphyC knockout mutants bent at the lamina joint in the far-red rich condition as the wild type plants, the osphyB knockout mutants no longer bent at the lamina joint in the far-red rich condition. These results suggest that PHYB acts as a sole photoreceptor in the lamina joint inclination response in rice.

• 한국작물학회지
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• 제51권4호
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• pp.348-355
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• 2006

Phenotypes of panicle, hull and seed of mutant rice (Oryza sativa L.) were characterized. Panicle mutants were classified in 4 groups with their internode length of main rachis, primary rachis, secondary rachis and pedicel. Hull and seed mutants were grouped into 12 based on their mutant characters in shape, size and color of seeds. These natural and spontaneous mutant collections showed distinct phenotypes to wild type rice. This might be useful for the identification of the functions of genetic factors in the Mendelian inheritance.

• Journal of Plant Biotechnology
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• 제37권2호
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• pp.133-143
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• 2010

Rice (Oryza sativa) is a major cereal crop that has been developed as a monocot model species. In past decades rice researchers have established valuable resources for functional genomics in rice, such as complete genome sequencing, high-density genetic maps, a full length cDNA database, genome-wide transcriptome data, and a large number of mutants. Of these, rice mutant lines are very important to definitively determine functions of genes associated with valuable agronomic traits. In this review we summarize the progress of functional genomics approaches in rice using T-DNA mutants.

• Journal of Plant Biotechnology
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• 제37권4호
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• pp.465-471
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• 2010

We assessed whether the cow1 mutant defects are associated with growth of Tos17 and T-DNA insertional rice in blue light (BL). Growth of oscow1 mutants which encoded a member of the YUCCA protein family was retarded in BL. Root to shoot ratios of the mutants were reduced about 2 times lower in the absence of NAA and about 2.5 times lower in the presence of NAA; the shoot growth was not significantly changed by NAA addition. Photosynthetic activity of the mutants was however inhibited in high light. Pigment analysis showed significant difference between wild-type (Chl a:b = 3.02) and mutants (3.84). Carotenoid contents of the mutants were also decreased considerably, implying the involvement of cow1 in pigment formation. These findings lead us to suggest that the growth retardation of oscow1 mutant plants by BL results from the difference of photosynthetic activity in part.

• 한국육종학회지
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• 제41권2호
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• pp.92-100
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• 2009

To investigate the mutagenecity of sodium azide (SA) and to select mutants having various agronomic characteristics in rice (Oryza sativa L. ssp. japonica), dry seeds of rice variety 'Suweon 472' were treated with 0, 0.5, 1.0, 2.0, and 4.0 mM SA solutions prepared in 0.1 M phosphate buffer (pH 3.0). Germination rate, seedling height and sterility were investigated in $M_1$ generation and chlorophyll mutations were observed in $M_3$ generation. Germination rate and seedling height decreased as the increase of SA concentration in $M_1$ generation, the maximum seed sterility (40.8%) was found at 4.0 mM SA concentration. Chlorophyll mutants were occurred in $M_3$ generation and the frequency calculated on a line basis was 13.5% at the same treatment. Many kinds of mutations for morphological and agronomic characters were observed and mutations with short culm and glabrous leaf were frequently found in $M_3$ generation. Interestingly, five mutant lines resistant to blast or bacterial blight (BB) were selected and evaluated with several isolates in $M_3$ generation although Suweon 472 has been known to be susceptible to blast and BB. These mutants showed all resistance to seven isolates of blast and a total of 76 lines among 2,567 lines evaluated showed resistant to race K1 of bacterial blight. Two mutant lines (440172 and 41272) showed different reaction to BB isolates from the other resistant mutants. A few kinds of endosperm mutants were also identified and most of them were waxy mutants.

• Plant Biotechnology Reports
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• 제3권2호
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• pp.167-174
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• 2009

To identify genes involved in rice Pi5-mediated disease resistance to Magnaporthe oryzae, we compared the proteomes of the RIL260 rice strain carrying the Pi5 resistance gene with its susceptible mutants M5465 and M7023. Proteins were extracted from the leaf tissues of both RIL260 and the mutant lines at 0, 24, and 48 h after M. oryzae inoculation and separated by two-dimensional polyacrylamide gel electrophoresis (2-DE). Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis identified eight proteins that were differently expressed between the resistant and susceptible plants (three down- and five up-regulated proteins in the mutants). The down-regulated proteins included a triosephosphate isomerase (spot no. 2210), a 2,3-bisphosphoglycerate-independent phosphoglycerate mutase (no. 3611), and an unknown protein (no. 4505). In addition, the five up-regulated proteins in the mutants were predicted to be a fructokinase I (no. 313), a glutathione S-transferase (no. 2310), an atpB of chloroplast ATP synthase (no. 3616), an aminopeptidase N (no. 3724), and an unknown protein (no. 308). These results suggest that proteomic analysis of rice susceptible mutants is a useful method for identifying novel proteins involved in resistance to the M. oryzae pathogen.