• 한국육종학회지
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• 제42권1호
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• pp.1-10
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• 2010

Five mutants were investigated at the molecular level to determine the factors responsible for mutated endosperm types. They were classified as high (HA) or low amylose (LA) phenotypes based on the amylose content in endosperm. The five were previously produced from Ilpum and Shindongjin cultivar treated with N-methyl-N-nitrosourea and gamma-ray irradiation, respectively. Analysis of the genomic structure and expression of Granule-bounded Starch Synthase I (GBSSI) genes revealed that mutants generally showed a higher incidence of nucleotide transition than transversion, and the $A:T{\rightarrow}G:C$ transition was particularly prevalent. The rates of nucleotide substitution in HA mutants were generally higher than those in the LA mutants, leading to higher substitutions of amino acid in the HA mutants. Neither nucleotide substitutions interfering with intron splicing or causing early termination of protein translation were found, nor any large-sized deletions or additions were found in all the mutants. In principle, amylose content can be regulated by three factors: internal alterations of GBSSI protein, the strength of gene expression, and other unknown external factors. Our results indicate that the endosperm mutants from Shindongjin arose from internal alterations of GBSSI proteins, which may be the result of amino acid substitutions. On the other hand, the Ilpum mutants might be principally caused by the alteration of gene expression level. Analysis of another three glutinous cultivars revealed that the major factor leading to glutinous phenotypes is the 23-bp duplicative motif (5'-ACGGGTTCCAGGGCCTCAAGCCC-3') commonly found in exon 2, which results in the premature termination of protein translation leading to the production of a non-functional GBSSI enzyme.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2001년도 제31회 학술심포지움 및 춘계학술대회
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• pp.84-84
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• 2001

• Molecules and Cells
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• 제41권7호
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• pp.665-675
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• 2018

Rice is a facultative short-day (SD) plant in which flowering is induced under SD conditions or by other environmental factors and internal genetic programs. Overexpression of Histone Deacetylase 701 (HDT701) accelerates flowering in hybrid rice. In this study, mutants defective in HDT701 flowered late under both SD and long-day conditions. Expression levels of florigens Heading date 3a (Hd3a) and Rice Flowering Locus T1 (RFT1), and their immediate upstream floral activator Early heading date 1 (Ehd1), were significantly decreased in the hdt701 mutants, indicating that HDT701 functions upstream of Ehd1 in controlling flowering time. Transcript levels of OsINDETERMINATE SPIKELET 1 (OsIDS1), an upstream repressor of Ehd1, were significantly increased in the mutants while those of OsGI and Hd1 were reduced. Chromatin-immunoprecipitation assays revealed that HDT701 directly binds to the promoter region of OsIDS1. These results suggest that HDT701 induces flowering by suppressing OsIDS1.

• Molecules and Cells
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• 제40권3호
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• pp.178-185
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• 2017

Nitrogen is one of the most important mineral elements for plant growth. We studied the functional roles of Oryza sativa DNA BINDING WITH ONE FINGER 18 (OsDOF18) in controlling ammonium uptake. The growth of null mutants of OsDOF18 was retarded in a medium containing ammonium as the sole nitrogen source. In contrast, those mutants grew normally in a medium with nitrate as the sole nitrogen source. The gene expression was induced by ammonium but not by nitrate. Uptake of ammonium was lower in osdof18 mutants than in the wild type, while that of nitrate was not affected by the mutation. This indicated that OsDOF18 is involved in regulating ammonium transport. Among the 10 ammonium transporter genes examined here, expression of OsAMT1;1, OsAMT1;3, OsAMT2;1, and OsAMT4;1 was reduced in osdof18 mutants, demonstrating that the ammonium transporter genes function downstream of OsDOF18. Genes for nitrogen assimilation were also affected in the mutants. These results provide evidence that OsDOF18 mediates ammonium transport and nitrogen distribution, which then affects nitrogen use efficiency.

• 한국작물학회지
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• 제36권3호
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• pp.197-203
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• 1991

화청벼와 IR24의 수정란에 N-methyl-N-nitros-ourea(MNU)를 처리하여 여러 종류의 배란 및 배 돌연변이체를 유기하였다. 그 결과는 다음과 같이 요약된다. 1. 변이체들에 대한 외관특성, SEM 검경 특성 및 amylose 함량 분석을 통하여 각각 dull, 찰성, 심백, 분질, sugary, shrunken, 유색종피 변이체들로 명명하였다. 2. 변이체들 중에서는 심백 변이체들의 비율이 74.8%로 가장 높았다. 3. 47320(dull)을 제외한 모든 변이 형질은 단순열성 돌연변이인 것으로 나타났다.

• The Plant Pathology Journal
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• 제26권2호
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• pp.159-169
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• 2010

Lesion mimic mutant (LMM) plants display spontaneous necrotic lesions on their leaves without any pathogenic infection. Specific rice LMMs designated as spotted leaf (spl) including spl1, spl3, spl4, spl5 and spl6 are genetically known as lesion resembling disease (lrd) mutant. The inheritance patterns in the $F_1$ and $F_2$ progenies of these mutants are controlled by recessive genetic factors. Lesion development in the rice LMMs were controlled by both development stages and environmental factors. The rice LMMs exhibited higher numbers of spots under $45^{\circ}C$ temperature than those under $30^{\circ}C$. Contents of chlorophyll were drastically reduced at 60 days old LMM leaves when the spot formation was severe. The levels of endogenous hydrogen peroxide were highest at 45 days old mutants but reduced at 60 days old. Transcription levels of stress related genes including thioredoxin peroxidase and protein disulfide isomerase were reduced in spotted leaves than those of non spotted leaves. It could be suggested that scavenging system against reactive oxygen species induced by either stresses or innate metabolisms may not work properly in the rice LMMs. As these rice LMMs autonomously expressed clear lesions of lrd phenotype without pathogen infection, it could be useful to understand stresses responses in plants.

• Journal of Plant Biology
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• 제22권3호
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• pp.85-91
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• 1979

Tolerance against mercuric chloride in mutants of Pyricularia oryzae Cavara induced by ultraviolet(UV) irradiation has been investigated. The tolerant isolates obtained using ultraviolet(UV) irradiation were maintained a high level of tolerance even after 15 times transfer to the chemical free media. Each isolate of mutants UM-1, UM-2, and UM-3 on the successive monoconidial culture has genetically homogeneous for tolerance. The tolerant isolates sporulated less and showed a higher percentage of germination of conidia on media without the chemical than the parental isolate. The xotins released from the parental and the tolerant isolates have been identified as piricularin and $\alpha$-picolinic acid by paper-chromatography. The tolerant isolates produced more piricularin and its virulence on seedlings of rice varieties were higher than the parental isolates. Both piricularin production and virulance on rice were highest in the UM-2 isolate.

• Journal of Plant Biology
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• 제14권3호
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• pp.29-35
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• 1971

Various types of short culm rice mutants were obtained by means of gamma-ray irradiation. In the present paper morphological observation and analysis of silicate content of the mutants are reported. 1. Short culm type had more useful characters than bushy and dwarf types. 2. In short culm and bushy types the number of nodes both above and under ground was similar to the mother varieties, while in dwarf type it decreased. 3. In short culm types the variation of length of above-ground culm and internodes tended to vary relattive to the mother varieties. 4. Positive correlation was found between culm length and the first and fourth internode length in short culm type. 5. Silicate content increased in short culm type-the increment being variety specific.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2007년도 6th OSONG INTERNATIONAL BIO-SYMPOSIUM
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• pp.224.1-224.1
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• 2007

• 한국식품과학회지
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• 제32권2호
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• pp.258-264
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• 2000

8품종 변이체 쌀로부터 전분을 분리하여 몇몇 이화학적 특성을 비교하였다. 일반품종 및 저아밀로오스 변이체 쌀 전분입자의 형태는 다변형인데 비해서 shr 및 분질미 전분입자의 형태는 구형을 나타내고 있었다. 남풍 CB243의 호화개시온도 및 호화종료온도가 특히 높았으며, 분질미 및 남풍 EM90의 호화엔탈피가 다른 품종들에 비해서 높았다. 15% $H_2SO_4$에 대한 가수분해도는 shr.이 가장 높았으며, 남풍 CB243이 가장 낮았다. X선 회절도는 8품종 모두 전형적인 A형이었다. 저아밀로오스 유전자가 도입된 품종일수록 glucoamylase에 의한 효소 가수분해도는 증가하고 있었다.