scholarly journals Near Immunity to Rice Tungro Spherical Virus Achieved in Rice by a Replicase-Mediated Resistance Strategy

1999 ◽  
Vol 89 (11) ◽  
pp. 1022-1027 ◽  
Author(s):  
H. Huet ◽  
S. Mahendra ◽  
J. Wang ◽  
E. Sivamani ◽  
C. A. Ong ◽  
...  
Keyword(s):  
Antisense Rna ◽  
Rice Tungro Bacilliform Virus ◽  
Japonica Rice ◽  
Rice Tungro Spherical Virus ◽  
Rice Plants ◽  
Antisense Orientation ◽  
Rice Tungro Disease ◽  
Sense Orientation ◽  
Moderate Resistance ◽  
High Level

Rice tungro disease is caused by rice tungro bacilliform virus (RTBV), which is responsible for the symptoms, and rice tungro spherical virus (RTSV), which assists transmission of both viruses by leafhoppers. Transgenic japonica rice plants (Oryza sativa) were produced containing the RTSV replicase (Rep) gene in the sense or antisense orientation. Over 70% of the plants contained one to five copies of the Rep gene, with integration occurring at a single locus in most cases. Plants producing antisense sequences exhibited significant but moderate resistance to RTSV (60%); accumulation of antisense RNA was substantial, indicating that the protection was not of the homology-dependent type. Plants expressing the full-length Rep gene, as well as a truncated Rep gene, in the (+)-sense orientation were 100% resistant to RTSV even when challenged with a high level of inoculum. Accumulation of viral RNA was low, leading us to conclude that RTSV Rep-mediated resistance is not protein-mediated but is of the cosuppression type. Resistance was effective against geographically distinct RTSV isolates. In addition, RTSV-resistant transgenic rice plants were unable to assist transmission of RTBV. Such transgenic plants could be used in an epidemiological approach to combat the spread of the tungro disease.

Transfer of transgenes for resistance to rice tungro disease into high-yielding rice cultivars through gene-based marker-assisted selection

2012 ◽  
Vol 150 (5) ◽  
pp. 610-618 ◽  
Author(s):  
S. ROY ◽  
A. BANERJEE ◽  
J. TARAFDAR ◽  
B. K. SENAPATI ◽  
I. DASGUPTA
Keyword(s):  
Marker Assisted Selection ◽  
Rice Tungro Bacilliform Virus ◽  
35S Promoter ◽  
Rice Cultivars ◽  
Rice Tungro Spherical Virus ◽  
Challenge Inoculation ◽  
Rice Line ◽  
Rice Tungro Disease ◽  
Sense Orientation ◽  
Simultaneous Infection

SUMMARYRice tungro disease (RTD), caused by the simultaneous infection of rice tungro bacilliform virus (RTBV) and rice tungro spherical virus (RTSV), is one of the major threats to sustainable rice production in South and Southeast Asia. Transgenic resistance against RTBV has been reported previously using an RNA interference (RNAi) construct (ORF IV of RTBV, placed both in sense and anti-sense orientation under CaMV 35S promoter), in the scented rice line Pusa Basmati-1 (PB-1). This construct was transferred to two high-yielding tungro-susceptible indica rice cultivars (IET4094 and IET4786) from the transgenic PB-1 rice line using back cross breeding till the BC2F3 stage. On challenge inoculation, the progenies (BC2F1) showed mild symptoms of tungro, in contrast to severe symptoms displayed by the recurrent parents. Segregation of the transgene indicated near homozygosity of the plants at the BC2F3 stage, implying that the lines can be used as a valuable resistance source for further breeding against RTD.

The effect of antisense RNA to fibronectin on the malignancy of hybrids between melanoma cells and normal fibroblasts

1989 ◽  
Vol 93 (3) ◽  
pp. 515-524
Author(s):  
D.M. Steel ◽  
H. Harris
Keyword(s):  
Cell Surface ◽  
Antisense Rna ◽  
Expression Vector ◽  
Melanoma Cells ◽  
Hybrid Cells ◽  
Immunofluorescence Analysis ◽  
Dramatic Decrease ◽  
Coding Sequences ◽  
Antisense Orientation ◽  
Sense Orientation

An expression vector containing a cDNA complementary to 1.3 kb of the 5′ coding sequences of the fibronectin gene in the antisense orientation with respect to its promoter was introduced by electroporation into hybrids between melanoma cells and normal fibroblasts in which malignancy was suppressed. Immunofluorescence analysis of clones transfected with the antisense cDNA showed a dramatic decrease in the amount of fibronectin on the cell surface compared to that seen on the surface of the untransfected hybrid cells or of cells transfected with fibronectin cDNA in the sense orientation or with the expression vector alone. Four out of five clones transfected with the antisense cDNA were highly tumorigenic, whereas transfectants containing either the sense fibronectin construct or the expression vector alone remained non-tumorigenic. These results suggest that antisense RNA to fibronectin may be able to abrogate the suppression of malignancy imposed on the hybrid cells by the fibroblast parent.

scholarly journals Single Nucleotide Polymorphisms in a Gene for Translation Initiation Factor (eIF4G) of Rice (Oryza sativa) Associated with Resistance to Rice tungro spherical virus

2010 ◽  
Vol 23 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Jong-Hee Lee ◽  
Muhammad Muhsin ◽  
Genelou A. Atienza ◽  
Do-Yeon Kwak ◽  
Suk-Man Kim ◽  
...  
Keyword(s):  
Translation Initiation ◽  
Recessive Gene ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Rice Tungro Bacilliform Virus ◽  
Nucleotide Polymorphisms ◽  
Rice Tungro Spherical Virus ◽  
Single Nucleotide ◽  
Rice Tungro Disease ◽  
Backcross Populations

Rice tungro disease (RTD) is a serious constraint to rice production in South and Southeast Asia. RTD is caused by Rice tungro spherical virus (RTSV) and Rice tungro bacilliform virus. Rice cv. Utri Merah is resistant to RTSV. To identify the gene or genes involved in RTSV resistance, the association of genotypic and phenotypic variations for RTSV resistance was examined in backcross populations derived from Utri Merah and rice germplasm with known RTSV resistance. Genetic analysis revealed that resistance to RTSV in Utri Merah was controlled by a single recessive gene (tsv1) mapped within an approximately 200-kb region between 22.05 and 22.25 Mb of chromosome 7. A gene for putative translation initiation factor 4G (eIF4Gtsv1) was found in the tsv1 region. Comparison of eIF4Gtsv1 gene sequences among susceptible and resistant plants suggested the association of RTSV resistance with one of the single nucleotide polymorphism (SNP) sites found in exon 9 of the gene. Examination of the SNP site in the eIF4Gtsv1 gene among various rice plants resistant and susceptible to RTSV corroborated the association of SNP or deletions in codons for Val1060-1061 of the predicted eIF4Gtsv1 with RTSV resistance in rice.

scholarly journals Suppression of Two Tungro Viruses in Rice by Separable Traits Originating from Cultivar Utri Merah

2009 ◽  
Vol 22 (10) ◽  
pp. 1268-1281 ◽  
Author(s):  
Jaymee R. Encabo ◽  
Pepito Q. Cabauatan ◽  
Rogelio C. Cabunagan ◽  
Kouji Satoh ◽  
Jong-Hee Lee ◽  
...  
Keyword(s):  
Serological Test ◽  
Gene Expression Pattern ◽  
Global Gene Expression ◽  
Rice Tungro Bacilliform Virus ◽  
Near Isogenic Lines ◽  
Rice Tungro Spherical Virus ◽  
Chain Reaction ◽  
Rice Tungro Disease ◽  
Polymerase Chain ◽  
The Individual

Rice tungro disease (RTD) is caused by Rice tungro spherical virus (RTSV) and Rice tungro bacilliform virus (RTBV) transmitted by green leafhoppers. Rice cv. Utri Merah is highly resistant to RTD. To define the RTD resistance of Utri Merah, near-isogenic lines (NIL, BC5 or BC6) developed from Utri Merah and susceptible cv. Taichung Native 1 (TN1) were evaluated for reactions to RTSV and RTBV. TW16 is an NIL (BC5) resistant to RTD. RTBV was able to infect both TN1 and TW16 but the levels of RTBV were usually significantly lower in TW16 than in TN1. Infection of RTSV was confirmed in TN1 by a serological test but not in TW16. However, the global gene-expression pattern in an RTSV-resistant NIL (BC6), TW16-69, inoculated with RTSV indicated that RTSV can also infect the resistant NIL. Infection of RTSV in TW16 was later confirmed by reverse-transcription polymerase chain reaction but the level of RTSV was considerably lower in TW16 than in TN1. Examination for virus accumulation in another NIL (BC6), TW16-1029, indicated that all plants of TW16-1029 were resistant to RTSV, whereas the resistance to RTBV and symptom severity were segregating among the individual plants of TW16-1029. Collectively, these results suggest that RTD resistance of Utri Merah involves suppression of interacting RTSV and RTBV but the suppression trait for RTSV and for RTBV is inherited separately.

scholarly journals Characterization of Oryza rufipogon–Derived Resistance to Tungro Disease in Rice

Plant Disease ◽  
2007 ◽  
Vol 91 (11) ◽  
pp. 1386-1391 ◽  
Author(s):  
Yuji Shibata ◽  
Rogelio C. Cabunagan ◽  
Pepito Q. Cabauatan ◽  
Il-Ryong Choi
Keyword(s):  
Interspecific Hybridization ◽  
Resistance Mechanisms ◽  
Oryza Rufipogon ◽  
Rice Tungro Bacilliform Virus ◽  
Rice Cultivars ◽  
Susceptible Parent ◽  
Rice Tungro Spherical Virus ◽  
Rice Tungro Disease ◽  
Apparent Resistance

Rice tungro disease (RTD) is caused by the interaction between Rice tungro spherical virus (RTSV) and Rice tungro bacilliform virus (RTBV), both of which are transmitted by green leafhoppers (GLH). In order to define the resistance against RTD in rice cv. Matatag 9 which was developed by interspecific hybridization between RTD-susceptible cv. IR64 and Oryza rufipogon, the reactions of Matatag 9 to the viruses and GLH were evaluated in comparison with RTD-susceptible and -resistant rice cultivars. The incidences of infection with RTSV and RTBV in Matatag 9 were significantly lower than those in the susceptible parent cv. IR64; however, no substantial differences in virus accumulation were observed between IR64 and Matatag 9 once infected with the viruses. Symptoms in Matatag 9 infected with RTBV and RTSV were milder than those observed in IR64. A higher level of antixenosis to GLH was observed in Matatag 9 compared with IR64. The levels of antibiosis against GLH in Matatag 9 were comparable with those in another GLH-resistant cultivar, and significantly higher than those in RTD-susceptible cultivars. Collectively, these results suggest that tolerance to tungro viruses and resistance to GLH both contribute to the apparent resistance to RTD in Matatag 9, although possible involvement of other resistance mechanisms cannot be excluded.

scholarly journals Infection with an asymptomatic virus in rice results in a delayed drought response

2020 ◽  
Vol 47 (3) ◽  
pp. 239 ◽  
Author(s):  
Jaymee R. Encabo ◽  
Reena Jesusa A. Macalalad-Cabral ◽  
Jerlie Mhay K. Matres ◽  
Sapphire Charlene Thea P. Coronejo ◽  
Gilda B. Jonson ◽  
...  
Keyword(s):  
Drought Stress ◽  
Abiotic Stresses ◽  
Water Status ◽  
Drought Response ◽  
Plant Responses ◽  
Leaf Rolling ◽  
Rice Tungro Spherical Virus ◽  
Biotic And Abiotic Stresses ◽  
Rice Plants ◽  
Increased Susceptibility

Infection of viruses in plants often modifies plant responses to biotic and abiotic stresses. In the present study we examined the effects of Rice tungro spherical virus (RTSV) infection on drought response in rice. RTSV infection delayed the onset of leaf rolling by 1–2 days. During the delay in drought response, plants infected with RTSV showed higher stomatal conductance and less negative leaf water potential under drought than those of uninfected plants, indicating that RTSV-infected leaves were more hydrated. Other growth and physiological traits of plants under drought were not altered by infection with RTSV. An expression analysis of genes for drought response-related transcription factors showed that the expression of OsNAC6 and OsDREB2a was less activated by drought in RTSV-infected plants than in uninfected plants, further suggesting improved water status of the plants due to RTSV infection. RTSV accumulated more in plants under drought than in well-watered plants, indicating the increased susceptibility of rice plants to RTSV infection by drought. Collectively, these results indicated that infection with RTSV can transiently mitigate the influence of drought stress on rice plants by increasing leaf hydration, while drought increased the susceptibility of rice plants to RTSV.

Gene expression responses to Rice tungro spherical virus in susceptible and resistant near-isogenic rice plants

2013 ◽  
Vol 171 (1) ◽  
pp. 111-120 ◽  
Author(s):  
Kouji Satoh ◽  
Hiroaki Kondoh ◽  
Teresa B. De Leon ◽  
Reena Jesusa A. Macalalad ◽  
Rogelio C. Cabunagan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Rice Tungro Spherical Virus ◽  
Rice Plants

scholarly journals Development of Papaya Breeding Lines with Transgenic Resistance to Papaya ringspot virus

Plant Disease ◽  
2004 ◽  
Vol 88 (4) ◽  
pp. 352-358 ◽  
Author(s):  
Michael J. Davis ◽  
Zhentu Ying
Keyword(s):  
Transgenic Line ◽  
Carica Papaya ◽  
Ringspot Virus ◽  
Papaya Ringspot Virus ◽  
Transgenic Resistance ◽  
Breeding Lines ◽  
Antisense Orientation ◽  
Resistant Lines ◽  
Sense Orientation ◽  
Transgenic Lines

Papaya (Carica papaya) was transformed via Agrobacterium-mediated transformation with four constructs containing either the unmodified or modified coat protein (CP) gene of Florida isolate H1K of Papaya ringspot virus (PRSV). The CP genes were in the sense orientation (S-CP), antisense orientation (AS-CP), sense orientation with a frame-shift mutation (FS-CP), or sense orientation mutated with three-in-frame stop codons (SC-CP). In all, 256 putative transgenic lines with the CP constructs were inoculated mechanically with PRSV H1K. None of the lines was immune to PRSV; however, highly resistant lines were found in each CP transgene group. For breeding purposes, 21 PRSV-resistant lines representing the four transgene constructs were selected and crossed with six papaya genotypes. The lines from the FS-CP and SC-CP transgene groups were highly fertile, but those from the S-CP and AS-CP transgene groups were practically infertile. Plants derived from 54 crosses and representing 17 transgenic lines were planted in the field. After 1 year in the field, 293 of the 1,258 the plants (23.3%) became naturally infected with PRSV; whereas, 29 of 30 of the nontransgenic control plants (96.7%) became infected. The incidence of PRSV infection varied in the R1 progeny depending on both the transgenic line and the nontransgenic parent.

Resistance to azoxystrobin and thiophanate-methyl is widespread in Colletotrichum spp. isolates from the Mid-Atlantic Strawberry Fields

Plant Disease ◽  
2020 ◽  
Author(s):  
Qiuchen Luo ◽  
Anita Schoeneberg ◽  
Mengjun Hu
Keyword(s):  
Cyt B ◽  
Thiophanate Methyl ◽  
Colletotrichum Species ◽  
Predominant Species ◽  
Strawberry Anthracnose ◽  
Colletotrichum Spp ◽  
Moderate Resistance ◽  
High Level ◽  
Host Tissues

Multiple Colletotrichum species have been found to be responsible for strawberry anthracnose, and prevalence of each species seems to vary by regions and/or host tissues. In this study, a total of 200 Colletotrichum isolates were obtained from different strawberry cultivars displaying anthracnose symptoms in the Mid-Atlantic fields. Analysis of g3pdh, tub2, and/or ITS sequences revealed four Colletotrichum species, including C. nymphaeae, C. fioriniae, C. siamense, and C. lineola. C. nymphaeae was the predominant species, representing 90% of all isolates collected. This species was found from all strawberry organs/tissues examined, whereas C. siamense and C. fioriniae were limited to the crown and fruit, respectively. Further, all Colletotrichum isolates were screened for resistance to azoxystrobin in vitro, and all C. siamense isolates were additionally screened for resistance to thiophanate-methyl. The overall frequency of resistance to azoxystrobin and thiophanate-methyl was 48.0 % and 67.0 %, respectively. G143A in the cytochrome b gene (cyt b) was found in all C. nymphaeae and C. siamense isolates with high level of resistance, with EC50 > 100 µg/ml, while F129L was found in two of the five C. nymphaeae isolates with moderate resistance, with EC50 values ranging from 2.6 to 7.8 µg/ml. All C. fioriniae isolates tested were found to be less sensitive to azoxystrobin, with EC50 values ranging from 9.7 to 14.4 µg/ml, despite no mutations detected in cyt b. Moreover, E198A in tub2 was linked with C. siamense isolates resistant to thiophanate-methyl (EC50 > 100 µg/ml). These results revealed that resistance in Colletotrichum spp. to primary fungicides was widespread in the Mid-Atlantic strawberry fields.

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