scholarly journals Breeding and Characterization of The World’s First Practical Rice Variety With Resistance to Brown Spot (Bipolaris Oryzae)

2021 ◽  
Author(s):  
Kengo Matsumoto ◽  
Yuya Ota ◽  
Tomohiro Yamakawa ◽  
Teppei Ono ◽  
Satomi Seta ◽  
...  
Keyword(s):  
Agronomic Traits ◽  
Rice Variety ◽  
Recessive Gene ◽  
Brown Spot ◽  
Resistant Variety ◽  
Isogenic Line ◽  
Bipolaris Oryzae ◽  
Trait Locus ◽  
Grain Width ◽  
Serious Disease

Abstract Background: Brown spot (BS) caused by Bipolaris oryzae is a serious disease of rice and decreases grain yield. Breeding for BS resistance is an economical solution but has not hitherto been achieved.Results: To develop a practical BS-resistant variety, we introduced a chromosomal segment including a quantitative trait locus (QTL) for BS resistance, qBSfR11, derived from the BS-resistant local resource ‘Tadukan’, into the genetic background of the high-yielding but susceptible ‘Mienoyume’. Resistance is controlled by a single recessive gene in a 1.3-Mbp region. We named this gene bsr1 (brown spot resistance 1). The near-isogenic line bsr1-NIL had a greater yield with larger grain width than Mienoyume but similar other agronomic traits in fields where BS was mild; it had a significantly lower BS disease score and a 28.8% higher yield in fields where BS was more severe, and it showed resistance to multiple isolates of BS fungus. It showed stable resistance to BS and had excellent agricultural traits in the presence of BS.Conclusions: We developed the bsr1-NIL with resistance to BS and applied it for variety registration to Ministry of Agriculture, Forestry and Fisheries in Japan as ‘Mienoyume BSL’. It is the world’s first practical breeding variety with resistance to BS.

Studies on the behaviour of some fungal diseases of rice in the mangrove swamp ecology at Warri, south eastern Nigeria

2003 ◽  
Vol 51 (4) ◽  
pp. 429-436
Author(s):  
E. A. Maji ◽  
E. D: Imolehin
Keyword(s):  
Disease Incidence ◽  
Block Design ◽  
Rice Variety ◽  
N Fertilization ◽  
Brown Spot ◽  
Bipolaris Oryzae ◽  
Southeastern Nigeria ◽  
Mangrove Swamp ◽  
Main Plot ◽  
Cropping Seasons

Studies on the ecological behaviour of Cochliobolus miyabeanus (Ito et Kurib.) Drechsl. ex Dast., syn. Bipolaris oryzae (Breda de Haan Shoem.), the causal agent of brown spot in rice (Oryza sativa L.), were carried out in the tidal mangrove swamp at Warri Experimental Farm, Southeastern Nigeria. A split randomised complete block design with four replications was used. Monthly transplantings from July to September formed the main plot, which was subdivided into control and N-treated subplots. Disease incidence increased when transplanting was delayed. This was probably due to the fact that flowering coincided with environmental conditions favourable for disease development from November to February. Nitrogen fertilization at 40 kg N/ha significantly (P=0.05) reduced C. miyabeanus incidence in 1997/1998, but not in the 1998/1999 and 1999/2000 cropping seasons at the same site. The grain yields of ROK 5, a medium-duration improved rice variety (approx. 150 days), were significantly (P=0.05) reduced in late-transplanted crops (September to November) in spite of adequate N fertilization. Mangrove mud was not an important source of C. miyabeanus propagules. The incidence of leaf scald caused by Monographella albescens (Thum) Parkinson, Sivanesan and Booth syn. Microdochium oryzae (Hashioka and Yokogi) Samuels and Hallet, and of leaf smut caused by Etyloma oryzae Miyake was generally stimulated by N application.

scholarly journals Diversity and pathogenicity of the rice brown spot pathogen, Bipolaris oryzae (Breda de Haan) Shoem. in Bangladesh assessed by genetic fingerprint analysis

1970 ◽  
Vol 38 (2) ◽  
pp. 119-125 ◽  
Author(s):  
MM Kamal ◽  
MAT Mia
Keyword(s):  
Yield Loss ◽  
Rice Variety ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Brown Spot ◽  
Pathogenicity Test ◽  
Fingerprint Analysis ◽  
Bipolaris Oryzae ◽  
Repeat Analysis ◽  
Genetic Fingerprint

A survey on the occurrence of rice brown spot pathogen, Bipolaris oryzae (Breda de Haan) Shoem. was carried out across Bangladesh. A representative set of 152 isolates were characterized based on DNA fingerprinting, using variable number tandem repeat analysis and assessed their phylogenetic identity, diversity and pathogenicity. The analysis showed considerable diversity among the isolates, being separated into 12 fingerprint types at 75% similarity level. Majority of the samples possessed one fingerprint type. Pathogenicity test with nine fingerprint types on rice variety BR24, showed 20.5-84.5% germination failure, 2.50-12.50, 5.84-11.67 and 7.50-14.17% post-emergence seedling death at 15, 30 and 45 days after transplanting and 18.75-22.50% yield loss. Significant differences in aggressiveness were observed among the isolates of the same fingerprint types.   Key words: Bipolaris oryzae; Rice brown spot; Pathogenicity; Agarose-synergel; Fingerprints DOI: 10.3329/bjb.v38i2.5135 Bangladesh J. Bot. 38(2): 119-125, 2009 (December)

scholarly journals Application of Wood Vinegar for Fungal Disease Controls in Paddy Rice

2016 ◽  
pp. 77-85 ◽  
Author(s):  
Wilawan Chuaboon ◽  
Nattapone Ponghirantanachoke ◽  
Dusit Athinuwat
Keyword(s):  
Disease Incidence ◽  
Rice Variety ◽  
Fungal Diseases ◽  
Brown Spot ◽  
Curvularia Lunata ◽  
Bipolaris Oryzae ◽  
Promising Alternative ◽  
Shoot Height ◽  
Wood Vinegar ◽  
Brown Leaf

A survey of an outbreak of fungal diseases of rice variety Phitsanulok2 (PLS91014-16-1-5-1) was conducted in Thailand during June 2014 to January 2015 using aW-random sampling pat-tern. The study revealed the incidence of several diseases including brown spot (Bipolaris oryzae), narrow brown leaf streak (Cercospora oryzae), and dirty panicle (Alternaria padwickii, C. oryzae, Curvularia lunata, Fusarium semitectum, and B. oryzae). This study evaluated the ef-ficacy of wood vinegar for control of these fungal diseases. A compleel randomized design was used, using the above variety in 3 replications. In the laboratory we found wood vinegar to be effective in inhibiting growth of representative pathogens such as C. lunata,B. oryzae,F. semi-tectum, and A. padwickii, the causal agent of dirty panicle disease. The field results confirmed the efficacy of wood vinegar under greenhouse conditions, with significantly reduced disease incidence of brown spot and dirty panicle, and significantly enhanced germination, seedling vigor,shoot height, root length, and fresh weight, when compared with the untreated control. However, seed treatment and 6 foliar sprays of wood vinegar under field conditions at Ang Thong showed no significant differences from the conventional treatment in suppression of brown spot, narrow brown leaf streak, and dirty panicle. The result demonstrates a promising alternative approach to control of key rice diseases.

scholarly journals Integration of high-density genetic mapping with transcriptome analysis uncovers numerous agronomic QTL and reveals candidate genes for the control of tillering in sorghum

2021 ◽  
Author(s):  
Rajanikanth Govindarajulu ◽  
Ashley N Hostetler ◽  
Yuguo Xiao ◽  
Srinivasa R Chaluvadi ◽  
Margarita Mauro-Herrera ◽  
...  
Keyword(s):  
Agronomic Traits ◽  
Interspecific Cross ◽  
Crop Improvement ◽  
Differentially Expressed ◽  
Plant Domestication ◽  
Sorghum Propinquum ◽  
Ril Population ◽  
Trait Locus ◽  
Genomic Regions ◽  
Low Coverage

Abstract Phenotypes such as branching, photoperiod sensitivity, and height were modified during plant domestication and crop improvement. Here, we perform quantitative trait locus (QTL) mapping of these and other agronomic traits in a recombinant inbred line (RIL) population derived from an interspecific cross between Sorghum propinquum and Sorghum bicolor inbred Tx7000. Using low-coverage Illumina sequencing and a bin-mapping approach, we generated ∼1920 bin markers spanning ∼875 cM. Phenotyping data were collected and analyzed from two field locations and one greenhouse experiment for six agronomic traits, thereby identifying a total of 30 QTL. Many of these QTL were penetrant across environments and co-mapped with major QTL identified in other studies. Other QTL uncovered new genomic regions associated with these traits, and some of these were environment-specific in their action. To further dissect the genetic underpinnings of tillering, we complemented QTL analysis with transcriptomics, identifying 6189 genes that were differentially expressed during tiller bud elongation. We identified genes such as Dormancy Associated Protein 1 (DRM1) in addition to various transcription factors that are differentially expressed in comparisons of dormant to elongating tiller buds and lie within tillering QTL, suggesting that these genes are key regulators of tiller elongation in sorghum. Our study demonstrates the usefulness of this RIL population in detecting domestication and improvement-associated genes in sorghum, thus providing a valuable resource for genetic investigation and improvement to the sorghum community.

scholarly journals Cloning of long sterile lemma (lsl2), a single recessive gene that regulates spike germination in rice (Oryza sativa L.)

2020 ◽  
Author(s):  
dewei yang ◽  
Niqing He ◽  
Xianghua Zheng ◽  
Yanmei Zhen ◽  
Zhenxin Xie ◽  
...  
Keyword(s):  
Seed Germination ◽  
Agronomic Traits ◽  
Oryza Sativa L ◽  
Gene Prediction ◽  
Germination Rate ◽  
Rice Genome ◽  
Recessive Gene ◽  
Floral Organ ◽  
Monocotyledonous Plant ◽  
Sterile Lemma

Abstract Background: Rice is a typical monocotyledonous plant and an important cereal crop. The structural units of rice flowers are spikelets and florets, and floral organ development and spike germination affect rice reproduction and yield.Results: In this study, we identified a novel long sterile lemma (lsl2) mutant from an EMS population. First, we mapped the lsl2 gene between the markers Indel7-22 and Indel7-27, which encompasses a 25-kb region. The rice genome annotation indicated the presence of four candidate genes in this region. Through gene prediction and cDNA sequencing, we confirmed that the target gene in the lsl2 mutant is allelic to LONG STERILE LEMMA1 (G1)/ELONGATED EMPTY GLUME (ELE), hereafter referred to as lsl2. Further analysis of the lsl2 and LSL2 proteins showed a one-amino-acid change, namely, the mutation of serine (Ser) 79 to proline (Pro) in lsl2 compared with LSL2, and this mutation might change the function of the protein. Knockout experiments showed that the lsl2 gene is responsible for the long sterile lemma phenotype. The lsl2 gene might reduce the damage induced by spike germination by decreasing the seed germination rate, but other agronomic traits of rice were not changed in the lsl2 mutant. Taken together, our results demonstrate that the lsl2 gene will have specific application prospects in future rice breeding.Conclusions: The lsl2 gene is responsible for the long sterile lemma phenotype and might reduce the damage induced by spike germination by decreasing the seed germination rate.

scholarly journals Cloning of long sterile lemma (lsl2), a single recessive gene that regulates spike germination in rice (Oryza sativa L.)

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Dewei Yang ◽  
Niqing He ◽  
Xianghua Zheng ◽  
Yanmei Zhen ◽  
Zhenxin Xie ◽  
...  
Keyword(s):  
Seed Germination ◽  
Agronomic Traits ◽  
Oryza Sativa L ◽  
Gene Prediction ◽  
Germination Rate ◽  
Rice Genome ◽  
Recessive Gene ◽  
Floral Organ ◽  
Monocotyledonous Plant ◽  
Sterile Lemma

Abstract Background Rice is a typical monocotyledonous plant and an important cereal crop. The structural units of rice flowers are spikelets and florets, and floral organ development and spike germination affect rice reproduction and yield. Results In this study, we identified a novel long sterile lemma (lsl2) mutant from an EMS population. First, we mapped the lsl2 gene between the markers Indel7–22 and Indel7–27, which encompasses a 25-kb region. The rice genome annotation indicated the presence of four candidate genes in this region. Through gene prediction and cDNA sequencing, we confirmed that the target gene in the lsl2 mutant is allelic to LONG STERILE LEMMA1 (G1)/ELONGATED EMPTY GLUME (ELE), hereafter referred to as lsl2. Further analysis of the lsl2 and LSL2 proteins showed a one-amino-acid change, namely, the mutation of serine (Ser) 79 to proline (Pro) in lsl2 compared with LSL2, and this mutation might change the function of the protein. Knockout experiments showed that the lsl2 gene is responsible for the long sterile lemma phenotype. The lsl2 gene might reduce the damage induced by spike germination by decreasing the seed germination rate, but other agronomic traits of rice were not changed in the lsl2 mutant. Taken together, our results demonstrate that the lsl2 gene will have specific application prospects in future rice breeding. Conclusions The lsl2 gene is responsible for the long sterile lemma phenotype and might reduce the damage induced by spike germination by decreasing the seed germination rate.

Dynamics of the rice blast fungal population in the field after deployment of an improved rice variety containing known resistance genes

Plant Disease ◽  
2020 ◽  
Author(s):  
Wenjuan Wang ◽  
Jing Su ◽  
Kailing Chen ◽  
Jianyuan Yang ◽  
Shen Chen ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Resistance Genes ◽  
Rice Blast ◽  
Rice Variety ◽  
Field Population ◽  
Pcr Analysis ◽  
Resistant Variety ◽  
Pathogenicity Test ◽  
Line Field ◽  
Isogenic Lines

Rice blast, caused by the fungus Magnaporthe oryzae, is one of the most destructive diseases of rice worldwide. Management through the deployment of host resistance genes would be facilitated by understanding the dynamics of the pathogen’s population in the field. Here, to investigate the mechanism underlying the breakdown of disease resistance, we conducted a six-year field experiment to monitor the evolution of M. oryzae populations in Qujiang from Guangdong. The new variety of XYZ carrying R genes Pi50 and Pib was developed using the susceptible elite variety, MBYZ, as the recurrent line. Field trails of disease resistance assessment revealed that the disease indices of XYZ in 2012, 2013, 2016, and 2017 were 0.19, 0.39, 0.70, and 0.90, respectively, indicating that XYZ displayed a very rapid increase of disease severity in the field. To investigate the mechanism underlying the quick erosion of resistance of XYZ, we collected isolates from both XYZ and MBYZ for pathogenicity test against 6 different isogenic lines. The isolates collected from XYZ showed a similar virulence spectrum across 4 different years whereas those from MBYZ showed increasing virulence to the Pi50 and Pib isogenic lines from 2012 to 2017. Molecular analysis of AvrPib in the isolates from MBYZ identified four different AvrPib haplotypes, i.e., AvrPib-AP1-1, AvrPib-AP1-2, avrPib-AP2, and avrPib-AP3, verified by sequencing. AvrPib-AP1-1 and AvrPib-AP1-2 are avirulent to Pib whereas avrPib-AP2 and avrPib-AP3 are virulent. Insertions of a Pot3 and an Mg-SINE were identified in avrPib-AP2 and avrPib-AP3, respectively. Two major lineages based on rep-PCR analysis were further deduced in the field population, implying that the field population is composed of genetically related isolates. Our data suggest that clonal propagation and quick dominancy of virulent isolates against the previously resistant variety could be the major genetic events contributing to the loss of varietal resistance against rice blast in the field.

scholarly journals Sensitivity of Bipolaris oryzae Isolates Pathogenic on Cultivated Wild Rice to the Quinone Outside Inhibitor Azoxystrobin

Plant Disease ◽  
2019 ◽  
Vol 103 (8) ◽  
pp. 1910-1917 ◽  
Author(s):  
Claudia V. Castell-Miller ◽  
Deborah A. Samac
Keyword(s):  
Cytochrome B ◽  
Fungicide Resistance ◽  
Wild Rice ◽  
Brown Spot ◽  
Bipolaris Oryzae ◽  
Qoi Fungicides ◽  
Quinone Outside Inhibitor ◽  
Group I ◽  
Mitochondrial Cytochrome B

The occurrence of fungal brown spot, caused by Bipolaris oryzae, has increased in cultivated wild rice (Zizania palustris) paddies in spite of the use of azoxystrobin-based fungicides. The active ingredient blocks electron transfer at the quinone outside inhibitor (QoI) site in the mitochondrial cytochrome b within the bc1 complex, thus obstructing respiration. The in vitro averaged EC50 of baseline isolates collected in 2007 before widespread fungicide use was estimated to be 0.394 µg/ml with PROBIT and 0.427 µg/ml with linear regression analyses. Isolates collected during 2008, 2015, and 2016 had a range of sensitivity as measured by relative spore germination (RG) at a discriminatory dose of 0.4 µg/ml azoxystrobin. Isolates with a higher (≥80%) and lower RG (≤40%) had the wild type nucleotides at amino acid positions F129, G137, and G143 of cytochrome b, sites known to be associated with QoI fungicide resistance. Two Group I introns were found in the QoI target area. The splicing site for the second intron was found immediately after the codon for G143. A mutation for fungicide resistance at this location would hinder splicing and severely reduce fitness. B. oryzae expresses an alternative oxidase in vitro, which allows the fungus to survive inhibition of respiration by azoxystrobin. This research indicates that B. oryzae has not developed resistance to QoI fungicides, although monitoring for changes in sensitivity should be continued. Judicious use of QoI fungicides within an integrated disease management system will promote an effective and environmentally sound control of the pathogen in wild rice paddies.

Sign in / Sign up

Export Citation Format

Share Document