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Adam H, Gutiérrez A, Couderc M, Sabot F, Ntakirutimana F, Serret J, Orjuela J, Tregear J, Jouannic S, Lorieux M. Genomic introgressions from African rice (Oryza glaberrima) in Asian rice (O. sativa) lead to the identification of key QTLs for panicle architecture. BMC Genomics 2023; 24:587. [PMID: 37794325 PMCID: PMC10548634 DOI: 10.1186/s12864-023-09695-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 09/21/2023] [Indexed: 10/06/2023] Open
Abstract
BACKGROUND Developing high yielding varieties is a major challenge for breeders tackling the challenges of climate change in agriculture. The panicle (inflorescence) architecture of rice is one of the key components of yield potential and displays high inter- and intra-specific variability. The genus Oryza features two different crop species: Asian rice (Oryza sativa L.) and the African rice (O. glaberrima Steud.). One of the main morphological differences between the two independently domesticated species is the structure (or complexity) of the panicle, with O. sativa displaying a highly branched panicle, which in turn produces a larger number of grains than that of O. glaberrima. The gene regulatory network that governs intra- and interspecific panicle diversity is still under-studied. RESULTS To identify genetic factors linked to panicle architecture diversity in the two species, we used a set of 60 Chromosome Segment Substitution Lines (CSSLs) issued from third generation backcross (BC3DH) and carrying genomic segments from O. glaberrima cv. MG12 in the genetic background of O. sativa Tropical Japonica cv. Caiapó. Phenotypic data were collected for rachis and primary branch length, primary, secondary and tertiary branch number and spikelet number. A total of 15 QTLs were localized on chromosomes 1, 2, 3, 7, 11 and 12, QTLs associated with enhanced secondary and tertiary branch numbers were detected in two CSSLs. Furthermore, BC4F3:5 lines carrying different combinations of substituted segments were produced to decipher the effects of the identified QTL regions on variations in panicle architecture. A detailed analysis of phenotypes versus genotypes was carried out between the two parental genomes within these regions in order to understand how O. glaberrima introgression events may lead to alterations in panicle traits. CONCLUSION Our analysis led to the detection of genomic variations between O. sativa cv. Caiapó and O. glaberrima cv. MG12 in regions associated with enhanced panicle traits in specific CSSLs. These regions contain a number of key genes that regulate panicle development in O. sativa and their interspecific genomic variations may explain the phenotypic effects observed.
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Affiliation(s)
- Hélène Adam
- UMR DIADE, University of Montpellier, IRD, Cirad, Montpellier, France.
| | | | - Marie Couderc
- UMR DIADE, University of Montpellier, IRD, Cirad, Montpellier, France
| | - François Sabot
- UMR DIADE, University of Montpellier, IRD, Cirad, Montpellier, France
| | | | - Julien Serret
- UMR DIADE, University of Montpellier, IRD, Cirad, Montpellier, France
| | - Julie Orjuela
- UMR DIADE, University of Montpellier, IRD, Cirad, Montpellier, France
| | - James Tregear
- UMR DIADE, University of Montpellier, IRD, Cirad, Montpellier, France
| | - Stefan Jouannic
- UMR DIADE, University of Montpellier, IRD, Cirad, Montpellier, France.
| | - Mathias Lorieux
- UMR DIADE, University of Montpellier, IRD, Cirad, Montpellier, France.
- Agrobiodiversity Unit, Alliance Bioversity-CIAT, Cali, Colombia.
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Anato VKS, Agnoun Y, Houndjo J, Oludare A, Agbangla C, Akoroda M, Adetimirin VO. Resistance of Oryza sativa and Oryza glaberrima Genotypes to RBe24 Isolate of Rice Yellow Mottle Virus in Benin and Effects of Silicon on Host Response. Plant Pathol J 2021; 37:375-388. [PMID: 34365749 PMCID: PMC8357567 DOI: 10.5423/ppj.oa.09.2020.0180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 07/15/2021] [Accepted: 07/15/2021] [Indexed: 06/13/2023]
Abstract
Rice yellow mottle virus (RYMV) is the most harmful virus that affects irrigated and lowland rice in Africa. The RBe24 isolate of the virus is the most pathogenic strain in Benin. A total of 79 genotypes including susceptible IR64 (Oryza sativa) and the resistant TOG5681 (O. glaberrima) as checks were screened for their reactions to RBe24 isolate of RYMV and the effects of silicon on the response of host plants to the virus investigated. The experiment was a three-factor factorial consisting of genotypes, inoculation level (inoculated vs. non-inoculated), and silicon dose (0, 5, and 10 g/plant) applied as CaSiO3 with two replications and carried out twice in the screen house. Significant differences were observed among the rice genotypes. Fifteen highly resistant and eight resistant genotypes were identified, and these were mainly O. glaberrima. Silicon application did not affect disease incidence and severity at 21 and 42 days after inoculation (DAI); it, however, significantly increased plant height of inoculated (3.6% for 5 g CaSiO3/plant and 6.3% for 10 g CaSiO3/plant) and non-inoculated (1.9% for 5 g CaSiO3/plant and 4.9% for 10 g CaSiO3/plant) plants at 42 DAI, with a reduction in the number of tillers (12.3% for both 5 and 10 g CaSiO3/plant) and leaves (26.8% for 5 g CaSiO3/plant and 28% for 10 g CaSiO3/plant) under both inoculation treatments. Our results confirm O. glaberrima germplasm as an important source of resistance to RYMV, and critical in developing a comprehensive strategy for the control of RYMV in West Africa.
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Affiliation(s)
- Vital Kouessi Sixte Anato
- Pan African University Institute of Life and Earth Sciences (PAULESI), University of Ibadan, Ibadan 200284, Nigeria
| | - Yves Agnoun
- Université Nationale d’Agriculture (UNA), 01 B.P. 55, Porto-Novo, Benin
| | - Joèl Houndjo
- Pan African University Institute of Life and Earth Sciences (PAULESI), University of Ibadan, Ibadan 200284, Nigeria
| | | | | | - Malachy Akoroda
- Pan African University Institute of Life and Earth Sciences (PAULESI), University of Ibadan, Ibadan 200284, Nigeria
- Department of Crop and Horticultural Sciences, University of Ibadan, Ibadan 200284, Nigeria
| | - Victor O. Adetimirin
- Pan African University Institute of Life and Earth Sciences (PAULESI), University of Ibadan, Ibadan 200284, Nigeria
- Department of Crop and Horticultural Sciences, University of Ibadan, Ibadan 200284, Nigeria
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Wambugu PW, Ndjiondjop MN, Henry R. Genetics and Genomics of African Rice ( Oryza glaberrima Steud) Domestication. Rice (N Y) 2021; 14:6. [PMID: 33415579 PMCID: PMC7790969 DOI: 10.1186/s12284-020-00449-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 12/17/2020] [Indexed: 06/12/2023]
Abstract
African rice (Oryza glaberrima Steud) is one of the two independently domesticated rice species, the other one being Asian rice (Oryza sativa L.). Despite major progress being made in understanding the evolutionary and domestication history of African rice, key outstanding issues remain controversial. There appears to be an underlying difficulty in identifying the domestication centre and number of times the crop has been domesticated. Advances in genomics have provided unprecedented opportunities for understanding the genetic architecture of domestication related traits. For most of the domestication traits, the underlying genes and mutations have been identified. Comparative analysis of domestication genes between Asian and African rice has revealed that the two species went through an independent but convergent evolution process. The genetic and developmental basis of some of the domestic traits are conserved not only between Asian and African rice but also with other domesticated crop species. Analysis of genome data and its interpretation is emerging as a major challenge facing studies of domestication in African rice as key studies continue giving contradictory findings and conclusions. Insights obtained on the domestication of this species are vital for guiding crop improvement efforts.
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Affiliation(s)
- Peterson W. Wambugu
- Kenya Agricultural and Livestock Research Organization, Genetic Resources Research Institute, P.O. Box 30148, Nairobi, 00100 Kenya
| | - Marie-Noelle Ndjiondjop
- M’bé Research Station, Africa Rice Center (AfricaRice), 01 B.P. 2551 Bouaké 01, Côte d’Ivoire
| | - Robert Henry
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, QLD 4072 Australia
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Badro H, Ndjiondjop MN, Furtado A, Henry R. Sequence Variants Linked to Key Traits in Interspecific Crosses between African and Asian Rice. Plants (Basel) 2020; 9:E1653. [PMID: 33256095 DOI: 10.3390/plants9121653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/20/2020] [Accepted: 11/24/2020] [Indexed: 11/16/2022]
Abstract
Asian and African rice gene pools vary in many traits that are important in rice breeding. The genetic basis of these differences was evaluated by analysis of important agronomic traits in crosses between African and Asian rice. Trait-associated variants (TAVs) influencing three quantitative agronomic traits, heading date (Hd), tiller number at maturity (T), and 1000 grain weight (TGW), were identified by association analysis of crosses between Asian and African rice. Populations were developed by crossing WAB56-104 (Oryza sativa) and CG14 (Oryza glaberrima). DNA from plants with extremely high or low values for these phenotypes was bulked and sequenced. The reference genome of O. sativa cv Nipponbare was used in general association analysis and candidate gene analysis. A total of 5152 non-synonymous single nucleotide polymorphisms (SNPs) across 3564 genes distinguished the low and the high bulks for Hd, T, and TGW traits; 611 non-synonymous SNPs across 447 genes were found in KEGG pathways. Six non-synonymous SNPs were found in the sequences of LOC107275952, LOC4334529, LOC4326177, LOC107275432, LOC4335790, and LOC107275425 genes associated with Hd, T, and TGW traits. These genes were involved in: abscisic-acid biosynthesis, carotenoid biosynthesis, starch and sucrose metabolism, and cytokinin biosynthesis. Analysis of 24 candidate genes associated with Hd, T, and TGW traits showed seven non-synonymous variations in the sequence of Hd3a and Ehd2 from the Hd genes (not in a KEGG pathway), D10 and D53 from the T genes (strigolactones biosynthetic pathway), and Gn1a and GIF1 from the TGW genes (cytokinin biosynthetic and starch and sucrose metabolism pathways). This study identified significant differences in allele frequencies supported by high sequence depth in analysis of bulks displaying high and low values for these key traits. These trait-associated variants are likely to be useful in rice improvement.
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Hamzelou S, Kamath KS, Masoomi-Aladizgeh F, Johnsen MM, Atwell BJ, Haynes PA. Wild and Cultivated Species of Rice Have Distinctive Proteomic Responses to Drought. Int J Mol Sci 2020; 21:ijms21175980. [PMID: 32825202 PMCID: PMC7504292 DOI: 10.3390/ijms21175980] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/13/2020] [Accepted: 08/13/2020] [Indexed: 12/25/2022] Open
Abstract
Drought often compromises yield in non-irrigated crops such as rainfed rice, imperiling the communities that depend upon it as a primary food source. In this study, two cultivated species (Oryza sativa cv. Nipponbare and Oryza glaberrima cv. CG14) and an endemic, perennial Australian wild species (Oryza australiensis) were grown in soil at 40% field capacity for 7 d (drought). The hypothesis was that the natural tolerance of O. australiensis to erratic water supply would be reflected in a unique proteomic profile. Leaves from droughted plants and well-watered controls were harvested for label-free quantitative shotgun proteomics. Physiological and gene ontology analysis confirmed that O. australiensis responded uniquely to drought, with superior leaf water status and enhanced levels of photosynthetic proteins. Distinctive patterns of protein accumulation in drought were observed across the O. australiensis proteome. Photosynthetic and stress-response proteins were more abundant in drought-affected O. glaberrima than O. sativa, and were further enriched in O. australiensis. In contrast, the level of accumulation of photosynthetic proteins decreased when O. sativa underwent drought, while a narrower range of stress-responsive proteins showed increased levels of accumulation. Distinctive proteomic profiles and the accumulated levels of individual proteins with specific functions in response to drought in O. australiensis indicate the importance of this species as a source of stress tolerance genes.
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Affiliation(s)
- Sara Hamzelou
- Department of Molecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia; (S.H.); (K.S.K.); (M.M.J.)
| | - Karthik Shantharam Kamath
- Department of Molecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia; (S.H.); (K.S.K.); (M.M.J.)
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, NSW 2109, Australia
| | - Farhad Masoomi-Aladizgeh
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia; (F.M.-A.); (B.J.A.)
| | - Matthew M. Johnsen
- Department of Molecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia; (S.H.); (K.S.K.); (M.M.J.)
| | - Brian J. Atwell
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia; (F.M.-A.); (B.J.A.)
| | - Paul A. Haynes
- Department of Molecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia; (S.H.); (K.S.K.); (M.M.J.)
- Correspondence:
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John EN, Jones KR. Evaluation of Unconventional Supplements to the Diet of Intensively Reared Agouti ( Dasyprocta leporina) in Trinidad, West Indies. Vet Sci 2020; 7:E108. [PMID: 32784963 DOI: 10.3390/vetsci7030108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 07/28/2020] [Accepted: 08/06/2020] [Indexed: 11/24/2022] Open
Abstract
A feed trial was carried out to evaluate potential unconventional feed resources such as Trichanthera gigantica and moruga hill rice (Oryza glaberrima) as a partial supplementation to the diet of adult male agoutis (Dasyprocta leporina). Supplemental feeding of the agouti will decrease feeding cost to produce this animal and aid in sustainable agricultural practices. Male agoutis were used as this physiological state was the easiest to attain as well as male animals are generally used for meat production. The trial consisted of 16 male agoutis that were allocated into four dietary treatments using a completely randomized experimental design. Four diet treatments were used in the experiment; treatment 1 (T1) was the positive control which consisted of rabbit ration whilst treatment 2 (T2) to 4 (T4) had different ratios of O. glaberrima, Trichanthera gigantica and Rabbit Ration. The feeding trial had 8-week duration. T2 consisted of 5% T. gigantica, 35% O. glaberrima supplemented for rabbit ration. T3 had 10% T. gigantica and 40% O. glaberrima supplemented for rabbit ration. T4 consisted of 15% Trichanthera and 45% O. glaberrima supplemented for rabbit ration in the diet. Proximate analysis showed that Dry Matter (DM) and Ash was highest in T4 and lowest in T2. Whilst ether extract (EE) and crude protein (CP) were highest in T2 and lowest in T4. Crude fiber (CF) was highest in T3 and lowest in T2. The weights of the agoutis at the start of the experiment (2595 g–2971 g) were not significantly different to their final weight (2469–2762 g) (p > 0.05). There was a significant difference seen between treatments groups and weeks of the experiment (p < 0.05). There was no significant difference in the interactions between treatment and weeks (p > 0.05). T1 and T2 were not significantly different (p > 0.05) with respect to average daily gain (−0.98 g/d, −1.61 g/d) and weight loss (55 g, 90 g). T2 can be used as an alternative feed source than rabbit ration (control diet) for adult male agoutis. As the final body mass of the male agoutis did not change with the inclusion of 40% Trichanthera and Moruga hill rice, this substitution can be used to maintain male agoutis before slaughter. However, higher amounts of supplements may be detrimental to this animal.
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Dong L, Liu S, Kyaing MS, Xu P, Tharreau D, Deng W, Li X, Bi Y, Zeng L, Li J, Zhou J, Tao D, Yang Q. Identification and Fine Mapping of Pi69(t), a New Gene Conferring Broad-Spectrum Resistance Against Magnaporthe oryzae From Oryza glaberrima Steud. Front Plant Sci 2020; 11:1190. [PMID: 32849738 PMCID: PMC7426465 DOI: 10.3389/fpls.2020.01190] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 07/22/2020] [Indexed: 05/28/2023]
Abstract
The discovery and deployment of new broad-spectrum resistance (R) genes from cultivated rice and its wild relatives is a strategy to broaden the genetic basis of modern rice cultivars to combat rice blast disease. Oryza glaberrima possessing many valuable traits for tolerance to biotic and abiotic stresses, is an elite gene pool for improvement of Asian cultivated rice. An introgression line IL106 derived from O. glaberrima (Acc. IRGC100137) confers complete resistance to Magnaporthe oryzae in blast nursery. Genetic analysis using 2185 BC6F2 progenies derived from a cross between IL106 and the recurrent parent Dianjingyou 1 showed that IL106 harbors a single dominant resistance gene against M. oryzae strain 09BSH-10-5A. This gene was preliminarily mapped on the long arm of chromosome 6 of rice in a region of ca. 0.9 cM delimited by two SSR markers (RM20650 and RM20701). In order to finely map this gene, 17,100 additional progenies were further analyzed. As a result, this gene was further narrowed down to a region flanked by two molecular markers STS69-15 and STS69-7, and co-segregated with 3 molecular markers, RM20676, STS69-21 and STS69-22 on the long arm of chromosome 6. Based on reference genome sequences, this R gene was mapped in silico in 76.1-Kb and 67.7-Kb physical intervals, and containing 4 and 3 NBS-LRR candidate genes in O. sativa cultivar Nipponbare and O. glaberrima cultivar CG14, respectively. Because no blast resistance gene was finely mapped in this physical interval before, this R gene was considered as not described yet and designated as Pi69(t), which is the first identified and finely mapped blast R gene from O. glaberrima, as far as we know. Evaluation of IL106 with 151 blast strains collected from 6 countries in Asia showed that 148 strains are avirulent on IL106, suggesting that Pi69(t) is a broad-spectrum blast R gene, and a promising resistant resource for improvement of Asian cultivated rice.
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Affiliation(s)
- Liying Dong
- Agricultural Environment and Resources Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, China
| | - Shufang Liu
- Agricultural Environment and Resources Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, China
| | - May Sandar Kyaing
- Agricultural Environment and Resources Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, China
- Biotechnology Research Department, Ministry of Education, Mandalay, Myanmar
| | - Peng Xu
- Food Crops Research Institute/Yunnan Key Laboratory for Rice Genetic Improvement, Yunnan Academy of Agricultural Sciences, Kunming, China
- Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Kunming, China
| | - Didier Tharreau
- Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), UMR BGPI, TA A 54 K, Montpellier, France
- BGPI, Univ Montpellier, CIRAD, INRA, Montpellier, SupAgro, Montpellier, France
| | - Wei Deng
- Food Crops Research Institute/Yunnan Key Laboratory for Rice Genetic Improvement, Yunnan Academy of Agricultural Sciences, Kunming, China
| | - Xundong Li
- Agricultural Environment and Resources Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, China
| | - Yunqing Bi
- Agricultural Environment and Resources Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, China
| | - Li Zeng
- Agricultural Environment and Resources Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, China
| | - Jing Li
- Food Crops Research Institute/Yunnan Key Laboratory for Rice Genetic Improvement, Yunnan Academy of Agricultural Sciences, Kunming, China
| | - Jiawu Zhou
- Food Crops Research Institute/Yunnan Key Laboratory for Rice Genetic Improvement, Yunnan Academy of Agricultural Sciences, Kunming, China
| | - Dayun Tao
- Food Crops Research Institute/Yunnan Key Laboratory for Rice Genetic Improvement, Yunnan Academy of Agricultural Sciences, Kunming, China
| | - Qinzhong Yang
- Agricultural Environment and Resources Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, China
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Pidon H, Chéron S, Ghesquière A, Albar L. Allele mining unlocks the identification of RYMV resistance genes and alleles in African cultivated rice. BMC Plant Biol 2020; 20:222. [PMID: 32429875 PMCID: PMC7236528 DOI: 10.1186/s12870-020-02433-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/07/2020] [Indexed: 05/24/2023]
Abstract
BACKGROUND Rice yellow mottle virus (RYMV) is a major rice pathogen in Africa. Three resistance genes, i.e. RYMV1, RYMV2 and RYMV3, have been previously described. RYMV1 encodes the translation initiation factor eIF(iso)4G1 and the best candidate genes for RYMV2 and RYMV3 encode a homolog of an Arabidopsis nucleoporin (CPR5) and a nucleotide-binding domain and leucine-rich repeat containing domain (NLR) protein, respectively. High resistance is very uncommon in Asian cultivated rice (Oryza sativa), with only two highly resistant accessions identified so far, but it is more frequent in African cultivated rice (Oryza glaberrima). RESULTS Here we report the findings of a resistance survey in a reference collection of 268 O. glaberrima accessions. A total of 40 resistant accessions were found, thus confirming the high frequency of resistance to RYMV in this species. We analysed the variability of resistance genes or candidate genes in this collection based on high-depth Illumina data or Sanger sequencing. Alleles previously shown to be associated with resistance were observed in 31 resistant accessions but not in any susceptible ones. Five original alleles with a frameshift or untimely stop codon in the candidate gene for RYMV2 were also identified in resistant accessions. A genetic analysis revealed that these alleles, as well as T-DNA insertions in the candidate gene, were responsible of RYMV resistance. All 40 resistant accessions were ultimately linked to a validated or candidate resistance allele at one of the three resistance genes to RYMV. CONCLUSION This study demonstrated that the RYMV2 resistance gene is homologous to the Arabidopsis CPR5 gene and revealed five new resistance alleles at this locus. It also confirmed the close association between resistance and an amino-acid substitution in the leucine-rich repeat of the NLR candidate for RYMV3. We also provide an extensive overview of the genetic diversity of resistance to RYMV in the O. glaberrima species, while underlining the contrasted pattern of diversity between O. glaberrima and O. sativa for this trait. The different resistance genes and alleles will be instrumental in breeding varieties with sustainable field resistance to RYMV.
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Affiliation(s)
- Hélène Pidon
- DIADE, Univ. Montpellier, IRD, Montpellier, France
- Present Address: Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Seeland, Germany
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Cubry P, Tranchant-Dubreuil C, Thuillet AC, Monat C, Ndjiondjop MN, Labadie K, Cruaud C, Engelen S, Scarcelli N, Rhoné B, Burgarella C, Dupuy C, Larmande P, Wincker P, François O, Sabot F, Vigouroux Y. The Rise and Fall of African Rice Cultivation Revealed by Analysis of 246 New Genomes. Curr Biol 2018; 28:2274-2282.e6. [PMID: 29983312 DOI: 10.1016/j.cub.2018.05.066] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 04/10/2018] [Accepted: 05/24/2018] [Indexed: 12/23/2022]
Abstract
African rice (Oryza glaberrima) was domesticated independently from Asian rice. The geographical origin of its domestication remains elusive. Using 246 new whole-genome sequences, we inferred the cradle of its domestication to be in the Inner Niger Delta. Domestication was preceded by a sharp decline of most wild populations that started more than 10,000 years ago. The wild population collapse occurred during the drying of the Sahara. This finding supports the hypothesis that depletion of wild resources in the Sahara triggered African rice domestication. African rice cultivation strongly expanded 2,000 years ago. During the last 5 centuries, a sharp decline of its cultivation coincided with the introduction of Asian rice in Africa. A gene, PROG1, associated with an erect plant architecture phenotype, showed convergent selection in two rice cultivated species, Oryza glaberrima from Africa and Oryza sativa from Asia. In contrast, a shattering gene, SH5, showed selection signature during African rice domestication, but not during Asian rice domestication. Overall, our genomic data revealed a complex history of African rice domestication influenced by important climatic changes in the Saharan area, by the expansion of African agricultural society, and by recent replacement by another domesticated species.
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Affiliation(s)
- Philippe Cubry
- Institut de Recherche pour le Développement, UMR DIADE, 911 Avenue Agropolis, 34394 Montpellier, France
| | - Christine Tranchant-Dubreuil
- Institut de Recherche pour le Développement, UMR DIADE, 911 Avenue Agropolis, 34394 Montpellier, France; SouthGreen Development Platform, Agropolis Campus, Montpellier, France
| | - Anne-Céline Thuillet
- Institut de Recherche pour le Développement, UMR DIADE, 911 Avenue Agropolis, 34394 Montpellier, France
| | - Cécile Monat
- Institut de Recherche pour le Développement, UMR DIADE, 911 Avenue Agropolis, 34394 Montpellier, France; SouthGreen Development Platform, Agropolis Campus, Montpellier, France
| | | | - Karine Labadie
- CEA, Institut de Biologie François Jacob, Genoscope, 2 Rue Gaston Crémieux, 91057 Evry, France; CNRS, UMR 8030, CP5706, Evry, France; Université d'Evry, UMR 8030, CP5706, Evry, France
| | - Corinne Cruaud
- CEA, Institut de Biologie François Jacob, Genoscope, 2 Rue Gaston Crémieux, 91057 Evry, France; CNRS, UMR 8030, CP5706, Evry, France; Université d'Evry, UMR 8030, CP5706, Evry, France
| | - Stefan Engelen
- CEA, Institut de Biologie François Jacob, Genoscope, 2 Rue Gaston Crémieux, 91057 Evry, France; CNRS, UMR 8030, CP5706, Evry, France; Université d'Evry, UMR 8030, CP5706, Evry, France
| | - Nora Scarcelli
- Institut de Recherche pour le Développement, UMR DIADE, 911 Avenue Agropolis, 34394 Montpellier, France
| | - Bénédicte Rhoné
- Institut de Recherche pour le Développement, UMR DIADE, 911 Avenue Agropolis, 34394 Montpellier, France; Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Lyon, France
| | - Concetta Burgarella
- Institut de Recherche pour le Développement, UMR DIADE, 911 Avenue Agropolis, 34394 Montpellier, France
| | | | - Pierre Larmande
- Institut de Recherche pour le Développement, UMR DIADE, 911 Avenue Agropolis, 34394 Montpellier, France; SouthGreen Development Platform, Agropolis Campus, Montpellier, France; Institut de Biologie Computationnelle (IBC), Université Montpellier 2, 860 Rue St Priest, 34095 Montpellier Cedex 5, France
| | - Patrick Wincker
- CEA, Institut de Biologie François Jacob, Genoscope, 2 Rue Gaston Crémieux, 91057 Evry, France; CNRS, UMR 8030, CP5706, Evry, France; Université d'Evry, UMR 8030, CP5706, Evry, France
| | - Olivier François
- Université Grenoble-Alpes, CNRS, UMR 5525 TIMC-IMAG, 38042 Grenoble, France
| | - François Sabot
- Institut de Recherche pour le Développement, UMR DIADE, 911 Avenue Agropolis, 34394 Montpellier, France; SouthGreen Development Platform, Agropolis Campus, Montpellier, France; Université de Montpellier, Place Eugène Bataillon, 34000 Montpellier, France.
| | - Yves Vigouroux
- Institut de Recherche pour le Développement, UMR DIADE, 911 Avenue Agropolis, 34394 Montpellier, France; Université de Montpellier, Place Eugène Bataillon, 34000 Montpellier, France.
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10
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Li J, Zhou J, Xu P, Deng X, Deng W, He M, Yang Y, Zhang Y, Tao D. Neutral alleles at hybrid sterility loci of Oryza glaberrima from AA genome relatives in Genus Oryza. Breed Sci 2018; 68:343-351. [PMID: 30100801 PMCID: PMC6081293 DOI: 10.1270/jsbbs.18006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 03/11/2018] [Indexed: 05/10/2023]
Abstract
Hybrid sterility between Oryza sativa and O. glaberrima is a main reproduction barrier when transferring the favorable alleles from O. glaberrima to O. sativa and it happens due to allelic interaction at sterility loci. Neutral alleles at each locus have the potential to overcome the sterility between the two cultivated rice species. In this study, an O. sativa cultivar Dianjingyou 1 (DJY1) and its near-isogenic lines (NILs) harboring the single sterility allele S1-glab, S19-glab, S20-glab, S37-glab, S38-glab and S39-glab as the tested lines were crossed with O. glaberrima, O. rufipogon, O. nivara, O. glumaepatula, O. barthii, O. meridionalis and O. sativa so as to detect the neutral alleles of these loci. Pollen fertility was investigated in the paired F1s based on two seasons' result and genotypic segregation was also analyzed in some F2 populations to confirm the results of pollen fertility investigation. The neutral alleles of S38-n and S39-n were identified based upon the pollen fertility and genotypic segregation analysis for the first time. The neutral alleles of sterility loci detected from present report have the potential to know of the nature of interspecific hybrid sterility, and to overcome the interspecific hybrid sterility between O. sativa and O. glaberrima.
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Affiliation(s)
- Jing Li
- Food Crops Research Institute, Yunnan Academy of Agricultural Sciences (YAAS),
Kunming 650200,
P. R. China
| | - Jiawu Zhou
- Food Crops Research Institute, Yunnan Academy of Agricultural Sciences (YAAS),
Kunming 650200,
P. R. China
| | - Peng Xu
- Food Crops Research Institute, Yunnan Academy of Agricultural Sciences (YAAS),
Kunming 650200,
P. R. China
| | - Xianneng Deng
- Food Crops Research Institute, Yunnan Academy of Agricultural Sciences (YAAS),
Kunming 650200,
P. R. China
| | - Wei Deng
- Food Crops Research Institute, Yunnan Academy of Agricultural Sciences (YAAS),
Kunming 650200,
P. R. China
| | - Mingzhu He
- East China Normal University,
Shanghai 200241,
P. R. China
| | - Ying Yang
- Food Crops Research Institute, Yunnan Academy of Agricultural Sciences (YAAS),
Kunming 650200,
P. R. China
| | - Yu Zhang
- Food Crops Research Institute, Yunnan Academy of Agricultural Sciences (YAAS),
Kunming 650200,
P. R. China
| | - Dayun Tao
- Food Crops Research Institute, Yunnan Academy of Agricultural Sciences (YAAS),
Kunming 650200,
P. R. China
- Corresponding author (e-mail: )
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11
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Yamamoto N, Garcia R, Suzuki T, Solis CA, Tada Y, Venuprasad R, Kohli A. Comparative whole genome re-sequencing analysis in upland New Rice for Africa: insights into the breeding history and respective genome compositions. Rice (N Y) 2018; 11:33. [PMID: 29766351 PMCID: PMC5953909 DOI: 10.1186/s12284-018-0224-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Accepted: 04/30/2018] [Indexed: 05/20/2023]
Abstract
BACKGROUND Increasing rice demand is one of the consequences of the steadily improving socio-economic status of the African countries. New Rice for Africa (NERICA), which are interspecific hybrids between Asian and African rice varieties, are one of successful breeding products utilizing biodiversity across the two different rice crop species. Upland NERICA varieties (NU) exhibit agronomic traits of value for the harsh eco-geography, including shorter duration, higher yield and stress tolerance, compared to local African varieties. However, the molecular basis of the traits in NU varieties is largely unknown. RESULTS Whole genome re-sequencing was performed of four NU lines (3, 4, 5, and 7) and for the parental Oryza sativa WAB56-104 and Oryza glaberrima CG14. The k-mer analysis predicted large genomes for the four NU lines, most likely inherited from WAB56-104. Approximately 3.1, 0.10, and 0.40 million single nucleotide polymorphisms, multi nucleotide polymorphisms, and short insertions/deletions were mined between the parental lines, respectively. Integrated analysis with another four NU lines (1, 2, 8, and 9) showed that the ratios of the donor CG14 allelic sites in the NU lines ranged from 1.3 to 9.8%. High resolution graphical genotype indicated genome-level similarities and common genetic events during the breeding process: five xyloglucan fucosyltransferase from O. glaberrima were introgressed in common. Segregation of genic segments revealed potential causal genes for some agronomic traits including grain shattering, awnness, susceptibility to bacterial leaf bright, and salt tolerance. Analysis of unmapped sequences against the reference cultivar Nipponbare indicated existence of unique genes for pathogen and abiotic stress resistance in the NU varieties. CONCLUSIONS The results provide understanding of NU genomes for rice improvement for Africa reinforcing local capacity for food security and insights into molecular events in breeding of interspecific hybrid crops.
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Affiliation(s)
- Naoki Yamamoto
- International Rice Research Institute, Los Baños, Laguna, Philippines.
| | - Richard Garcia
- International Rice Research Institute, Los Baños, Laguna, Philippines
| | - Tomohiro Suzuki
- Utsunomiya University, 350 Mine-machi, Utsunomiya, Tochigi, Japan
| | | | - Yuichi Tada
- Tokyo University of Technology, 1404-1 Katakura, Hachioji, Tokyo, Japan
| | | | - Ajay Kohli
- International Rice Research Institute, Los Baños, Laguna, Philippines.
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12
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Ndjiondjop MN, Semagn K, Sow M, Manneh B, Gouda AC, Kpeki SB, Pegalepo E, Wambugu P, Sié M, Warburton ML. Assessment of Genetic Variation and Population Structure of Diverse Rice Genotypes Adapted to Lowland and Upland Ecologies in Africa Using SNPs. Front Plant Sci 2018; 9:446. [PMID: 29686690 PMCID: PMC5900792 DOI: 10.3389/fpls.2018.00446] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 03/22/2018] [Indexed: 05/04/2023]
Abstract
Using interspecific crosses involving Oryza glaberrima Steud. as donor and O. sativa L. as recurrent parents, rice breeders at the Africa Rice Center developed several 'New Rice for Africa (NERICA)' improved varieties. A smaller number of interspecific and intraspecific varieties have also been released as 'Advanced Rice for Africa (ARICA)'. The objective of the present study was to investigate the genetic variation, relatedness, and population structure of 330 widely used rice genotypes in Africa using DArTseq-based single nucleotide polymorphisms (SNPs). A sample of 11 ARICAs, 85 NERICAs, 62 O. sativa spp. japonica, and 172 O. sativa spp. indica genotypes were genotyped with 27,560 SNPs using diversity array technology (DArT)-based sequencing (DArTseq) platform. Nearly 66% of the SNPs were polymorphic, of which 15,020 SNPs were mapped to the 12 rice chromosomes. Genetic distance between pairs of genotypes that belong to indica, japonica, ARICA, and NERICA varied from 0.016 to 0.623, from 0.020 to 0.692, from 0.075 to 0.763, and from 0.014 to 0.644, respectively. The proportion of pairs of genotypes with genetic distance > 0.400 was the largest within NERICAs (35.1% of the pairs) followed by ARICAs (18.2%), japonica (17.4%), and indica (5.6%). We found one pair of japonica, 11 pairs of indica, and 35 pairs of NERICA genotypes differing by <2% of the total scored alleles, which was due to 26 pairs of genotypes with identical pedigrees. Cluster analysis, principal component analysis, and the model-based population structure analysis all revealed two distinct groups corresponding to the lowland (primarily indica and lowland NERICAs) and upland (japonica and upland NERICAs) growing ecologies. Most of the interspecific lowland NERICAs formed a sub-group, likely caused by differences in the O. glaberrima genome as compared with the indica genotypes. Analysis of molecular variance revealed very great genetic differentiation (FST = 0.688) between the lowland and upland ecologies, and 31.2% of variation attributable to differences within cluster groups. About 8% (1,197 of 15,020) of the 15,020 SNPs were significantly (P < 0.05) different between the lowland and upland ecologies and formed contrasting haplotypes that could clearly discriminate lowland from upland genotypes. This is the first study using high density markers that characterized NERICA and ARICA varieties in comparison with indica and japonica varieties widely used in Africa, which could aid rice breeders on parent selection for developing new improved rice germplasm.
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Affiliation(s)
- Marie Noelle Ndjiondjop
- Africa Rice Center (AfricaRice), Bouaké, Côte d’Ivoire
- *Correspondence: Marie Noelle Ndjiondjop, Kassa Semagn,
| | - Kassa Semagn
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
- *Correspondence: Marie Noelle Ndjiondjop, Kassa Semagn,
| | | | | | | | | | | | - Peterson Wambugu
- Genetic Resources Research Institute, Kenya Agricultural & Livestock Research Organization, Nairobi, Kenya
| | | | - Marilyn L. Warburton
- Corn Host Plant Resistance Research Unit, United States Department of Agriculture-Agricultural Research Service, Starkville, MS, United States
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13
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Marengo M, Barbiroli A, Bonomi F, Casiraghi MC, Marti A, Pagani MA, Manful J, Graham-Acquaah S, Ragg E, Fessas D, Hogenboom JA, Iametti S. Macromolecular Traits in the African Rice Oryza glaberrima and in Glaberrima/Sativa Crosses, and Their Relevance to Processing. J Food Sci 2017; 82:2298-2305. [PMID: 28850662 DOI: 10.1111/1750-3841.13853] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 06/12/2017] [Accepted: 07/27/2017] [Indexed: 11/29/2022]
Abstract
Molecular properties of proteins and starch were investigated in 2 accessions of Oryza glaberrima and Oryza sativa, and in one NERICA cross between the 2 species, to assess traits that could be relevant to transformation into specific foods. Protein nature and organization in O. glaberrima were different from those in O. sativa and in NERICA. Despite the similar cysteine content in all samples, thiol accessibility in O. glaberrima proteins was higher than in NERICA or in O. sativa. Inter-protein disulphide bonds were important for the formation of protein aggregates in O. glaberrima, whereas non-covalent protein-protein interactions were relevant in NERICA and O. sativa. DSC and NMR studies indicated only minor differences in the structure of starch in these species, as also made evident by their microstructural features. Nevertheless, starch gelatinization in O. glaberrima was very different from what was observed in O. sativa and NERICA. The content of soluble species in gelatinized starch from the various species in the presence/absence of treatments with specific enzymes indicated that release of small starch breakdown products was lowest in O. glaberrima, in particular from the amylopectin component. These findings may explain the low glycemic index of O. glaberrima, and provide a rationale for extending the use of O. glaberrima in the production of specific rice-based products, thus improving the economic value and the market appeal of African crops. PRACTICAL APPLICATION The structural features of proteins and starch in O. glaberrima are very different from those in O. sativa and in the NERICA cross. These results appear useful as for extending the use of O. glaberrima cultivars in the design and production of specific rice-based products (for example, pasta), that might, in turn, improve the economic value and the market appeal of locally sourced raw materials, by introducing added-value products on the African market.
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Affiliation(s)
- Mauro Marengo
- Dipto. di Scienze per gli Alimenti, la Nutrizione e l'Ambiente (DeFENS), Univ.à degli Studi di Milano, Italy
| | - Alberto Barbiroli
- Dipto. di Scienze per gli Alimenti, la Nutrizione e l'Ambiente (DeFENS), Univ.à degli Studi di Milano, Italy
| | - Francesco Bonomi
- Dipto. di Scienze per gli Alimenti, la Nutrizione e l'Ambiente (DeFENS), Univ.à degli Studi di Milano, Italy
| | - Maria Cristina Casiraghi
- Dipto. di Scienze per gli Alimenti, la Nutrizione e l'Ambiente (DeFENS), Univ.à degli Studi di Milano, Italy
| | - Alessandra Marti
- Dipto. di Scienze per gli Alimenti, la Nutrizione e l'Ambiente (DeFENS), Univ.à degli Studi di Milano, Italy
| | - Maria Ambrogina Pagani
- Dipto. di Scienze per gli Alimenti, la Nutrizione e l'Ambiente (DeFENS), Univ.à degli Studi di Milano, Italy
| | | | | | - Enzio Ragg
- Dipto. di Scienze per gli Alimenti, la Nutrizione e l'Ambiente (DeFENS), Univ.à degli Studi di Milano, Italy
| | - Dimitrios Fessas
- Dipto. di Scienze per gli Alimenti, la Nutrizione e l'Ambiente (DeFENS), Univ.à degli Studi di Milano, Italy
| | - Johannes A Hogenboom
- Dipto. di Scienze per gli Alimenti, la Nutrizione e l'Ambiente (DeFENS), Univ.à degli Studi di Milano, Italy
| | - Stefania Iametti
- Dipto. di Scienze per gli Alimenti, la Nutrizione e l'Ambiente (DeFENS), Univ.à degli Studi di Milano, Italy
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14
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Pidon H, Ghesquière A, Chéron S, Issaka S, Hébrard E, Sabot F, Kolade O, Silué D, Albar L. Fine mapping of RYMV3: a new resistance gene to Rice yellow mottle virus from Oryza glaberrima. Theor Appl Genet 2017; 130:807-818. [PMID: 28144699 DOI: 10.1007/s00122-017-2853-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 01/04/2017] [Indexed: 05/24/2023]
Abstract
A new resistance gene against Rice yellow mottle virus was identified and mapped in a 15-kb interval. The best candidate is a CC-NBS-LRR gene. Rice yellow mottle virus (RYMV) disease is a serious constraint to the cultivation of rice in Africa and selection for resistance is considered to be the most effective management strategy. The aim of this study was to characterize the resistance of Tog5307, a highly resistant accession belonging to the African cultivated rice species (Oryza glaberrima), that has none of the previously identified resistance genes to RYMV. The specificity of Tog5307 resistance was analyzed using 18 RYMV isolates. While three of them were able to infect Tog5307 very rapidly, resistance against the others was effective despite infection events attributed to resistance-breakdown or incomplete penetrance of the resistance. Segregation of resistance in an interspecific backcross population derived from a cross between Tog5307 and the susceptible Oryza sativa variety IR64 showed that resistance is dominant and is controlled by a single gene, named RYMV3. RYMV3 was mapped in an approximately 15-kb interval in which two candidate genes, coding for a putative transmembrane protein and a CC-NBS-LRR domain-containing protein, were annotated. Sequencing revealed non-synonymous polymorphisms between Tog5307 and the O. glaberrima susceptible accession CG14 in both candidate genes. An additional resistant O. glaberrima accession, Tog5672, was found to have the Tog5307 genotype for the CC-NBS-LRR gene but not for the putative transmembrane protein gene. Analysis of the cosegregation of Tog5672 resistance with the RYMV3 locus suggests that RYMV3 is also involved in Tog5672 resistance, thereby supporting the CC-NBS-LRR gene as the best candidate for RYMV3.
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Affiliation(s)
- Hélène Pidon
- Plant Diversity Adaptation and Development Research Unit, Institut de Recherche pour le Développement - Université de Montpellier, Montpellier, France
| | - Alain Ghesquière
- Plant Diversity Adaptation and Development Research Unit, Institut de Recherche pour le Développement - Université de Montpellier, Montpellier, France
| | - Sophie Chéron
- Plant Diversity Adaptation and Development Research Unit, Institut de Recherche pour le Développement - Université de Montpellier, Montpellier, France
| | - Souley Issaka
- Africa Rice Center, Cotonou, Benin
- FSAE, Université de Tillabéri, Tillabéri, Niger
| | - Eugénie Hébrard
- Interactions Plantes Microorganismes Environnement, Institut de Recherche pour le Développement - Centre de Coopération Internationale en Recherche Agronomique pour le Développement - Université de Montpellier, Montpellier, France
| | - François Sabot
- Plant Diversity Adaptation and Development Research Unit, Institut de Recherche pour le Développement - Université de Montpellier, Montpellier, France
| | - Olufisayo Kolade
- Plant Diversity Adaptation and Development Research Unit, Institut de Recherche pour le Développement - Université de Montpellier, Montpellier, France
- Africa Rice Center, Cotonou, Benin
- International Institute of Tropical Agriculture, Ibadan, Nigeria
| | | | - Laurence Albar
- Plant Diversity Adaptation and Development Research Unit, Institut de Recherche pour le Développement - Université de Montpellier, Montpellier, France.
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15
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Petitot AS, Kyndt T, Haidar R, Dereeper A, Collin M, de Almeida Engler J, Gheysen G, Fernandez D. Transcriptomic and histological responses of African rice ( Oryza glaberrima) to Meloidogyne graminicola provide new insights into root-knot nematode resistance in monocots. Ann Bot 2017; 119:885-899. [PMID: 28334204 PMCID: PMC5604615 DOI: 10.1093/aob/mcw256] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 11/24/2016] [Indexed: 05/06/2023]
Abstract
BACKGROUND AND AIMS The root-knot nematode Meloidogyne graminicola is responsible for production losses in rice ( Oryza sativa ) in Asia and Latin America. The accession TOG5681 of African rice, O. glaberrima , presents improved resistance to several biotic and abiotic factors, including nematodes. The aim of this study was to assess the cytological and molecular mechanisms underlying nematode resistance in this accession. METHODS Penetration and development in M. graminicola in TOG5681 and the susceptible O. sativa genotype 'Nipponbare' were compared by microscopic observation of infected roots and histological analysis of galls. In parallel, host molecular responses to M. graminicola were assessed by root transcriptome profiling at 2, 4 and 8 d post-infection (dpi). Specific treatments with hormone inhibitors were conducted in TOG5681 to assess the impact of the jasmonic acid and salicylic acid pathways on nematode penetration and reproduction. KEY RESULTS Penetration and development of M. graminicola juveniles were reduced in the resistant TOG5681 in comparison with the susceptible accession, with degeneration of giant cells observed in the resistant genotype from 15 dpi onwards. Transcriptome changes were observed as early as 2 dpi, with genes predicted to be involved in defence responses, phenylpropanoid and hormone pathways strongly induced in TOG5681, in contrast to 'Nipponbare'. No specific hormonal pathway could be identified as the major determinant of resistance in the rice-nematode incompatible interaction. Candidate genes proposed as involved in resistance to M. graminicola in TOG5681 were identified based on their expression pattern and quantitative trait locus (QTL) position, including chalcone synthase, isoflavone reductase, phenylalanine ammonia lyase, WRKY62 transcription factor, thionin, stripe rust resistance protein, thaumatins and ATPase3. CONCLUSIONS This study provides a novel set of candidate genes for O. glaberrima resistance to nematodes and highlights the rice- M. graminicola pathosystem as a model to study plant-nematode incompatible interactions.
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Affiliation(s)
- Anne-Sophie Petitot
- Institut de Recherche pour le Développement, UMR 186 IPME (IRD-UM2-Cirad) 911, avenue Agropolis, BP 64501 34394 Montpellier Cedex 5, France
| | - Tina Kyndt
- Department of Molecular Biotechnology, Ghent University, Coupure links 653, 9000 Gent, Belgium
| | - Rana Haidar
- Institut de Recherche pour le Développement, UMR 186 IPME (IRD-UM2-Cirad) 911, avenue Agropolis, BP 64501 34394 Montpellier Cedex 5, France
| | - Alexis Dereeper
- Institut de Recherche pour le Développement, UMR 186 IPME (IRD-UM2-Cirad) 911, avenue Agropolis, BP 64501 34394 Montpellier Cedex 5, France
| | - Myriam Collin
- UMR 232 DIADE (IRD-UM2-Cirad) 911, avenue Agropolis BP 64501, 34394 Montpellier Cedex 5, France
| | - Janice de Almeida Engler
- Institut National de la Recherche Agronomique, UMR IBSV INRA/CNRS/UNS, 400, Route de Chappes BP167, 06903 Sophia Antipolis Cedex, France
| | - Godelieve Gheysen
- Department of Molecular Biotechnology, Ghent University, Coupure links 653, 9000 Gent, Belgium
| | - Diana Fernandez
- Institut de Recherche pour le Développement, UMR 186 IPME (IRD-UM2-Cirad) 911, avenue Agropolis, BP 64501 34394 Montpellier Cedex 5, France
- For correspondence. E-mail
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16
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Ta KN, Sabot F, Adam H, Vigouroux Y, De Mita S, Ghesquière A, Do NV, Gantet P, Jouannic S. miR2118-triggered phased siRNAs are differentially expressed during the panicle development of wild and domesticated African rice species. Rice (N Y) 2016; 9:10. [PMID: 26969003 PMCID: PMC4788661 DOI: 10.1186/s12284-016-0082-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 03/06/2016] [Indexed: 05/27/2023]
Abstract
BACKGROUND Rice exhibits a wide range of panicle structures. To explain these variations, much emphasis has been placed on changes in transcriptional regulation, but no large-scale study has yet reported on changes in small RNA regulation in the various rice species. To evaluate this aspect, we performed deep sequencing and expression profiling of small RNAs from two closely related species with contrasting panicle development: the cultivated African rice Oryza glaberrima and its wild relative Oryza barthii. RESULTS Our RNA-seq analysis revealed a dramatic difference between the two species in the 21 nucleotide small RNA population, corresponding mainly to miR2118-triggered phased siRNAs. A detailed expression profiling during the panicle development of O. glaberrima and O. barthii using qRT-PCRs and in situ hybridization, confirmed a delayed expression of the phased siRNAs as well as their lncRNA precursors and regulators (miR2118 and MEL1 gene) in O. glaberrima compared to O. barthii. We provide evidence that the 21-nt phasiRNA pathway in rice is associated with male-gametogenesis but is initiated in spikelet meristems. CONCLUSION Differential expression of the miR2118-triggered 21-nt phasiRNA pathway between the two African rice species reflects differential rates of determinate fate acquisition of panicle meristems between the two species.
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Affiliation(s)
- K. N. Ta
- />IRD, UMR DIADE, 911, avenue Agropolis, BP64501, F-34394 Montpellier, Cedex 5 France
- />LMI RICE, National Key Laboratory for Plant Cell Biotechnology, Agronomical Genetics Institute, Pham Van Dong road, Hanoi, Vietnam
| | - F. Sabot
- />IRD, UMR DIADE, 911, avenue Agropolis, BP64501, F-34394 Montpellier, Cedex 5 France
| | - H. Adam
- />IRD, UMR DIADE, 911, avenue Agropolis, BP64501, F-34394 Montpellier, Cedex 5 France
| | - Y. Vigouroux
- />IRD, UMR DIADE, 911, avenue Agropolis, BP64501, F-34394 Montpellier, Cedex 5 France
| | - S. De Mita
- />IRD, UMR DIADE, 911, avenue Agropolis, BP64501, F-34394 Montpellier, Cedex 5 France
- />Present address: INRA, Université de Lorraine, UMR 1136 Interactions Arbres/Microorganismes, F-54280 Champenoux, France
| | - A. Ghesquière
- />IRD, UMR DIADE, 911, avenue Agropolis, BP64501, F-34394 Montpellier, Cedex 5 France
| | - N. V. Do
- />LMI RICE, National Key Laboratory for Plant Cell Biotechnology, Agronomical Genetics Institute, Pham Van Dong road, Hanoi, Vietnam
| | - P. Gantet
- />LMI RICE, National Key Laboratory for Plant Cell Biotechnology, Agronomical Genetics Institute, Pham Van Dong road, Hanoi, Vietnam
- />Université de Montpellier, UMR DIADE, Place Eugène Bataillon, F-34095 Montpellier, Cedex 5 France
| | - S. Jouannic
- />IRD, UMR DIADE, 911, avenue Agropolis, BP64501, F-34394 Montpellier, Cedex 5 France
- />LMI RICE, National Key Laboratory for Plant Cell Biotechnology, Agronomical Genetics Institute, Pham Van Dong road, Hanoi, Vietnam
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17
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Rodenburg J, Cissoko M, Kayeke J, Dieng I, Khan ZR, Midega CA, Onyuka EA, Scholes JD. Do NERICA rice cultivars express resistance to Striga hermonthica (Del.) Benth. and Striga asiatica (L.) Kuntze under field conditions? Field Crops Res 2015; 170:83-94. [PMID: 26089591 PMCID: PMC4459690 DOI: 10.1016/j.fcr.2014.10.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 10/14/2014] [Accepted: 10/15/2014] [Indexed: 05/04/2023]
Abstract
The parasitic weeds Striga asiatica and Striga hermonthica cause high yield losses in rain-fed upland rice in Africa. Two resistance classes (pre- and post-attachment) and several resistant genotypes have been identified among NERICA (New Rice for Africa) cultivars under laboratory conditions (in vitro) previously. However, little is known about expression of this resistance under field conditions. Here we investigated (1) whether resistance exhibited under controlled conditions would express under representative Striga-infested field conditions, and (2) whether NERICA cultivars would achieve relatively good grain yields under Striga-infested conditions. Twenty-five rice cultivars, including all 18 upland NERICA cultivars, were screened in S. asiatica-infested (in Tanzania) and S. hermonthica-infested (in Kenya) fields during two seasons. Additionally, a selection of cultivars was tested in vitro, in mini-rhizotron systems. For the first time, resistance observed under controlled conditions was confirmed in the field for NERICA-2, -5, -10 and -17 (against S. asiatica) and NERICA-1 to -5, -10, -12, -13 and -17 (against S. hermonthica). Despite high Striga-infestation levels, yields of around 1.8 t ha-1 were obtained with NERICA-1, -9 and -10 (in the S. asiatica-infested field) and around 1.4 t ha-1 with NERICA-3, -4, -8, -12 and -13 (in the S. hermonthica-infested field). In addition, potential levels of tolerance were identified in vitro, in NERICA-1, -17 and -9 (S. asiatica) and in NERICA-1, -17 and -10 (S. hermonthica). These findings are highly relevant to rice agronomists and breeders and molecular geneticists working on Striga resistance. In addition, cultivars combining broad-spectrum resistance with good grain yields in Striga-infested fields can be recommended to rice farmers in Striga-prone areas.
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Affiliation(s)
- Jonne Rodenburg
- Africa Rice Center (AfricaRice), East and Southern Africa, P.O. Box 33581, Dar es Salaam, Tanzania
- Corresponding author. Tel.: +255 688425335.
| | - Mamadou Cissoko
- Africa Rice Center (AfricaRice), East and Southern Africa, P.O. Box 33581, Dar es Salaam, Tanzania
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Juma Kayeke
- Mikocheni Agricultural Research Institute (MARI), Dar es Salaam, Tanzania
| | - Ibnou Dieng
- Africa Rice Center (AfricaRice), 01 BP2031, Cotonou, Benin
| | - Zeyaur R. Khan
- International Centre of Insect Physiology and Ecology (ICIPE), P.O. Box 30772, Nairobi 00100, Kenya
| | - Charles A.O. Midega
- International Centre of Insect Physiology and Ecology (ICIPE), P.O. Box 30772, Nairobi 00100, Kenya
| | - Enos A. Onyuka
- Africa Rice Center (AfricaRice), East and Southern Africa, P.O. Box 33581, Dar es Salaam, Tanzania
- International Crops Research Institute of the Semi-Arid Tropics (ICRISAT), Eastern and Southern Africa, P.O. Box 39063, Nairobi, Kenya
| | - Julie D. Scholes
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
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Nabholz B, Sarah G, Sabot F, Ruiz M, Adam H, Nidelet S, Ghesquière A, Santoni S, David J, Glémin S. Transcriptome population genomics reveals severe bottleneck and domestication cost in the African rice ( Oryza glaberrima). Mol Ecol 2014; 23:2210-27. [PMID: 24684265 DOI: 10.1111/mec.12738] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 03/19/2014] [Indexed: 12/17/2022]
Abstract
The African cultivated rice (Oryza glaberrima) was domesticated in West Africa 3000 years ago. Although less cultivated than the Asian rice (O. sativa), O. glaberrima landraces often display interesting adaptation to rustic environment (e.g. drought). Here, using RNA-seq technology, we were able to compare more than 12,000 transcripts between 9 O. glaberrima, 10 wild O. barthii and one O. meridionalis individuals. With a synonymous nucleotide diversity πs = 0.0006 per site, O. glaberrima appears as the least genetically diverse crop grass ever documented. Using approximate Bayesian computation, we estimated that O. glaberrima experienced a severe bottleneck during domestication. This demographic scenario almost fully accounts for the pattern of genetic diversity across O. glaberrima genome as we detected very few outliers regions where positive selection may have further impacted genetic diversity. Moreover, the large excess of derived nonsynonymous substitution that we detected suggests that the O. glaberrima population suffered from the 'cost of domestication'. In addition, we used this genome-scale data set to demonstrate that (i) O. barthii genetic diversity is positively correlated with recombination rate and negatively with gene density, (ii) expression level is negatively correlated with evolutionary constraint, and (iii) one region on chromosome 5 (position 4-6 Mb) exhibits a clear signature of introgression with a yet unidentified Oryza species. This work represents the first genome-wide survey of the African rice genetic diversity and paves the way for further comparison between the African and the Asian rice, notably regarding the genetics underlying domestication traits.
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Affiliation(s)
- Benoit Nabholz
- Institut des Sciences de l'Evolution-Montpellier, UMR CNRS-UM2 5554, University Montpellier II, Montpellier, France; UMR AGAP 1334, Montpellier SupAgro, Montpellier, France
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19
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Cho S, Nuijten E, Shewfelt RL, Kays SJ. Aroma chemistry of African Oryza glaberrima and Oryza sativa rice and their interspecific hybrids. J Sci Food Agric 2014; 94:727-735. [PMID: 23907855 DOI: 10.1002/jsfa.6329] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 07/23/2013] [Accepted: 07/30/2013] [Indexed: 06/02/2023]
Abstract
BACKGROUND To increase rice production in Africa, considerable research has focused on creating interspecific hybrids between African (Oryza glaberrima Steud.) and Asian (O. sativa L.) rice in an attempt to obtain the positive attributes of each in new cultivars. Since flavor is a key criterion in consumer acceptance of rice, as an initial inquiry we characterized and compared the aroma chemistry of selected cultivars of African O. sativa ssp. japonica, O. sativa ssp. indica, O. glaberrima, and their interspecific hybrids grown in West Africa, using gas chromatography-mass spectrometry, gas chromatography-olfactometry and descriptive sensory analysis. RESULTS Of 41 volatiles identified across seven representative rice cultivars grown in West Africa, 3,5,5-trimethyl-2-cyclopenten-1-one, styrene, eucalyptol, linalool, myrtenal and L-α-terpineol had not been previously reported in rice. Thirty-three odor-active compounds were characterized. 4-Ethylphenol and (E,E)-2,4-heptadienal were unique to O. glaberrima, and pyridine, eucalyptol and myrtenal were described only in an interspecific hybrid. Descriptive sensory analysis indicated 'cooked grain', 'barny' and 'earthy' attributes were statistically different among the cultivars. CONCLUSION The aroma chemistry data suggest that it should be possible to separate African cultivars into distinct flavor types thereby facilitating selection of new cultivars with superior flavor in African rice breeding programs.
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Affiliation(s)
- Sungeun Cho
- Department of Horticulture, 1111 Plant Sciences Bldg., University of Georgia, Athens, GA, 30602, USA
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20
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Xu P, Zhou J, Li J, Hu F, Deng X, Feng S, Ren G, Zhang Z, Deng W, Tao D. Mapping three new interspecific hybrid sterile loci between Oryza sativa and O. glaberrima. Breed Sci 2014; 63:476-82. [PMID: 24757387 PMCID: PMC3949584 DOI: 10.1270/jsbbs.63.476] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 12/09/2013] [Indexed: 05/10/2023]
Abstract
Hybrid sterility hinders the transfer of useful traits between Oryza sativa and O. glaberrima. In order to further understand the nature of interspecific hybrid sterility between these two species, a strategy of multi-donors was used to elucidate the range of interspecific hybrid sterility in this study. Fifty-nine accessions of O. glaberrima were used as female parents for hybridization with japonica cultivar Dianjingyou 1, after several backcrossings using Dianjingyou 1 as the recurrent parent and 135 BC6F1 sterile plants were selected for genotyping and deducing hybrid sterility QTLs. BC6F1 plants containing heterozygous target markers were selected and used to raise BC7F1 mapping populations for QTL confirmation and as a result, one locus for gamete elimination on chromosome 1 and two loci for pollen sterility on chromosome 4 and 12, which were distinguished from previous reports, were confirmed and designated as S37(t), S38(t) and S39(t), respectively. These results will be valuable for understanding the range of interspecific hybrid sterility, cloning these genes and improving rice breeding through gene introgression.
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Affiliation(s)
- Peng Xu
- Food Crops Research Institute, Yunnan Academy of Agricultural Sciences (YAAS),
Kunming 650200,
P. R. China
| | - Jiawu Zhou
- Food Crops Research Institute, Yunnan Academy of Agricultural Sciences (YAAS),
Kunming 650200,
P. R. China
| | - Jing Li
- Food Crops Research Institute, Yunnan Academy of Agricultural Sciences (YAAS),
Kunming 650200,
P. R. China
| | - Fengyi Hu
- Food Crops Research Institute, Yunnan Academy of Agricultural Sciences (YAAS),
Kunming 650200,
P. R. China
| | - Xianneng Deng
- Food Crops Research Institute, Yunnan Academy of Agricultural Sciences (YAAS),
Kunming 650200,
P. R. China
| | - Sufeng Feng
- Yunnan Agricultural University,
Kunming 650201,
P. R. China
| | - Guangyun Ren
- Yunnan Agricultural University,
Kunming 650201,
P. R. China
| | - Zhi Zhang
- Yunnan Agricultural University,
Kunming 650201,
P. R. China
| | - Wei Deng
- Food Crops Research Institute, Yunnan Academy of Agricultural Sciences (YAAS),
Kunming 650200,
P. R. China
| | - Dayun Tao
- Food Crops Research Institute, Yunnan Academy of Agricultural Sciences (YAAS),
Kunming 650200,
P. R. China
- Corresponding author (e-mail: )
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Budot BO, Encabo JR, Ambita IDV, Atienza-Grande GA, Satoh K, Kondoh H, Ulat VJ, Mauleon R, Kikuchi S, Choi IR. Suppression of cell wall-related genes associated with stunting of Oryza glaberrima infected with Rice tungro spherical virus. Front Microbiol 2014; 5:26. [PMID: 24550897 PMCID: PMC3912842 DOI: 10.3389/fmicb.2014.00026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 01/15/2014] [Indexed: 11/30/2022] Open
Abstract
Rice tungro disease is a complex disease caused by the interaction between Rice tungro bacilliform virus and Rice tungro spherical virus (RTSV). RTSV alone does not cause recognizable symptoms in most Asian rice (Oryza sativa) plants, whereas some African rice (O. glaberrima) plants were found to become stunted by RTSV. Stunting of rice plants by virus infections usually accompanies the suppression of various cell wall-related genes. The expression of cell wall-related genes was examined in O. glaberrima and O. sativa infected with RTSV to see the relationship between the severity of stunting and the suppression of cell wall-related genes by RTSV. The heights of four accessions of O. glaberrima were found to decline by 14-34% at 28 days post-inoculation (dpi) with RTSV, whereas the height reduction of O. sativa plants by RTSV was not significant. RTSV accumulated more in O. glaberrima plants than in O. sativa plants, but the level of RTSV accumulation was not correlated with the degree of height reduction among the four accessions of O. glaberrima. Examination for expression of genes for cellulose synthase A5 (CESA5) and A6 (CESA6), cellulose synthase-like A9 (CSLA9) and C7, and α-expansin 1 (expansin 1) and 15 precursors in O. glaberrima and O. sativa plants between 7 and 28 dpi with RTSV showed that the genes such as those for CESA5, CESA6, CSLA9, and expansin 1were more significantly suppressed in stunted plants of O. glaberrima at 14 dpi with RTSV than in O. sativa, suggesting that stunting of O. glaberrima might be associated with these cell wall-related genes suppressed by RTSV. Examination for expression of these genes in O. sativa plants infected with other rice viruses in previous studies indicated that the suppression of the expansin 1 gene is likely to be a signature response commonly associated with virus-induced stunting of Oryza species. These results suggest that stunting of O. glaberrima by RTSV infection might be associated with the suppression of these cell wall-related genes at the early stage of infection with RTSV.
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Affiliation(s)
- Bernard O. Budot
- Plant Breeding, Genetics, and Biotechnology Division, International Rice Research InstituteMetro Manila, Philippines
| | - Jaymee R. Encabo
- Plant Breeding, Genetics, and Biotechnology Division, International Rice Research InstituteMetro Manila, Philippines
| | - Israel Dave V. Ambita
- Plant Breeding, Genetics, and Biotechnology Division, International Rice Research InstituteMetro Manila, Philippines
| | - Genelou A. Atienza-Grande
- Plant Breeding, Genetics, and Biotechnology Division, International Rice Research InstituteMetro Manila, Philippines
| | - Kouji Satoh
- Plant Genome Research Unit, Agrogenomics Research Center, National Institute of Agrobiological SciencesTsukuba, Ibaraki, Japan
| | - Hiroaki Kondoh
- Plant Genome Research Unit, Agrogenomics Research Center, National Institute of Agrobiological SciencesTsukuba, Ibaraki, Japan
| | - Victor J. Ulat
- T. T. Chang Genetic Resources Center, International Rice Research InstituteMetro Manila, Philippines
| | - Ramil Mauleon
- T. T. Chang Genetic Resources Center, International Rice Research InstituteMetro Manila, Philippines
| | - Shoshi Kikuchi
- Plant Genome Research Unit, Agrogenomics Research Center, National Institute of Agrobiological SciencesTsukuba, Ibaraki, Japan
| | - Il-Ryong Choi
- Plant Breeding, Genetics, and Biotechnology Division, International Rice Research InstituteMetro Manila, Philippines
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Vigueira CC, Li W, Olsen KM. The role of Bh4 in parallel evolution of hull colour in domesticated and weedy rice. J Evol Biol 2013; 26:1738-49. [PMID: 23859433 DOI: 10.1111/jeb.12171] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 03/19/2013] [Accepted: 03/28/2013] [Indexed: 11/29/2022]
Abstract
The two independent domestication events in the genus Oryza that led to African and Asian rice offer an extremely useful system for studying the genetic basis of parallel evolution. This system is also characterized by parallel de-domestication events, with two genetically distinct weedy rice biotypes in the US derived from the Asian domesticate. One important trait that has been altered by rice domestication and de-domestication is hull colour. The wild progenitors of the two cultivated rice species have predominantly black-coloured hulls, as does one of the two U.S. weed biotypes; both cultivated species and one of the US weedy biotypes are characterized by straw-coloured hulls. Using Black hull 4 (Bh4) as a hull colour candidate gene, we examined DNA sequence variation at this locus to study the parallel evolution of hull colour variation in the domesticated and weedy rice system. We find that independent Bh4-coding mutations have arisen in African and Asian rice that are correlated with the straw hull phenotype, suggesting that the same gene is responsible for parallel trait evolution. For the U.S. weeds, Bh4 haplotype sequences support current hypotheses on the phylogenetic relationship between the two biotypes and domesticated Asian rice; straw hull weeds are most similar to indica crops, and black hull weeds are most similar to aus crops. Tests for selection indicate that Asian crops and straw hull weeds deviate from neutrality at this gene, suggesting possible selection on Bh4 during both rice domestication and de-domestication.
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Affiliation(s)
- C C Vigueira
- Department of Biology, Washington University, St. Louis, MO, USA
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Abstract
• The genetics of arsenic tolerance in plants has not been extensively studied and no arsenic tolerance gene has been genetically mapped. • Screening 20 diverse genotypes of rice for reduced root growth in 13.3 m arsenate identified marked differences in tolerance. The most sensitive variety, Dawn, is known to be highly susceptible to straighthead, a condition linked to arsenic contamination of soil. • Screening 108 recombinant inbred lines of the Bala × Azucena mapping population revealed the presence of a major gene, AsTol, which mapped between markers RZ516 and RG213 on chromosome 6. • This gene is a good target for further characterisation. It should prove valuable for investigations into the physiological and molecular mechanism behind arsenic tolerance in plants and may lead to strategies aimed at breeding for arsenic contaminated regions.
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Affiliation(s)
- Tapash Dasgupta
- Department of Plant and Soil Science, School of Biological Sciences, University of Aberdeen, Aberdeen AB24 3UU, UK
- Present address; University College of Agriculture, Calcutta University, 35 B.C. Road, Kolkata 700 019 West Bengal, India; 3Present address; Department of Soil, Water & Environment, University of Dhaka, Dhaka-1000, Bangldesh
| | - Shahid A Hossain
- Department of Plant and Soil Science, School of Biological Sciences, University of Aberdeen, Aberdeen AB24 3UU, UK
| | - Andrew A Meharg
- Department of Plant and Soil Science, School of Biological Sciences, University of Aberdeen, Aberdeen AB24 3UU, UK
| | - Adam H Price
- Department of Plant and Soil Science, School of Biological Sciences, University of Aberdeen, Aberdeen AB24 3UU, UK
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