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Heo SH, Kim SY, Mo SY, Park HY. Development of S Haplotype-Specific Markers to Identify Genotypes of Self-Incompatibility in Radish ( Raphanus sativus L.). PLANTS (BASEL, SWITZERLAND) 2024; 13:725. [PMID: 38475571 DOI: 10.3390/plants13050725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 02/25/2024] [Accepted: 03/01/2024] [Indexed: 03/14/2024]
Abstract
Radish (Raphanus sativus L.), a root vegetable belonging to the Brassicaceae family, is considered one of the representative crops displaying sporophytic self-incompatibility (SSI). The utilization of a self-incompatibility system in F1 breeding can improve the efficiency of cross-combinations, leading to a reduction in breeding time and aiding in the development of novel F1 varieties. The successful implementation of this system necessitates the rapid and accurate identification of S haplotypes in parental lines. In this study, we identified a total of nine S haplotypes among 22 elite radish lines through Sanger sequencing. Subsequently, we obtained sequences for showing a 95% similarity to nine S haplotypes, along with sequences identified by other researchers using BLAST. Following this, multiple sequence alignment (MSA) was conducted to identify SRK and SLG sequence similarities, as well as polymorphisms within the class I and II groups. Subsequently, S haplotype-specific marker sets were developed, targeting polymorphic regions of SRK and SLG alleles. These markers successfully amplified each of the nine S haplotypes. These markers will play a crucial role in the rapid and precise identification of parental S haplotypes in the radish F1 breeding process, proving instrumental in the radish F1 purity test.
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Affiliation(s)
- Seong-Ho Heo
- Department of Bioresources Engineering, Sejong University, Seoul 05006, Republic of Korea
- Institute of Breeding Research, DASAN Co., Ltd., Pyeongtaek 17864, Republic of Korea
| | - Su-Yeon Kim
- Department of Bioresources Engineering, Sejong University, Seoul 05006, Republic of Korea
| | - Suk-Yeon Mo
- Department of Bioresources Engineering, Sejong University, Seoul 05006, Republic of Korea
| | - Han-Yong Park
- Department of Bioresources Engineering, Sejong University, Seoul 05006, Republic of Korea
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Ohata M, Takada Y, Sato Y, Okamoto T, Murase K, Takayama S, Suzuki G, Watanabe M. MLPK function is not required for self-incompatibility in the S 29 haplotype of Brassica rapa L. PLANT REPRODUCTION 2023:10.1007/s00497-023-00463-w. [PMID: 37099188 PMCID: PMC10363064 DOI: 10.1007/s00497-023-00463-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 04/09/2023] [Indexed: 06/19/2023]
Abstract
S29 haplotype does not require the MLPK function for self-incompatibility in Brassica rapa. Self-incompatibility (SI) in Brassicaceae is regulated by the self-recognition mechanism, which is based on the S-haplotype-specific direct interaction of the pollen-derived ligand, SP11/SCR, and the stigma-side receptor, SRK. M locus protein kinase (MLPK) is known to be one of the positive effectors of the SI response. MLPK directly interacts with SRK, and is phosphorylated by SRK in Brassica rapa. In Brassicaceae, MLPK was demonstrated to be essential for SI in B. rapa and Brassica napus, whereas it is not essential for SI in Arabidopsis thaliana (with introduced SRK and SP11/SCR from related SI species). Little is known about what determines the need for MLPK in SI of Brassicaceae. In this study, we investigated the relationship between S-haplotype diversity and MLPK function by analyzing the SI phenotypes of different S haplotypes in a mlpk/mlpk mutant background. The results have clarified that in B. rapa, all the S haplotypes except the S29 we tested need the MLPK function, but the S29 haplotype does not require MLPK for the SI. Comparative analysis of MLPK-dependent and MLPK-independent S haplotype might provide new insight into the evolution of S-haplotype diversity and the molecular mechanism of SI in Brassicaceae.
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Affiliation(s)
- Mayu Ohata
- Graduate School of Life Sciences, Tohoku University, Sendai, 980-8577, Japan
| | - Yoshinobu Takada
- Graduate School of Life Sciences, Tohoku University, Sendai, 980-8577, Japan.
| | - Yui Sato
- Graduate School of Life Sciences, Tohoku University, Sendai, 980-8577, Japan
| | - Takumi Okamoto
- Graduate School of Life Sciences, Tohoku University, Sendai, 980-8577, Japan
- Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, 422-8526, Japan
| | - Kohji Murase
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan
| | - Seiji Takayama
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan
| | - Go Suzuki
- Division of Natural Science, Osaka Kyoiku University, Kashiwara, 582-8582, Japan
| | - Masao Watanabe
- Graduate School of Life Sciences, Tohoku University, Sendai, 980-8577, Japan.
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Yamamoto M, Ishii T, Ogura M, Akanuma T, Zhu XY, Kitashiba H. S haplotype collection in Brassicaceae crops-an updated list of S haplotypes. BREEDING SCIENCE 2023; 73:132-145. [PMID: 37404351 PMCID: PMC10316313 DOI: 10.1270/jsbbs.22091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 01/07/2023] [Indexed: 07/06/2023]
Abstract
Self-incompatibility is the system that inhibits pollen germination and pollen tube growth by self-pollen. This trait is important for the breeding of Brassica and Raphanus species. In these species, self-incompatibility is governed by the S locus, which contains three linked genes (a set called the S haplotype), i.e., S-locus receptor kinase, S-locus cysteine-rich protein/S-locus protein 11, and S-locus glycoprotein. A large number of S haplotypes have been identified in Brassica oleracea, B. rapa, and Raphanus sativus to date, and the nucleotide sequences of their many alleles have also been registered. In this state, it is important to avoid confusion between S haplotypes, i.e., an identical S haplotype with different names and a different S haplotype with an identical S haplotype number. To mitigate this issue, we herein constructed a list of S haplotypes that are easily accessible to the latest nucleotide sequences of S-haplotype genes, together with revisions to and an update of S haplotype information. Furthermore, the histories of the S-haplotype collection in the three species are reviewed, the importance of the collection of S haplotypes as a genetic resource is discussed, and the management of information on S haplotypes is proposed.
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Affiliation(s)
- Masaya Yamamoto
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki Aza Aoba Aobaku, Sendai, Miyagi 980-8572, Japan
| | - Tomoko Ishii
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki Aza Aoba Aobaku, Sendai, Miyagi 980-8572, Japan
| | - Marina Ogura
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki Aza Aoba Aobaku, Sendai, Miyagi 980-8572, Japan
| | - Takashi Akanuma
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki Aza Aoba Aobaku, Sendai, Miyagi 980-8572, Japan
| | - Xing-Yu Zhu
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki Aza Aoba Aobaku, Sendai, Miyagi 980-8572, Japan
| | - Hiroyasu Kitashiba
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki Aza Aoba Aobaku, Sendai, Miyagi 980-8572, Japan
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Ni M, Yi X, Wang Q, Wang J, Wang S, Liu L, Xu L, Wang Y. Classification and Identification of S Haplotypes in Radish Based on SRK Kinase Domain Sequence Analysis. PLANTS 2022; 11:plants11172304. [PMID: 36079686 PMCID: PMC9459979 DOI: 10.3390/plants11172304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 08/25/2022] [Accepted: 08/26/2022] [Indexed: 11/25/2022]
Abstract
Radish is a typical self-incompatible crop. The rapid and accurate identification of S haplotypes can circumvent the blindness of the hybrid combination process, which is critical in radish heterosis utilization and the breeding of new varieties. In this study, based on the gene sequence which encodes the S-locus receptor kinase (SRK) of radish, and the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis, the S haplotypes were identified among 79 cultivated radish genotypes. The PCR results indicated that 79 radish genotypes could be divided into 48 Class I, 13 Class II, and 17 Class I/II S haplotypes. Sequence alignment confirmed that the Class I materials contained 19 S haplotypes, of which three haplotypes (‘NAU-S53’, ‘NAU-S54’ and ‘NAU-S55’) were identified for the first time in radish. After digestion using the Hinf I restriction endonuclease, the SRK domain of DNA fragments of different genotypes showed high polymorphism. Homozygous materials S haplotypes could be quickly distinguished by the differences in the digested bands. Molecular identification of the S haplotype was highly consistent with the field pollination and pollen tube germination results. These results would provide an important approach for the rapid identification of radish S haplotypes and the efficient utilization of self-incompatibility in heterosis breeding.
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Li B, Zhang X, Liu Z, Wang L, Song L, Liang X, Dou S, Tu J, Shen J, Yi B, Wen J, Fu T, Dai C, Gao C, Wang A, Ma C. Genetic and Molecular Characterization of a Self-Compatible Brassica rapa Line Possessing a New Class II S Haplotype. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10122815. [PMID: 34961286 PMCID: PMC8709392 DOI: 10.3390/plants10122815] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/01/2021] [Accepted: 12/03/2021] [Indexed: 05/20/2023]
Abstract
Most flowering plants have evolved a self-incompatibility (SI) system to maintain genetic diversity by preventing self-pollination. The Brassica species possesses sporophytic self-incompatibility (SSI), which is controlled by the pollen- and stigma-determinant factors SP11/SCR and SRK. However, the mysterious molecular mechanism of SI remains largely unknown. Here, a new class II S haplotype, named BrS-325, was identified in a pak choi line '325', which was responsible for the completely self-compatible phenotype. To obtain the entire S locus sequences, a complete pak choi genome was gained through Nanopore sequencing and de novo assembly, which provided a good reference genome for breeding and molecular research in B. rapa. S locus comparative analysis showed that the closest relatives to BrS-325 was BrS-60, and high sequence polymorphism existed in the S locus. Meanwhile, two duplicated SRKs (BrSRK-325a and BrSRK-325b) were distributed in the BrS-325 locus with opposite transcription directions. BrSRK-325b and BrSCR-325 were expressed normally at the transcriptional level. The multiple sequence alignment of SCRs and SRKs in class II S haplotypes showed that a number of amino acid variations were present in the contact regions (CR II and CR III) of BrSCR-325 and the hypervariable regions (HV I and HV II) of BrSRK-325s, which may influence the binding and interaction between the ligand and the receptor. Thus, these results suggested that amino acid variations in contact sites may lead to the SI destruction of a new class II S haplotype BrS-325 in B. rapa. The complete SC phenotype of '325' showed the potential for practical breeding application value in B. rapa.
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Affiliation(s)
- Bing Li
- National Sub-Center of Rapeseed Improvement in Wuhan, National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (B.L.); (L.W.); (X.L.); (S.D.); (J.T.); (J.S.); (B.Y.); (J.W.); (T.F.); (C.D.)
| | - Xueli Zhang
- Wuhan Vegetable Research Institute, Wuhan Academy of Agricultural Sciences, Wuhan 430345, China; (X.Z.); (L.S.)
| | - Zhiquan Liu
- Hunan Vegetable Research Institute, Hunan Academy of Agricultural Science, Changsha 410125, China;
| | - Lulin Wang
- National Sub-Center of Rapeseed Improvement in Wuhan, National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (B.L.); (L.W.); (X.L.); (S.D.); (J.T.); (J.S.); (B.Y.); (J.W.); (T.F.); (C.D.)
| | - Liping Song
- Wuhan Vegetable Research Institute, Wuhan Academy of Agricultural Sciences, Wuhan 430345, China; (X.Z.); (L.S.)
| | - Xiaomei Liang
- National Sub-Center of Rapeseed Improvement in Wuhan, National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (B.L.); (L.W.); (X.L.); (S.D.); (J.T.); (J.S.); (B.Y.); (J.W.); (T.F.); (C.D.)
| | - Shengwei Dou
- National Sub-Center of Rapeseed Improvement in Wuhan, National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (B.L.); (L.W.); (X.L.); (S.D.); (J.T.); (J.S.); (B.Y.); (J.W.); (T.F.); (C.D.)
| | - Jinxing Tu
- National Sub-Center of Rapeseed Improvement in Wuhan, National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (B.L.); (L.W.); (X.L.); (S.D.); (J.T.); (J.S.); (B.Y.); (J.W.); (T.F.); (C.D.)
| | - Jinxiong Shen
- National Sub-Center of Rapeseed Improvement in Wuhan, National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (B.L.); (L.W.); (X.L.); (S.D.); (J.T.); (J.S.); (B.Y.); (J.W.); (T.F.); (C.D.)
| | - Bin Yi
- National Sub-Center of Rapeseed Improvement in Wuhan, National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (B.L.); (L.W.); (X.L.); (S.D.); (J.T.); (J.S.); (B.Y.); (J.W.); (T.F.); (C.D.)
| | - Jing Wen
- National Sub-Center of Rapeseed Improvement in Wuhan, National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (B.L.); (L.W.); (X.L.); (S.D.); (J.T.); (J.S.); (B.Y.); (J.W.); (T.F.); (C.D.)
| | - Tingdong Fu
- National Sub-Center of Rapeseed Improvement in Wuhan, National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (B.L.); (L.W.); (X.L.); (S.D.); (J.T.); (J.S.); (B.Y.); (J.W.); (T.F.); (C.D.)
| | - Cheng Dai
- National Sub-Center of Rapeseed Improvement in Wuhan, National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (B.L.); (L.W.); (X.L.); (S.D.); (J.T.); (J.S.); (B.Y.); (J.W.); (T.F.); (C.D.)
| | - Changbin Gao
- Wuhan Vegetable Research Institute, Wuhan Academy of Agricultural Sciences, Wuhan 430345, China; (X.Z.); (L.S.)
- Correspondence: (C.G.); (A.W.); (C.M.); Tel.: +86-27-8728-18-07 (C.M.)
| | - Aihua Wang
- Wuhan Vegetable Research Institute, Wuhan Academy of Agricultural Sciences, Wuhan 430345, China; (X.Z.); (L.S.)
- Correspondence: (C.G.); (A.W.); (C.M.); Tel.: +86-27-8728-18-07 (C.M.)
| | - Chaozhi Ma
- National Sub-Center of Rapeseed Improvement in Wuhan, National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (B.L.); (L.W.); (X.L.); (S.D.); (J.T.); (J.S.); (B.Y.); (J.W.); (T.F.); (C.D.)
- Correspondence: (C.G.); (A.W.); (C.M.); Tel.: +86-27-8728-18-07 (C.M.)
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Genete M, Castric V, Vekemans X. Genotyping and De Novo Discovery of Allelic Variants at the Brassicaceae Self-Incompatibility Locus from Short-Read Sequencing Data. Mol Biol Evol 2021; 37:1193-1201. [PMID: 31688901 DOI: 10.1093/molbev/msz258] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Plant self-incompatibility (SI) is a genetic system that prevents selfing and enforces outcrossing. Because of strong balancing selection, the genes encoding SI are predicted to maintain extraordinarily high levels of polymorphism, both in terms of the number of functionally distinct S-alleles that segregate in SI species and in terms of their nucleotide sequence divergence. However, because of these two combined features, documenting polymorphism of these genes also presents important methodological challenges that have so far largely prevented the comprehensive analysis of complete allelic series in natural populations, and also precluded the obtention of complete genic sequences for many S-alleles. Here, we develop a powerful methodological approach based on a computationally optimized comparison of short Illumina sequencing reads from genomic DNA to a database of known nucleotide sequences of the extracellular domain of SRK (eSRK). By examining mapping patterns along the reference sequences, we obtain highly reliable predictions of S-genotypes from individuals collected from natural populations of Arabidopsis halleri. Furthermore, using a de novo assembly approach of the filtered short reads, we obtain full-length sequences of eSRK even when the initial sequence in the database was only partial, and we discover putative new SRK alleles that were not initially present in the database. When including those new alleles in the reference database, we were able to resolve the complete diploid SI genotypes of all individuals. Beyond the specific case of Brassicaceae S-alleles, our approach can be readily applied to other polymorphic loci, given reference allelic sequences are available.
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Affiliation(s)
- Mathieu Genete
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France
| | - Vincent Castric
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France
| | - Xavier Vekemans
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France
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Kawamura K, Kawanabe T, Shimizu M, Okazaki K, Kaji M, Dennis ES, Osabe K, Fujimoto R. Genetic characterization of inbred lines of Chinese cabbage by DNA markers; towards the application of DNA markers to breeding of F1 hybrid cultivars. Data Brief 2015; 6:229-37. [PMID: 26862564 PMCID: PMC4707182 DOI: 10.1016/j.dib.2015.11.058] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 11/21/2015] [Accepted: 11/25/2015] [Indexed: 11/30/2022] Open
Abstract
Chinese cabbage (Brassica rapa L. var. pekinensis) is an important vegetable in Asia, and most Japanese commercial cultivars of Chinese cabbage use an F1 hybrid seed production system. Self-incompatibility is successfully used for the production of F1 hybrid seeds in B. rapa vegetables to avoid contamination by non-hybrid seeds, and the strength of self-incompatibility is important for harvesting a highly pure F1 seeds. Prediction of agronomically important traits such as disease resistance based on DNA markers is useful. In this dataset, we identified the S haplotypes by DNA markers and evaluated the strength of self-incompatibility in Chinese cabbage inbred lines. The data described the predicted disease resistance to Fusarium yellows or clubroot in 22 Chinese cabbage inbred lines using gene associated or gene linked DNA markers.
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Affiliation(s)
- Kazutaka Kawamura
- Graduate School of Science and Technology, Niigata University, Ikarashi-ninocho, Niigata 950-2181, Japan
| | - Takahiro Kawanabe
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan
| | - Motoki Shimizu
- Graduate School of Science and Technology, Niigata University, Ikarashi-ninocho, Niigata 950-2181, Japan
| | - Keiichi Okazaki
- Graduate School of Science and Technology, Niigata University, Ikarashi-ninocho, Niigata 950-2181, Japan
| | - Makoto Kaji
- Watanabe seed Co., Ltd., Machiyashiki, Misato-cho, Miyagi 987-0003, Japan
| | | | - Kenji Osabe
- Plant Epigenetics Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Ryo Fujimoto
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan; JST PRESTO, Honcho 4-1-8, Kawaguchi, Saitama 332-0012, Japan
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Ishida M, Kakizaki T, Morimitsu Y, Ohara T, Hatakeyama K, Yoshiaki H, Kohori J, Nishio T. Novel glucosinolate composition lacking 4-methylthio-3-butenyl glucosinolate in Japanese white radish (Raphanus sativus L.). TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2015; 128:2037-2046. [PMID: 26152572 DOI: 10.1007/s00122-015-2564-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Accepted: 06/13/2015] [Indexed: 06/04/2023]
Abstract
Genetic analysis and gene mapping of the 4-methylthio-3-butenyl glucosinolate-less trait of white radish were performed and a white radish cultivar with new glucosinolate composition was developed. A spontaneous mutant having significantly low 4-methylthio-3-butenyl glucosinolate (4MTB-GSL) content was identified from a landrace of Japanese white radish (Raphanus sativus L.) through intensive evaluation of glucosinolate profiles of 632 lines including genetic resources and commercial cultivars using high-performance liquid chromatography (HPLC) analysis. A line lacking 4MTB-GSL was developed using the selected mutant as a gene source. Genetic analyses of F1, F2, and BC1F1 populations of this line suggested that the 4MTB-GSL-less trait is controlled by a single recessive allele. Using SNP and SCAR markers, 96 F2 plants were genotyped, and a linkage map having nine linkage groups with a total map distance of 808.3 cM was constructed. A gene responsible for the 4MTB-GSL-less trait was mapped between CL1753 and CL5895 at the end of linkage group 1. The genetic distance between these markers was 4.2 cM. By selfing and selection of plants lacking 4MTB-GSL, a new cultivar, 'Daikon parental line No. 5', was successfully developed. This cultivar was characterized by glucoerucin, which accounted for more than 90% of the total glucosinolates (GSLs). The total GSL content in roots was ca. 12 μmol/g DW, significantly lower than those in common white radish cultivars. Significance of this line in radish breeding is discussed.
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Affiliation(s)
- Masahiko Ishida
- NARO Institute of Vegetable and Tea Science, Tsukuba Vegetable Research Station, 3-1-1 Kannondai, Tsukuba, 305-8666, Japan
| | - Tomohiro Kakizaki
- NARO Institute of Vegetable and Tea Science, 360 Kusawa, Ano, Tsu, Mie, 514-2392, Japan
| | - Yasujiro Morimitsu
- The Department of Food and Nutritional Sciences, The Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo, 112-8610, Japan
| | - Takayoshi Ohara
- NARO Institute of Vegetable and Tea Science, 360 Kusawa, Ano, Tsu, Mie, 514-2392, Japan
| | - Katsunori Hatakeyama
- NARO Institute of Vegetable and Tea Science, 360 Kusawa, Ano, Tsu, Mie, 514-2392, Japan
| | - Hitoshi Yoshiaki
- NARO Institute of Vegetable and Tea Science, 360 Kusawa, Ano, Tsu, Mie, 514-2392, Japan
| | - Junna Kohori
- NARO Institute of Vegetable and Tea Science, 360 Kusawa, Ano, Tsu, Mie, 514-2392, Japan
| | - Takeshi Nishio
- Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori Amamiya-machi, Aoba-ku, Sendai, Miyagi, 981-8555, Japan.
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Zhai W, Zhang J, Yang Y, Ma C, Liu Z, Gao C, Zhou G, Tu J, Shen J, Fu T. Gene expression and genetic analysis reveal diverse causes of recessive self-compatibility in Brassica napus L. BMC Genomics 2014; 15:1037. [PMID: 25432521 PMCID: PMC4301934 DOI: 10.1186/1471-2164-15-1037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Accepted: 11/19/2014] [Indexed: 11/21/2022] Open
Abstract
Background Brassica napus (AACC) is self-compatible, although its ancestor species Brassica rapa (AA) and Brassica oleracea (CC) are self-incompatible. Most B.napus accessions have dominant self-compatibility (SC) resulting from an insertion of 3.6 kb in the promoter region of BnSCR-1 on the A genome, while recessive SC in B.napus has rarely been observed. Expression and cloning of SRK and SCR genes and genetic analysis were carried out to dissect bases of recessive SC in B.napus. Results Eleven accessions were screened to identify stable recessive SC and had the S genotype BnS-7 on the A genome and BnS-6 on the C genome similarly to BrS-29 and BoS-15, respectively. In eight SC accessions, BnSCR-7 and BnSCR-6 were nearly undetectable and harbored no structural mutations in the promoters, while SRK genes were expressed at normal levels and contained intact CDS, with the exception of BnSRK-7 in line C32. SRK and SCR genes were expressed normally but their CDSs had no mutations in three SC accessions. In self-incompatible S-1300 and 11 F1 hybrids, SRK genes and BnSCR-1300 transcripts were present at high levels, while expression of the BnSCR-7 and BnSCR-6 were absent. Plants of S genotype S1300S1300 were completely SI, while SI phenotypes of SBnS-7SBnS-7 and S1300SBnS-7 plants were segregated in BC1 and F2 populations. Conclusions The recessive SC in eight accessions is caused by the loss of function of BnSCR-7 and BnSCR-6 in pollen. Translational repression contributes to the recessive SC in three accessions, whose SRK and SCR genes were expressed normally and had identical CDSs to BrS-29 or BoS-15. SI in 11 F1 hybrids relies on the expression of BnSCR-1300 rather than SRK genes. Other factor(s) independent of the S locus are involved in recessive SC. Therefore, diverse causes underlie recessive SC in B. napus, yielding insight into these complex mechanisms. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-1037) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | - Chaozhi Ma
- National Key Laboratory of Crop Genetic Improvement, National Center of Rapeseed Improvement in Wuhan, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
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10
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Lao X, Suwabe K, Niikura S, Kakita M, Iwano M, Takayama S. Physiological and genetic analysis of CO2-induced breakdown of self-incompatibility in Brassica rapa. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:939-51. [PMID: 24376255 PMCID: PMC3935559 DOI: 10.1093/jxb/ert438] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Self-incompatibility (SI) of the Brassicaceae family can be overcome by CO2 gas treatment. This method has been used for decades as an effective means to obtain a large amount of inbred seeds which can then be used for F1 hybrid seed production; however, the molecular mechanism by which CO2 alters the SI pathway has not been elucidated. In this study, to obtain new insights into the mechanism of CO2-induced SI breakdown, the focus was on two inbred lines of Brassica rapa (syn. campestris) with different CO2 sensitivity. Physiological examination using X-ray microanalysis suggested that SI breakdown in the CO2-sensitive line was accompanied by a significant accumulation of calcium at the pollen-stigma interface. Pre-treatment of pollen or pistil with CO2 gas before pollination showed no effect on the SI reaction, suggesting that some physiological process after pollination is necessary for SI to be overcome. Genetic analyses using F1 progeny of a CO2-sensitive × CO2-insensitive cross suggested that CO2 sensitivity is a semi-dominant trait in these lines. Analysis of F2 progeny suggested that CO2 sensitivity could be a quantitative trait, which is controlled by more than one gene. Quantitative trait locus (QTL) analyses identified two major loci, BrSIO1 and BrSIO2, which work additively in overcoming SI during CO2 treatment. No QTL was detected at the loci previously shown to affect SI stability, suggesting that CO2 sensitivity is determined by novel genes. The QTL data presented here should be useful for determining the responsible genes, and for the marker-assisted selection of desirable parental lines with stable but CO2-sensitive SI in F1 hybrid breeding.
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Affiliation(s)
- Xintian Lao
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Keita Suwabe
- Graduate School of Bioresources, Mie University, Tsu 514-8507, Japan
| | | | - Mitsuru Kakita
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Megumi Iwano
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Seiji Takayama
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
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11
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Zeng F, Cheng B. Self-(in)compatibility inheritance and allele-specific marker development in yellow mustard ( Sinapis alba). MOLECULAR BREEDING : NEW STRATEGIES IN PLANT IMPROVEMENT 2013; 33:187-196. [PMID: 24482603 PMCID: PMC3890562 DOI: 10.1007/s11032-013-9943-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 08/10/2013] [Indexed: 05/27/2023]
Abstract
Yellow mustard (Sinapis alba) has a sporophytic self-incompatibility reproduction system. Genetically stable self-incompatible (SI) and self-compatible (SC) inbred lines have recently been developed in this crop. Understanding the S haplotype of different inbred lines and the inheritance of the self-(in)compatibility (SI/SC) trait is very important for breeding purposes. In this study, we used the S-locus gene-specific primers in Brassica rapa and Brassica oleracea to clone yellow mustard S-locus genes of SI lines Y514 and Y1130 and SC lines Y1499 and Y1501. The PCR amplification results and DNA sequences of the S-locus genes revealed that Y514 carried the class I S haplotype, while Y1130, Y1499, and Y1501 had the class II S haplotype. The results of our genetic studies indicated that self-incompatibility was dominant over self-compatibility and controlled by a one-gene locus in the two crosses of Y514 × Y1499 and Y1130 × Y1501. Of the five S-locus gene polymorphic primer pairs, Sal-SLGI and Sal-SRKI each generated one dominant marker for the SI phenotype of Y514; Sal-SLGII and Sal-SRKII produced dominant marker(s) for the SC phenotype of Y1501 and Y1499; Sal-SP11II generated one dominant marker for Y1130. These markers co-segregated with the SI/SC phenotype in the F2 populations of the two crosses. In addition, co-dominant markers were developed by mixing the two polymorphic primer pairs specific for each parent in the multiplex PCR, which allowed zygosity to be determined in the F2 populations. The SI/SC allele-specific markers have proven to be very useful for the selection of the desirable SC genotypes in our yellow mustard breeding program.
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Affiliation(s)
- Fangqin Zeng
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, SK S7N 0X2 Canada
| | - Bifang Cheng
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, SK S7N 0X2 Canada
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12
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Hatakeyama K, Horisaki A, Niikura S, Narusaka Y, Abe H, Yoshiaki H, Ishida M, Fukuoka H, Matsumoto S. Mapping of quantitative trait loci for high level of self-incompatibility in Brassica rapa L. Genome 2010; 53:257-65. [PMID: 20616857 DOI: 10.1139/g10-001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The level of self-incompatibility (SI) is important to the purity of F1 seeds produced using the SI system of Brassica vegetables. To analyze the genetic basis of the level of SI, we generated an F2 population derived from a cross between a turnip inbred line showing a high level of SI and a Chinese cabbage inbred line showing a low level, and evaluated the level of SI under insect pollination in two years. We constructed a detailed linkage map of Brassica rapa from the F2 progeny, consisting of SSR, SNP, indel, and CAPS loci segregating into 10 linkage groups covering approximately 700 cM. Five quantitative trait loci (QTL) for high-level SI were identified. The phenotypic variation explained by the QTL ranged between 7.2% and 23.8%. Two QTL were detected in both years. Mapping of SI-related genes revealed that these QTL were co-localized with SLG on R07 and MLPK on R03. This is the first report of QTL for high-level SI evaluated under insect pollination in a Brassica vegetable. Our results could be useful for the marker-assisted selection of parental lines with a stable SI.
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Affiliation(s)
- Katsunori Hatakeyama
- National Institute of Vegetable and Tea Science (NIVTS), 360, Kusawa, Ano, Tsu, Mie 514-2392, Japan.
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13
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Udagawa H, Ishimaru Y, Li F, Sato Y, Kitashiba H, Nishio T. Genetic analysis of interspecific incompatibility in Brassica rapa. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2010; 121:689-696. [PMID: 20414635 DOI: 10.1007/s00122-010-1340-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 04/03/2010] [Indexed: 05/29/2023]
Abstract
In interspecific pollination of Brassica rapa stigmas with Brassica oleracea pollen grains, pollen tubes cannot penetrate stigma tissues. This trait, called interspecific incompatibility, is similar to self-incompatibility in pollen tube behaviors of rejected pollen grains. Since some B. rapa lines have no interspecific incompatibility, genetic analysis of interspecific incompatibility was performed using two F(2) populations. Analysis with an F(2) population between an interspecific-incompatible line and a self-compatible cultivar 'Yellow sarson' having non-functional alleles of S-locus genes and MLPK, the stigmas of which are compatible with B. oleracea pollen grains, revealed no involvement of the S locus and MLPK in the difference of their interspecific incompatibility phenotypes. In QTL analysis of the strength of interspecific incompatibility, three peaks of LOD scores were found, but their LOD scores were as high as the threshold value, and the variance explained by each QTL was small. QTL analysis using another F(2) population derived from selected parents having the highest and lowest levels of interspecific incompatibility revealed five QTLs with high LOD scores, which did not correspond to those found in the former population. The QTL having the highest LOD score was found in linkage group A02. The effect of this QTL on interspecific incompatibility was confirmed by analyzing backcrossed progeny. Based on synteny of this QTL region with Arabidopsis thaliana chromosome 5, a possible candidate gene, which might be involved in interspecific incompatibility, is discussed.
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Affiliation(s)
- H Udagawa
- Laboratory of Plant Breeding and Genetics, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, Miyagi, 981-8555, Japan
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14
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Takuno S, Oikawa E, Kitashiba H, Nishio T. Assessment of genetic diversity of accessions in Brassicaceae genetic resources by frequency distribution analysis of S haplotypes. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2010; 120:1129-1138. [PMID: 20039015 DOI: 10.1007/s00122-009-1240-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Accepted: 12/08/2009] [Indexed: 05/28/2023]
Abstract
Plant genetic resources are important sources of genetic variation for improving crop varieties as breeding materials. Conservation of such resources of allogamous species requires maintenance of the genetic diversity within each accession to avoid inbreeding depression and loss of rare alleles. For assessment of genetic diversity in the self-incompatibility locus (S locus), which is critically involved in the chance of mating, we developed a dot-blot genotyping method for self-incompatibility (S) haplotypes and applied it to indigenous, miscellaneous landraces of Brassica rapa, provided by the IPK Gene Bank (Gatersleben, Germany) and the Tohoku University Brassica Seed Bank (Sendai, Japan), in which landraces are maintained using different population sizes. This method effectively determined S genotypes of more than 500 individuals from the focal landraces. Although our results suggest that these landraces might possess sufficient numbers of S haplotypes, the strong reduction of frequencies of recessive S haplotypes occurred, probably owing to genetic drift. Based on these results, we herein discuss an appropriate way to conserve genetic diversity of allogamous plant resources in a gene bank.
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Affiliation(s)
- S Takuno
- Laboratory of Plant Breeding and Genetics, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba, Sendai, Miyagi, 981-8555, Japan
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15
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Hadj-Arab H, Chèvre AM, Gaude T, Chable V. Variability of the self-incompatibility reaction in Brassica oleracea L. with S 15 haplotype. ACTA ACUST UNITED AC 2009; 23:141-51. [PMID: 20490967 DOI: 10.1007/s00497-009-0119-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2009] [Accepted: 10/26/2009] [Indexed: 10/20/2022]
Abstract
Self-incompatibility (SI) is thought to have played a key role in the evolution of species as it promotes their outcrossing through the recognition and rejection of self-pollen grains. In most species, SI is under the control of a complex, multiallelic S-locus. The recognition system is associated with quantitative variations of the strength of the SI reaction; the origin of these variations is still not elucidated. To define the genetic regulations involved, we studied the variability of the SI response in homozygous S 15 S 15 plants in cauliflower. These plants were obtained from a self-progeny of a self-compatible (SC) plant heterozygous for S 15, which was generated after five selfing generations from one strongly self-incompatible initial plant. We found a continuous phenotypic variation for SI response in the offspring plants homozygous for the S 15 haplotype, from the strict SI reaction to self-compatibility, with a great proportion of the plants being partially self-compatible (PSC). Decrease in SI levels was also observed during the life of the flower. The number of pollen tubes passing through the stigma barrier was higher when counted 3 or 5 days after pollination than one day after pollination. Analysis of the expression of the two key genes regulating self-pollen recognition in cauliflower, the S-locus receptor kinase (SRK) and S-locus cysteine-rich (SCR/SP11) genes, revealed that self-compatibility or PSC was associated with decreased SRK or SCR/SP11 expression. Our work shows the particularly high level of phenotypic plasticity of the SI response associated with certain S-haplotypes in cauliflower.
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Affiliation(s)
- Houria Hadj-Arab
- USTHB FSB Laboratoire de Biologie et Physiologie des Organismes, BP 32 El-Alia, 16111, Alger, Algerie.
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16
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Zhang X, Ma C, Tang J, Tang W, Tu J, Shen J, Fu T. Distribution of S haplotypes and its relationship with restorer-maintainers of self-incompatibility in cultivated Brassica napus. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2008; 117:171-179. [PMID: 18404257 DOI: 10.1007/s00122-008-0763-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Accepted: 03/28/2008] [Indexed: 05/26/2023]
Abstract
Brassica napus (AACC, 2n = 38) is a self-compatible amphidiploid plant that arose from the interspecies hybridization of two self-incompatible species, B. rapa (AA, 2n = 20) and B. oleracea (CC, 2n = 18). Self-incompatibility (S) haplotypes in one self-incompatible line and 124 cultivated B. napus lines were detected using S-locus-specific primers, and their relationships with restorer-maintainers were investigated. Two class I (S-I ( SLG ) a and S-I ( SLG ) b) and four class II (S-II ( SLG ) a, S-II ( SLG ) b, S-II ( SP11 ) a and S-II ( SP11 ) b) S haplotypes were observed, of which S-II ( SP11 ) b was newly identified. The nucleotide sequence of SP11 showed little similarity to the reported SP11 alleles. The lines were found to express a total of eleven S genotypes. The self-incompatible line had a specific genotype consisting of S-II ( SP11 ) a, similar to B. rapa S-60, and S-II ( SLG ) a, similar to B. oleracea S-15. Restorers expressed six genotypes: the most common genotype contained S-I ( SLG ) a, similar to B. rapa S-47, and S-II ( SLG ) b, similar to B. oleracea S-15. Maintainers expressed nine genotypes: the predominant genotype was homozygous for two S haplotypes, S-II ( SLG ) a and S-II ( SP11 ) b. One genotype was specific to restorers and four genotypes were specific to maintainers, whereas five genotypes were expressed in both restorers and maintainers. This suggests that there is no definitive correlation between the distribution of S genotypes and restorer-maintainers of self-incompatibility. The finding that restorers and maintainers express unique genotypes, and share some common genotypes, would be valuable for detecting the interaction of S haplotypes in inter- or intra-genomes as well as for developing markers-assisted selection in self-incompatibility hybrid breeding.
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Affiliation(s)
- Xingguo Zhang
- National Key Laboratory of Crop Genetic Improvement, National Center of Rapeseed Improvement in Wuhan, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
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17
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Okamoto S, Odashima M, Fujimoto R, Sato Y, Kitashiba H, Nishio T. Self-compatibility in Brassica napus is caused by independent mutations in S-locus genes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2007; 50:391-400. [PMID: 17425715 DOI: 10.1111/j.1365-313x.2007.03058.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Brassica napus is an amphidiploid species with the A genome from Brassica rapa and the C genome from Brassica oleracea. Although B. rapa, B. oleracea and artificially synthesized amphidiploids with the AC genome are self-incompatible, B. napus is self-compatible. Six S genotypes were identified in B. napus, five of which had class I S haplotypes from one species and a class II S haplotype from the other species, and mutations causing self-compatibility were identified in three of these S genotypes. The most predominant S genotype (BnS-1;BnS-6), which is that of cv. 'Westar', had a class I S haplotype similar to B. rapa S-47 (BrS-47) and a class II S haplotype similar to B. oleracea S-15 (BoS-15). The stigmas of 'Westar' rejected the pollen grains of both BrS-47 and BoS-15, while reciprocal crossings were compatible. Insertion of a DNA fragment of about 3.6 kb was found in the promoter region of the SP11/SCR allele of BnS-1, and transcripts of SP11/SCR were not detected in 'Westar'. The nucleotide sequence of the SP11 genomic DNA of BnS-6 was 100% identical to that of SP11 of BoS-15. Class I SP11 alleles from one species showed dominance over class II SP11 alleles from the other species in artificially synthesized B. napus lines, suggesting that the non-functional dominant SP11 allele suppressed the expression of the recessive SP11 allele in 'Westar'. Two other S genotypes in B. napus also had non-functional class I S haplotypes together with recessive BnS-6. These observations suggest independent origins of self-compatibility in B. napus.
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Affiliation(s)
- Shunsuke Okamoto
- Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan
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18
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Fujimoto R, Sugimura T, Fukai E, Nishio T. Suppression of gene expression of a recessive SP11/SCR allele by an untranscribed SP11/SCR allele in Brassica self-incompatibility. PLANT MOLECULAR BIOLOGY 2006; 61:577-87. [PMID: 16897476 DOI: 10.1007/s11103-006-0032-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2005] [Accepted: 02/22/2006] [Indexed: 05/08/2023]
Abstract
Mutations in the S locus of a self-compatible cultivar Yellow Sarson in Brassica rapa, which has a self-compatible class-I S haplotype, S-f2, were investigated. S-28 in Brassica oleracea was found to be a member of an interspecific pair with S-f2 in B. rapa. The original S haplotype of S-f2 was identified to be S-54 in B. rapa. Sequence comparison of alleles in S-f2 with those in S-54 and B. oleracea S-28 revealed insertion of a retrotransposon-like sequence in the first intron of SRK and 89-bp deletion in the promoter region of SP11. No transcripts of SRK and SP11 were detected in S-f2 homozygotes, suggesting that the insertion and the deletion in SRK and SP11, respectively, caused the loss of the function of these genes. Promoter assay using transgenic plants indicated that the SP11 promoter of S-f2 has no activity. Heterozygotes of S-f2 and a normal class-II S haplotype, S-60, in B. rapa were found to be self-compatible. Interestingly, transcription of SP11-60 was revealed to be suppressed in the S-f2/S-60 heterozygotes, suggesting that an untranscribed class-I SP11 allele suppresses the expression of a recessive class-II SP11 allele in the anthers of S heterozygotes. Similar phenomenon was observed in heterozygotes of a self-compatible class-I S haplotype and a self-incompatible class-II S haplotype in B. oleracea.
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Affiliation(s)
- Ryo Fujimoto
- Graduate School of Agricultural Science, Tohoku University, 981-8555 Aoba-ku, Sendai, Japan
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19
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Sato Y, Sato K, Nishio T. Interspecific pairs of class II S haplotypes having different recognition specificities between Brassica oleracea and Brassica rapa. PLANT & CELL PHYSIOLOGY 2006; 47:340-5. [PMID: 16381659 DOI: 10.1093/pcp/pci250] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
There are several pairs of similar class I S haplotypes between Brassica oleracea and Brassica rapa. The similar S halotypes in these interspecific pairs have been reported to have the same recognition specificities. In the present study, three interspecific pairs showing a high sequence similarity were found in class II S haplotypes, i.e. between BoS-2b (B. oleracea S-2b) and BrS-44 (B. rapa S-44), between BoS-5 and BrS-40, and between BoS-15 and BrS-60. By pollination tests using interspecific hybrids between B. oleracea and B. rapa, BoS-5 and BoS-2b were revealed to have slightly and completely different recognition specificities from those of BrS-40 and BrS-44, respectively. The recognition reaction between SP11 and SRK of BoS-15 was suggested to be incomplete. The regions of class II SP11 and SRK important for self-recognition specificity and the diversification of class II S haplotypes are discussed herein.
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Affiliation(s)
- Yutaka Sato
- Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
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20
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Fujimoto R, Sugimura T, Nishio T. Gene conversion from SLG to SRK resulting in self-compatibility in Brassica rapa. FEBS Lett 2005; 580:425-30. [PMID: 16376883 DOI: 10.1016/j.febslet.2005.12.028] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2005] [Revised: 11/21/2005] [Accepted: 12/06/2005] [Indexed: 10/25/2022]
Abstract
Self-compatible S-54 homozygotic plants were found in progenies of an F(1) hybrid cultivar in Chinese cabbage. Pollination tests revealed that this self-compatibility is controlled by the S locus and caused by the loss of the recognition function of the stigma. SRK, the gene for the recognition molecule in the stigma, was normally transcribed and translated in the self-compatible plants. The 1034-bp region in the receptor domain of SRK in the self-compatible plants was 100% identical to SLG in S-54, while that in self-incompatible S-54 homozygotic plants was 95.1% identical. These results suggest that the self-compatibility of the S-54 homozygotes is due to amino-acid changes caused by gene conversion from SLG to SRK.
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Affiliation(s)
- Ryo Fujimoto
- Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan
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21
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Ekuere UU, Parkin IAP, Bowman C, Marshall D, Lydiate DJ. Latent S alleles are widespread in cultivated self-compatible Brassica napus. Genome 2005; 47:257-65. [PMID: 15060578 DOI: 10.1139/g03-120] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The genetic control of self-incompatibility in Brassica napus was investigated using crosses between resynthesized lines of B. napus and cultivars of oilseed rape. These crosses introduced eight C-genome S alleles from Brassica oleracea (S16, S22, S23, S25, S29, S35, S60, and S63) and one A-genome S allele from Brassica rapa (SRM29) into winter oilseed rape. The inheritance of S alleles was monitored using genetic markers and S phenotypes were determined in the F1, F2, first backcross (B1), and testcross (T1) generations. Two different F1 hybrids were used to develop populations of doubled haploid lines that were subjected to genetic mapping and scored for S phenotype. These investigations identified a latent S allele in at least two oilseed rape cultivars and indicated that the S phenotype of these latent alleles was masked by a suppressor system common to oilseed rape. These latent S alleles may be widespread in oilseed rape varieties and are possibly associated with the highly conserved C-genome S locus of these crop types. Segregation for S phenotype in subpopulations uniform for S genotype suggests the existence of suppressor loci that influenced the expression of the S phenotype. These suppressor loci were not linked to the S loci and possessed suppressing alleles in oilseed rape and non-suppressing alleles in the diploid parents of resynthesized B. napus lines.
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Affiliation(s)
- U U Ekuere
- John Innes Centre, Norwich Research Park, UK.
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22
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Haffani YZ, Gaude T, Cock JM, Goring DR. Antisense suppression of thioredoxin h mRNA in Brassica napus cv. Westar pistils causes a low level constitutive pollen rejection response. PLANT MOLECULAR BIOLOGY 2004; 55:619-30. [PMID: 15604705 DOI: 10.1007/s11103-004-1126-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In Brassica , the thioredoxin h proteins, THL1 and THL2, were previously found to be potential inhibitors of the S receptor kinase (SRK) in the Brassica self-incompatibility response. To investigate the biological roles of THL1 and THL2 in pollen-pistil interactions, the stigma-specific SLR1 promoter was used to drive antisense THL1/2 expression in Brassica napus cv. Westar. This cultivar is normally compatible, but antisense suppression of THL1/2 led to a low level constitutive rejection of all Brassica napus pollen tested. Fluorescence microscopy revealed that the pollen rejection was a typical Brassica self-incompatibility rejection response with reduced pollen adhesion, germination and pollen tube growth. In addition, Westar was found to express the SLG(15) and SRK(15) proteins which may be the target of regulation by THL1 and THL2. Thus, these results indicate that the THL1 and THL2 are required for full pollen acceptance in B. napus cv. Westar.
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Affiliation(s)
- Yosr Z Haffani
- Department of Botany, University of Toronto, Ontario, Canada M5S 3B2
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23
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Fukai E, Fujimoto R, Nishio T. Genomic organization of the S core region and the S flanking regions of a class-II S haplotype in Brassica rapa. Mol Genet Genomics 2003; 269:361-9. [PMID: 12684882 DOI: 10.1007/s00438-003-0844-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2002] [Accepted: 03/19/2003] [Indexed: 10/26/2022]
Abstract
The nucleotide sequence of an 86.4-kb region that includes the SP11, SRK, and SLG genes of Brassica rapa S-60 (a class-II S haplotype) was determined. In the sequenced region, 13 putative genes were found besides SP11-60, SRK-60, and SLG-60. Five of these sequences were isolated as cDNAs, five were homologues of known genes, cDNAs, or ORFs, and three are hypothetical ORFs. Based on their nucleotide sequences, however, some of them are thought to be non-functional. Two regions of colinearity between the class-II S-60 and Brassica class-I S haplotypes were identified, i.e., S flanking region 1 which shows partial colinearity of non-genic sequences and S flanking region 2 which shows a high level of colinearity. The observed colinearity made it possible to compare the order of SP-11, SRK, and SLG genes in the S locus between the five sequenced S haplotypes. It emerged that the order of SRK and SLG in class-II S-60 is the reverse of that in the four class-I S haplotypes reported so far, and the order of SP11, SRK and SLG is the opposite of that in the class-I haplotype S-910. The possible gene designated as SAN1 (S locus Anther-expressed Non-coding RNA like-1), which is located in the region between SP11-60 and SRK-60, has features reminiscent of genes for non-coding RNAs (ncRNAs), but no homologous sequences were found in the databases. This sequence is transcribed in anthers but not in stigmas or leaves. These features of the genomic structure of S-60 are discussed with special reference to the characteristics of class-II S haplotypes.
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Affiliation(s)
- E Fukai
- Graduate School of Agricultural Science, Tohoku University, Aoba-ku, 981-8555, Sendai, Japan
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24
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Sato K, Nishio T, Kimura R, Kusaba M, Suzuki T, Hatakeyama K, Ockendon DJ, Satta Y. Coevolution of the S-locus genes SRK, SLG and SP11/SCR in Brassica oleracea and B. rapa. Genetics 2002; 162:931-40. [PMID: 12399400 PMCID: PMC1462302 DOI: 10.1093/genetics/162.2.931] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Brassica self-incompatibility (SI) is controlled by SLG and SRK expressed in the stigma and by SP11/SCR expressed in the anther. We determined the sequences of the S domains of 36 SRK alleles, 13 SLG alleles, and 14 SP11 alleles from Brassica oleracea and B. rapa. We found three S haplotypes lacking SLG genes in B. rapa, confirming that SLG is not essential for the SI recognition system. Together with reported sequences, the nucleotide diversities per synonymous and nonsynonymous site (pi(S) and pi(N)) at the SRK, SLG, and SP11 loci within B. oleracea were computed. The ratios of pi(N):pi(S) for SP11 and the hypervariable region of SRK were significantly >1, suggesting operation of diversifying selection to maintain the diversity of these regions. In the phylogenetic trees of 12 SP11 sequences and their linked SRK alleles, the tree topology was not significantly different between SP11 and SRK, suggesting a tight linkage of male and female SI determinants during the evolutionary course of these haplotypes. Genetic exchanges between SLG and SRK seem to be frequent; three such recent exchanges were detected. The evolution of S haplotypes and the effect of gene conversion on self-incompatibility are discussed.
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Affiliation(s)
- Keiichi Sato
- Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan
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25
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Miege C, Ruffio-Châble V, Schierup MH, Cabrillac D, Dumas C, Gaude T, Cock JM. Intrahaplotype polymorphism at the Brassica S locus. Genetics 2001; 159:811-22. [PMID: 11606555 PMCID: PMC1461823 DOI: 10.1093/genetics/159.2.811] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The S locus receptor kinase and the S locus glycoproteins are encoded by genes located at the S locus, which controls the self-incompatibility response in Brassica. In class II self-incompatibility haplotypes, S locus glycoproteins can be encoded by two different genes, SLGA and SLGB. In this study, we analyzed the sequences of these genes in several independently isolated plants, all of which carry the same S haplotype (S(2)). Two groups of S(2) haplotypes could be distinguished depending on whether SRK was associated with SLGA or SLGB. Surprisingly, SRK alleles from the two groups could be distinguished at the sequence level, suggesting that recombination rarely occurs between haplotypes of the two groups. An analysis of the distribution of polymorphisms along the S domain of SRK showed that hypervariable domains I and II tend to be conserved within haplotypes but to be highly variable between haplotypes. This is consistent with these domains playing a role in the determination of haplotype specificity.
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Affiliation(s)
- C Miege
- Reproduction et Développement des Plantes, UMR 5667 CNRS-INRA-ENSL, Ecole Normale Supérieure de Lyon, 69364 Lyon, France
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26
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Hatakeyama K, Takasaki T, Suzuki G, Nishio T, Watanabe M, Isogai A, Hinata K. The S receptor kinase gene determines dominance relationships in stigma expression of self-incompatibility in Brassica. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2001; 26:69-76. [PMID: 11359611 DOI: 10.1046/j.1365-313x.2001.01009.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Self-incompatibility (SI) in Brassica is sporophytically controlled by the multi-allelic S locus. SI phenotypes of the stigma and pollen in an S heterozygote are determined by the two S haplotypes it carries; the two haplotypes may be co-dominant or exhibit a dominant/recessive relationship. Because the S receptor kinase (SRK) gene of the S locus was recently shown to determine the S haplotype specificity of the stigma, we wished to investigate whether SRK also plays a role in the dominance relationships between S haplotypes. We crossed plants carrying an SRK28 transgene with plants homozygous for one of five S haplotypes that are either co-dominant with, or recessive to, S28 haplotype in the stigma, and analyzed the SI phenotypes of the progeny. In all cases, the SI phenotype of the stigma of plants carrying the SRK28 transgene could be predicted by the known dominance relationships between the S haplotype(s) and the S28 haplotype. Moreover, in the S43 homozygote carrying the SRK28 transgene where the S43 phenotype in the stigma was masked by the presence of the SRK28, the transcript level of SRK28 was found to be much lower than that of SRK43. All these results suggest that the dominance relationships between S haplotypes in the stigma are determined by SRK, but not by virtue of its relative expression level.
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Affiliation(s)
- K Hatakeyama
- Research Institute of Seed Production Co. Ltd., 6-6-3 Minamiyoshinari, Aoba-ku, Sendai, 989-3204, Japan
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27
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Suzuki T, Kusaba M, Matsushita M, Okazaki K, Nishio T. Characterization of Brassica S-haplotypes lacking S-locus glycoprotein. FEBS Lett 2000; 482:102-8. [PMID: 11018531 DOI: 10.1016/s0014-5793(00)02048-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Self-incompatibility (SI) in Brassica is regulated by a single multi-allelic locus, S, which contains highly polymorphic stigma-expressed genes, SLG and SRK. While SRK is shown to be the determinant of female SI specificity, SLG is thought to assist the function of SRK. Here we report that the SLG genes of self-incompatible S(18) and S(60) homozygotes of Brassica oleracea have an in-frame stop codon and a 23 bp deletion resulting in a frame-shift, respectively. The finding that these SLG genes do not encode functional SLG proteins suggests that SLG is not essential for SI. The possible role of SLG in SI was discussed.
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Affiliation(s)
- T Suzuki
- Institute of Radiation Breeding, National Institute of Agrobiological Resources, P.O. Box 3, Ohmiya-machi, Naka-gun, Ibaraki 319-2293, Japan
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28
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Abstract
Self-incompatibility in Brassica entails the rejection of pollen grains that express specificities held in common with the seed parent. In Brassica, pollen specificity is encoded at the multipartite S-locus, a complex region comprising many expressed genes. A number of species within the Brassicaceae express sporophytic self-incompatibility, under which individual pollen grains bear specificities determined by one or both S-haplotypes of the pollen parent. Classical genetic and nucleotide-level analyses of the S-locus have revealed a dichotomy in sequence and function among S-haplotypes; in particular, all class I haplotypes show dominance over all class II haplotypes in determination of pollen specificity. Analysis of an evolutionary model that explicitly incorporates features of the Brassica system, including the class dichotomy, indicates that class II haplotypes may invade populations at lower rates and decline to extinction at higher rates than class I haplotypes. This analysis suggests convergence to an evolutionarily persistent state characterized by the maintenance in high frequency of a single class II haplotype together with many class I haplotypes, each in low frequency. This expectation appears to be consistent with empirical observations of high frequencies of relatively few distinct recessive haplotypes.
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Affiliation(s)
- M K Uyenoyama
- Department of Zoology, Duke University, Durham, North Carolina 27708-0325, USA.
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29
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Takasaki T, Hatakeyama K, Suzuki G, Watanabe M, Isogai A, Hinata K. The S receptor kinase determines self-incompatibility in Brassica stigma. Nature 2000; 403:913-6. [PMID: 10706292 DOI: 10.1038/35002628] [Citation(s) in RCA: 295] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The self-incompatibility possessed by Brassica is an intraspecific reproductive barrier by which the stigma rejects self-pollen but accepts non-self-pollen for fertilization. The molecular/biochemical bases of recognition and rejection have been intensively studied. Self-incompatibility in Brassica is sporophytically controlled by the polymorphic S locus. Two tightly linked polymorphic genes at the S locus, S receptor kinase gene (SRK) and S locus glycoprotein gene (SLG), are specifically expressed in the papillar cells of the stigma, and analyses of self-compatible lines of Brassica have suggested that together they control stigma function in self-incompatibility interactions. Here we show, by transforming self-incompatible plants of Brassica rapa with an SRK28 and an SLG28 transgene separately, that expression of SRK28 alone, but not SLG28 alone, conferred the ability to reject self (S28)-pollen on the transgenic plants. We also show that the ability of SRK28 to reject S28 pollen was enhanced by SLG28. We conclude that SRK alone determines S haplotype specificity of the stigma, and that SLG acts to promote a full manifestation of the self-incompatibility response.
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Affiliation(s)
- T Takasaki
- Research Institute of Seed Production Co., Ltd., Sendai, Japan.
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30
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Kusaba M, Matsushita M, Okazaki K, Satta Y, Nishio T. Sequence and structural diversity of the S locus genes from different lines with the same self-recognition specificities in Brassica oleracea. Genetics 2000; 154:413-20. [PMID: 10628999 PMCID: PMC1460907 DOI: 10.1093/genetics/154.1.413] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Self-incompatibility (SI) is a mechanism for preventing self-fertilization in flowering plants. In Brassica, it is controlled by a single multi-allelic locus, S, and it is believed that two highly polymorphic genes in the S locus, SLG and SRK, play central roles in self-recognition in stigmas. SRK is a putative receptor protein kinase, whose extracellular domain exhibits high similarity to SLG. We analyzed two pairs of lines showing cross-incompatibility (S(2) and S(2-b); S(13) and S(13-b)). In S(2) and S(2-b), SRKs were more highly conserved than SLGs. This was also the case with S(13) and S(13-b). This suggests that the SRKs of different lines must be conserved for the lines to have the same self-recognition specificity. In particular, SLG(2-b) showed only 88. 5% identity to SLG(2), which is comparable to that between the SLGs of different S haplotypes, while SRK(2-b) showed 97.3% identity to SRK(2) in the S domain. These findings suggest that the SLGs in these S haplotypes are not important for self-recognition in SI.
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Affiliation(s)
- M Kusaba
- Institute of Radiation Breeding, National Institute of Agrobiological Resources, Ministry of Agriculture, Forestry and Fisheries, Ohmiya-machi, Naka-gun, Ibaraki, 319-2293, Japan.
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31
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Kusaba M, Nishio T. Comparative analysis of S haplotypes with very similar SLG alleles in Brassica rapa and Brassica oleracea. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 1999; 17:83-91. [PMID: 10069069 DOI: 10.1046/j.1365-313x.1999.00355.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Self-incompatibility in Brassica is controlled by a single multi-allelic locus (the S locus) which harbors at least two highly polymorphic genes, SLG and SRK. SRK is a putative transmembrane receptor kinase and its amino acid sequence of the extracellular domain of SRK (the S domain) exhibits high homology to that of SLG. The amino acid sequences of the SLGs of S8 and S46 haplotypes of B. rapa are very similar and those of S23 and S29 haplotypes of B. oleracea were also found to be almost identical. In both cases, SLG and the S domain of SRK of the same haplotype were less similar. This seems to contradict the idea that SLG and SRK of the same haplotype have the same self-recognition specificity. In the transmembrane-kinase domain, the SRK alleles of the S8 and S46 haplotypes had almost identical nucleotide sequences in spite of their lower homology in the S domain. Such a cluster of nucleotide substitutions is probably due to recombination or related events, although recombination in the S locus is thought to be suppressed. Based on our observations, the recognition mechanism and the evolution of self-incompatibility in Brassica are discussed.
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Affiliation(s)
- M Kusaba
- Institute of Radiation Breeding National Institute of Agrobiological Resources, Ministry of Agriculture, Forestry and Fisheries, Ibaraki, Japan.
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32
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Hatakeyama K, Takasaki T, Watanabe M, Hinata K. Molecular characterization of S locus genes, SLG and SRK, in a pollen-recessive self-incompatibility haplotype of Brassica rapa L. Genetics 1998; 149:1587-97. [PMID: 9649545 PMCID: PMC1460250 DOI: 10.1093/genetics/149.3.1587] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In Brassica species that exhibit self-incompatibility, two genes, SLG and SRK, at the S locus are involved in the recognition reaction with self and non-self pollen. From a pollen-recessive S29 haplotype of Brassica rapa, both cDNA and genomic DNA clones for these two genes were isolated and characterized. The nucleotide sequence for the S domain of SRK29 showed a high degree of similarity with that of SLG29, and they belong to Class II type. RNA gel blot analysis showed that the transcript of SLG29 consisted of the first and second exons, and no other transcript containing any part of the intron sequence was detected. Because no transmembrane domain was encoded by the second exon of SLG29, SLG29 was designated a secreted type glycoprotein. SLGs of two other pollen-recessive haplotypes, S40 and S44, of B. rapa also had a similar structure to that of SLG29. Previously, SLG2 from a pollen-recessive haplotype, S2, of Brassica oleracea was found to produce two different transcripts, one for the secreted type glycoprotein and the other for a putative membrane-anchored form of SLG. Therefore, the nature of these SLGs from pollen-recessive haplotypes of B. rapa is different from that of SLG2 of B. oleracea.
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Affiliation(s)
- K Hatakeyama
- Research Institute of Seed Production Co., Ltd., 6-6-3, Minamiyoshinari, Aoba-ku, Sendai, 989-3204, Japan.
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33
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Kusaba M, Nishio T, Satta Y, Hinata K, Ockendon D. Striking sequence similarity in inter- and intra-specific comparisons of class I SLG alleles from Brassica oleracea and Brassica campestris: implications for the evolution and recognition mechanism. Proc Natl Acad Sci U S A 1997; 94:7673-8. [PMID: 9207151 PMCID: PMC23881 DOI: 10.1073/pnas.94.14.7673] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Self-incompatibility in Brassica is controlled by a single multi-allelic locus (S locus), which contains at least two highly polymorphic genes expressed in the stigma: an S glycoprotein gene (SLG) and an S receptor kinase gene (SRK). The putative ligand-binding domain of SRK exhibits high homology to the secretory protein SLG, and it is believed that SLG and SRK form an active receptor kinase complex with a self-pollen ligand, which leads to the rejection of self-pollen. Here, we report 31 novel SLG sequences of Brassica oleracea and Brassica campestris. Sequence comparisons of a large number of SLG alleles and SLG-related genes revealed the following points. (i) The striking sequence similarity observed in an inter-specific comparison (95.6% identity between SLG14 of B. oleracea and SLG25 of B. campestris in deduced amino acid sequence) suggests that SLG diversification predates speciation. (ii) A perfect match of the sequences in hypervariable regions, which are thought to determine S specificity in an intra-specific comparison (SLG8 and SLG46 of B. campestris) and the observation that the hypervariable regions of SLG and SRK of the same S haplotype were not necessarily highly similar suggests that SLG and SRK bind different sites of the pollen ligand and that they together determine S specificity. (iii) Comparison of the hypervariable regions of SLG alleles suggests that intragenic recombination, together with point mutations, has contributed to the generation of the high level of sequence variation in SLG alleles. Models for the evolution of SLG/SRK are presented.
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Affiliation(s)
- M Kusaba
- Institute of Radiation Breeding, National Institute of Agrobiological Resources, Ministry of Agriculture, Forestry and Fisheries, Ohmiya Naka-gun, Ibaraki 319-22, Japan
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