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A new synthetic allotetraploid (A1A1G2G2) between Gossypium herbaceum and G. australe: bridging for simultaneously transferring favorable genes from these two diploid species into upland cotton.

Liu Q, Chen Y, Chen Y, Wang Y, Chen J, Zhang T, Zhou B - PLoS ONE (2015)

Bottom Line: Creating synthetic allotetraploid cotton from these two species would lay the foundation for simultaneously transferring favorable genes into cultivated tetraploid cotton.Here, we crossed G. herbaceum (as the maternal parent) with G. australe to produce an F1 interspecific hybrid and doubled its chromosome complement with colchicine, successfully generating a synthetic tetraploid.The synthetic allotetraploid will be quite useful for polyploidy evolutionary studies and as a bridge for transferring favorable genes from these two diploid species into Upland cotton through hybridization.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Crop Genetics & Germplasm Enhancement, MOE Hybrid Cotton R&D Engineering Research Center, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China.

ABSTRACT
Gossypium herbaceum, a cultivated diploid cotton species (2n = 2x = 26, A1A1), has favorable traits such as excellent drought tolerance and resistance to sucking insects and leaf curl virus. G. australe, a wild diploid cotton species (2n = 2x = 26, G2G2), possesses numerous economically valuable characteristics such as delayed pigment gland morphogenesis (which is conducive to the production of seeds with very low levels of gossypol as a potential food source for humans and animals) and resistance to insects, wilt diseases and abiotic stress. Creating synthetic allotetraploid cotton from these two species would lay the foundation for simultaneously transferring favorable genes into cultivated tetraploid cotton. Here, we crossed G. herbaceum (as the maternal parent) with G. australe to produce an F1 interspecific hybrid and doubled its chromosome complement with colchicine, successfully generating a synthetic tetraploid. The obtained tetraploid was confirmed by morphology, cytology and molecular markers and then self-pollinated. The S1 seedlings derived from this tetraploid gradually became flavescent after emergence of the fifth true leaf, but they were rescued by grafting and produced S2 seeds. The rescued S1 plants were partially fertile due to the existence of univalents at Metaphase I of meiosis, leading to the formation of unbalanced, nonviable gametes lacking complete sets of chromosomes. The S2 plants grew well and no flavescence was observed, implying that interspecific incompatibility, to some extent, had been alleviated in the S2 generation. The synthetic allotetraploid will be quite useful for polyploidy evolutionary studies and as a bridge for transferring favorable genes from these two diploid species into Upland cotton through hybridization.

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Related in: MedlinePlus

Genomic in situ hybridization showing the chromosome components of an S2 mitotic cell of the new synthetic allotetraploid (Slides were stained in 4’, 6-diamidino-2-phenylindole [DAPI]).Red signals indicate the 26 chromosomes of G. australe (probe labeled with digoxigenin-11-dUTP) and blue signals indicate the 26 chromosomes of G. herbaceum (stained with DAPI).
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pone.0123209.g002: Genomic in situ hybridization showing the chromosome components of an S2 mitotic cell of the new synthetic allotetraploid (Slides were stained in 4’, 6-diamidino-2-phenylindole [DAPI]).Red signals indicate the 26 chromosomes of G. australe (probe labeled with digoxigenin-11-dUTP) and blue signals indicate the 26 chromosomes of G. herbaceum (stained with DAPI).

Mentions: To confirm the authenticity of the synthetic allotetraploid and to examine its genome components, we performed GISH under standard stringency conditions using G2 gDNA from G. australe labeled with digoxigenin (DIG)-Nick Translation Mix DNA as a labeled probe and A1 gDNA from G. herbaceum race kuljianum cv Hongxingcaomian as unlabeled DNA. Somatic S2 mitotic cells were used as targets. Red hybridization signals were consistently detected on 26 chromosomes (G2 genome) and blue signals were detected on the other 26 chromosomes (A1 genome) in over 30 well-spread somatic chromosome cells that were observed. Thus, the chromosomes from the two genomes could clearly be differentiated based on color (Fig 2). Therefore, the authenticity of the new synthetic allotetraploid has been confirmed and its genome components can be readily discriminated as well.


A new synthetic allotetraploid (A1A1G2G2) between Gossypium herbaceum and G. australe: bridging for simultaneously transferring favorable genes from these two diploid species into upland cotton.

Liu Q, Chen Y, Chen Y, Wang Y, Chen J, Zhang T, Zhou B - PLoS ONE (2015)

Genomic in situ hybridization showing the chromosome components of an S2 mitotic cell of the new synthetic allotetraploid (Slides were stained in 4’, 6-diamidino-2-phenylindole [DAPI]).Red signals indicate the 26 chromosomes of G. australe (probe labeled with digoxigenin-11-dUTP) and blue signals indicate the 26 chromosomes of G. herbaceum (stained with DAPI).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4400159&req=5

pone.0123209.g002: Genomic in situ hybridization showing the chromosome components of an S2 mitotic cell of the new synthetic allotetraploid (Slides were stained in 4’, 6-diamidino-2-phenylindole [DAPI]).Red signals indicate the 26 chromosomes of G. australe (probe labeled with digoxigenin-11-dUTP) and blue signals indicate the 26 chromosomes of G. herbaceum (stained with DAPI).
Mentions: To confirm the authenticity of the synthetic allotetraploid and to examine its genome components, we performed GISH under standard stringency conditions using G2 gDNA from G. australe labeled with digoxigenin (DIG)-Nick Translation Mix DNA as a labeled probe and A1 gDNA from G. herbaceum race kuljianum cv Hongxingcaomian as unlabeled DNA. Somatic S2 mitotic cells were used as targets. Red hybridization signals were consistently detected on 26 chromosomes (G2 genome) and blue signals were detected on the other 26 chromosomes (A1 genome) in over 30 well-spread somatic chromosome cells that were observed. Thus, the chromosomes from the two genomes could clearly be differentiated based on color (Fig 2). Therefore, the authenticity of the new synthetic allotetraploid has been confirmed and its genome components can be readily discriminated as well.

Bottom Line: Creating synthetic allotetraploid cotton from these two species would lay the foundation for simultaneously transferring favorable genes into cultivated tetraploid cotton.Here, we crossed G. herbaceum (as the maternal parent) with G. australe to produce an F1 interspecific hybrid and doubled its chromosome complement with colchicine, successfully generating a synthetic tetraploid.The synthetic allotetraploid will be quite useful for polyploidy evolutionary studies and as a bridge for transferring favorable genes from these two diploid species into Upland cotton through hybridization.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Crop Genetics & Germplasm Enhancement, MOE Hybrid Cotton R&D Engineering Research Center, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China.

ABSTRACT
Gossypium herbaceum, a cultivated diploid cotton species (2n = 2x = 26, A1A1), has favorable traits such as excellent drought tolerance and resistance to sucking insects and leaf curl virus. G. australe, a wild diploid cotton species (2n = 2x = 26, G2G2), possesses numerous economically valuable characteristics such as delayed pigment gland morphogenesis (which is conducive to the production of seeds with very low levels of gossypol as a potential food source for humans and animals) and resistance to insects, wilt diseases and abiotic stress. Creating synthetic allotetraploid cotton from these two species would lay the foundation for simultaneously transferring favorable genes into cultivated tetraploid cotton. Here, we crossed G. herbaceum (as the maternal parent) with G. australe to produce an F1 interspecific hybrid and doubled its chromosome complement with colchicine, successfully generating a synthetic tetraploid. The obtained tetraploid was confirmed by morphology, cytology and molecular markers and then self-pollinated. The S1 seedlings derived from this tetraploid gradually became flavescent after emergence of the fifth true leaf, but they were rescued by grafting and produced S2 seeds. The rescued S1 plants were partially fertile due to the existence of univalents at Metaphase I of meiosis, leading to the formation of unbalanced, nonviable gametes lacking complete sets of chromosomes. The S2 plants grew well and no flavescence was observed, implying that interspecific incompatibility, to some extent, had been alleviated in the S2 generation. The synthetic allotetraploid will be quite useful for polyploidy evolutionary studies and as a bridge for transferring favorable genes from these two diploid species into Upland cotton through hybridization.

Show MeSH
Related in: MedlinePlus