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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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A strategy for the development of varieties with the trait of high-gossypol plants with low- gossypol seeds.
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pone.0123209.g008: A strategy for the development of varieties with the trait of high-gossypol plants with low- gossypol seeds.

Mentions: Here, we propose a new strategy for the development of varieties with the trait of high-gossypol plants with low- gossypol seeds to largely eliminate the role of Gl3 in conferring gossypol synthesis (Fig 8). Firstly, the A1A1G2G2 tetraploid is employed to cross with Upland cotton (AADD) to produce the tri-species hybrid (AA1DG2). For the obtained hybrid of AA1DG2, genetic recombination between A and A1 genome chromosomes often occur due to their close relationship while very little or no recombination occurs between D and G2 genome chromosomes under natural conditions due to distant relationship. To facilitate exchanges of D and G2 genome chromosomes, secondly, radiation should be employed on seeds or pollens of the tri-species hybrid (AA1DG2) to induce chromosome translocations between D and G2 genome chromosomes. Finally, the progenies derived from radiation inducement will be self-pollinated and characterized by combination of molecular cytogenetics, molecular markers and morphology to identify chromosome translocations between D and G2 genome chromosomes, particulary Chr. D12 translocated by 12G. If Chr. D12 is translocated by 12G and Gl3 is replaced by Gl2au from G. australe via chromosome translocation, the translocation line should possess the traits of high-gossypol plants with low- gossypol seeds introgressed from G.australe. This research is under way.


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)

A strategy for the development of varieties with the trait of high-gossypol plants with low- gossypol seeds.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0123209.g008: A strategy for the development of varieties with the trait of high-gossypol plants with low- gossypol seeds.
Mentions: Here, we propose a new strategy for the development of varieties with the trait of high-gossypol plants with low- gossypol seeds to largely eliminate the role of Gl3 in conferring gossypol synthesis (Fig 8). Firstly, the A1A1G2G2 tetraploid is employed to cross with Upland cotton (AADD) to produce the tri-species hybrid (AA1DG2). For the obtained hybrid of AA1DG2, genetic recombination between A and A1 genome chromosomes often occur due to their close relationship while very little or no recombination occurs between D and G2 genome chromosomes under natural conditions due to distant relationship. To facilitate exchanges of D and G2 genome chromosomes, secondly, radiation should be employed on seeds or pollens of the tri-species hybrid (AA1DG2) to induce chromosome translocations between D and G2 genome chromosomes. Finally, the progenies derived from radiation inducement will be self-pollinated and characterized by combination of molecular cytogenetics, molecular markers and morphology to identify chromosome translocations between D and G2 genome chromosomes, particulary Chr. D12 translocated by 12G. If Chr. D12 is translocated by 12G and Gl3 is replaced by Gl2au from G. australe via chromosome translocation, the translocation line should possess the traits of high-gossypol plants with low- gossypol seeds introgressed from G.australe. This research is under way.

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