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A New Synthetic Amphiploid (AADDAA) between Gossypium hirsutum and G. arboreum Lays the Foundation for Transferring Resistances to Verticillium and Drought.

Chen Y, Wang Y, Zhao T, Yang J, Feng S, Nazeer W, Zhang T, Zhou B - PLoS ONE (2015)

Bottom Line: Here, we improved an embryo rescue technique to overcome the cross-incompatibility between these two parents for transferring favorable genes from G. arboreum into G. hirsutum.Preliminary assessments of resistance at seedling stage indicate that the synthetic amphiploid showed highly resistant to Verticillium and drought.The synthetic amphiploid between G. hirsutum × G. arboreum would lay the foundation for developing G. arboreum-introgressed lines with the uniform genetic background of G. hirsutum acc TM-1, which would greatly enhance and simplify the mining, isolation, characterization, cloning and use of G. arboreum-specific desirable genes in future cotton breeding programs.

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, People's Republic of China.

ABSTRACT
Gossypium arboreum, a cultivated cotton species (2n = 26, AA) native to Asia, possesses invaluable characteristics unavailable in the tetraploid cultivated cotton gene pool, such as resistance to pests and diseases and tolerance to abiotic stresses. However, it is quite difficult to transfer favorable traits into Upland cotton through conventional methods due to the cross-incompatibility of G. hirsutum (2n = 52, AADD) and G. arboreum. Here, we improved an embryo rescue technique to overcome the cross-incompatibility between these two parents for transferring favorable genes from G. arboreum into G. hirsutum. Our results indicate that MSB2K supplemented with 0.5 mg l(-1) kinetin and 250 mg(-1) casein hydrolysate is an efficient initial medium for rescuing early (3 d after pollination) hybrid embryos. Eight putative hybrids were successfully obtained, which were further verified and characterized by cytology, molecular markers and morphological analysis. The putative hybrids were subsequently treated with different concentrations of colchicine solution to double their chromosomes. The results demonstrate that four putative hybrid plants were successfully chromosome-doubled by treatment with 0.1% colchicine for 24 h and become amphiploid, which were confirmed by cytological observation, self-fertilization and backcrossing. Preliminary assessments of resistance at seedling stage indicate that the synthetic amphiploid showed highly resistant to Verticillium and drought. The synthetic amphiploid between G. hirsutum × G. arboreum would lay the foundation for developing G. arboreum-introgressed lines with the uniform genetic background of G. hirsutum acc TM-1, which would greatly enhance and simplify the mining, isolation, characterization, cloning and use of G. arboreum-specific desirable genes in future cotton breeding programs.

No MeSH data available.


Related in: MedlinePlus

The amphiploids obtained by doubling chromosome complements in interspecific F1 hybrids between G. hirsutum and G. arboreum were confirmed by observation on chromosome configuration at metaphase I of meiosis in pollen mother cells and GISH on somatic cells.A, Univalent, bivalents and trivalent. Arrowhead (yellow) and arrow (red) indicate the univalent and trivalent, respectively. B, Bivalents, quadrivalents and pentavalent. Arrowhead (yellow) and arrow (red) indicate the quadrivalent and pentavalent, respectively. C, Red signals indicate the 52 chromosomes of A subgenome of G. hirsutum and G. arboreum and blue signals indicate the 26 chromosomes of D subgenome of G. hirsutum (stained with DAPI). The results demonstrate that the amphiploid is hexaploid and its genome component is 2n = 6x = AAAADD = 78. Scale bars, 10 μm.
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pone.0128981.g005: The amphiploids obtained by doubling chromosome complements in interspecific F1 hybrids between G. hirsutum and G. arboreum were confirmed by observation on chromosome configuration at metaphase I of meiosis in pollen mother cells and GISH on somatic cells.A, Univalent, bivalents and trivalent. Arrowhead (yellow) and arrow (red) indicate the univalent and trivalent, respectively. B, Bivalents, quadrivalents and pentavalent. Arrowhead (yellow) and arrow (red) indicate the quadrivalent and pentavalent, respectively. C, Red signals indicate the 52 chromosomes of A subgenome of G. hirsutum and G. arboreum and blue signals indicate the 26 chromosomes of D subgenome of G. hirsutum (stained with DAPI). The results demonstrate that the amphiploid is hexaploid and its genome component is 2n = 6x = AAAADD = 78. Scale bars, 10 μm.

Mentions: The putative hybrid F1 plants, which were confirmed by cytology, molecular markers and morphological observation, were treated with different concentrations of colchicine for 24, 36 and 48 h. The results show that among 30 plants treated with 0.1% colchicine for 24 h, 22.22% (four out of 18 plants survived, while 12 died) of interspecific hybrid F1 plants exhibited gigantism (Table 4) and had improved fertility, and they set bolls and produced several seeds. To understand why these plants produced seeds, we collected young flower buds from these plants and observed their chromosome associations. The results indicate that the number of univalents significantly decreased while the numbers of bivalents and multivalents greatly increased (Fig 5A and 5B), even if there were too many chromosomes to discriminate, which suggests that these plants were chromosome-doubled and were therefore putative amphiploids, i.e., hexaploids. Therefore, to further verify the genome components of the putative amphiploids, S1 plants derived from the putative amphiploids by self-pollination were used to identify chromosome numbers by GISH using somatic mitotic cells of the root tips. The results demonstrate that their genome components contained four sets of A genome (red signals) and one set of D subgenome (blue signals) and had a total of 78 chromosomes, i.e., 2n = 6x = AAAADD = 78 (Fig 5C), which further confirms the authenticity of the amphiploids. Now S1 plants grow very well.


A New Synthetic Amphiploid (AADDAA) between Gossypium hirsutum and G. arboreum Lays the Foundation for Transferring Resistances to Verticillium and Drought.

Chen Y, Wang Y, Zhao T, Yang J, Feng S, Nazeer W, Zhang T, Zhou B - PLoS ONE (2015)

The amphiploids obtained by doubling chromosome complements in interspecific F1 hybrids between G. hirsutum and G. arboreum were confirmed by observation on chromosome configuration at metaphase I of meiosis in pollen mother cells and GISH on somatic cells.A, Univalent, bivalents and trivalent. Arrowhead (yellow) and arrow (red) indicate the univalent and trivalent, respectively. B, Bivalents, quadrivalents and pentavalent. Arrowhead (yellow) and arrow (red) indicate the quadrivalent and pentavalent, respectively. C, Red signals indicate the 52 chromosomes of A subgenome of G. hirsutum and G. arboreum and blue signals indicate the 26 chromosomes of D subgenome of G. hirsutum (stained with DAPI). The results demonstrate that the amphiploid is hexaploid and its genome component is 2n = 6x = AAAADD = 78. Scale bars, 10 μm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4465178&req=5

pone.0128981.g005: The amphiploids obtained by doubling chromosome complements in interspecific F1 hybrids between G. hirsutum and G. arboreum were confirmed by observation on chromosome configuration at metaphase I of meiosis in pollen mother cells and GISH on somatic cells.A, Univalent, bivalents and trivalent. Arrowhead (yellow) and arrow (red) indicate the univalent and trivalent, respectively. B, Bivalents, quadrivalents and pentavalent. Arrowhead (yellow) and arrow (red) indicate the quadrivalent and pentavalent, respectively. C, Red signals indicate the 52 chromosomes of A subgenome of G. hirsutum and G. arboreum and blue signals indicate the 26 chromosomes of D subgenome of G. hirsutum (stained with DAPI). The results demonstrate that the amphiploid is hexaploid and its genome component is 2n = 6x = AAAADD = 78. Scale bars, 10 μm.
Mentions: The putative hybrid F1 plants, which were confirmed by cytology, molecular markers and morphological observation, were treated with different concentrations of colchicine for 24, 36 and 48 h. The results show that among 30 plants treated with 0.1% colchicine for 24 h, 22.22% (four out of 18 plants survived, while 12 died) of interspecific hybrid F1 plants exhibited gigantism (Table 4) and had improved fertility, and they set bolls and produced several seeds. To understand why these plants produced seeds, we collected young flower buds from these plants and observed their chromosome associations. The results indicate that the number of univalents significantly decreased while the numbers of bivalents and multivalents greatly increased (Fig 5A and 5B), even if there were too many chromosomes to discriminate, which suggests that these plants were chromosome-doubled and were therefore putative amphiploids, i.e., hexaploids. Therefore, to further verify the genome components of the putative amphiploids, S1 plants derived from the putative amphiploids by self-pollination were used to identify chromosome numbers by GISH using somatic mitotic cells of the root tips. The results demonstrate that their genome components contained four sets of A genome (red signals) and one set of D subgenome (blue signals) and had a total of 78 chromosomes, i.e., 2n = 6x = AAAADD = 78 (Fig 5C), which further confirms the authenticity of the amphiploids. Now S1 plants grow very well.

Bottom Line: Here, we improved an embryo rescue technique to overcome the cross-incompatibility between these two parents for transferring favorable genes from G. arboreum into G. hirsutum.Preliminary assessments of resistance at seedling stage indicate that the synthetic amphiploid showed highly resistant to Verticillium and drought.The synthetic amphiploid between G. hirsutum × G. arboreum would lay the foundation for developing G. arboreum-introgressed lines with the uniform genetic background of G. hirsutum acc TM-1, which would greatly enhance and simplify the mining, isolation, characterization, cloning and use of G. arboreum-specific desirable genes in future cotton breeding programs.

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, People's Republic of China.

ABSTRACT
Gossypium arboreum, a cultivated cotton species (2n = 26, AA) native to Asia, possesses invaluable characteristics unavailable in the tetraploid cultivated cotton gene pool, such as resistance to pests and diseases and tolerance to abiotic stresses. However, it is quite difficult to transfer favorable traits into Upland cotton through conventional methods due to the cross-incompatibility of G. hirsutum (2n = 52, AADD) and G. arboreum. Here, we improved an embryo rescue technique to overcome the cross-incompatibility between these two parents for transferring favorable genes from G. arboreum into G. hirsutum. Our results indicate that MSB2K supplemented with 0.5 mg l(-1) kinetin and 250 mg(-1) casein hydrolysate is an efficient initial medium for rescuing early (3 d after pollination) hybrid embryos. Eight putative hybrids were successfully obtained, which were further verified and characterized by cytology, molecular markers and morphological analysis. The putative hybrids were subsequently treated with different concentrations of colchicine solution to double their chromosomes. The results demonstrate that four putative hybrid plants were successfully chromosome-doubled by treatment with 0.1% colchicine for 24 h and become amphiploid, which were confirmed by cytological observation, self-fertilization and backcrossing. Preliminary assessments of resistance at seedling stage indicate that the synthetic amphiploid showed highly resistant to Verticillium and drought. The synthetic amphiploid between G. hirsutum × G. arboreum would lay the foundation for developing G. arboreum-introgressed lines with the uniform genetic background of G. hirsutum acc TM-1, which would greatly enhance and simplify the mining, isolation, characterization, cloning and use of G. arboreum-specific desirable genes in future cotton breeding programs.

No MeSH data available.


Related in: MedlinePlus