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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

Embryo rescue of G. hirsutum × G. arboreum hybrid ovules.A, Ovules on MSB2K produced numerous fibers and calli; B, Ovules on MSB2K+1.0 mg l-1 IAA+0.2 mg l-1 Kin+250 mg l-1 CH produced numerous calli; C, Ovules on MSB2K+0.5 mg l-1 KIN+250 mg l-1 CH grew well, with little callus production; D, Ovule germination; E, Embryo isolation; F, All leaves of plantlets dropped; G, Healthy plantlets; H, Grafted plantlets.
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pone.0128981.g001: Embryo rescue of G. hirsutum × G. arboreum hybrid ovules.A, Ovules on MSB2K produced numerous fibers and calli; B, Ovules on MSB2K+1.0 mg l-1 IAA+0.2 mg l-1 Kin+250 mg l-1 CH produced numerous calli; C, Ovules on MSB2K+0.5 mg l-1 KIN+250 mg l-1 CH grew well, with little callus production; D, Ovule germination; E, Embryo isolation; F, All leaves of plantlets dropped; G, Healthy plantlets; H, Grafted plantlets.

Mentions: Medium composition significantly affects the growth and germination of ovules [23], with different genotypes responding to different media [25]. Sacks [23] used MSB2K medium without growth regulators and obtained efficient ovule growth for G. hirsutum × G. arboreum. However, in the current study, only fibers and calli grew well on MSB2K medium, while ovules did not (Fig 1A), which revealed that the ovules did not grow well on medium lacking growth regulators. Gill and Bajaj [18] and Thengane et al. [20] also failed to germinate G. hirsutum × G. arboreum ovules on medium lacking growth regulators. These results are inconsistent with the results of Stewart and Hsu [17], who found that more G. hirsutum × G. arboreum hybrid seedlings were produced on medium without growth regulators than on media containing various combinations of IAA and Kin. We also found that more calli emerged on the medium used by Gill and Bajaj [18] than on medium containing only one plant hormone, i.e., Kin (Fig 1B). Thengane et al. [20]found that cultured ovules produce more callus on medium containing IAA than on medium without this hormone. Therefore, we improved the culture medium used for embryo rescue by removing the IAA and increasing the concentration of Kin. The results indicate that embryos developed well on this medium, while they did not develop fibers, and little callus was produced (Fig 1C; Table 1). The embryos were cultured on MSB2K medium supplemented with 0.5 mg l-1 Kin and 250 mg l-1CH as basal medium for 30 days (Table 2). The results showed that ~ 97% of the ovules were viable and 91% of the embryos expanded (Table 3). Therefore, we believe that MSB2K medium containing 0.5 mg l-1 Kin and 250 mg l-1 CH is suitable medium for hybrid embryo rescue.


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)

Embryo rescue of G. hirsutum × G. arboreum hybrid ovules.A, Ovules on MSB2K produced numerous fibers and calli; B, Ovules on MSB2K+1.0 mg l-1 IAA+0.2 mg l-1 Kin+250 mg l-1 CH produced numerous calli; C, Ovules on MSB2K+0.5 mg l-1 KIN+250 mg l-1 CH grew well, with little callus production; D, Ovule germination; E, Embryo isolation; F, All leaves of plantlets dropped; G, Healthy plantlets; H, Grafted plantlets.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0128981.g001: Embryo rescue of G. hirsutum × G. arboreum hybrid ovules.A, Ovules on MSB2K produced numerous fibers and calli; B, Ovules on MSB2K+1.0 mg l-1 IAA+0.2 mg l-1 Kin+250 mg l-1 CH produced numerous calli; C, Ovules on MSB2K+0.5 mg l-1 KIN+250 mg l-1 CH grew well, with little callus production; D, Ovule germination; E, Embryo isolation; F, All leaves of plantlets dropped; G, Healthy plantlets; H, Grafted plantlets.
Mentions: Medium composition significantly affects the growth and germination of ovules [23], with different genotypes responding to different media [25]. Sacks [23] used MSB2K medium without growth regulators and obtained efficient ovule growth for G. hirsutum × G. arboreum. However, in the current study, only fibers and calli grew well on MSB2K medium, while ovules did not (Fig 1A), which revealed that the ovules did not grow well on medium lacking growth regulators. Gill and Bajaj [18] and Thengane et al. [20] also failed to germinate G. hirsutum × G. arboreum ovules on medium lacking growth regulators. These results are inconsistent with the results of Stewart and Hsu [17], who found that more G. hirsutum × G. arboreum hybrid seedlings were produced on medium without growth regulators than on media containing various combinations of IAA and Kin. We also found that more calli emerged on the medium used by Gill and Bajaj [18] than on medium containing only one plant hormone, i.e., Kin (Fig 1B). Thengane et al. [20]found that cultured ovules produce more callus on medium containing IAA than on medium without this hormone. Therefore, we improved the culture medium used for embryo rescue by removing the IAA and increasing the concentration of Kin. The results indicate that embryos developed well on this medium, while they did not develop fibers, and little callus was produced (Fig 1C; Table 1). The embryos were cultured on MSB2K medium supplemented with 0.5 mg l-1 Kin and 250 mg l-1CH as basal medium for 30 days (Table 2). The results showed that ~ 97% of the ovules were viable and 91% of the embryos expanded (Table 3). Therefore, we believe that MSB2K medium containing 0.5 mg l-1 Kin and 250 mg l-1 CH is suitable medium for hybrid embryo rescue.

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