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Reprogramming of cassava (Manihot esculenta) microspores towards sporophytic development.

Perera PI, Ordoñez CA, Dedicova B, Ortega PE - AoB Plants (2014)

Bottom Line: In two cassava genotypes, different developmental stages of microspores were found to initiate sporophytic cell divisions, that is, with tetrads of TMS 60444 and with mid or late uni-nucleate microspores of SM 1219-9.A low frequency of the reprogramming and the presence of non-responsive microspores among the responsive ones in tetrads were found to be related to the viability and exine formation of the microspores.This paves the way for the development of an efficient technique for the production of homozygous lines in cassava.

View Article: PubMed Central - PubMed

Affiliation: Agrobiodiversity Research Area, International Center for Tropical Agriculture, A.A. 6713, Cali, Colombia Present address: Department of Horticulture and Landscape Gardening, Faculty of Agriculture and Plantation Management, Wayamba University, Gonawila, Makandura, Sri Lanka prasanthi1970@yahoo.com.

No MeSH data available.


Related in: MedlinePlus

Fluorescence micrographs of nuclei in cultured tetrads of M. esculenta genotype TMS 60444. (A–C) A fresh tetrad without fluorescence and with partial and full fluorescence under a green filter. (D–F) Cultured tetrad containing an enlarged microspore undergoing mitosis under partial and full fluorescence with a green filter and full fluorescence with a blue filter (scale bars = 22 µm).
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PLU022F8: Fluorescence micrographs of nuclei in cultured tetrads of M. esculenta genotype TMS 60444. (A–C) A fresh tetrad without fluorescence and with partial and full fluorescence under a green filter. (D–F) Cultured tetrad containing an enlarged microspore undergoing mitosis under partial and full fluorescence with a green filter and full fluorescence with a blue filter (scale bars = 22 µm).

Mentions: The nuclear status of the responding and non-responding microspores of tetrads in TMS was studied by staining the nuclei with DAPI. The degree of chromatin condensation in the nucleus was used as a marker to distinguish the status of the nuclei in the cell cycle. Fresh and non-responsive microspores in tetrads contained a single prominent nucleus (Fig. 8A). The study revealed cells with different nuclear status (as shown in Fig. 8B) even though they did not show any remarkable cell enlargement and were considered as non-responsive tetrads by visual observation. In microspores that did not show a significant enlargement, a nuclear division (Fig. 8B) was observed, indicating that reprogramming was occurring even without a visual sign. These results clearly demonstrated that visual counts did not reflect actual reprogramming frequency, which should actually be higher than that present in Fig. 4. However, confirming the visual observation of division in microspores of tetrads, the structures with four (Fig. 9A), eight (Fig. 9B) and multiple (Fig. 9C) cells with prominent nuclei were clearly demonstrated by DAPI staining. Furthermore, MCSs derived from the tetrad microspores showed numerous stained nuclei (Fig. 9D). However, in some cases, it was difficult to recognize whether the structures were multi-cellular or multi-nuclear because cell walls are difficult to see. In genotype SM, unfortunately, auto-fluorescence of the exine of the microspores prevented visualization of the nucleus despite the exine-digestion procedure.Figure 8.


Reprogramming of cassava (Manihot esculenta) microspores towards sporophytic development.

Perera PI, Ordoñez CA, Dedicova B, Ortega PE - AoB Plants (2014)

Fluorescence micrographs of nuclei in cultured tetrads of M. esculenta genotype TMS 60444. (A–C) A fresh tetrad without fluorescence and with partial and full fluorescence under a green filter. (D–F) Cultured tetrad containing an enlarged microspore undergoing mitosis under partial and full fluorescence with a green filter and full fluorescence with a blue filter (scale bars = 22 µm).
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4061485&req=5

PLU022F8: Fluorescence micrographs of nuclei in cultured tetrads of M. esculenta genotype TMS 60444. (A–C) A fresh tetrad without fluorescence and with partial and full fluorescence under a green filter. (D–F) Cultured tetrad containing an enlarged microspore undergoing mitosis under partial and full fluorescence with a green filter and full fluorescence with a blue filter (scale bars = 22 µm).
Mentions: The nuclear status of the responding and non-responding microspores of tetrads in TMS was studied by staining the nuclei with DAPI. The degree of chromatin condensation in the nucleus was used as a marker to distinguish the status of the nuclei in the cell cycle. Fresh and non-responsive microspores in tetrads contained a single prominent nucleus (Fig. 8A). The study revealed cells with different nuclear status (as shown in Fig. 8B) even though they did not show any remarkable cell enlargement and were considered as non-responsive tetrads by visual observation. In microspores that did not show a significant enlargement, a nuclear division (Fig. 8B) was observed, indicating that reprogramming was occurring even without a visual sign. These results clearly demonstrated that visual counts did not reflect actual reprogramming frequency, which should actually be higher than that present in Fig. 4. However, confirming the visual observation of division in microspores of tetrads, the structures with four (Fig. 9A), eight (Fig. 9B) and multiple (Fig. 9C) cells with prominent nuclei were clearly demonstrated by DAPI staining. Furthermore, MCSs derived from the tetrad microspores showed numerous stained nuclei (Fig. 9D). However, in some cases, it was difficult to recognize whether the structures were multi-cellular or multi-nuclear because cell walls are difficult to see. In genotype SM, unfortunately, auto-fluorescence of the exine of the microspores prevented visualization of the nucleus despite the exine-digestion procedure.Figure 8.

Bottom Line: In two cassava genotypes, different developmental stages of microspores were found to initiate sporophytic cell divisions, that is, with tetrads of TMS 60444 and with mid or late uni-nucleate microspores of SM 1219-9.A low frequency of the reprogramming and the presence of non-responsive microspores among the responsive ones in tetrads were found to be related to the viability and exine formation of the microspores.This paves the way for the development of an efficient technique for the production of homozygous lines in cassava.

View Article: PubMed Central - PubMed

Affiliation: Agrobiodiversity Research Area, International Center for Tropical Agriculture, A.A. 6713, Cali, Colombia Present address: Department of Horticulture and Landscape Gardening, Faculty of Agriculture and Plantation Management, Wayamba University, Gonawila, Makandura, Sri Lanka prasanthi1970@yahoo.com.

No MeSH data available.


Related in: MedlinePlus