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1

Isolated microspores as a source doubled haploids of barley

100%
Oleszczuk S., Zimny J.
Biotechnologia
|
2001
|
issue 1
139-142
EN
In vitro techniques for doubled haploids (DH) production allow for obtaining homozygous lines in a single generation. This is connected with shorter breeding cycle of the new variety. DH lines have a potential for being used in the selection of recombinants, stabilising of transformed lines and molecular mapping. DH lines are produced from isolated microspores through haploid embryogenesis. Microspore culture has several advantages over anther culture: it reduces the time of cultures, enables monitoring of the earliest phase of embryogenesis, allows for direct development embryos, facilitates the in vitro selection and mutation, allows for avoiding regeneration from somatic anther tissues. Moreover, microspore culture appears to be a promising tool in genetic manipulations (transformation, mutagenesis) and it can be used as a source of protoplasts and suspensions. Here we report on how to induce microspore embryogenesis, resulting in plant formation. The switch of microspore development from gametophytic to sporophytic pathway has been stimulated by various stress factors like cold and heat shock, starvation. Stress treatment not only stops pollen development but also re-programmes the microspore towards embryo formation. The effects of various parameters including pretreatment, carbohydrates and nurse culture have been investigated. After optimising the culture conditions we were able to regenerate high number of fertile plants.
2

In vitro culture of cereal microspores

100%
Oleszczuk S., Zimny J.
Biotechnologia
|
2000
|
issue 2
142-160
EN
The development of microspore culture methods in the Poaceae family has received considerable attention in recent years. Isolated microspore culture can be induced in vitro to switch their development from gametophytic to a sporophytic patway, resulting in embryoid or callus formation. Different stresses like cold or heat shock and nitrogen starvation have been identified as the major trigger in inducing microspore embryogenesis. Microspore culture appears to be a promising toll for future production of double haploids in cereals. Isolated microspore culture has several advantages over anther culture in genetic manipulation and haploid study, such as: direct observation of microspore development, unique possibility to study plant embryogenesis, easier in vitro selection and mutation, easier transformation of single cells. Moreover, isolated microspores are the most efficient way of double haploid regeneration. Many factors such as genotypes, physiological status of donor plants, stage of microspores development, pretreatment of anthers or spikes, method of microspores isolation, culture media, nurse culture and culture conditions, have a great influence on microspore culture. These and other problems concerning in vitro culture of isolated microspore are discussed in this review.
3

Microsporidia infect the Liophloeus lentus (Insecta, Coleoptera) ovarioles, developing oocytes and eggs.

88%
Swiatek P., Gorkiewicz T.
Folia Biologica
|
2006
|
vol. 54
|
issue 1-2
61-67
EN
In the ovarioles of Liophloeus lentus (Insecta, Coleoptera, Curculionidae) two types of bacteria and parasitic microorganisms belonging to Microsporidia have been found. This study shows that the different microsporidian life stages (meronts, sporonts, sporoblasts and spores) infect the outer ovariole sheath, trophic chambers, follicular cells, late previtellogenic and vitellogenic oocytes and eggs. In trophic chambers the parasites are very abundant and are distributed unevenly, i.e. their large mass occupies the syncytial cytoplasm between the nurse cell nuclei, whereas the neck region of the trophic chamber (which houses young oocytes, prefollicular cells and trophic cords) is almost free of parasites. The developing oocytes and eggs contain a lower number of parasites which are usually distributed in the cortical ooplasm. The gross morphology of the ovaries is similar in infected and non-infected specimens. Similarly, the presence of a parasite seems to not disturb the course of oogensis. The only difference was found in the ultrastructure of mitochondria in young previtellogenic oocytes. In the infected females they are unusual i.e. bigger and spherical with tubullar cristae, whereas in the non-infected insects they are elongated and have lamellar cristae. As oogenesis progresses the unusual mitochondria rapidly change their morphology and become similar to the mitochondria in non-infected females. Taking into account the distribution of parasites within the ovarioles, it is suggested that they infect growing oocytes via outer ovariole sheath and follicular epithelium rather than via trophic cords.
4

Microspore culture of winter oilseed rape (Brassica napus L.) in conjunction with other in vitro technologies

75%
Cegielska-Taras T., Szala L., Bartkowiak-Broda I.
Biotechnologia
|
2001
|
issue 1
81-86
EN
Microspore culture in conjuction with other technologies such as selection, mutagenesis and transformation has been used for the production of novel genotypes of Brassica napus L. for crop improvement. The example of in vitro selection of microspore - derived embryos includes: a) ploidy level, b) seed oil composition (for example: high level of erucic acid), c) genotypes with restorer gene for CMS-ogura system (by means of isozyme marker PGI-2 ), d) herbicide resistant forms. Efficiency of microspore mutagnesis has been tested by the treatment of freshly isolated microspores with UV and MNU. Direct delivery of foreign gene to the microspores (microprojectile bombardment) combined with the use of Agrobacterium tumefaciens to microspore derived embryos seems to be a promising way of oilseed rape transformation.
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