Morpho-histology and genotype dependence of in vitro morphogenesis in mature embryo cultures of wheat

Abstract

Cellular totipotency is one of the basic principles of plant biotechnology. Currently, the success of the procedure used to produce transgenic plants is directly proportional to the successful insertion of foreign DNA into the genome of suitable target tissue/cells that are able to regenerate plants. The mature embryo (ME) is increasingly recognized as a valuable explant for developing regenerable cell lines in wheat biotechnology. We have previously developed a regeneration procedure based on fragmented ME in vitro culture. Before we can use this regeneration system as a model for molecular studies of the morphogenic pathway induced in vitro and investigate the functional links between regenerative capacity and transformation receptiveness, some questions need to be answered. Plant regeneration from cultured tissues is genetically controlled. Factors such as age/degree of differentiation and physiological conditions affect the response of explants to culture conditions. Plant regeneration in culture can be achieved through embryogenesis or organogenesis. In this paper, the suitability of ME tissues for tissue culture and the chronological series of morphological data observed at the macroscopic level are documented. Genetic variability at each step of the regeneration process was evaluated through a varietal comparison of several elite wheat cultivars. A detailed histological analysis of the chronological sequence of morphological events during ontogeny was conducted. Compared with cultures of immature zygotic embryos, we found that the embryogenic pathway occurs slightly earlier and is of a different origin in our model. Cytological, physiological, and some biochemical aspects of somatic embryo formation in wheat ME culture are discussed.

Tissue culture efficiency of wheat species with different genomic formulas

“…Mature wheat embryos are thought to be more recalcitrant to tissue culture than immature embryos, due to differences in the physiological and biochemical tissue status (Özgen et al 1998, Filippov et al 2006, Delporte et al 2014, Yang et al 2015. The acquisition of embryogenic competence in tissues of zygotic wheat embryos was shown to depend significantly on the endogenous level of growth regulators and total contents of phenols and soluble sugars (Jiménez andBangerth 2001, Yang et al 2015).…”

“…The acquisition of embryogenic competence in tissues of zygotic wheat embryos was shown to depend significantly on the endogenous level of growth regulators and total contents of phenols and soluble sugars (Jiménez andBangerth 2001, Yang et al 2015). With regard to the dormancy of the mature embryos at the stage of culture initiation, the particular interaction of the medium and other environmental parameters with genotype-specific endogenous factors was frequently required to achieve efficient morphogenesis, especially in endosperm-supported culture (Filippov et al 2006, Bi et al 2007, Chauhan et al 2007, Yu et al 2008, Miroshnichenko et al 2011, Yin et al 2011, Chang et al 2012, Delporte et al 2014). With the media tested here however, immature embryos are the preferable explant material.…”

“…Efficient in vitro culture of mature wheat embryos was established by two main techniques. Embryos should be isolated from mature in the same way as from immature seeds, followed by placing the entire (Chauhan et al 2007(Chauhan et al , Özgen et al 2015, or longitudinally bisected (Zale et al 2004, Yu et al 2008 or multiple divided embryos (Delporte et al 2014) on callus induction medium. Alternatively, in vitro plant regeneration under endosperm-supported culture may be achieved by placing the whole seed with the wounded mature embryo on induction medium (Özgen et al 1998(Özgen et al , Filippov et al 2006).…”

Mechanisms of Damaging Effect of Mangenese in Toxic Concentrations on Cellular and Subcellular Levels

“…Не смотря на то, что каллусные культуры пшеницы реализуют морфогенетические программы различными путями (геммогенез, ризогенез, гемморизогенез, соматический эмбриогенез) установлено, что начало реализации каждого пути морфогенеза связано с формированием в толще морфогенного каллуса морфогенетических очагов, представленных главным образом меристематическими клетками (Konieczny et al, 2003;Круглова, Катасонова, 2009;Сельдимирова и др., 2011;Delporte et al, 2014). По мере дальнейшего культивирования меристематические очаги постепенно приобретают отчетливую зональность, оформляется эпидермальный слой, происходит инвагинация его поверхности.…”

Enhancement of Somatic Embryogenesis by Mature and Immature Seeds in Wheat (Triticum aestivum L.)

“…also have been gaining importance for the creation of new variability (Saika and Toki, 2010;Croughan and Chu, 1991;Ho and Vasil, 1983). Among them, the genotype and nutrient composition are major sources of variation in in vitro culture (Delporte et al, 2014;Khatun et al, 2003;Khanna and Raina, 1998). Callus culture through mature and immature embryo has often been applied to solve some practical problems in wheat breeding systems.…”