Pseudo-embryogenic structures in anther and isolated microspore cultures in vitro: a cautionary guide

Abstract

This review describes sources of structures of non-microspore origin observed in anther and microspore cultures. Various characteristics of these structures may cause a wrong diagnosis of these structures as embryos or cell/tissue clusters of microspore origin. Here we suggest such structures to be named as pseudoembryogenic structures. The introduction of pseudo-embryogenic structures and their origins could be helpful to distinguish them from true microspore-derived structures. Prompted by certain environmental cues, somatic cells existing as a contamination in immature pollen (microspores) cultures can lead to the formation of 'pseudo-embryos' commonly known as embryoids. The pseudo-embryogenic structures may be classified in the following groups: (i) pseudo-star-like structures; pseudo-multicellular structures; (ii) pseudo-embryos with pseudo-suspensors; (iii) contaminating bacteria appearing as callus colonies; (iv) calli and embryos of somatic origin; (v) giant tetrad-like structures; (vi) anther wall cells. The exact origin of these structures is discussed in this paper, and some recommendations are proposed in order to avoid misinterpretation.

ANTHER-DERIVED CALLUS FORMATION IN BITTER MELON (Momordica charantia L.) AS INFLUENCED BY MICROSPORE DEVELOPMENT STAGE AND MEDIUM COMPOSITION

“…Однако ассортимент гибридов этой культуры остается ограниченным из-за сложности и длительности селекционного процесса. Современная селекция F 1 гибридов в основном зависит от наличия инбредных линий, при этом именно их создание отличается сложностью (9). Для получения инбредных линий традиционными методами селекции необходимо проводить самоопыления в течение 5-7 поколений (10,11).…”

Efficiency of three haplomethods in durum wheat (Triticum turgidum subsp. durum Desf.): isolated microspore culture, gynogenesis and wheat × maize crosses

“…induced microspores; Figure 2a) appeared after 7 days of culture can be embryogenic and evolve into pro-embryos. As described by Bal et al (2012), the star-like microspores contained several compartments surrounding a circle in the center (Figure 2a). Compared with the other methods, the microspores culture seems to be more influenced by the growing conditions and the physiological stage of mother plants (Cistué et al 2009;Rituraj et al 2013), genotypes (Cistué et al 2006), stress treatment (Jacquard 2007;Soriano et al 2008), composition of induction medium (Cistué et al 2009), and the inclusion of co-culture ovaries (Castillo et al 2015) that might explain the low rate of induction.…”

Microgametophyte Development in Cannabis sativa L. and First Androgenesis Induction Through Microspore Embryogenesis

“…On the other hand, our research constitutes the first illustration of the early events of microspore embryogenesis ontogeny in C. sativa . It is worth noting how analysis of nuclear dynamics through fluorescence microscopy proved to be the best option for unequivocal differentiation among embryogenic and gametophytic development of microspores, being also a useful tool for avoiding wrong diagnoses of different structures which could be incorrectly classified as embryos and/or multicellular structures of microspore origin ( Bal et al, 2012 ). This represents a common problem in microspore embryogenesis research, specially with new species which have never been submitted to androgenesis induction experiments.…”