Experimental modelling of exine-like structures

Gabarayeva, Nina I.; Grigorjeva, Valentina V.

doi:10.1080/00173134.2013.818165

Cited by 21 publications

(9 citation statements)

References 75 publications

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“…This observation supports the importance of the callosic special cell wall for the establishment of exine patterns, as was suggested previously (Blackmore et al, 2007(Blackmore et al, , 2010Gabarayeva et al, 2018a). In our earlier experiments (Gabarayeva and Grigorjeva, 2013 we managed to obtain some columellate-like or lamellate-like patterns. However, in this study we generated much more distinct columellate and lamellate patterns, mimicking natural developing and mature ectexines and endexines.…”

Section: Discussionsupporting

confidence: 91%

“…The first experimental efforts to replicate spore wall structures in vitro were undertaken by Hemsley and coauthors (Hemsley et al, 1996, 1998. We followed these modelling experiments using another method and generated structures resembling several separate exine layers (Gabarayeva and Grigorjeva, 2013, but did not simulate the widespread columellate ectexine or combined layers of ectexine and endexine.…”

Section: Introductionmentioning

confidence: 99%

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Mimicking pollen and spore walls: self-assembly in action

2019

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Background and Aims Decades of research have attempted to elucidate the underlying developmental mechanisms that give rise to the enormous diversity of pollen and spore exines. The organization of the exine starts with the establishment of an elaborate glycocalyx within which the subsequent accumulation of sporopollenin occurs. Ontogenetic studies using transmission electron microscopy of over 30 species from many different groups have shown that the sequence of structures observed during development of the exine corresponds to the sequence of self-assembling micellar mesophases (including liquid crystals) observed at increasing concentrations of surfactants. This suggested that self-assembly plays an important part in exine pattern determination. Some patterns resembling separate layers of spore and pollen grain walls have been obtained experimentally, in vitro, by self-assembly. However, to firmly establish this idea, columellate and granulate exines, the most widespread forms, needed to be simulated experimentally. Methods We used our original method, preparing mixtures of substances analogous to those known to occur in the periplasmic space of developing microspores, then leaving the mixtures undisturbed for specific periods of time to allow the process of self-assembly to occur. We developed our method further by using new substances analogous to those present in the periplasmic space and performing the experiments in a thin layer, more closely resembling the dimensions of the periplasmic space. Key Results The artificial microstructures obtained from our in vitro self-assembly experiments closely resembled the main types of exines, including tectate–columellate, granulate, alveolate and structureless, and permitted comparison with both developing and mature microspore walls. Compared with the previous attempts, we managed to simulate columellate and granulate exines, including lamellate endexine. Conclusions Our results show that simple physico-chemical interactions are able to generate patterns resembling those found in exines, supporting the idea that exine development in nature involves an interplay between the genome and self-assembly.

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Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Mimicking pollen and spore walls: self-assembly in action

2019

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“…A physicochemical approach was developed to cutin synthesis that proposes that cutin could be the result of spontaneous, nonprotein-mediated, chemical interactions and reactions in a supramolecular self-assembling process [67]. Similar processes have been reported in the formation of other plant barrier biopolymers, such as sporopollenin [68,69] and lignin [70].…”

Section: The Role Of Acyltransferasesmentioning

confidence: 97%

Plant cutin genesis: unanswered questions

Domínguez

Heredia‐Guerrero

Heredia

2015

Trends in Plant Science

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“…These are described in Gabarayeva et al (). In brief, we adapted our original, simple method (Gabarayeva & Grigorjeva, , ), preparing mixtures of substances, mostly surfactants, which either occur naturally in the periplasmic space of the developing microspores or are substitutes analogous to naturally occurring substances. We prepared different combinations of substances and used them at different concentrations.…”

Section: Methodsmentioning

confidence: 99%

“…To demonstrate the role of self‐assembly in exine pattern formation, a series of in vitro experiments was undertaken in which some exine‐like patterns developed in colloidal mixtures by self‐assembly, without any genomic participation (Hemsley et al , , , ; Gabarayeva & Grigorjeva, , , ; Gabarayeva et al , ). Previous findings (Lavrentovich et al ,; Radja et al , ) are similar to and add to our interpretation (Gabarayeva & Hemsley, ; Hemsley & Gabarayeva, ) and, together with our modeling experiments, support the idea that physicochemical processes play a very important role in pollen wall development.…”

Section: Introductionmentioning

confidence: 99%

Artificial pollen walls simulated by the tandem processes of phase separation and self‐assemblyin vitro

2019

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Despite numerous attempts to elucidate the developmental mechanisms responsible for the observed diversity of pollen and spore walls, the processes involved remained obscure until the structures observed during exine development were recognized as a sequence of selfassembling micellar mesophases. To confirm this, a series of in vitro experiments was undertaken in which exine-like patterns were generated in colloidal mixtures by self-assembly, without any genomic participation. The intention was to test whether all the main types of exine structure could be simulated experimentally.Mixtures of substances, analogous to those involved in microspore development, were left undisturbed while water evaporated and self-assembly occurred. We varied the substances, their combinations and concentrations, and the physical constraints to make the experiments closer to the situation in nature. The resulting dry films were then examined using transmission electron microscopy.A variety of microstructures, simulating the full range of exine types, was obtained by micellar self-assembly. Moreover, the signs of related physicochemical process (i.e. phase separation) were also observed.Simple, energy-efficient, physical-chemical interactions, phase separation and self-assembly, are capable of generating exine-like patterns, providing evidence that these processes share control of exine formation with the well-documented program of gene expression.

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Experimental modelling of exine-like structures

Cited by 21 publications

References 75 publications

Mimicking pollen and spore walls: self-assembly in action

Mimicking pollen and spore walls: self-assembly in action

Plant cutin genesis: unanswered questions

Artificial pollen walls simulated by the tandem processes of phase separation and self‐assemblyin vitro

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