Two Self-Incompatibility Sites Occur Simultaneously in the Same Acianthera Species (Orchidaceae, Pleurothallidinae)

In most species of Pleurothallidinae, the self-incompatibility site occurs in the stylar canal inside the column, which is typical of gametophytic self-incompatibility (GSI). However, in some species of Acianthera, incompatible pollen tubes with anomalous morphology reach the ovary, as those are obstructed in the column. We investigated if a distinct self-incompatibility (SI) system is acting on the ovary of A. johannensis, which is a species with partial self-incompatibility, contrasting with a full SI species, A. fabiobarrosii. We analyzed the morphology and development of pollen tubes in the column, ovary, and fruit using light, epifluorescence, and transmission electron microscopy. Our results show that the main reaction site in A. johannensis is in the stylar canal inside the column, which was also recorded in A. fabiobarrosii. Morphological and cytological characteristics of the pollen tubes with obstructed growth in the column indicated a process of programmed cell death in these tubes, showing a possible GSI reaction. In addition, partially self-incompatible individuals of A. johannensis exhibit a second SI site in the ovary. We suggest that this self-incompatibility site in the ovary is only an extension of GSI that acts in the column, differing from the typical late-acting self-incompatibility system recorded in other plant groups.

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The formation of the tryphine coating the pollen grains of Raphanus , and its properties relating to the self-incompatibility system

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1973.0040 ◽

1973 ◽

Vol 184 (1075) ◽

pp. 149-165 ◽

Cited By ~ 95

Keyword(s):

Granular Material ◽

Pollen Grains ◽

The Self ◽

Self Incompatibility ◽

Pollen Maturation ◽

Incompatible Pollen ◽

Incompatibility System ◽

Two Stages ◽

Stimulation Of ◽

Incompatible Pollen Tube

The tryphine that coats the pollen grains of Raphanus is tapetally synthesized and is composed of a fibro-granular and a lipidic component. The fibro-granular material is proteinaceous and is secreted by cisternae of the endoplasmic reticulum. The lipidic component is derived, mainly, from degraded elaioplasts. The fibro-granular material is applied to the pollen exine first, followed by the lipidic mass. The tryphine condenses during the final stages of pollen maturation and dries down to form a thick, highly viscous coating. The major part of the condensation appears to result from dehydration. The tryphine, extracted from the pollen by a centrifugal method and mounted in a membrane, appears to be capable of penetrating the outer layers of a stigma of the same species and, if the pollen from which it was derived is incompatible with respect to the stigma, the stimulation of the production of the callosic reaction body in a manner similar to an incompatible pollen tube. It is proposed that, in Raphanus , substances responsible for the initiation of at least two stages in the self-incompatibility system are held in the tryphine.

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Cytochemical and ultrastructural differences between intraspecific compatible and incompatible pollinations in Raphanus

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1973.0002 ◽

1973 ◽

Vol 183 (1070) ◽

pp. 21-38 ◽

Cited By ~ 100

Keyword(s):

Pollen Tube ◽

The Self ◽

Self Incompatibility ◽

Second Stage ◽

Incompatible Pollen ◽

Large Numbers ◽

Third Stage ◽

Incompatibility System ◽

Three Stages ◽

Two Stages

Examination of the behaviour of pollen on the style of Raphanus , following compatible and incompatible intraspecific pollinations, has revealed the self-incompatibility system in this species to be composed of at least three stages. The first, on which no information has been obtained in this study, involves the germination of the grain. The second stage concerns the ability of the pollen tube to penetrate the cuticle of the stigmatic papilla. It is possible that cutinase is deficient in incompatible pollen tubes but, in most instances, the outer layers of the stigmatic wall are penetrated. The third stage involves the interaction of substances secreted by the pollen tube with products of the stigmatic cytoplasm. The interaction is swiftly followed by the deposition, in the stigma, of a layered callosic body. This is formed immediately under the point of penetration and takes about 6 h to develop fully. Development of the pollen tube ceases as the first layers of callose are laid down. It is possible that the substances in the pollen responsible for the initiation of the second two stages are held in the tapetally synthesized tryphine, thus accounting for the sporophytic control of pollen compatibility in this species. The mature stigma contains large numbers of crystalline protein bodies, but it is not known whether they play any role in the self-incompatibility system.

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Cytological Observation and Transcriptome Comparative Analysis of Self-Pollination and Cross-Pollination in Dendrobium Officinale

Genes ◽

10.3390/genes12030432 ◽

2021 ◽

Vol 12 (3) ◽

pp. 432

Author(s):

Yaling Chen ◽

Benchang Hu ◽

Fantao Zhang ◽

Xiangdong Luo ◽

Jiankun Xie

Keyword(s):

Pollen Tubes ◽

The Self ◽

Dendrobium Officinale ◽

Self Incompatibility ◽

Related Gene ◽

Cytological Observation ◽

Lectin Receptor ◽

Cross Pollination ◽

Self Pollination ◽

Medicinal Value

Dendrobium officinale is a rare and traditional medicinal plant with high pharmacological and nutritional value. The self-incompatibility mechanism of D. officinale reproductive isolation was formed in the long-term evolution process, but intraspecific hybridization of different germplasm resources leads to a large gap in the yield, quality, and medicinal value of D. officinale. To investigate the biological mechanism of self-incompatibility in D. officinale, cytological observation and the transcriptome analysis was carried out on the samples of self-pollination and cross-pollination in D. officinale. Results for self-pollination showed that the pollen tubes could grow in the style at 2 h, but most of pollen tubes stopped growing at 4 h, while a large number of cross-pollinated pollen tubes grew along the placental space to the base of ovary, indicating that the self-incompatibility of D. officinale may be gametophyte self-incompatibility. A total of 63.41 G basesum of D. officinale style samples from non-pollinated, self-pollination, and cross-pollination by RNA-seq were obtained, and a total of 1944, 1758, and 475 differentially expressed genes (DEGs) in the comparison of CK (non-pollinated) vs. HF (cross-pollination sample), CK vs. SF (self-pollination sample) and SF vs. HF were identified, respectively. Forty-one candidate genes related to self-incompatibility were found by function annotation of DEGs, including 6 Ca2+ signal genes, 4 armed repeat containing (ARC) related genes, 11 S-locus receptor kinase (SRK) related genes, 2 Exo70 family genes, 9 ubiquitin related genes, 1 fatty acid related gene, 6 amino acid-related genes, 1 pollen-specific leucine-rich repeat extensin-like protein (LRX) related gene and 1 lectin receptor-like kinases (RLKs) related gene, showed that self-incompatibility mechanism of D. officinale involves the interaction of multiple genes and pathways. The results can provide a basis for the study of the self-incompatibility mechanism of D. officinale, and provide ideas for the preservation and utilization of high-quality resources of D. officinale.

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Action of the Style Product of the Self-Incompatibility Gene of Nicotiana alata (S-RNase) on in Vitro-Grown Pollen Tubes.

The Plant Cell ◽

10.1105/tpc.3.3.271 ◽

1991 ◽

pp. 271-283 ◽

Cited By ~ 66

Author(s):

J. E. Gray ◽

B. A. McClure ◽

I. Bonig ◽

M. A. Anderson ◽

A. E. Clarke

Keyword(s):

Pollen Tubes ◽

The Self ◽

Nicotiana Alata ◽

Self Incompatibility

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Ultrastructural Aspects of the Self-Incompatibility Mechanism in Lycopersicum Peruvianum Mill

Journal of Cell Science ◽

10.1242/jcs.12.2.403 ◽

1973 ◽

Vol 12 (2) ◽

pp. 403-419 ◽

Cited By ~ 1

Author(s):

D. DE NETTANCOURT ◽

M. DEVREUX ◽

A. BOZZINI ◽

M. CRESTI ◽

E. PACINI ◽

...

Keyword(s):

Pollen Tube ◽

Tube Wall ◽

Degradation Mechanism ◽

Embryo Sac ◽

Pollen Tubes ◽

Self Incompatibility ◽

Weak Reaction ◽

General Hypothesis ◽

Incompatible Pollen ◽

Compatible Pollen

The experimental results obtained show that the tip of the incompatible pollen tube bursts open after the outer-wall has considerably expanded in the intercellular spaces of the conducting tissue and the inner-wall has disappeared and numerous particles have accumulated in the tube cytoplasm. These particles, which measure approximately 0.2 µm in diameter and give a weak reaction to the test of Thiéry, differ in many respects from the vesicles normally present in compatible pollen tubes growing through the style; they appear to resemble, in some cases, the spheres which are discharged by the compatible pollen tubes after they have reached the embryo-sac. It is considered that these observations support the current belief that the tube wall is the site of action for the incompatibility proteins and suggest that self-incompatibility is not a passive process resulting from lack of growth stimulation but an active event which leads to the destruction of the incompatible pollen tubes. The degradation mechanism involved appears similar to the one which enables the compatible pollen tube to release its contents in the degenerated synergid and presents some analogies with the lytic process taking place in virus-infected cells. The general hypothesis is presented that the particles observed in the cytoplasm of self-incompatible pollen tubes consist of a mixture of incompatibility proteins and of basic constituents of the tube wall.

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Alterations in the Actin Cytoskeleton of Pollen Tubes Are Induced by the Self-Incompatibility Reaction in Papaver rhoeas

The Plant Cell ◽

10.1105/tpc.12.7.1239 ◽

2000 ◽

Vol 12 (7) ◽

pp. 1239-1251 ◽

Cited By ~ 97

Author(s):

Anja Geitmann ◽

Benjamin N. Snowman ◽

Anne Mie C. Emons ◽

Vernonica E. Franklin-Tong

Keyword(s):

Actin Cytoskeleton ◽

Pollen Tubes ◽

The Self ◽

Self Incompatibility ◽

Papaver Rhoeas ◽

Incompatibility Reaction

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Incompatibility Alleles in Portuguese Hazelnut Landraces

ISRN Agronomy ◽

10.5402/2012/154723 ◽

2012 ◽

Vol 2012 ◽

pp. 1-6

Author(s):

Sandra Martins ◽

Mercè Rovira ◽

Ana Paula Silva ◽

Valdemar Carnide

Keyword(s):

Higher Plants ◽

Pollen Tubes ◽

The Self ◽

Single Locus ◽

Self Incompatibility ◽

Multiple Alleles ◽

Breeding Programmes ◽

Incompatibility Alleles ◽

Related Individuals ◽

New Cultivars

In many higher plants, selffertilization and genetically related individuals are prevented by pollen-stigma incompatibility. In the genus Corylus, incompatibility is of the sporophytic type and controlled by a single locus with multiple alleles. The objective of this study is to identify the S-alleles present in a collection of Portuguese landraces in order to select the most appropriate landraces for establishment of future orchards and for breeding programmes. Ten major Portuguese hazelnut landraces were submitted to controlled pollinations in the field, with 18 genotypes whose S-alleles are known. The pollen tubes were observed at 100X under a florescence microscope to evaluate their development. Three landraces were revealed to have S2 allele, two have S5, and four have one of the S3, S5, S10, and S18 alleles. One landrace was compatible with the 18 S-alleles tested and for two landraces, it was possible to identify both alleles. The information of the self-incompatibility relationship between these old cultivars is obviously useful for selecting the most suitable pollinators for planning new orchards and for new cultivars development.

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