The ScRALF3 secreted peptide is involved in sporophyte to gametophyte signalling and affects pollen mitosis I

The apical and floral development of Claytonia caroliniana var. caroliniana has been studied concurrently with soil temperature, in a sugar maple forest of the Stoneham mountain, Québec. Apical cellular activity begins early in May, while the flowering stems of the year are present. At the beginning of July, external apical development becomes visible. In the first days of August, 9 months before flowering, the foliar and floral structures of the next year are already present in the soil. Meiosis takes place at the beginning of October and first pollen mitosis follows shortly after, in the middle of the same month. From that time, well developed individuals, without chlorophyll, are present just under the litter. They can occasionally turn green and reach the upper surface of the litter in November or December, where they will spend wintertime under the snow, at a temperature oscillating between 0 and −4 °C. This behaviour is quite close to the survival strategy of hemicryptophytes. The active epigeous growth period begins in the middle of April, with the melting of snow. Second pollen mitosis and flowering take place at this time, rapidly followed by seed setting, dissemination, and destruction of the aerial portion of the plant. Cytoecological investigations to study possible influence of environmental factors on chromosomal anomalies in primordia should thus be conducted during the year preceding the flowering of Claytonia.

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Tradescantia cytogenetic tests (root-tip mitosis, pollen mitosis, pollen mother-cell meiosis)

Mutation Research/Reviews in Genetic Toxicology ◽

10.1016/0165-1110(82)90047-1 ◽

1982 ◽

Vol 99 (3) ◽

pp. 293-302 ◽

Cited By ~ 47

Author(s):

Te-Hsiu Ma

Keyword(s):

Pollen Mother Cell ◽

Mother Cell ◽

Root Tip ◽

Pollen Mitosis

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The Arabidopsis thaliana gametophytic mutation gemini pollen1 disrupts microspore polarity, division asymmetry and pollen cell fate

Development ◽

10.1242/dev.125.19.3789 ◽

1998 ◽

Vol 125 (19) ◽

pp. 3789-3799 ◽

Cited By ~ 3

Author(s):

S.K. Park ◽

R. Howden ◽

D. Twell

Keyword(s):

Arabidopsis Thaliana ◽

Cell Fate ◽

Asymmetric Cell Division ◽

Marker Gene ◽

Generative Cell ◽

Polar Axis ◽

Cell Polarization ◽

Pollen Mitosis ◽

Daughter Cells ◽

Potential Mode

Pollen development and male gametogenesis are critically dependent upon cell polarization leading to a highly asymmetric cell division termed pollen mitosis I. A mutational approach was adopted in Arabidopsis thaliana to identify genes involved these processes. Four independent gemini pollen mutants were isolated which produce divided or twin-celled pollen. The gemini pollen1 mutant was characterized in detail and shown to act gametophytically resulting in reduced transmission through both sexes. gemini pollen1 showed an incompletely penetrant phenotype resulting in equal, unequal and partial divisions at pollen mitosis I. The division planes in gemini pollen1 were shown to be aligned with the polar axis (as in wild type) and evidence was obtained for incomplete nuclear migration, which could account for altered division symmetry. gemini pollen1 also showed division phenotypes consistent with spatial uncoupling of karyokinesis and cytokinesis suggesting that GEMINI POLLEN1 may be required for the localization of phragmoplast activity. Cell fate studies showed that in both equal and unequal divisions a vegetative cell marker gene was activated in both daughter cells. Daughter cells with a range of intermediate or hybrid vegetative/generative cell fates suggests that cell fate is quantitatively related to cell size. The potential mode of action of GEMINI POLLEN1 and its effects on cell fate are discussed in relation to proposed models of microspore polarity and cell fate determination.

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B CHROMOSOME NONDISJUNCTION IN CORN: CONTROL BY FACTORS NEAR THE CENTROMERE

Genetics ◽

10.1093/genetics/97.2.379 ◽

1981 ◽

Vol 97 (2) ◽

pp. 379-389

Author(s):

Wayne R Carlson ◽

Tau-San Chou

Keyword(s):

B Chromosome ◽

B Chromosomes ◽

Translocation Chromosome ◽

Pollen Mitosis ◽

Second Pollen Mitosis ◽

Chromosome Nondisjunction

ABSTRACT B chromosomes of corn are stable at all mitotic and meiotic divisions of the plant except the second pollen mitosis. In the latter division, B chromosomes undego mitotic nondisjunction at rates as high as 98%. Studies by several workers on B-A translocation chromosomes have provided evidence for the existence of four factors on the B chromosome that control nondisjunction and are separable from the centromere. Two of these factors, referred to here as factors 3 and 4, flank the B chromosome centromere. Factor 3 is the centromere-adjacent heterochromatin in the long arm of the B chromosome; factor 4 is located in the minute short arm. Evidence is presented here supporting the existence of factors 3 and 4. Deficiencies that include each factor were identified following centromeric misdivision events, with breaks at or near the centromere of a B-translocation chromosome. B chromosomes lacking factors 3 or 4 show much less nondisjunction than do chromosomes containing them. The possible function of factor 4 in nondisjuntion is also discussed.

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The unusualdRempretrotransposon is abundant, highly mutagenic, and mobilized only in the second pollen mitosis of some maize lines

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2010234117 ◽

2020 ◽

Vol 117 (30) ◽

pp. 18091-18098

Author(s):

Qinghua Wang ◽

Jun Huang ◽

Yubin Li ◽

Hugo K. Dooner

Keyword(s):

Spontaneous Mutation ◽

Male Meiosis ◽

Normal Embryo ◽

Ltr Retrotransposons ◽

Pollen Mitosis ◽

Low Copy Number ◽

Frequent Mutations ◽

Second Pollen Mitosis ◽

Mutant Phenotypes ◽

Insertion Mutants

The frequent mutations recovered recently from the pollen of select maize lines resulted from the meiotic mobilization of specific low-copy number long-terminal repeat (LTR) retrotransposons, which differ among lines. Mutations that arise at male meiosis produce kernels with concordant mutant phenotypes in both endosperm and embryo because the two sperms that participate in double fertilization are genetically identical. Those are in a majority. However, a small minority of kernels with a mutant endosperm carry a nonconcordant normal embryo, pointing to a postmeiotic or microgametophytic origin. In this study, we have identified the basis for those nonconcordant mutations. We find that all are produced by transposition of a defective LTR retrotransposon that we have termeddRemp(defective retroelement mobile in pollen). This element has several unique properties. Unlike the mutagenic LTR retrotransposons identified previously,dRempis present in hundreds of copies in all sequenced lines. It seems to transpose only at the second pollen mitosis because alldRempinsertion mutants are nonconcordant yet recoverable in either the endosperm or the embryo. Although it does not move in most lines,dRempis highly mobile in the Corn Belt inbred M14, identified earlier by breeders as being highly unstable. Lastly, it can be recovered in an array of structures, ranging from solo LTRs to tandemdRemprepeats containing several internal LTRs, suggestive of extensive recombination during retrotransposition. These results shed further light on the spontaneous mutation process and on the possible basis for inbred instability in maize.

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The Gametic Non-Lethal Gene Gal on Chromosome 5 Is Indispensable for the Transmission of the Co-Induced Semidwarfing Gene d60 in Rice

Biology ◽

10.3390/biology8040094 ◽

2019 ◽

Vol 8 (4) ◽

pp. 94

Author(s):

Motonori Tomita ◽

Takatoshi Tanisaka

Keyword(s):

Genetic Model ◽

Recessive Gene ◽

Male Gamete ◽

Lethal Gene ◽

Single Recessive Gene ◽

Pollen Mitosis ◽

Chromosome 5 ◽

Second Pollen Mitosis ◽

Generation Sequencing ◽

Simple Sequence

The gametic lethal gene gal in combination with the semidwarfing gene d60 causes complementary lethality in rice. Here, we attempted to ascertain the existence of gal and clarify male gamete abortion caused by d60 and gal. Through the F2 to F4 generations derived from the cross between D60gal-homozygous and d60Gal-homozygous, progenies of the partial sterile plants (D60d60Galgal) were segregated in a ratio of 1 semidwarf (1 d60d60GalGal):2 tall and quarter sterile (2 D60d60Galgal):6 tall (2 D60d60GalGal:1 D60D60GalGal:2 D60D60Galgal:1 D60D60galgal), which is skewed from the Mendelian ratio of 1 semidwarf:3 tall. However, the F4 generation was derived from fertile and tall heterozygous F2 plants (D60d60GalGal), which were segregated in the Mendelian ratio of 1[semidwarf (d60d60GalGal)]:2[1 semidwarf:3 tall (D60d60GalGal)]:1[tall (D60D60GalGal)]. The backcrossing of D60Gal-homozygous tall F4 plants with Hokuriku 100 resulted in fertile BCF1 and BCF2 segregated in a ratio of 1 semidwarf:3 tall, proving that d60 is inherited as a single recessive gene in the D60d60GalGal genetic background (i.e., in the absence of gal). Further, gal was localized on chromosome 5, which is evident from the deviated segregation of d1 as 1:8 and linkage with simple sequence repeat (SSR) markers. Next-generation sequencing identified the candidate SNP responsible for Gal. In F1 and sterile F2, at the binucleate stage, partial pollen discontinued development. Degraded pollen lost vegetative nuclei, but second pollen mitosis raising two generative nuclei was observed. Thus, our study describes a novel genetic model for a reproductive barrier. This is the first report on such a complementary lethal gene, whose mutation allows the transmission of a co-induced valuable semidwarfing gene d60.

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MYB81, a microspore‐specific GAMYB transcription factor, promotes pollen mitosis I and cell lineage formation in Arabidopsis

The Plant Journal ◽

10.1111/tpj.14564 ◽

2019 ◽

Vol 101 (3) ◽

pp. 590-603 ◽

Cited By ~ 2

Author(s):

Sung‐Aeong Oh ◽

Thuong Nguyen Thi Hoai ◽

Hyo‐Jin Park ◽

Mingmin Zhao ◽

David Twell ◽

...

Keyword(s):

Transcription Factor ◽

Cell Lineage ◽

Pollen Mitosis

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Pollen development in orchids

Journal of Cell Science ◽

10.1242/jcs.99.2.273 ◽

1991 ◽

Vol 99 (2) ◽

pp. 273-281 ◽

Cited By ~ 1

Author(s):

R. C. BROWN ◽

B. E. LEMMON

Keyword(s):

Plasma Membrane ◽

Nuclear Envelope ◽

Pollen Development ◽

Nuclear Migration ◽

Pollen Mitosis ◽

Polar Structure ◽

Microtubular Cytoskeleton ◽

Distal Surface

Cytoplasmic preparation for the unequal first mitosis in non-vacuolate pollen of moth orchids (Phalaenopsis) includes reorganization of the microtubular cytoskeleton and nuclear migration. Following meiotic cytokinesis, both microtubules and F-actin are unpolarized in microspores of persistent tetrads. Microtubules radiate from the centrally located nucleus and F-actin forms a reticulate pattern in the cytoplasm. Polarization of the microspores is marked by a dramatic reorganization of microtubules while the pattern of F-actin remains unchanged. We describe a novel system of microtubules at the generative pole (GPMS), which forms a polar structure structure at the distal surface and marks the path of nuclear migration prior to pollen mitosis. The GPMS consists of numerous microtubules that extend between the plasma membrane and nuclear envelope. The nucleus becomes displaced toward the generative pole and flattened in association with microtubules of the GPMS. Initiation of the GPMS is marked by a localized proliferation of ER and clearing of large organelles from the generative pole.

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