Slowing Development Facilitates Arabidopsis mgt Mutants to Accumulate Enough Magnesium for Pollen Formation and Fertility Restoration

Magnesium (Mg) is an abundant and important cation in cells. Plants rely on Mg transporters to take up Mg from the soil, and then Mg is transported to anthers and other organs. Here, we showed that MGT6+/− plants display reduced fertility, while mgt6 plants are fertile. MGT6 is expressed in the anther at the early stages. Pollen mitosis and intine formation are impaired in aborted pollen grains (PGs) of MGT6+/− plants, which is similar to the defective pollen observed in mgt5 and mgt9 mutants. These results suggest that Mg deficiency leads to pollen abortion in MGT6+/− plants. Our data showed that mgt6 organs including buds develop significantly slower and mgt6 stamens accumulate a higher level of Mg, compared with wild-type (WT) and MGT6+/− plants. These results indicate that slower bud development allows mgt6 to accumulate sufficient amounts of Mg in the pollen, explaining why mgt6 is fertile. Furthermore, we found that mgt6 can restore fertility of mgt5, which has been reported to be male sterile due to defects in Mg transport from the tapetum to microspores and that an additional Mg supply can restore its fertility. Interestingly, mgt5 fertility is recovered when grown under short photoperiod conditions, which is a well-known factor regulating plant fertility. Taken together, these results demonstrate that slow development is a general mechanism to restore mgts fertility, which allows other redundant magnesium transporter (MGT) members to transport sufficient Mg for pollen formation.

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Male fertility restoration of wheat in Hordeum chilense cytoplasm is associated with 6HchS chromosome addition

Australian Journal of Agricultural Research ◽

10.1071/ar07239 ◽

2008 ◽

Vol 59 (3) ◽

pp. 206 ◽

Cited By ~ 29

Author(s):

A. C. Martín ◽

S. G. Atienza ◽

M. C. Ramírez ◽

F. Barro ◽

A. Martín

Keyword(s):

Bread Wheat ◽

Fertility Restoration ◽

Triticum Aestivum L ◽

Abnormal Development ◽

Hordeum Chilense ◽

Alloplasmic Line ◽

Male Sterile ◽

Pollen Abortion ◽

Reduced Height ◽

Pollen Stage

We report a new cytoplasmic male sterility (CMS) source in bread wheat (Triticum aestivum L.) designated as msH1. CMS has been identified during the process of obtaining alloplasmic bread wheat in different Hordeum chilense Roem. Schultz. cytoplasms. It was observed that when using the H. chilense H1 accession, the corresponding alloplasmic line was male sterile. This alloplasmic wheat is stable under different environmental conditions and it does not exhibit developmental or floral abnormalities, showing only slightly reduced height and some delay in heading. On examining microsporogenesis in the alloplasmic line, it was found that different stages of meiosis were completed normally, but abnormal development occurred at the uninucleate-pollen stage at the first mitosis, resulting in failure of anther exertion and pollen abortion. Fertility restoration of the CMS phenotype caused by the H. chilense cytoplasm was associated with the addition of chromosome 6HchS from H. chilense accession H1. Thus, some fertility restoration genes appear to be located in this chromosome arm. Considering the features displayed by the msH1 system, we consider that it has a great potential for the development of viable technology for hybrid wheat production.

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Pollen and Spikelet Analysis in F1 Rice Hybrids and their Parents

Nepal Agriculture Research Journal ◽

10.3126/narj.v8i0.11605 ◽

2014 ◽

Vol 8 ◽

pp. 120-126 ◽

Cited By ~ 1

Author(s):

Bal K. Joshi ◽

Laxmi P. Subedi ◽

Santa B. Gurung ◽

Ram C. Sharma

Keyword(s):

Pollen Fertility ◽

Practical Importance ◽

Pollen Grains ◽

Gene Interaction ◽

Pollen Sterility ◽

Spikelet Fertility ◽

High Fertility ◽

Male Sterile ◽

Pollen Abortion ◽

Spikelet Sterility

Pollen analysis can be used to discriminate between different species, identify possible interspecies hybrids, identify restorer and maintainer lines, useful to study genetics of restorer gene, interaction between chromosome and cytoplasm and relationship between parents. Pollen abortion system of male sterility is an important tool in hybrid rice production and spikelet is the major yield components. Nine improved cultivars, six landraces and three wild aborted cytoplasmic-genetic male sterile (CMS) lines were used to analyze pollen and spikelet in F1 rice hybrids and their parents. The frequency of pollen categories and its relationship to spikelet fertility were investigated. Pollen sterility of the F1s was determined by staining pollen grains in 1% potassium iodide-iodine (I-KI) solution. Spikelet fertility was determined by counting the total number of seed set in proportion to the total number of spikelets. Correlation and regression coefficients for some traits were computed. In hybrids, pollen fertility ranged from 0.5 to 82% and spikelet fertility from 0 to 87%. Pollen fertility varied from 28 to 97%, while spikelet fertility from 73 to 91% in pollen parents. The highest and the lowest percentages of pollen fertility were found in Chaite-6 and Chiunde cultivars respectively. Spikelet fertility percentage varied widely among hybrids and many hybrids had lower spikelet fertility percentage than their parents. Therefore, it is of practical importance to understand the causes of high spikelet sterility in hybrids for possible increase in spikelet fertility. Highly significant positive correlation was found between stained round fertile (SRF) pollen and spikelet fertility. The positive value of correlation and regression coefficient on SRF and spikelet fertility were found between F1 and mid parent, and F1 and male parent. High fertility of cross may be due to the presence of a wide compatibility gene or restorer genes in the cultivar. Lower pollen and spikelet fertility of the crosses was attributed to effect of the genetic background of the tester parent. Nepal Agric. Res. J. Vol. 8, 2007, pp. 120-126 DOI: http://dx.doi.org/10.3126/narj.v8i0.11605

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Abnormal Microspore Development Leads to Pollen Abortion in a Seedless Mutant of ‘Ougan’ Mandarin (Citrus suavissima Hort. ex Tanaka)

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.132.6.777 ◽

2007 ◽

Vol 132 (6) ◽

pp. 777-782 ◽

Cited By ~ 22

Author(s):

Zhiyong Hu ◽

Min Zhang ◽

Qigen Wen ◽

Jie Wei ◽

Hualin Yi ◽

...

Keyword(s):

Pollen Viability ◽

Pollen Grains ◽

Pollen Grain ◽

Mature Pollen ◽

Abnormal Development ◽

Microspore Development ◽

Wild Type ◽

Pollen Abortion ◽

Tetrad Stage ◽

In The Wild

Seedlessness is of commercial importance in citrus (Citrus L.). Seedless ‘Ougan’ mandarin (C. suavissima) was selected from a bud sport mutation that occurred in ‘Ougan’ mandarin. We analyzed their pollen viability through KI-I2 and FDA staining, and examined the anthers of wild-type (seedy) and seedless mutant ‘Ougan’ mandarin using histological and cytochemical methods to characterize the process of pollen development. No pollen fertility was detected in this mutant. Pollen abortion in anthers of the mutant occurred at the tetrad stage of microspore development, and almost all the tetrads were abnormal. The mutant had heterogeneous microspore populations, including monads, dyads, triads, tetrads, and polyads in the same microsporangium. Pollen grain number per anther of the mutant was 21.9% less than the wild type. Morphology of mature pollen grains using SEM showed that the shape of mature pollen grains from both wild type and mutant is similar, but the microsporangia of the latter contained pollen grains of more variable sizes. At the early mature pollen grain stage, abundant starch grains and lipids appeared in the wild type's pollen, but fewer amounts were observed in the mutant. Moreover, the tapetal cells of the wild type accumulated lipids, but not those of the mutant. Results indicated that the abnormal development of the microspore led to pollen abortion in the mutant, and this could be the reason for its seedlessness. However, the genetic reasons for the aberrant tetrads are not clear and are under investigation.

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ARABIDOPSIS POLLEN ABORTION MUTANT 2, Encoding an Unknown Protein with Three WD40-Repeats, Is Essential for Late Pollen Mature in Arabidopsis thaliana

10.21203/rs.2.11828/v1 ◽

2019 ◽

Author(s):

Zhaoxia Ma ◽

Xueqin Zhang ◽

Liqun Chen ◽

Guobin Zhang ◽

Yue Liu ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Pollen Grains ◽

Subcellular Localisation ◽

Pollen Abortion ◽

Homologous Proteins ◽

Unknown Protein ◽

Development Processes ◽

Pollen Formation ◽

Arabidopsis Pollen ◽

Wd40 Repeats

Abstract Background In flowering plants, pollen formation is a very complex process. It is strictly regulated by various genetic factors. Some of these factors have been identified, but the regulatory mechanism concerning the process of late pollen maturing remains unknown. Results Previously we identified and reported an ARABIDOPSIS POLLEN ABORTION MUTANT 2 (APAM2) gene which was required for pollen formation in Arabidopsis thaliana. In this study, we further analysed the phenotype of atapam2 and the subcellular localisation of AtAPAM2. Mutation in AtAPAM2 drastically affected male gametophytic function, impacted the late pollen mature process, and resulted in mature pollen grains from atapam2/+ plants being shrivelled and dead. It was expressed among seedlings, roots, stems, leaves, siliques, flowers, and pollen grains. However, its expression levels in flowers and pollen grains were much higher than in other tissues. Gene AtAPAM2 encodes an unknown protein with three WD40-repeats with localisation in plasma membrane and nucleus, and homologous proteins exist in many species. Conclusions We determined that AtAPAM2 may play a role in pollen formation and other development processes by interacting with other proteins, but we did not identify the protein that interacts with it.

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ARABIDOPSIS POLLEN ABORTION MUTANT 2, Encoding an Unknown Protein with Three WD40-Repeats, Is Essential for Late Pollen Mature in Arabidopsis thaliana

10.21203/rs.2.11828/v2 ◽

2019 ◽

Author(s):

Zhaoxia Ma ◽

Xueqin Zhang ◽

Liqun Chen ◽

Guobin Zhang ◽

Yue Liu ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Pollen Grains ◽

Pollen Abortion ◽

Homologous Proteins ◽

Complex Process ◽

Unknown Protein ◽

Development Processes ◽

Pollen Formation ◽

Arabidopsis Pollen ◽

Wd40 Repeats

Abstract Background In flowering plants, pollen formation is a very complex process. It is strictly regulated by various genetic factors. Some of these factors have been identified, but the regulatory mechanism concerning the process of late pollen maturing remains unknown.Results Previously we identified and reported an ARABIDOPSIS POLLEN ABORTION MUTANT 2 (APAM2) gene which was required for pollen formation in Arabidopsis thaliana. In this study, we further analysed the phenotype of atapam2 and the expression pattern of AtAPAM2. Mutation in AtAPAM2 drastically affected male gametophytic function, impacted the late pollen mature process, and resulted in mature pollen grains from atapam2/+ plants being shrivelled and dead. It was expressed among seedlings, roots, stems, leaves, siliques, flowers, and pollen grains. However, its expression levels in flowers and pollen grains were much higher than in other tissues. AtAPAM2 encodes an unknown protein with three WD40-repeats with localisation in plasma membrane and nucleus, and homologous proteins exist in many species.Conclusions We determined that AtAPAM2 may play a role in pollen formation and other development processes by interacting with other proteins, but we did not identify the protein that interacts with it.

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Absence of microspore polarity, symmetric divisions and pollen cell fate in Brachiaria decumbens (Gramineae)

Genome ◽

10.1139/g02-114 ◽

2003 ◽

Vol 46 (1) ◽

pp. 83-88 ◽

Cited By ~ 15

Author(s):

Roberto Gargione Junqueira Filho ◽

Andréa Beatriz Mendes-Bonato ◽

Maria Suely Pagliarini ◽

Nilton Cesar Pires Bione ◽

Cacilda Borges do Valle ◽

...

Keyword(s):

Cell Fate ◽

Nuclear Polarization ◽

Male Gametophyte ◽

Chromatin Condensation ◽

Generative Cell ◽

Pollen Grains ◽

Pollen Mitosis ◽

Male Sterile ◽

Brachiaria Decumbens ◽

Pollen Cell

Meiotic division and male gametophyte development were analyzed in one tetraploid (2n = 4x = 36) accession of Brachiaria decumbens cv. Basilisk that showed some pollen sterility. Meiotic process was typical of polyploids in that it consisted of multiple chromosome associations. Precocious chromosome migration to the poles, laggards, and micronucleus formation were abundant in both meiosis I and II and resulted in tetrads with micronuclei. After callose dissolution, microspores were released into the anther locule and had the semblance of being normal. Although each microspore initiated its differentiation by pollen mitosis, in 43.24% of the microspores, nuclear polarization was not observed and the typical hemispherical cell plate was not detected. Division was symmetric and microspores lacked differentiation between the vegetative and the generative cell. Both nuclei were of equal size, presented equal chromatin condensation, and had a spherical shape. After the first pollen mitosis and cytokinesis, each cell underwent a new symmetric mitosis without nuclear polarization. At the end of the second pollen mitosis, four equal nuclei were observed in each pollen grain. After the second cytokinesis, the cells gave rise to four equal-sized pollen grains with a similar tetrad configuration that initially remained together. Sterile pollen grains resulted from abnormal pollen mitosis. This anomaly may be explained by a mutation, probably affecting microtubule cytoskeleton formation. The importance of this male-sterile mutation for Brachiaria breeding programs is discussed.Key words: Brachiaria decumbens, male sterility, pollen mitosis, microspore polarity, symmetric division, pollen cell fate, grasses.

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Meiotic behaviour of extra chromosomes in fertility restored Polima CMS Brassica napus plants

Genome ◽

10.1139/g88-073 ◽

1988 ◽

Vol 30 (3) ◽

pp. 438-442 ◽

Cited By ~ 1

Author(s):

William Tai ◽

Peter B. E. McVetty

Keyword(s):

Brassica Napus ◽

Fertility Restoration ◽

Extra Chromosome ◽

Pollen Grains ◽

Backcross Progeny ◽

Male Sterile ◽

High Frequencies ◽

B Genome ◽

Mother Cells ◽

Very High Frequencies

Crosses were made between Brassica napus (2n = 38) with the 'Polima' cytoplasmic male sterile system and variety 'Zem' of B. juncea. Fertility was partially restored in backcross progeny with an extra chromosome (2n = 39) that was believed to be a member of the B genome of B. juncea. Among more than 40 self-pollinated offspring plants studied, fertility restoration was transmitted only through those plants with two extra chromosomes (2n = 40). Anthers of these plants were either full or shriveled with small swollen protrusions. Full and round pollen grains were found in full anthers and in the swollen portion of shriveled anthers. These pollen grains were stained darkly with I2-KI solution and full seed set was obtained from bagged flowers. Meiotic studies in plants with 2n = 40 showed 18 bivalents + 1 quadrivalent at diakinesis in most of the pollen mother cells analyzed. The chromosomes segregated equally at anaphase I and behaved normally at other meiotic stages. The presence of a single quadrivalent in the backcross progeny was highly consistent and occurred in very high frequencies. It is believed that the extra chromosomes belong to the B genome of B. juncea and take part in the quadrivalent formation.Key words: Brassica napus, cytoplasmic male sterility, aneuploidy, Polima, Brassica juncea, rapeseed cytogenetics.

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The effects of Rf5 and Rf6 on fertility restoration in Honglian-type cytoplasmic male sterile (CMS) lines of japonica rice (Oryza sativa L. ssp. japonica)

10.21203/rs.3.rs-319365/v1 ◽

2021 ◽

Author(s):

Honggen Zhang ◽

Ruixuan Wang ◽

Zuopeng Xu ◽

Xiangqiang Zhao ◽

Hailin Gao ◽

...

Keyword(s):

Oryza Sativa L ◽

Fertility Restoration ◽

Pollen Grains ◽

Japonica Rice ◽

Male Sterile ◽

Fertility Restorer ◽

Dosage Effects ◽

Abortive Pollen ◽

Critical Insight ◽

Insight Into

Abstract The Honglian (HL)-type cytoplasmic male sterility (CMS) has only been used in the development of three-line indica rice hybrids, and the fertility of HL-type indica CMS lines can be restored by two nonallelic fertility-restorer (Rf) genes, Rf5 and Rf6. For the development of HL-type japonica hybrid combinations, it is therefore necessary to determine whether Rf5 and Rf6 can restore the fertility of HL-type japonica CMS lines. Here, we genetically characterized HL-type japonica CMS lines and the ability of Rf5 and Rf6 to restore fertility for breeding HL-type japonica hybrids. I2-KI pollen staining revealed that HL-type japonica CMS lines and their derived testcross F1 hybrids had stained abortive pollen grains, unlike HL-type indica CMS lines. Crossing experiments showed that Rf5 and Rf6 partially restored the fertility of HL-type japonica CMS lines, and Rf6 showed higher restorability than Rf5. Furthermore, we found that there were additive and dosage effects of Rf5 and Rf6 with respect to fertility restoration in HL-type japonica CMS lines. These results give critical insight into the breeding of HL-type japonica CMS lines and restorers, which will be helpful for the development of commercial HL-type japonica hybrids.

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Understanding male sterility in Miconia species (Melastomataceae): a morphological approach

Australian Journal of Botany ◽

10.1071/bt12076 ◽

2012 ◽

Vol 60 (6) ◽

pp. 506 ◽

Cited By ~ 8

Author(s):

Priscila Andressa Cortez ◽

Sandra Maria Carmello-Guerreiro ◽

Simone Pádua Teixeira

Keyword(s):

Pollen Tube ◽

Male Sterility ◽

Developmental Stages ◽

Rare Event ◽

Pollen Grains ◽

Pollen Grain ◽

Male Sterile ◽

Pollen Abortion ◽

Large Numbers ◽

Morphological Approach

Pollen abortion occurs in virtually all species and often does not prejudice reproductive success. However, large numbers of abnormal pollen grains are characteristic of some groups. Among them is Miconia, in which partial and complete male sterility is often related to apomixis. In this study, we compared the morphology of pollen grains over several developmental stages in Miconia species with different rates of male sterility. Our aim was to improve the knowledge of mechanisms that lead to male sterility in this ecologically important tropical group. Routine techniques for microscopy were used to examine anthers in several developmental stages collected from the apomictic species Miconia albicans and M. stenostachya. Both species are completely male sterile since even the pollen grains with apparently normal cytoplasm were not able to develop a pollen tube. Meiosis is a rare event in M. albicans anthers and happens in an irregular way in M. stenostachya, leading to the pollen abortion. M. albicans has more severe abnormalities than M. stenostachya since even the microspores and pollen grain walls were affected. Moreover, in M. stenostachya, most mitosis occurring during microgametogenesis was also abnormal, leading to the formation of bicellular pollen grains with two similar cells, in addition to the formation of pollen grains of different sizes. Notably, abnormalities in both species did not reach the production of Übisch bodies, suggesting little or no tapetum involvement in male sterility in these two species.

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Mutator-Induced Mutations of the rf1 Nuclear Fertility Restorer of T-Cytoplasm Maize Alter the Accumulation of T-urfl3 Mitochondrial Transcripts

Genetics ◽

10.1093/genetics/143.3.1383 ◽

1996 ◽

Vol 143 (3) ◽

pp. 1383-1394

Author(s):

Roger P Wise ◽

Carren L Dill ◽

Patrick S Schnable

Keyword(s):

Pollen Fertility ◽

Fertility Restoration ◽

Mitochondrial Rna ◽

Induced Mutations ◽

Male Sterile ◽

Fertility Restorer ◽

Restorer Genes ◽

Mitochondrial Transcripts ◽

Ecori Restriction ◽

Fertility Restorer Genes

Abstract Dominant alleles of the rf1 and rf2 nuclear-encoded fertility restorer genes are necessary for restoration of pollen fertility in T-cytoplasm maize. To further characterize fertility restoration mediated by the Rf1 allele, 123,500 gametes derived from plants carrying the Mutator transposable element family were screened for rf1-mutant alleles (rf1-m) Four heritable rf1-m alleles were recovered from these populations. Three rf1-m alleles were derived from the progenitor allele Rf1-IAl53 and one was derived from Rf1-Ky21. Cosegregation analysis revealed 5.5- and 2.4kb Mu1-hybridizing EcoRI restriction fragments in all of the male-sterile and none of the male-fertile plants in families segregating for rf1-m3207 and rf1-m3310, respectively. Mitochondrial RNA gel blot analyses indicated that all four rf1-m alleles in male-sterile plants cosegregated with the altered steady-state accumulation of 1.6 and O.6-kb T-urf13 transcripts, demonstrating that these transcripts are Rf1 dependent. Plants carrying a leaky mutant, rf1-m7323, revealed variable levels of Rf1-associated, T-urf13 transcripts and the degree of pollen fertility. The ability to obtain rf1-m derivatives from Rf1 indicates that Rf1 alleles produce a functional gene product necessary for the accumulation of specific T-urf13 transcripts in T-cytoplasm maize.

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