Cell fusion and chromatin degeneration in an inbred line of maize

Caetano, Creucí María; Pagliarini, Maria Suely; Brasil, Edward Madureira

doi:10.1590/s1415-47571999000100014

Cited by 20 publications

(12 citation statements)

References 17 publications

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“…These syncytes must have resulted from cell fusion in premeiotic mitosis because they were observed from the early stages of meiosis. In another group of genotypes, also cultivated in cerrado soils, one inbred line showed syncyte formation (Caetano-Pereira et al, 1999). In some plants the syncytes showed progressive nuclear degeneration at the beginning of meiosis, producing pycnotic micronuclei and incomplete cell cycle, while in other plants, meiosis was complete despite syncyte formation.…”

Section: Resultsmentioning

confidence: 97%

Meiotic behavior of economically important plant species: the relationship between fertility and male sterility

2000

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Meiosis is an event of high evolutionary stability which culminates in a reduction of chromosome number. The normal and harmonious course of meiosis ensures gamete viability. The cytologic events of gametogenesis are controlled by a large number of genes that act from premeiotic to postmeiotic mitosis. Mutations in these genes cause anomalies that may impair fertility, and many abnormalities affecting plant fertility or causing total male sterility have been detected during the evaluation of meiotic behavior in some species. Some of these abnormalities have been frequently described in the literature, while others have not been previously reported. The most frequent abnormalities found in the species analyzed were irregular chromosome segregation, cytomixis, chromosome stickiness, mixoploidy, chromosome fragmentation, syncyte formation, abnormal spindles, and failure of cytokinesis. Uncommon abnormalities, such as chromosome elimination during microsporogenesis, were found in one species. Original meiotic mutations affecting different steps of meiosis were also observed in these species, especially in maize, Paspalum and soybean. Some mutants present characteristics that may be exploited successfully in breeding programs because they cause total male sterility.
A meiose é um evento de alta estabilidade evolucionária que culmina na redução do número de cromossomos. O curso normal e harmonioso da meiose garante a viabilidade gamética. Os eventos citológicos da gametogênese são controlados por um grande número de genes que atuam desde as mitoses pré-meióticas até as pós-meióticas. Mutações nestes genes causam anomalias que podem afetar a fertilidade. Durante a avaliação do comportamento meiótico em algumas espécies de plantas, muitas anormalidades que afetaram a fertilidade ou causaram total macho-esterilidade foram detectadas. Algumas das anormalidades encontradas já eram descritas na literatura, enquanto outras eram totalmente desconhecidas. As anormalidades mais freqüentes nas espécies analisadas foram segregação irregular de cromossomos, citomixia, aderências cromossômicas, mixoploidia, fragmentação cromossômica, formação de sincícios, fusos anormais e falta de citocinese. Eliminação de cromossomos, uma anormalidade meiótica rara, foi observada em uma espécie de Paspalum. Mutantes meióticos nunca antes descritos, afetando diferentes passos da meiose, foram observados em algumas espécies, especialmente em milho, soja e Paspalum. Alguns mutantes apresentam características que podem ser exploradas com sucesso em programas de melhoramento, pois causam total macho-esterilidade

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Section: Resultsmentioning

confidence: 97%

Meiotic behavior of economically important plant species: the relationship between fertility and male sterility

2000

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“…Since the first report of syncyte formation through cell fusion in Lactuca sativa L. by Gates & Rees (1921), a number of cases have been reported (Levan, 1941; Price, 1956; Katayama, 1964; Mehra & Kalia, 1973; Sarbhoy, 1980; Padmaja, 1988; Caetano‐Pereira et al, 1999; Mendes‐Bonato et al, 2001, 2003; Boldrini et al, 2006; Risso‐Pascotto et al, 2006; Singhal & Kumar, 2008; Kim et al, 2009; Kumar et al, 2010, 2011). We here record for the first time the formation of syncytes and consequently 2 n or double‐sized pollen grains in the accession of L. longiflora var.…”

Section: Discussionmentioning

confidence: 99%

Syncytes during male meiosis resulting in 2n pollen grain formation in Lindelofia longiflora var. falconeri

Singhal

Rana

Kumar

2011

J of Sytematics Evolution

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Lindelofia longiflora (Royle ex Benth.) Baill. var. falconeri (Cl.) Brand (Family: Boraginaceae) is investigated cytologically (n= 12) for the first time from the cold deserts of Pangi Valley, Chamba District (Himachal Pradesh) in India. We report the formation of syncytes and 2n pollen grains in the species. During meiosis, the majority of the pollen mother cells (PMCs) exhibited 12 bivalents, equal segregation of chromosomes during anaphases, regular tetrads, and normal‐sized pollen grain formation. Occasionally, two proximate PMCs fused during the early stages of prophase‐I and resulted in the formation of syncytes. The frequency of syncytes in the accession is rather low, at 25 out of 1866 (1.33%). Such syncyte PMCs are detectable during meiosis due to their larger size compared to typical PMCs. The syncytes or polyploid cells showed normal 24 bivalents and depicted perfectly regular meiotic course. But the products of such PMCs yield 2n or larger sized pollen grains that are almost double the size of typical normal or n pollen grains. The origin of syncytes as a consequence of the fusion of meiocytes during the early stages of meiosis‐I could be attributed to low temperature stress conditions prevailing in the Pangi Valley, where temperature during May and June dip to below freezing, the time the plants enters the reproductive/flowering bud stage. It is possible that such apparently fertile 2n pollen grains originating from syncytes might play a role in the origin of intraspecific polyploids in the species.

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“…Another interesting aspect of the syncytes is that many of them showed severe chromosome stickiness. Cell fusion leading to syncyte formation is a phenomenon widely reported in higher plants (Nirmala & Rao 1996;Caetano-Pereira et al 1999). Syncyte formation may be induced by genetic and environmental factors (Nirmala & Rao 1996) and generally leads to the formation of abnormal pollen grains.…”

Section: Meiotic Analysismentioning

confidence: 99%

EMS, sodium azide and gamma rays induced meiotic anomalies in Delphinium malabaricum (Huth) Munz

2013

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Meiotic cell division is a dynamic cellular process controlled by a large number of genes that act from premeiotic to postmeiotic mitosis. Mutation in these genes may cause anomalies that impair plant fertility. In this study, an attempt has therefore been made to understand the effects of ethyl methane sulfonate (EMS), sodium azide (SA) and gamma rays on the meiotic configuration of Delphinium malabaricum. The results demonstrated that the mutagens cause various types of cytological aberrations, such as univalents, chromatin bridges, laggards, fragments, stickiness and multinucleated cells. The maximum aberrations were found at higher doses/concentrations of the mutagens. The highest percentage of pollen mother cells showing abnormalities was induced by EMS followed by gamma rays and SA. The mutagen impact on chromosomal anomalies increased the frequency of pollen sterility.

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Cell fusion and chromatin degeneration in an inbred line of maize

Cited by 20 publications

References 17 publications

Meiotic behavior of economically important plant species: the relationship between fertility and male sterility

Meiotic behavior of economically important plant species: the relationship between fertility and male sterility

Syncytes during male meiosis resulting in 2n pollen grain formation in Lindelofia longiflora var. falconeri

EMS, sodium azide and gamma rays induced meiotic anomalies in Delphinium malabaricum (Huth) Munz

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