The Arabidopsis Mutant jason Produces Unreduced First Division Restitution Male Gametes through a Parallel/Fused Spindle Mechanism in Meiosis II

Abstract Salicylic acid (SA) is required for resistance to many diseases in higher plants. SA-dependent cell death and defense-related responses have been correlated with disease resistance. The accelerated cell death 5 mutant of Arabidopsis provides additional genetic evidence that SA regulates cell death and defense-related responses. However, in acd5, these events are uncoupled from disease resistance. acd5 plants are more susceptible to Pseudomonas syringae early in development and show spontaneous SA accumulation, cell death, and defense-related markers later in development. In acd5 plants, cell death and defense-related responses are SA dependent but they do not confer disease resistance. Double mutants with acd5 and nonexpressor of PR1, in which SA signaling is partially blocked, show greatly attenuated cell death, indicating a role for NPR1 in controlling cell death. The hormone ethylene potentiates the effects of SA and is important for disease symptom development in Arabidopsis. Double mutants of acd5 and ethylene insensitive 2, in which ethylene signaling is blocked, show decreased cell death, supporting a role for ethylene in cell death control. We propose that acd5 plants mimic P. syringae-infected wild-type plants and that both SA and ethylene are normally involved in regulating cell death during some susceptible pathogen infections.

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Molecular Mapping of Segregation Distortion Loci in Aegilops tauschii

Genetics ◽

10.1093/genetics/149.1.319 ◽

1998 ◽

Vol 149 (1) ◽

pp. 319-327 ◽

Cited By ~ 1

Author(s):

J D Faris ◽

B Laddomada ◽

B S Gill

Keyword(s):

Segregation Distortion ◽

Molecular Mapping ◽

Aegilops Tauschii ◽

Distorted Segregation ◽

F2 Population ◽

Male Gametes ◽

Skewed Segregation ◽

Segregation Ratios ◽

Backcross Populations ◽

Intraspecific Hybrids

Abstract Distorted segregation ratios of genetic markers are often observed in progeny of inter- and intraspecific hybrids and may result from competition among gametes or from abortion of the gamete or zygote. In this study, 194 markers mapped in an Aegilops tauschii F2 population were surveyed for distorted segregation ratios. Region(s) with skewed segregation ratios were detected on chromosomes 1D, 3D, 4D, and 7D. These distorter loci are designated as QSd.ksu-1D, QSd.ksu-3D, QSd.ksu-4D, and QSd.ksu-7D. Three regions of segregation distortion identified on chromosome 5D were analyzed in two sets of reciprocal backcross populations to analyze the effect of sex and cytoplasm on segregation distortion. Extreme distortion of marker segregation ratios was observed in populations in which the F1 was used as the male parent, and ratios were skewed in favor of TA1691 alleles. There was some evidence of differential transmission caused by nucleo-cytoplasmic interactions. Our results agree with other studies stating that loci affecting gametophyte competition in male gametes are located on 5DL. The distorter loci on 5DL are designated as QSd.ksu-5D.1, QSd.ksu-5D.2, and QSd.ksu-5D.3.

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Two Loci Contribute Epistastically to Heterospecific Pollen Rejection, a Postmating Isolating Barrier Between Species

G3 Genes|Genome|Genetics ◽

10.1534/g3.117.041673 ◽

2017 ◽

Vol 7 (7) ◽

pp. 2151-2159 ◽

Cited By ~ 6

Author(s):

Jennafer A P Hamlin ◽

Natasha A Sherman ◽

Leonie C Moyle

Keyword(s):

Female Choice ◽

Genetic Basis ◽

Reproductive Tract ◽

Interspecific Cross ◽

Solanum Species ◽

Female Reproductive Tract ◽

Solanum Pennellii ◽

Heterospecific Pollen ◽

Male Gametes ◽

Pollen Rejection

Abstract Recognition and rejection of heterospecific male gametes occurs in a broad range of taxa, although the complexity of mechanisms underlying these components of postmating cryptic female choice is poorly understood. In plants, the arena for postmating interactions is the female reproductive tract (pistil), within which heterospecific pollen tube growth can be arrested via active molecular recognition and rejection. Unilateral incompatibility (UI) is one such postmating barrier in which pollen arrest occurs in only one direction of an interspecific cross. We investigated the genetic basis of pistil-side UI between Solanum species, with the specific goal of understanding the role and magnitude of epistasis between UI QTL. Using heterospecific introgression lines (ILs) between Solanum pennellii and S. lycopersicum, we assessed the individual and pairwise effects of three chromosomal regions (ui1.1, ui3.1, and ui12.1) previously associated with interspecific UI among Solanum species. Specifically, we generated double introgression (‘pyramided’) genotypes that combined ui12.1 with each of ui1.1 and ui3.1, and assessed the strength of UI pollen rejection in the pyramided lines, compared to single introgression genotypes. We found that none of the three QTL individually showed UI rejection phenotypes, but lines combining ui3.1 and ui12.1 showed significant pistil-side pollen rejection. Furthermore, double ILs (DILs) that combined different chromosomal regions overlapping ui3.1 differed significantly in their rate of UI, consistent with at least two genetic factors on chromosome three contributing quantitatively to interspecific pollen rejection. Together, our data indicate that loci on both chromosomes 3 and 12 are jointly required for the expression of UI between S. pennellii and S. lycopersicum, suggesting that coordinated molecular interactions among a relatively few loci underlie the expression of this postmating prezygotic barrier. In addition, in conjunction with previous data, at least one of these loci appears to also contribute to conspecific self-incompatibility (SI), consistent with a partially shared genetic basis between inter- and intraspecific mechanisms of postmating prezygotic female choice.

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Specific transgenerational imprinting effects of the endocrine disruptor methoxychlor on male gametes

Reproduction ◽

10.1530/rep-10-0400 ◽

2011 ◽

Vol 141 (2) ◽

pp. 207-216 ◽

Cited By ~ 82

Author(s):

Christelle Stouder ◽

Ariane Paoloni-Giacobino

Keyword(s):

Adult Male ◽

Endocrine Disrupting Chemicals ◽

Methylation Pattern ◽

Imprinted Genes ◽

Male Mice ◽

Systematic Analysis ◽

Adult Mice ◽

Male Gametes ◽

Pregnant Mice ◽

Methylation Defects

Endocrine-disrupting chemicals (EDCs), among which methoxychlor (MXC), have been reported to affect the male reproductive system. This study evaluates the possible deleterious effects of MXC on imprinted genes. After administration of the chemical in adult male mice or in pregnant mice we analyzed by pyrosequencing possible methylation defects in two paternally imprinted (H19 and Meg3 (Gtl2)) and three maternally imprinted (Mest (Peg1), Snrpn, and Peg3) genes in the sperm and in the tail, liver, and skeletal muscle DNAs of the adult male mice and of the male offspring. MXC treatment of adult mice decreased the percentages of methylated CpGs of Meg3 and increased those of Mest, Snrpn, and Peg3 in the sperm DNA. MXC treatment of pregnant mice decreased the mean sperm concentrations by 30% and altered the methylation pattern of all the imprinted genes tested in the F1 offspring. In the latter case, MXC effects were transgenerational but disappeared gradually from F1 to F3. MXC did not affect imprinting in the somatic cells, suggesting that it exerts its damaging effects via the process of reprogramming that is unique to gamete development. A systematic analysis at the CpG level showed a heterogeneity in the CpG sensitivity to MXC. This observation suggests that not only DNA methylation but also other epigenetic modifications can explain the transgenerational effects of MXC. The reported effects of EDCs on human male spermatogenesis might be mediated by complex imprinting alterations analogous to those described in this study.

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Production of hydroxy fatty acids in the seeds of Arabidopsis thaliana

Biochemical Society Transactions ◽

10.1042/bst0280947 ◽

2000 ◽

Vol 28 (6) ◽

pp. 947-950 ◽

Cited By ~ 12

Author(s):

M. Smith ◽

H. Moon ◽

L. Kunst

Keyword(s):

Fatty Acids ◽

Arabidopsis Thaliana ◽

Seed Oil ◽

Desaturase Activity ◽

Hydroxy Fatty Acids ◽

Specific Expression ◽

Oleate Desaturase ◽

Arabidopsis Mutant ◽

Mutant Lines ◽

Seed Specific Expression

Seed-specific expression in Arabidopsis thaliana of oleate hydroxylase enzymes from castor bean and Lesquerella fendleri resulted in the accumulation of hydroxy fatty acids in the seed oil. By using various Arabidopsis mutant lines it was shown that the endoplasmic reticulum (ER) n–-3 desaturase (FAD3) and the FAE1 condensing enzyme are involved in the synthesis of polyunsaturated and very-long-chain hydroxy fatty acids, respectively. In Arabidopsis plants with an active ER Δ12-oleate desaturase the presence of hydroxy fatty acids corresponded to an increase in the levels of 18:1 and a decrease in 18:2 levels. Expression in yeast indicates that the castor hydroxylase also has a low level of desaturase activity.

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Improvement of arabidopsis mutant screens based on luciferase imagingin planta

Plant Molecular Biology Reporter ◽

10.1007/bf02673364 ◽

1996 ◽

Vol 14 (4) ◽

pp. 320-329 ◽

Cited By ~ 7

Author(s):

Baudouin Michelet ◽

Nam-Hai Chua

Keyword(s):

Arabidopsis Mutant

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