Antheridiogen concentration and spore size predict gametophyte size in Ceratopteris richardii

Botany ◽  
2012 ◽  
Vol 90 (3) ◽  
pp. 175-179 ◽  
Author(s):  
Mike Ganger ◽  
Tiffany Sturey
Keyword(s):  
Sex Determination ◽  
Environmental Sex Determination ◽  
Wild Type ◽  
Ceratopteris Richardii ◽  
Spore Size ◽  
Male Development ◽  
Homosporous Fern ◽  
Type C ◽  
Slow Growing ◽  
Genetic Mutants

In many plants females invest more in reproduction than males. In organisms that exhibit environmental sex determination, individuals in low-quality environments or who are slow growing are expected to develop into males. The gametophytes of Ceratopteris richardii Brongn., a homosporous fern, may develop as males or hermaphrodites. Hermaphrodites secrete a pheromone called antheridiogen that induces undifferentiated spores to develop as males. Given that induction is not 100% in the presence of antheridiogen, it is hypothesized that resources may alter C. richardii gender decisions. An experiment was undertaken to determine (i) whether spore size predicts gender, (ii) whether spore size predicts gametophyte size, (iii) whether antheridiogen negatively affects the growth of C. richardii, and (iv) whether wild-type C. richardii and him1 mutants (genetic mutants disposed to male development regardless of antheridiogen presence) behave similarly in their response to antheridiogen. Spore size was not predictive of gender but was positively related to both male and hermaphrodite gametophyte size. Antheridiogen was found to slow the growth of male and hermaphrodite gametophytes of the wild type and male gametophytes of the him1 mutant. These results are supportive of the idea that gender may be determined indirectly through antheridiogen’s effect on gametophyte growth.

scholarly journals ACTIVITY OF THE SEX-DETERMINING GENE tra-2 IS MODULATED TO ALLOW SPERMATOGENESIS IN THE C. ELEGANS HERMAPHRODITE

Genetics ◽  
1986 ◽  
Vol 114 (1) ◽  
pp. 53-76
Author(s):  
Tabitha Doniach
Keyword(s):  
Sex Determination ◽  
Regulatory Genes ◽  
The State ◽  
The Self ◽  
Wild Type ◽  
Gain Of Function ◽  
C Elegans ◽  
Male Development ◽  
In The Wild ◽  
Mode Of Regulation

ABSTRACT In the nematode C. elegans, there are two sexes, the self-fertilizing hermaphrodite (XX) and the male (XO). The hermaphrodite is essentially a female that makes sperm for a brief period before oogenesis. Sex determination in C. elegans is controlled by a pathway of autosomal regulatory genes, the state of which is determined by the X:A ratio. One of these genes, tra-2, is required for hermaphrodite development, but not for male development, because null mutations in tra-2 masculinize XX animals but have no effect on XO males. Dominant, gain-of-function tra-2 mutations have now been isolated that completely feminize the germline of XX animals so that they make only oocytes and no sperm and, thus, are female. Most of the tra-2(dom) mutations do not correspondingly feminize XO animals, so they do not appear to interfere with control by her-1, a gene thought to negatively regulate tra-2 in XO animals. Thus, these mutations appear to cause gain of tra-2 function in the XX animal only. Dosage studies indicate that 5 of 7 tra-2(dom) alleles are hypomorphic, so they do not simply elevate XX tra-2 activity overall. These properties suggest that in the wild type, tra-2 activity is under two types of control: (1) in males, it is inactivated by her-1 to allow male development to occur, and (2) in hermaphrodites, tra-2 is active but transiently inactivated by another, unknown, regulator to allow hermaphrodite spermatogenesis; this mode of regulation is hindered by the tra-2(dom) mutations, thereby resulting in XX females.

scholarly journals Sex-determining genes in the homosporous fern Ceratopteris

Development ◽  
1994 ◽  
Vol 120 (7) ◽  
pp. 1949-1958 ◽  
Author(s):  
J.A. Banks
Keyword(s):  
Sex Determination ◽  
Double Mutant ◽  
Single Gene ◽  
Regulatory Pathway ◽  
Male Development ◽  
Gene Mutant ◽  
Sex Type ◽  
Homosporous Fern ◽  
Mutant Phenotypes ◽  
Sporophyte Development

Haploid Ceratopteris gametophytes are either hermaphroditic or male. The determinate of sex type is the pheromone antheridiogen (ACE) which is secreted by the meristic hermaphrodite and promotes ameristic male development of sexually undetermined gametophytes. Several mutations effecting the sex of the haploid gametophyte have been isolated and are described. The hermaphroditic (her) mutants are insensitive to ACE and develop as meristic hermaphrodites. These mutations effect ameristic male development in the presence of ACE but have no effect on hermaphroditic development. While most her mutations also have no effect on diploid sporophyte development, some partially ACE-insensitive her mutations have profound effects on sporophyte development. The transformer (tra) mutation effects both meristem and archegonia formation and causes the gametophyte to be an ameristic male under conditions that promote hermaphroditic development. The feminization (fem) mutation effects antheridia development in both male and hermaphroditic gametophytes and causes the gametophyte to develop as a meristic female in the absence or presence of the pheromone. The her1 tra1 double mutant is male in the absence or presence of ACE, indicating that tra1 is epistatic to her1. The phenotypes of her1, tra1 and fem1 single gene mutant phenotypes and the her1 tra1 double mutant phenotype are used to deduce a model suggesting how the products of these genes might interact in a regulatory pathway to control sex determination.

scholarly journals Genetic Interactions Among Sex-Determining Genes in the Fern Ceratopteris richardii

Genetics ◽  
1996 ◽  
Vol 142 (3) ◽  
pp. 973-985
Author(s):  
James R Eberle ◽  
Jo Ann Banks
Keyword(s):  
Linkage Analysis ◽  
Sex Determination ◽  
Genetic Interactions ◽  
Ceratopteris Richardii ◽  
Male Development ◽  
Sex Type

Abstract Haploid gametophytes of the fern Ceratopteris are either male or hermaphroditic. The determinant of sex type is the pheromone antheridiogen, which is secreted by the hermaphrodite and directs male development of young, sexually undetermined gametophytes. Three phenotypic classes of mutations that affect sex-determination were previously isolated and include the hermaphroditic (her), the transformer (tra) and feminization (fem) mutations. In the present study, linkage analysis and tests of epistasis among the different mutants have been performed to assess the possible interactions among these genes. The results indicate that sex determination in Ceratopteris involves at least seven interacting genes in addition to antheridiogen, the primary sex-determining signal. Two models describing how antheridiogen may influence the activity states of these genes and the sex of the gametophyte are discussed.

scholarly journals RNA Sequencing Reveals Rice Genes Involved in Male Reproductive Development under Temperature Alteration

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 663
Author(s):  
Sudthana Khlaimongkhon ◽  
Sriprapai Chakhonkaen ◽  
Keasinee Tongmark ◽  
Numphet Sangarwut ◽  
Natjaree Panyawut ◽  
...  
Keyword(s):  
High Temperature ◽  
Rna Sequencing ◽  
Reproductive Development ◽  
Yield Reduction ◽  
World Population ◽  
Rice Grain ◽  
Wild Type ◽  
Rice Plants ◽  
Male Development ◽  
Temperature Conditions

Rice (Oryza sativa L.) is one of the most important food crops, providing food for nearly half of the world population. Rice grain yields are affected by temperature changes. Temperature stresses, both low and high, affect male reproductive development, resulting in yield reduction. Thermosensitive genic male sterility (TGMS) rice is sterile at high temperature and fertile at low temperature conditions, facilitating hybrid production, and is a good model to study effects of temperatures on male development. Semithin sections of the anthers of a TGMS rice line under low (fertile) and high (sterile) temperature conditions showed differences starting from the dyad stage, suggesting that genes involved in male development play a role during postmeiotic microspore development. Using RNA sequencing (RNA-Seq), transcriptional profiling of TGMS rice panicles at the dyad stage revealed 232 genes showing differential expression (DEGs) in a sterile, compared to a fertile, condition. Using qRT-PCR to study expression of 20 selected DEGs using panicles of TGMS and wild type rice plants grown under low and high temperature conditions, revealed that six out of the 20 selected genes may be unique to TGMS, while the other 14 genes showed common responses to temperatures in both TGMS and wild-type rice plants. The results presented here would be useful for further investigation into molecular mechanisms controlling TGMS and rice responses to temperature alteration.

Myristylation is required for Tyr-527 dephosphorylation and activation of pp60c-src in mitosis

1993 ◽  
Vol 13 (3) ◽  
pp. 1464-1470
Author(s):  
S Bagrodia ◽  
S J Taylor ◽  
D Shalloway
Keyword(s):  
Kinase Activity ◽  
Tyrosine Phosphatase ◽  
Src Kinase ◽  
Indirect Evidence ◽  
Membrane Localization ◽  
Wild Type ◽  
Src Tyrosine Kinase ◽  
Amino Terminal ◽  
Membrane Bound ◽  
Type C

The chicken proto-oncoprotein c-Src is phosphorylated by p34cdc2 during mitosis concomitant with increased c-Src tyrosine kinase activity. On the basis of indirect evidence, we previously suggested that this is caused by partial dephosphorylation at Tyr-527, the phosphorylation of which suppresses c-Src kinase activity. In support of this hypothesis, we now show that treatment of cells with a protein tyrosine phosphatase inhibitor, sodium vanadate, blocks the mitotic increase in Src kinase activity. Also, we show that an amino-terminal mutation that prevents myristylation (and membrane localization) of c-Src does not interfere with the p34cdc2-mediated phosphorylations but blocks both mitotic dephosphorylation of Tyr-527 (in kinase-defective Src) and stimulation of c-Src kinase activity. Furthermore, in unsynchronized cells, the kinase activity of nonmyristylated c-Src is suppressed by 60% relative to wild-type c-Src, presumably because of increased Tyr-527 phosphorylation. Consistent with this, the Tyr-527 dephosphorylation rate measured in cell homogenates is much higher for wild-type, myristylated c-Src than for nonmyristylated c-Src. Tyr-527 phosphatase activity was primarily associated with the nonsoluble subcellular fraction. These findings suggest that the phosphatase(s) that acts on Tyr-527 is membrane bound and indicate that membrane localization of c-Src is necessary for its mitotic activation by dephosphorylation of Tyr-527.

Environmental Sex Determination Mechanisms in Reptiles

2013 ◽  
Vol 7 (1-3) ◽  
pp. 95-103 ◽  
Author(s):  
H. Merchant-Larios ◽  
V. Díaz-Hernández
Keyword(s):  
Sex Determination ◽  
Environmental Sex Determination ◽  
Sex Determination Mechanisms

Opportunistic heterotrophy in gametophytes of the homosporous fern Ceratopteris richardii

Botany ◽  
2009 ◽  
Vol 87 (8) ◽  
pp. 799-806 ◽  
Author(s):  
Deborah A. Alongi ◽  
Jeffrey P. Hill ◽  
Matthew J. Germino
Keyword(s):  
Sugar Transport ◽  
Light Limitation ◽  
Sugar Uptake ◽  
Growth Media ◽  
Ceratopteris Richardii ◽  
Glucose Depletion ◽  
Homosporous Fern ◽  
Preferential Uptake ◽  
Underlying Mechanisms ◽  
Exogenous Sugar

Fern gametophytes are extremely shade-tolerant, potentially existing for long periods under conditions of extreme light limitation. Many previous studies have demonstrated an increase in gametophyte growth and incidence of spontaneous transition to sporophyte morphology (apogamy) under culture on media containing exogenous sugar. However, these studies did not verify sugar uptake or quantify relative growth on media containing different sugar types. Here, we examine the extent of heterotrophy and underlying mechanisms of sugar transport in photosynthetic gametophytes of the fern Ceratopteris richardii Brongn. Exogenous sugar uptake, growth, and sugar transport were evaluated with assays of exogenous glucose depletion, experimental culture of gametophytes under different sugar and light conditions, and bioinformatic approaches. The glucose from the growth media was significantly depleted by gametophytes growing under all conditions, especially those in the dark compared with those exposed to higher light. Gametophyte area increased similarly when cultured on equimolar concentrations of either glucose or the disaccharide sucrose, likely due to preferential uptake of one of the monomers of sucrose. Although at least one gene with similarity to sucrose transporters is expressed in germinating spores, our results suggest a reliance on monosaccharide transport for exogenous sugar uptake. Glucose assimilation in both light and dark conditions constitutes nutritional opportunism and may enhance gametophyte survival in very low light.

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