scholarly journals Pistil Mating Type and Morphology Are Mediated by the Brassinosteroid Inactivating Activity of the S-Locus Gene BAHD in Heterostylous Turnera Species

2021 ◽  
Vol 22 (19) ◽  
pp. 10603
Author(s):  
Courtney M. Matzke ◽  
Hasan J. Hamam ◽  
Paige M. Henning ◽  
Kyra Dougherty ◽  
Joel S. Shore ◽  
...  
Keyword(s):  
Mating Type ◽  
Mutant Allele ◽  
Mating Types ◽  
Self Incompatibility ◽  
S Locus ◽  
Wild Type ◽  
Truncated Protein ◽  
Conserved Domain ◽  
Pistil Length

Heterostyly is a breeding system that promotes outbreeding through a combination of morphological and physiological floral traits. In Turnera these traits are governed by a single, hemizygous S-locus containing just three genes. We report that the S-locus gene, BAHD, is mutated and encodes a severely truncated protein in a self-compatible long homostyle species. Further, a self-compatible long homostyle mutant possesses a T. krapovickasii BAHD allele with a point mutation in a highly conserved domain of BAHD acyl transferases. Wild type and mutant TkBAHD alleles were expressed in Arabidopsis to assay for brassinosteroid (BR) inactivating activity. The wild type but not mutant allele caused dwarfism, consistent with the wild type possessing, but the mutant allele having lost, BR inactivating activity. To investigate whether BRs act directly in self-incompatibility, BRs were added to in vitro pollen cultures of the two mating types. A small morph specific stimulatory effect on pollen tube growth was found with 5 µM brassinolide, but no genotype specific inhibition was observed. These results suggest that BAHD acts pleiotropically to mediate pistil length and physiological mating type through BR inactivation, and that in regard to self-incompatibility, BR acts by differentially regulating gene expression in pistils, rather than directly on pollen.

scholarly journals Differential Suppression of priA2::kan Phenotypes in Escherichia coli K-12 by Mutations in priA, lexA, and dnaC

Genetics ◽  
1996 ◽  
Vol 143 (1) ◽  
pp. 5-13 ◽  
Author(s):  
Steven J Sandler ◽  
Hardeep S Samra ◽  
Alvin J Clark
Keyword(s):  
Escherichia Coli ◽  
Dna Replication ◽  
Mutant Allele ◽  
Wild Type ◽  
Suppressor Mutations ◽  
Dnab Helicase ◽  
K 12 ◽  
Extragenic Suppressors ◽  
Assembly Activity

Abstract First identified as an essential component of the ϕX174 in vitro DNA replication system, PriA has ATPase, helicase, translocase, and primosome-assembly activities. priA1::kan strains of Escherichia coli are sensitive to UV irradiation, deficient in homologous recombination following transduction, and filamentous. priA2::kan strains have eightfold higher levels of uninduced SOS expression than wild type. We show that (1) priA1::kan strains have eightfold higher levels of uninduced SOS expression, (2) priA2::kan strains are UVS and Rec−, (3) lexA3 suppresses the high basal levels of SOS expression of a priA2::kan strain, and (4) plasmid-encoded priA300 (K230R), a mutant allele retaining only the primosome-assembly activity of priA+, restores both UVR and Rec+ phenotypes to a priA2::kan strain. Finally, we have isolated 17 independent UVR Rec+ revertants of priA2::kan strains that carry extragenic suppressors. All 17 map in the C-terminal half of the dnaC gene. DnaC loads the DnaB helicase onto DNA as a prelude for primosome assembly and DNA replication. We conclude that priA's primosome-assembly activity is essential for DNA repair and recombination and that the dnaC suppressor mutations allow these processes to occur in the absence of priA.

scholarly journals Transcriptome and Network Analyses of Heterostyly in Turnera subulata Provide Mechanistic Insights: Are S-Loci a Red-Light for Pistil Elongation?

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 713 ◽  
Author(s):  
Paige M. Henning ◽  
Joel S. Shore ◽  
Andrew G. McCubbin
Keyword(s):  
Red Light ◽  
Genetic Networks ◽  
Light Signaling ◽  
Self Incompatibility ◽  
S Locus ◽  
Network Analyses ◽  
S Gene ◽  
Self Fertilization ◽  
Pistil Length ◽  
S Genes

Heterostyly employs distinct hermaphroditic floral morphs to enforce outbreeding. Morphs differ structurally in stigma/anther positioning, promoting cross-pollination, and physiologically blocking self-fertilization. Heterostyly is controlled by a self-incompatibility (S)-locus of a small number of linked S-genes specific to short-styled morph genomes. Turnera possesses three S-genes, namely TsBAHD (controlling pistil characters), TsYUC6, and TsSPH1 (controlling stamen characters). Here, we compare pistil and stamen transcriptomes of floral morphs of T. subulata to investigate hypothesized S-gene function(s) and whether hormonal differences might contribute to physiological incompatibility. We then use network analyses to identify genetic networks underpinning heterostyly. We found a depletion of brassinosteroid-regulated genes in short styled (S)-morph pistils, consistent with hypothesized brassinosteroid-inactivating activity of TsBAHD. In S-morph anthers, auxin-regulated genes were enriched, consistent with hypothesized auxin biosynthesis activity of TsYUC6. Evidence was found for auxin elevation and brassinosteroid reduction in both pistils and stamens of S- relative to long styled (L)-morph flowers, consistent with reciprocal hormonal differences contributing to physiological incompatibility. Additional hormone pathways were also affected, however, suggesting S-gene activities intersect with a signaling hub. Interestingly, distinct S-genes controlling pistil length, from three species with independently evolved heterostyly, potentially intersect with phytochrome interacting factor (PIF) network hubs which mediate red/far-red light signaling. We propose that modification of the activities of PIF hubs by the S-locus could be a common theme in the evolution of heterostyly.

scholarly journals Mating-Type Gene Structure and Spatial Distribution of Didymella tanaceti in Pyrethrum Fields

2016 ◽  
Vol 106 (12) ◽  
pp. 1521-1529 ◽  
Author(s):  
Tamieka L. Pearce ◽  
Jason B. Scott ◽  
Frank S. Hay ◽  
Sarah J. Pethybridge
Keyword(s):  
Spatial Distribution ◽  
Mating Type ◽  
Tan Spot ◽  
Mating Types ◽  
Tanacetum Cinerariifolium ◽  
Polymerase Chain ◽  
Type Gene ◽  
Mat Genes

Tan spot of pyrethrum (Tanacetum cinerariifolium) is caused by the ascomycete Didymella tanaceti. To assess the evolutionary role of ascospores in the assumed asexual species, the structure and arrangement of mating-type (MAT) genes were examined. A single MAT1-1 or MAT1-2 idiomorph was identified in all isolates examined, indicating that the species is heterothallic. The idiomorphs were flanked upstream and downstream by regions encoding pyridoxamine phosphate oxidase-like and DNA lyase-like proteins, respectively. A multiplex MAT-specific polymerase chain reaction assay was developed and used to genotype 325 isolates collected within two transects in each of four fields in Tasmania, Australia. The ratio of isolates of each mating-type in each transect was consistent with a 1:1 ratio. The spatial distribution of the isolates of the two mating-types within each transect was random for all except one transect for MAT1-1 isolates, indicating that clonal patterns of each mating-type were absent. However, evidence of a reduced selection pressure on MAT1-1 isolates was observed, with a second haplotype of the MAT1-1-1 gene identified in 4.4% of MAT1-1 isolates. In vitro crosses between isolates with opposite mating-types failed to produce ascospores. Although the sexual morph could not be induced, the occurrence of both mating-types in equal frequencies suggested that a cryptic sexual mode of reproduction may occur within field populations.

scholarly journals Impact of Mating Type, Serotype, and Ploidy on the Virulence of Cryptococcus neoformans

2008 ◽  
Vol 76 (7) ◽  
pp. 2923-2938 ◽  
Author(s):  
Xiaorong Lin ◽  
Kirsten Nielsen ◽  
Sweta Patel ◽  
Joseph Heitman
Keyword(s):  
Cryptococcus Neoformans ◽  
Mating Type ◽  
Pathogenic Fungi ◽  
Mating Types ◽  
Type Locus ◽  
Virulence Potential ◽  
The Impact ◽  
Ad Hybrids

ABSTRACT Hybridization with polyploidization is a significant biological force driving evolution. The effect of combining two distinct genomes in one organism on the virulence potential of pathogenic fungi is not clear. Cryptococcus neoformans, the most common cause of fungal infection of the central nervous system, has a bipolar mating system with a and α mating types and occurs as A (haploid), D (haploid), and AD hybrid (mostly diploid) serotypes. Diploid AD hybrids are derived either from a-α mating or from unisexual mating between haploid cells. The precise contributions of increased ploidy, the effect of hybridization between serotypes A and D, and the combination of mating types to the virulence potential of AD hybrids have remained elusive. By using in vitro and in vivo characterization of laboratory-constructed isogenic diploids and AD hybrids with all possible mating type combinations in defined genetic backgrounds, we found that higher ploidy has a minor negative effect on virulence in a murine inhalation model of cryptococcosis. The presence of both mating types a and α in AD hybrids did not affect the virulence potential, irrespective of the serotype origin. Interestingly, AD hybrids with only one mating type behaved differently, with the virulence of αADα strains similar to that of other hybrids, while aADa hybrids displayed significantly lower virulence due to negative epistatic interactions between the Aa and Da alleles of the mating type locus. This study provides insights into the impact of ploidy, mating type, and serotype on virulence and the impact of hybridization on the fitness and virulence of a eukaryotic microbial pathogen.

scholarly journals Positive control of sulphate reduction in Escherichia coli. The nature of the pleiotropic cysteineless mutants of E. coli K 12

1968 ◽  
Vol 110 (3) ◽  
pp. 597-602 ◽  
Author(s):  
M. C. Jones-Mortimer
Keyword(s):  
Escherichia Coli ◽  
Mutant Allele ◽  
Positive Control ◽  
Wild Type Allele ◽  
Wild Type ◽  
E Coli ◽  
Type Allele ◽  
K 12 ◽  
Sulphite Reductase

1. The function of the wild-type alleles of the pleiotropic mutants cysB and cysE of Escherichia coli was investigated. 2. The wild-type allele cysB+ is dominant to the mutant allele cysB in stable and transient heterozygotes. 3. The wild-type allele cysE+ is dominant to the mutant allele cysE, as predicted. 4. Sulphur-starved cultures of cysB or cysE strains contain less than 0·2nmole of free cysteine/mg. dry wt. 5. Complementation in vitro is not observed between extracts of cysB mutants and mutants lacking sulphite reductase only. 6. A scheme, involving positive control of the enzymes of sulphate activation and reduction, is suggested to account for the control of cysteine biosynthesis.

scholarly journals SLFL Genes Participate in the Ubiquitination and Degradation ofS-RNase in Self-Compatible Chinese Peach

2017 ◽  
Author(s):  
Qiuju Chen ◽  
Dong Meng ◽  
Wei Li ◽  
Zhaoyu Gu ◽  
Hui Yuan ◽  
...  
Keyword(s):  
Prunus Persica ◽  
Hypervariable Region ◽  
Self Incompatibility ◽  
S Locus ◽  
Yeast Two Hybrid ◽  
Peach Genome ◽  
General Inhibitor ◽  
Two Hybrid

AbstractThe gametophytic self-incompatibility (SI) mediated by S-RNase of Rosaceae, Solanaceae and Plantaginaceae, is controlled by two tightly linked genes located at highly polymorphic S-locus: the S-RNase for pistil specificity and the F-box gene (SFB/SLF) for pollen specificity, respectively. The F-box gene of peach (Prunus persica) isShaplotype-specific F-box (SFB). In this study, we selected 37 representative varieties according to the evolution route of peach and identified their S genotypes. We cloned pollen determinant genes mutantPperSFB1m, PperSFB2m, PperSFB4mand normalPperSFB2, and style determinant genesS1-RNase, S2-RNase, S2m-RNaseandS4-RNase.MutantPperSFBswere translated terminated prematurely because of fragment insertion. Yeast two-hybrid showed that mutant PperSFBs and normal PperSFB2 interacted with all S-RNases. NormalPperSFB2was divided into four parts: box, box-V1, V1-V2 and HVa-HVb. Protein interaction analyses showed that the box portion did not interact with S-RNases, both of the box-V1 and V1-V2 had interactions with S-RNases, while the hypervariable region ofPperSFB2HVa-HVb only interacted with S2-RNase. Bioinformatics analysis of peach genome revealed that there were other F-box genes located at S-locus, and of which three F-box genes were specifically expressed in pollen, namelyPperSLFL1, PperSLFL2andPperSLFL3, respectively. Phylogenetic analysis showed that PperSFBs and PperSLFLs were classified into two different clades. Yeast two-hybrid analysis revealed that as with PperSFBs, the three F-box proteins interacted with PperSSK1. Yeast two-hybrid and BiFC showed that PperSLFLs interacted with S-RNases with no allelic specificity. In vitro ubiquitination assay showed that PperSLFLs could tag ubiquitin molecules to PperS-RNases. In all, the above results suggest that threePperSLFLsare the appropriate candidates for the ‘general inhibitor’, which would inactivate the S-RNases in pollen tubes, and the role of three PperSLFL proteins is redundant, as S-RNase repressors involved in the self-incompatibility of peach.

scholarly journals In Vitroand Molecular Surveillance for Antimalarial Drug Resistance in Plasmodium falciparum Parasites in Western Kenya Reveals Sustained Artemisinin Sensitivity and Increased Chloroquine Sensitivity

2015 ◽  
Vol 59 (12) ◽  
pp. 7540-7547 ◽  
Author(s):  
Naomi W. Lucchi ◽  
Franklin Komino ◽  
Sheila Akinyi Okoth ◽  
Ira Goldman ◽  
Philip Onyona ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Plasmodium Falciparum ◽  
Antimalarial Drug ◽  
Mutant Allele ◽  
Surveillance Program ◽  
Wild Type ◽  
Antimalarial Drug Resistance ◽  
Western Kenya ◽  
Content Type

ABSTRACTMalaria control is hindered by the evolution and spread of resistance to antimalarials, necessitating multiple changes to drug policies over time. A comprehensive antimalarial drug resistance surveillance program is vital for detecting the potential emergence of resistance to antimalarials, including current artemisinin-based combination therapies. An antimalarial drug resistance surveillance study involving 203Plasmodium falciparummalaria-positive children was conducted in western Kenya between 2010 and 2013. Specimens from enrolled children were analyzedin vitrofor sensitivity to chloroquine (CQ), amodiaquine (AQ), mefloquine (MQ), lumefantrine, and artemisinin derivatives (artesunate and dihydroartemisinin) and for drug resistance allele polymorphisms inP. falciparum crt(Pfcrt),Pfmdr-1, and the K13 propeller domain (K13). We observed a significant increase in the proportion of samples with thePfcrtwild-type (CVMNK) genotype, from 61.2% in 2010 to 93.0% in 2013 (P< 0.0001), and higher proportions of parasites with elevated sensitivity to CQin vitro. The majority of isolates harbored the wild-type N allele inPfmdr-1codon 86 (93.5%), with only 7 (3.50%) samples with the N86Ymutant allele (the mutant nucleotide is underlined). Likewise, most isolates harbored the wild-typePfmdr-1D1246 allele (79.8%), with only 12 (6.38%) specimens with the D1246Ymutant allele and 26 (13.8%) with mixed alleles. All the samples had a single copy of thePfmdr-1gene (mean of 0.907 ± 0.141 copies). None of the sequenced parasites had mutations in K13. Our results suggest that artemisinin is likely to remain highly efficacious and that CQ sensitivity appears to be on the rise in western Kenya.

scholarly journals Altered mating-type identity in the fungus Podospora anserina leads to selfish nuclei, uniparental progeny, and haploid meiosis.

Genetics ◽  
1995 ◽  
Vol 140 (2) ◽  
pp. 493-503 ◽  
Author(s):  
D Zickler ◽  
S Arnaise ◽  
E Coppin ◽  
R Debuchy ◽  
M Picard
Keyword(s):  
Mating Type ◽  
Podospora Anserina ◽  
Wild Type ◽  
Selfish Behavior ◽  
Developmental Patterns ◽  
Filamentous Ascomycete ◽  
Type Identity ◽  
Mat Locus ◽  
Mat Genes

Abstract In wild-type crosses of the filamentous ascomycete Podospora anserina, after fertilization, only nuclei of opposite mating type can form dikaryons that undergo karyogamy and meiosis, producing biparental progeny. To determine the role played by the mating type in these steps, the four mat genes were mutagenized in vitro and introduced into a strain deleted for its mat locus. Genetic and cytological analyses of these mutant strain, crossed to each other and to wild type, showed that mating-type information is required for recognition of nuclear identity during the early steps of sexual reproduction. In crosses with strain carrying a mating-type mutation, two unusual developmental patterns were observed: monokaryotic cells, resulting in haploid meiosis, and uniparental dikaryotic cells providing, after karyogamy and meiosis, a uniparental progeny. Altered mating-type identity leads to selfish behavior of the mutant nucleus: it migrates alone or paired, ignoring its wild-type partner in all mutant x wild-type crosses. This behavior is nucleus-autonomous because, in the same cytoplasm, the wild-type nuclei form only biparental dikaryons. In P. anserina, mat genes are thus required to ensure a biparental dikaryotic state but appear dispensable for later stages, such as meiosis and sporulation.

scholarly journals GENETICS OF CHEMICAL INDUCTION OF CONJUGATION IN PARAMECIUM AURELIA

Genetics ◽  
1974 ◽  
Vol 76 (4) ◽  
pp. 703-714
Author(s):  
Donald L Cronkite
Keyword(s):  
Mating Type ◽  
Recessive Gene ◽  
Mating Types ◽  
Wild Type ◽  
Chemical Induction ◽  
Single Mating ◽  
In Cells

ABSTRACT Certain stocks of P. aurelia, syngen 8, could not be induced to conjugate in a solution (KCl + acriflavine + calcium-poor conditions) which was effective in inducing conjugation in other species of Paramecium as well as in other stocks of syngen 8. Both stocks could conjugate by interaction with cells of complementary mating type. Breeding analysis shows that each of the two stocks is homozygous for a recessive gene that blocks induction of conjugation by the KCl-acriflavine solution. These two genes are neither allelic nor linked. Analyses of the phenotypes of the two uninducibles and the wild type were carried out by attempting to induce mating in cells of a single mating type by exposing them to detached mating-reactive cilia from cells of complementary mating type and to the KCl-acriflavine solution, either sequentially or simultaneously. The results confirm the conclusions of others that there is at least one unique step in chemical induction not shared with induction by interaction of complementary mating types. But the results also indicate that there is more than one unique step in chemical induction and that the effects of the two genes described here operate during different periods of the hour required for chemical induction.

scholarly journals Unraveling How Candida albicans Forms Sexual Biofilms

2020 ◽  
Vol 6 (1) ◽  
pp. 14 ◽  
Author(s):  
Austin M. Perry ◽  
Aaron D. Hernday ◽  
Clarissa J. Nobile
Keyword(s):  
Candida Albicans ◽  
Mating Type ◽  
Fungal Species ◽  
Population Diversity ◽  
Transcriptional Networks ◽  
Host Immune System ◽  
Mating Types ◽  
Growth State ◽  
Primary Focus

Biofilms, structured and densely packed communities of microbial cells attached to surfaces, are considered to be the natural growth state for a vast majority of microorganisms. The ability to form biofilms is an important virulence factor for most pathogens, including the opportunistic human fungal pathogen Candida albicans. C. albicans is one of the most prevalent fungal species of the human microbiota that asymptomatically colonizes healthy individuals. However, C. albicans can also cause severe and life-threatening infections when host conditions permit (e.g., through alterations in the host immune system, pH, and resident microbiota). Like many other pathogens, this ability to cause infections depends, in part, on the ability to form biofilms. Once formed, C. albicans biofilms are often resistant to antifungal agents and the host immune response, and can act as reservoirs to maintain persistent infections as well as to seed new infections in a host. The majority of C. albicans clinical isolates are heterozygous (a/α) at the mating type-like (MTL) locus, which defines Candida mating types, and are capable of forming robust biofilms when cultured in vitro. These “conventional” biofilms, formed by MTL-heterozygous (a/α) cells, have been the primary focus of C. albicans biofilm research to date. Recent work in the field, however, has uncovered novel mechanisms through which biofilms are generated by C. albicans cells that are homozygous or hemizygous (a/a, a/Δ, α/α, or α/Δ) at the MTL locus. In these studies, the addition of pheromones of the opposite mating type can induce the formation of specialized “sexual” biofilms, either through the addition of synthetic peptide pheromones to the culture, or in response to co-culturing of cells of the opposite mating types. Although sexual biofilms are generally less robust than conventional biofilms, they could serve as a protective niche to support genetic exchange between mating-competent cells, and thus may represent an adaptive mechanism to increase population diversity in dynamic environments. Although conventional and sexual biofilms appear functionally distinct, both types of biofilms are structurally similar, containing yeast, pseudohyphal, and hyphal cells surrounded by an extracellular matrix. Despite their structural similarities, conventional and sexual biofilms appear to be governed by distinct transcriptional networks and signaling pathways, suggesting that they may be adapted for, and responsive to, distinct environmental conditions. Here we review sexual biofilms and compare and contrast them to conventional biofilms of C. albicans.

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