Molecular Phylogeny and Evolution of the Plant-Specific Seven-Transmembrane MLO Family

Devoto, Alessandra; Hartmann, H. Andreas; Piffanelli, Pietro; Elliott, Candace E.; Simmons, Carl R.; Taramino, Graziana; Goh, Chern-Sing; Cohen, Fred E.; Emerson, Brent C.; Schulze‐Lefert, Paul; Panstruga, Ralph

doi:10.1007/s00239-002-2382-5

Cited by 206 publications

(235 citation statements)

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“…Genes AtMlo5 and AtMlo9 encode two members of the family of heptahelical MLO membrane proteins [25] that are preferentially expressed during pollen development [Z.Y. Chen and co-workers, personal communication; S. Noir and R. Panstruga, unpublished].…”

Section: Resultsmentioning

confidence: 99%

A reference map of the Arabidopsis thaliana mature pollen proteome

Noir

Bräutigam

Colby

et al. 2005

Biochemical and Biophysical Research Communications

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137

145

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The male gametophyte (or pollen) plays an obligatory role during sexual reproduction of higher plants. The extremely reduced complexity of this organ renders pollen a valuable experimental system for studying fundamental aspects of plant biology such as cell fate determination, cell-cell interactions, cell polarity, and tip-growth. Here, we present the first reference map of the mature pollen proteome of the dicotyledonous model plant species, Arabidopsis thaliana. Based on two-dimensional gel electrophoresis, matrix-assisted laser desorption/ionization time-of-flight, and electrospray quadrupole time-of-flight mass spectrometry, we reproducibly identified 121 different proteins in 145 individual spots. The presence, subcellular localization, and functional classification of the identified proteins are discussed in relation to the pollen transcriptome and the full protein complement encoded by the nuclear Arabidopsis genome. Ó 2005 Elsevier Inc. All rights reserved.Keywords: Arabidopsis thaliana; Male gametophyte; Mass spectrometry; Mature pollen; Proteome; Two-dimensional gel electrophoresis In higher plants, development of the male gametophyte is a well-programmed and elaborate process. Male sporogenesis begins with the division of a diploid sporophytic cell giving rise to the anther wall of the stamen and the sporogenic cells. The latter cells then undergo several mitoses to differentiate into pollen mother cells. Subsequently, each diploid pollen mother cell forms a tetrad of haploid microspores via a round of DNA replication followed by two consecutive meiotic divisions. Each uninucleate microspore then undergoes an asymmetric mitotic division forming a large vegetative cell and a smaller generative cell (i.e., the bicellular pollen stage). In Arabidopsis, the generative cell undergoes another mitotic division giving rise to two sperm cells (i.e., the tricellular pollen stage). Following pollination, the vegetative cell controls the further development of the mature pollen grain and growth of the pollen tube into the style until both sperm cell nuclei are delivered to the embryo sac in the ovule, where they participate in double fertilization [1,2].The last two decades have been marked by increasing efforts to decipher the genetic and molecular basis of pollen development and functions [reviewed in 1,3,4]. In the model plant Arabidopsis thaliana, the extremely reduced, tricellular male gametophyte constitutes an ideal experimental system for analyses of important biological processes in higher plant reproduction. In addition, it represents a very useful model for studying fundamental aspects of plant biology such as cell fate determination, cell-cell interactions, cell polarity, and tip-growth [5][6][7].The availability of the full genome sequence of Arabidopsis [8] has made genome-wide, microarray-based analyses of the male gametophyte transcriptome of this model plant possible [9][10][11][12]. 13,977 male gametophyte-expressed mRNAs were recently identified using the ATH1 Genome Array, which cover...

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Section: Resultsmentioning

confidence: 99%

A reference map of the Arabidopsis thaliana mature pollen proteome

Noir

Bräutigam

Colby

et al. 2005

Biochemical and Biophysical Research Communications

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137

145

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“…Homozygous loss-of-function alleles of MLO (mlo) confer resistance to all known Bgh isolates, leading to the cessation of growth of fungal sporelings during cell wall penetration [36]. Barley MLO encodes the prototype of a plant-specific family of seven transmembrane domain proteins, accumulates in the plasma membrane, and interacts with the Ca 2þ sensor calmodulin via a calmodulin-binding site in its carboxy-terminal cytoplasmic tail [37][38][39][40]. The ror2 mutation was originally isolated as suppressor of mlo resistance (in a mlo null mutant background) and partially restores the susceptibility of mlo mutants to Bgh [41], suggesting that MLO might directly or indirectly antagonise ROR2 function.…”

Section: Suppression Of Disease Resistance At the Cell Wallmentioning

confidence: 99%

Knocking on the heaven’s wall: pathogenesis of and resistance to biotrophic fungi at the cell wall

Schulze‐Lefert

2004

Current Opinion in Plant Biology

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New findings challenge the traditional view of the plant cell wall as passive structural barrier to invasion by fungal microorganisms. A surveillance system for cell wall integrity appears to sense perturbation of the cell wall structure upon fungal attack and is interconnected with known plant defence signalling pathways. Biotrophic fungi might manipulate this surveillance system for the establishment of biotrophy. The attempts of fungi to invade also induce a sub-cellular polarisation in attacked cells, which activates an ancient vesicle-associated resistance response that possibly enables the focal transport of regulatory cargo and the secretion of toxic cargo. The underlying resistance machinery might have been subverted by biotrophic fungi for pathogenesis. IntroductionPenetration through the plant cell wall represents an Achilles heel in the pathogenesis of most biotrophic fungi and marks a lifestyle transition from extra-cellular to invasive growth. Modification of the plant cell wall was recognised for the first time as potential resistance mechanism almost 80 years ago following work in which 78 plant species and varieties were challenged with Alternaria spp. and other leaf-spotting fungi [1]. The termination of fungal pathogenesis at the cell wall was commonly associated with wall 'thickenings' and the formation of local additions or 'callosities' in the paramural space (i.e. the space between the cell wall and the plasma membrane). Formation of these cell wall appositions (CWAs) or papillae is usually accompanied by a co-localised accumulation of phenolics and reactive oxygen species [2][3][4][5][6]. The complex process of sub-cellular cell wall remodelling is tightly linked to the rapid disassembly and subsequent focal reassembly of the plant cytoskeleton at fungal entry sites, which is indicative of a pathogen-triggered cell polarisation [6][7][8][9]. There has been a long-standing controversy, however, over whether CWAs function in disease resistance or facilitate the entry of fungal pathogens into host cells by providing a structural collar for the intruder. New molecular genetic data from Arabidopsis and barley have indeed revealed that molecular processes at and in CWAs have Janus-faced functions, that is, functions for fungal pathogenesis and in resistance responses. Focal vesicle transport and vesicle fusion events that are dependent on SNAP (soluble N-ethylmaleimide-sensitive-factor-association protein) receptor (SNARE) proteins at the plasma membrane emerge as potential common underlying mechanisms that might be interconnected with a poorly understood cell wall integrity surveillance system. In this review, I discuss the seemingly paradoxical functions of these processes in establishing the biotrophic lifestyle and in disease resistance at the cell periphery.Linking cell wall structure to biotic stress signalling Callose, a (1!3)-b-D-glucan, has long been known to be synthesised and deposited rapidly at CWAs upon microbial attack. This polymer was thought to contribute to a physical barrie...

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“…In parallel to the GRAFS families, other GPCR families have arisen and/or evolved in specific lineages or species, such as the plant MLO receptors [51] and the insect gustatory receptors [52].…”

Section: Brief Overview Of Nomenclature Classification and Repertoiresmentioning

confidence: 99%

Present Perspectives on the Automated Classification of the G-Protein Coupled Receptors (GPCRs) at the Protein Sequence Level

Davies¹,

Gloriam²,

Secker³

et al. 2011

CTMC

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The G-protein coupled receptors -or GPCRs -comprise simultaneously one of the largest and one of the most multi-functional protein families known to modern-day molecular bioscience. From a drug discovery and pharmaceutical industry perspective, the GPCRs constitute one of the most commercially and economically important groups of proteins known. The GPCRs undertake numerous vital metabolic functions and interact with a hugely diverse range of small and large ligands. Many different methodologies have been developed to efficiently and accurately classify the GPCRs. These range from motif-based techniques to machine learning as well as a variety of alignment-free techniques based on the physiochemical properties of sequences. We review here the available methodologies for the classification of GPCRs. Part of this work focuses on how we have tried to build the intrinsically hierarchical nature of sequence relations, implicit within the family, into an adaptive approach to classification. Importantly, we also allude to some of the key innate problems in developing an effective approach to classifying the GPCRs: the lack of sequence similarity between the six classes that comprise the GPCR family and the low sequence similarity to other family members evinced by many newly revealed members of the family.3

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Molecular Phylogeny and Evolution of the Plant-Specific Seven-Transmembrane MLO Family

Cited by 206 publications

References 29 publications

A reference map of the Arabidopsis thaliana mature pollen proteome

A reference map of the Arabidopsis thaliana mature pollen proteome

Knocking on the heaven’s wall: pathogenesis of and resistance to biotrophic fungi at the cell wall

Present Perspectives on the Automated Classification of the G-Protein Coupled Receptors (GPCRs) at the Protein Sequence Level

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