Mariana Silva Artur | Wageningen University and Research Centre (original) (raw)

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Papers by Mariana Silva Artur

Living beings comprise a whole sequence of levels forming [such] a hierarchy. (…) Each level reli... more Living beings comprise a whole sequence of levels forming [such] a hierarchy. (…) Each level relies for its operations on all the levels below it. Each reduces the scope of the one immediately below it by imposing on it a boundary that harnesses it to the service of the next-higher level, and this control is transmitted stage by stage, down to the basic inanimate level. (...) Each separate level of existence is of course interesting in itself and can be studied in itself." (Polanyi, 1968) "The ability to reduce everything to simple fundamental laws does not imply the ability to start from those laws and reconstruct the universe. (…) At each stage entirely new laws, concepts, and generalizations are necessary, requiring inspiration and creativity to just as great a degree as in the previous one. We expect to encounter fascinating and, I believe, very fundamental questions at each stage in fitting together less complicated pieces into the more complicated system and understanding the basically new types of behaviour which can result." (Anderson, 1972) In the research field of desiccation tolerance (DT), we aim to 'unfold' the different underpinnings of life without water in tolerant plant species in order to 'unlock' this process in non-tolerant species. The idea of 'unlocking' DT arises in a context where food productivity and security are increasingly challenged by environmental changes such as increased drought, while the world population is predicted to steadily grow to over 8.3 billion of people in the year 2030 (FAO, 2017). In the development of new technologies to tackle these challenges, raising 'basic' questions and conducting fundamental research are of pivotal importance. In this thesis I will present results of a study encompassing genomics, evolution, protein biochemistry, and molecular biology, and then go to a more general and speculative discussion of the main findings. Such a multilevel approach can aid to the comprehension of the complexity of the different levels that the process of DT involves, and can provide transferrable knowledge to produce more stress-tolerant crops.

Emerging topics in life sciences, Apr 3, 2019

Plants being sessile organisms are well equipped genomically to respond to environmental stressor... more Plants being sessile organisms are well equipped genomically to respond to environmental stressors peculiar to their habitat. Evolution of plants onto land was enabled by the ability to tolerate extreme water loss (desiccation), a feature that has been retained within genomes but not universally expressed in most land plants today. In the majority of higher plants, desiccation tolerance (DT) is expressed only in reproductive tissues (seeds and pollen), but some 135 angiosperms display vegetative DT. Here, we review genome-level responses associated with DT, pointing out common and yet sometimes discrepant features, the latter relating to evolutionary adaptations to particular niches. Understanding DT can lead to the ultimate production of crops with greater tolerance of drought than is currently realized.

Cerne, 2023

Background: The aim of this research was to investigate the efficiency of methods to overcome pri... more Background: The aim of this research was to investigate the efficiency of methods to overcome primary dormancy and biochemical processes associated with germination of Erythrina falcata Benth seeds. Seeds were submitted to dormancy overcoming treatments and the water uptake pattern was analysed. We then evaluated the activity of the antioxidant enzymes SOD, CAT, and APX, and quantified lipid peroxidation levels, hydrogen peroxide content and total protein content. The experiments were performed in a completely randomized design and the statistical analysis used was Scott-Knott test at 5% probability. Results: Mechanical scarification with sandpaper leads to approximately 94% of germination in E. falcata, while control non-scarified seeds show only approximately 37% of germination. Treatments with hot water led to high mortality in E. falcata seeds. Rapid water absorption was observed in the first 18 hours of imbition when the seeds were scarified with sandpaper, and radicle emergence was observed after 36 hours. During imbibition there was an increase of antioxidant enzyme activity and a decrease in lipid peroxidation and H 2 O 2 production, suggesting an efficient mechanism for regulating imbibition damage. A decrease in the total protein content was observed during germination of E. falcata seeds. Conclusions: Mechanical scarification is an efficient method for breaking dormancy of E. falcata seeds. During germination of E. falcata seeds there is a reduction in the production of H 2 O 2 and lipid peroxidation, and an increase in the activity of antioxidant enzymes. The total protein content decreased along the germination time.

Plants transitioned from an aquatic to a terrestrial lifestyle during their evolution. On land, d... more Plants transitioned from an aquatic to a terrestrial lifestyle during their evolution. On land, drought became one of the major problems they encountered, as it impacts correct cell functioning necessary to support life. The evolution of morphophysiological and molecular adaptations to cope with and tolerate drough was undeniably useful to survive on land. Some of these adaptations appeared repeatedly in phylogenetically distant species, showing a signature of convergent evolution. Details of this convergent evolution are now being assessed thanks to recent developments on high throughput phenotyping and whole genome and transcriptome sequencing. Phylogenomic (comparative genomic) and comparative transcriptomic analyses are revealing complex, well-coordinated and intricate gain and loss of genes and co-option of gene regulatory networks underlying cell and tissue specific adaptations to moderate and extreme drought in phylogenetically distant species. Here we review recent research on signatures of convergent evolution of regulatory networks underlying carbon concentrating mechanisms such as C4 and CAM photosynthesis, desiccation tolerance in seeds and resurrection plants, and impermeabilization of root exodermis.

Emerging Topics in Life Sciences, 2019

The Plant Cell

An unexpected transporter mediating sucrose transfer in maize The yield, quality, and nutritional... more An unexpected transporter mediating sucrose transfer in maize The yield, quality, and nutritional value of seeds are complex traits whose development depends on the transport of sugars and other nutrients from maternal to filial tissues. The identification of nutrient transporters and their mechanisms of action in seeds can lay a foundation for breeding varieties with improved grain yield and quality. Last year, Bo Yang and colleagues (Yang et al. 2022) identified an unexpected sugar transporter in maize. While screening an ethyl methanesulfonate-mutagenized library for homozygous mutants of maize, the authors identified a line with altered kernel size named poorly filled kernel2109 (pfk2109). Using map-based cloning and sequencing, they identified the mutant gene, previously annotated as a nitrate transporter 1/peptide transporter (NRT1/PTR). NRT1/PTR-type transporters are known to transport nitrate, peptides, and ions (Léran et al. 2014). Due to the defects in sugar loading during the mutant grain development, Yang and coauthors (2022) renamed this maize gene as Sucrose and Glucose Carrier 1 (ZmSUGCAR1). The authors found that the ZmSUGCAR1 mRNA expression peak coincides with the most active grain-filling (storage) stage, and the proteins were specifically expressed in the basal endosperm transfer layer (BETL), which mediates nutrient transfer from maternal to seed tissue. The authors then generated complementation and CRISPR-Cas9-mediated knockout lines and showed that ZmSUGCAR1 acts as a sugar transporter able to import sucrose and glucose into the seed endosperm. Furthermore, the authors showed that ZmSUGCAR1 contributes to potassium loading but does not affect nitrate accumulation in the kernels. This study identified an unexpected sugar transporter crucial for maize grain development that complements the actions of other well-known sugar transporters, such as SWEETs (Fig. 1). November 2018: Innovation by whole-genome duplication Gene duplication is commonly observed in plant genomes and often leads to evolutionary novelty such as new gene functions. About 75% of flowering plants originated after consecutive whole-genome duplications commonly referred to as the gamma (γ) triplication event (Jiao et al. 2012). Zhicheng Zhang and coauthors (Zhang et al. 2018) decided to investigate the effect of the γ event on the MADS-box transcription factors. They used statistical methods to reconstruct protein interaction networks (PINs) between representatives of different MADS-box gene subfamilies before and after the γ triplication and from the origin of Arabidopsis and tomato. They reconstructed 26 ancestral proteins with high confidence, and by synthesizing their DNA sequences and performing a high-throughput yeast 2-hybrid (Y2H) assay, they genetically validated their proteinprotein interactions. Zhang et al. (2018) also looked at the gene dosages of the reconstructed ancestral proteins that In Brief

Cell, 2021

Highlights d Tomato cell type-resolution translatome atlas reveals cell type function d Conservat... more Highlights d Tomato cell type-resolution translatome atlas reveals cell type function d Conservation and repurposing in gene regulation between Arabidopsis and tomato d The tomato exodermis is lignified, suberized, and enriched for nitrogen regulation d The root meristem is molecularly homologous across plant species

Genome Biology and Evolution, 2018

Late embryogenesis abundant (LEA) proteins include eight multigene families that are expressed in... more Late embryogenesis abundant (LEA) proteins include eight multigene families that are expressed in response to water loss during seed maturation and in vegetative tissues of desiccation tolerant species. To elucidate LEA proteins evolution and diversification, we performed a comprehensive synteny and phylogenetic analyses of the eight gene families across 60 complete plant genomes. Our integrated comparative genomic approach revealed that synteny conservation and diversification contributed to LEA family expansion and functional diversification in plants. We provide examples that: 1) the genomic diversification of the Dehydrin family contributed to differential evolution of amino acid sequences, protein biochemical properties, and gene expression patterns, and led to the appearance of a novel functional motif in angiosperms; 2) ancient genomic diversification contributed to the evolution of distinct intrinsically disordered regions of LEA_1 proteins; 3) recurrent tandem-duplications contributed to the large expansion of LEA_2; and 4) dynamic synteny diversification played a role on the evolution of LEA_4 and its function on plant desiccation tolerance. Taken together, these results show that multiple evolutionary mechanisms have not only led to genomic diversification but also to structural and functional plasticity among LEA proteins which have jointly contributed to the adaptation of plants to water-limiting environments.

Frontiers in Plant Science, 2019

Plant, Cell & Environment