2. Call Fellows

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PLANT FELLOWS announced the new PLANT fellows on the beginning of May 2013

Six young plant scientists were chosen from the second call.

To learn more about their interesting research projects and their respective host organisations see their profiles below.

 

Dr. Christoph Grieder

 

ETH Zurich, Department of Environmental Systems Science, Institute of Agricultural Sciences, Group of Crop Science

Principal Investigator: Prof. Dr. Achim Walter

 

Project title:

Remote phenotyping: dynamic high throughput assessment of key physiological traits in the field to assist wheat breeding

To enhance wheat yield increases by breeding, a better understanding of the developmental components affecting yield under different environmental conditions in the field is required. Assessing the dynamic response of such physiological parameters in the field requires their efficient and precise measurement. Different phenotyping techniques have been used for non-invasive monitoring of plant traits. However, under field conditions, their temporal resolution is still limited, not allowing to link the response of a genotype to short-term changes in climatic conditions.

The aim of the awarded project is to establish and use a novel field phenotyping platform (FIP) to assist breeding and quantitative genetic studies with respect to the dynamic assessment of plant physiological parameters. The FIP is a worldwide unique system based on a commercially available cable-suspended camera system that will be equipped with sensors covering different spectral ranges. It will be available from the projects second field season. The field experiment consists of a small diversity panel of Swiss wheat varieties that will be extended by a larger association mapping panel in the second season. Sensor data will be verified by ground truth measurements in order to establish protocols for optimal handling of the sensors and to develop trait prediction models. Different statistical approaches will be employed for differentiation of genotypes according to their dynamic response to environmental stimuli. Our aim is to identify key parameters predictive for plant final performance that can be used in subsequent genetic mapping studies.

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Dr. Mariana Ricca

 

University of Zurich, Institute of Evolutionary Biology and Environmental Studies

Principal Investigator: Dr. Péter Szövényi and Prof. Dr. Kentaro Shimizu

 

Project title:

Parent-of-origin gene expression in the moss Physcomitrella patens

The parental conflict hypothesis predicts that parent of origin gene expression is expected to evolve whenever there is a difference in resource allocation to the offspring between parents. In flowering plants, evolutionary consequences of parental conflict are far reaching. Unequal parental contribution to the next generation, in particular genomic imprinting, has been proposed as the primary mechanism maintaining interspecies and interploidal barriers by inducing deficiencies in endosperm development.

Although the presence of endosperm is usually seen as a prerequisite for genomic imprinting, parental conflict is also predicted to occur in basal groups of land plants such as bryophytes lacking endosperm. Bryophytes exhibit the hallmark of parental conflict and experimental observations suggest the existence of genomic imprinting. Furthermore, genomic and molecular data predict that mosses and flowering plants share multiple molecular mechanisms known to be involved in the realization of the parental conflict in flowering plants. In spite of that, molecular evidence of imprinting, its mechanisms and evolutionary implications in this basal group of land plants are unknown. Our aim is to test predictions of the parental conflict hypothesis in the model moss Physcomitrella patens by assessing parent of origin gene expression in the sporophytic tissues in reciprocal interstrain and interploidal crosses.

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Dr. Chloe Manzanares

 

ETH Zurich, Department of Environmental Systems Science, Institute of Agricultural Sciences, Group of Forage Crop Genetics

Principal Investigator: Prof. Dr. Bruno Studer

 

Project title: ForageTILLING – a functional genomics platform for perennial ryegrass

Genetic diversity is a key factor in plant breeding where it is used to increase the gene pool of a breeding program. In allogamous forage grasses such as perennial ryegrass (Lolium perenne), the gene diversity is maintained through self-incompatibility, a genetic mechanism promoting cross pollination and genetic mixing. But genetic diversity can also be created through genetic engineering, for example through transcription activator-like effector nucleases (TALENs). However, these methods are relatively expensive and not established yet for some crop species. TILLING (Targeting Induced Local Lesions in Genomes) has evolved as a non-transgenic method to create mutants by inducing random mutations to a large number of plants, using chemical mutagen. This important functional genomic tool has been used in model species such as Arabidopsis thaliana, as well as in major crop species such as rice, wheat, maize and barley. As a reverse genetics approach, it allows the identification of an induced mutation in a specific gene of interest and to directly associate that mutation to its corresponding phenotype.

The project will focus on the construction of a perennial ryegrass TILLING population as a novel tool to identify important agronomical genes. In order to identify the mutants, the TILLING population will be screened using a targeted re-sequencing approach for genes controlling e.g. plant size, disease resistance or plant architecture. Any mutant will be phenotyped in order to characterize the gene function. Moreover, interesting phenotypes resulting from the TILLING approach can be used in breeding programs in order to improve varieties for a particular trait.

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Dr. Robert Bagchi

 

ETH Zurich, Department of Environmental Systems Science, Institute of Agricultural Sciences, Professorship of Ecosystem Management

Principal Investigator: Prof. Jaboury Ghazoul

 

Project title:

Using spatial patterns of trees to build mechanistic models of species distributions in tropical forests

The current species extinction crisis highlights the need to understand the processes that maintain biodiversity in natural ecosystems, especially in hyper-diverse tropical rainforests which are being rapidly degraded. Species diversity emerges from distributions of individual species, so understanding the drivers of species’ distributions constitutes an important step towards developing mechanistic models of diversity. Three processes are fundamental determinants of tree species distributions, namely seed dispersal, habitat filtering and competition. Although there are ecologically significant interactions between these three processes, most previous work has evaluated their contributions individually. Furthermore, the influence of these factors has been connected to species traits only rarely, which inhibits generalisations to other species and regions for which few data are available.

In this project we are investigating how habitat filtering and intra-specific competition interact to shape species distributions. In order to do so we are developing spatial statistical techniques for replicated point patterns and spatially dependent data. We are testing how seed, leaf and wood traits relate to habitat filtering and intra-specific competition. We are addressing three broad questions: 1) To what extent are species’ habitat preferences linked to species’ traits? 2) How are species’ clustering patterns influenced by species’ traits? 3) Is there a signal of intraspecific competition between individuals in the spatial distributions of species and is the strength of this related to species’ traits? By linking the influence of key drivers of species’ distributions to functional traits we aim to contribute towards a general theory of the distributions of species and ultimately diversity.

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Dr. Emily Moran

 

ETH Zurich, Department of Environmental Systems Science, Institute for Integrative Biology

Principal Investigator: Prof. Dr. Jonathan Levine

 

Project title: The consequences of gene flow and genetic diversity for performance and adaptive potential within populations of an invasive species

Theory suggests that the interaction between local genetic diversity of plant populations and dispersal between populations may have important consequences both for short-term performance and for future adaptive potential. Genetic diversity may affect population-level performance either via heterosis (where less inbred individuals are more fit across multiple environments) or via a sampling effect (where a diverse population is more likely to contain one or more genotypes that perform well in a particular environment).  However, the relative importance of these mechanisms in the field is unknown.  If either mechanism is operating, we would expect genetically diverse populations to perform better under novel environmental stresses.  Understanding the effect of genetic diversity on local fitness and adaptation is crucial given the stresses imposed by global change on natural systems.

Invasive species are a useful model system for investigating the effect of genetic diversity on population-level fitness and adaptation to new environments.  Many invasive species pass through an initial genetic bottleneck due to a small number of founders, but later mixing through natural and human-assisted spread can greatly increase genetic diversity.  This project focuses on invasive populations of Solidago canadensis in Switzerland.  First, we will measure the genetic diversity of naturally occuring populations using microsatellites to ask whether the level of genetic diversity observed can be explained by landscape connectivity or human activity.  Next, clones from a subset of these populations will be planted across an elevational gradient to test whether there is a positive relationship between genetic diversity and population performance due to heterosis or sampling effects, and whether there is evidence of local adaptation.  Finally, we will incorporate the data on population connectivity, fitness, and local adaptation into population models to ask how genetic diversity and evolution may affect invasive spread in Solidago canadensis under climate change.

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Dr. Nina Chumak

 

University of Zurich, Institute of Plant Biology

Principal Investigator: Prof. Dr. Ueli Grossniklaus

 

Project title: Identification and Characterization of components of apomixis in maize (zea mays L.)

Some plants can reproduce through apomixis, the asexual reproduction through seed. Although apomixis occurs in more than 400 species belonging to about 40 plant families, it is absent in major crops. The production of seeds though apomixis, which generates plants that are genetically identical to their mother, has an enormous agricultural potential to indefinitely maintain desired genotypes, e.g. the maintenance of heterozygosity in hybrids.

Gametophytic apomixis deviates from sexual development in three major steps that constitute the elements of apomixis: (1) meiosis is circumvented or aborted, leading to the formation of unreduced, unrecombined embryo sacs (apomeiosis); (2) embryogenesis initiates without fertilization of the unreduced egg cell (parthenogenesis); and (3) developmental adaptations allow the formation of functional endosperm.

To harness apomixis in crop plants, we have been searching for maize mutants displaying these individual elements of apomixis. Combining such mutations in one plant should result in apomixis and, thus, the production of clonal seeds.

The first aim of my project is to characterize a mutant displaying the first element of apomixis, apomeiosis, which leads to the formation of egg cells that have the identical genetic constitution as the mother plant. The mutant was found in a Mutator (Mu) transposon-based screen for mutants producing unreduced embryo sacs. The second aim is to perform a screen for mutants displaying parthenogenesis. To this end a line carrying active Mu transposons was crossed with the R1-nj marker that pigments the crown of the endosperm and the embryo. The absence of R1-nj pigmentation in the embryo is an indication for the possible parthenogenetic development of a haploid embryo. Haploids will be treated with colchicine to induce diploidization and will be pollinated with R1-nj to confirm the genetic basis of the observed phenotype. Promising parthenogenetic mutants will be analyzed at the genetic, cytological and molecular level.

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