Research Projects of the Department of Molecular Ecology
Research Projects in the Department of Molecular Ecology
As the coordinator of the analytical platform I am responsible for the development and optimization of analytical tools in the department of Molecular Ecology. My major research focus is the development of high throughput methods for the metabolic characterization of large populations of recombinant inbred lines (RILs). With a combination of targeted and untargeted metabolomics analysis and ecological phenotyping we are trying to identify important chemical traits mediating biotic interactions and the underlying genetic background regulating them. I am also a member of the Sonderforschungsbereich ‘ChemBioSys’ and the Cluster of Excellence ‘Balance of the Microverse’, which are funded by the German Science Foundation.
My main research focus is the identification of plant traits controlling the interactions with herbivores, their natural enemies as well as pollinators and the recruitment of the plant microbiome using the forward genetics MAGIC platform developed in the department over the last decade. The 26-parent MAGIC mapping population captures a large part of the natural variation found in Nicotiana attenuata throughout its native range. We will use a combination of natural history observations in the field, targeted as well as unbiased metabolomics analyses and microbiome sequencing to identify loci controlling traits involved in these complex ecological interactions. Functional tests using our reverse genetics platform will be conducted at our field sites in Utah and Arizona. This new approach will allow unbiased screening for novel, ecologically important traits and the underlying genetic control, which were elusive targets in reverse genetics experiments based on a priori knowledge of genes.
Plants have evolved the ability to produce a plethora of specialized metabolites. These chemicals have important ecological functions for plant survival in nature. For instance, plants respond to herbivores of pathogen attack by activating specific defense programs that include the production of bioactive specialized metabolites to eliminate or deter the attackers. This process is regulated by a signaling cascade that involves jasmonates (JA), ubiquitous oxylipin-derived phytohormines that also play essential roles in the regulation of many developmental and growth processes. Since the functional/ecological roles of JA-regulated specialized metabolites are largely unknown, I aim to disentangle JA-regulated metabolic pathways of functional significance in N. attenuata. My research has been focused on developing efficient means of manipulating biosynthesis of specialized metabolites (e.g. acyl sugar, triterpenes and phenolyic derivatives) for functional ecological studies through integrating the analysis of genomes, transcriptomes and metabolomes in the MAGIC-RIL population, wih the hope that this will lead to the eventual elucidation of functional/ecological roles of these important compounds.
Despite the fact that Nicotiana attenuata is a self-compatible species, more than 30% of seeds in natural populations come from opportunistic outcrossing. It has been shown recently in our department that NaS-like-RNases and SLF proteins, which are known to be the self-incompatibility determinants in Solanaceae, are involved in the mate selection process in N. attenuata. We also know that in this model plant, pollination by favored and non-favored pollen results in predictable differences in the magnitude of the post-pollination ethylene burst (PPEB). In my research project, I am interested in investigating whether and how the PPEB influences stylar NaS-like-RNase expression and activity. Furthermore, I will explore the variation in PPEB in our MAGIC population and use these data for QTL imputations to get better insight in the genetic architecture of mate selection. I am hoping that these results will provide answer to the question whether mate choice is adaptive and whether it contributes to better seed survival in the seed banks. Additionally, I am also studying different aspects of natural root morphology, both in the greenhouse environment and in the field.
Plants partner with an incredibly diverse list of microbiomes from their native soil. Microbiomes are the “extended phenotypes” of an active ecological society and a healthy microbiome is a prerequisite for an ecologically sustainable environment. My research question explores the “Recruitment and maintenance of the Nicotiana attenuata root microbiome” funded by the Balance of the Microverse cluster, Jena School of Microbial Communication. Through my research, I intend to understand the fundamental molecular mechanisms involved in plant-microbe interactions by experimentally manipulating the abundance and composition of a synthetic community of native microbes, and further exploring the quantitative genomics and metabolomics signatures of N. attenuata. We aim to understand how host plants recruit and maintain functional consortia by utilizing the extremely resourceful in-house molecular tool-box of N. attenuata along with high-throughput screening methods such as Nanostring nCounter, and HPLC-MS/MS approaches.
Arbuscular mycorrhizal fungi (AMF) establish symbiotic associations with a majority of terrestrial plants to form underground common mycorrhizal networks that connect neighbouring plants. My research mainly focuses on the mechanisms and ecological functions of AMF associations in N. attenuata. Using the AI-RILs and MAGIC-RILs growing in natural habitats and the high-through-put (HTP) screening method for AMF colonization. I use QTL mapping to identify targeted loci involved in AMF associations and investigate the function of the loci using well-established molecular, analytical and ecological tools, with the hope to elucidate the ecological functions of AMF associations in nature.
My work is broadly focused on dissecting the molecular underpinnings of plant herbivore interaction in an ecological context using the model species Nicotiana attenuata. In order to dissect this interaction, I leverage the natural variation present in the species through the MAGIC population, and understand the functional consequences from the plant’s side. I use various statistical and bioinformatic tools to dissect these ecological and bio-chemical traits and map them on the genome to gain functional and evolutionary insights of the same. My current project is particularly focused on elucidating the early defense signaling components involved in jasmonic acid (JA) signaling and also the degradation of it. By integrating genomic, transcriptomic, and metabolomic data of the MAGIC population and the diverse reverse genetic toolbox in the department, I plan to disentangle this molecular network to gain a holistic functional understanding of JA signaling pathway and its role in plant defense.
Pooja Snehrashmi Mehta
The plant microbiome plays an important role in the protection of plants from various ecological hardships. Nicotiana attenuata uses its microbiome to defend itself against root rot and wilt diseases. It also improves its own phenotype through energy conservation by engaging microbes in performing tasks like nutrient assimilation. Little is known about the basic process involved in the early recruitment of a balanced plant microbiome. Our project focuses on understanding the question: Do plants sculpt their own microbiome by employing a fraction of microbes from the environmental marketplace by the provision of nutrients in the form of root exudates? To gain a functional understanding of the microbiome, we intend to use a native synthetic microbial consortium (nSynCom) in a gnotobiotic system during germination stages. We study alterations in the early germination stage recruitment by using high-throughput molecular platforms to monitor absolute variations in the nSynCom. In order to decipher the metabolite driving the community dynamics, we will exploit the transgenic line toolbox backed by targeted and untargeted metabolome platforms. Further, to study the natural variations observed in the recruitment and maintenance of the microbiome, we will explore Multi-Parent Advanced Generation Inter-Cross (MAGIC) and their microbiome associations through Quantitative Trait Loci (QTL) imputations, eventually testing the hypothesis in field.
Triterpenes are widely distributed in the plant kingdom and have a wide range of applications in medicinal, agricultural, and industrial areas. As an ecological model plant, N. attenuata’s triterpene reservoir and their ecological significance remain largely undiscovered; my research interest is to uncover the ecological functions of triterpenes in N. attenuata by utilizing metabolomics, biochemical, genetic and ecological approaches
I'm responsible for bioinformatics training & support, for which I'm currently involved in three efforts: (1) assistance in the preparation of the second Nicotiana attenuata genome assembly for publication, which will also include updating the NaDH data hub, (2) training & support in use of the QTL pipeline with the MAGIC population to identify the genomic positions of ecologically relevant genes, and (3) general organization and management of smRNA, sequencing, & transformation construct datasets, as well as standardizing data & metadata collection/storage, all in an effort to increase accessibility. Additionally, I'm involved in wet lab efforts, currently aiding in the expansion and execution of high-throughput transformations of N. attenuata and N. obtusifolia.