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Olena Vatamaniuk Lab

Mineral Ion Homeostasis and Heavy Metal Detoxification

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Research Projects

The Role of Copper and Transcriptional Regulatory Networks Governing Copper Homeostasis in Pollen Fertility in A. thaliana

Copper is an essential micronutrient that is involved in important biological processes including respiration, photosynthesis, and scavenging of oxidative stress in all organisms. In addition to these functions, plants require copper for the perception of hormones, cell wall dynamics, response to pathogens and reproduction. Although copper is recognized as an essential micronutrient for plant fertility, very little is known which reproductive structures require copper, how copper acts to ensure plant fertility and which transcriptional networks coordinate copper transport processes and plant reproduction. Using RNA-seq analysis, we identified a novel transcription factor, CITF1 (Cu-deficiency Induced Transcription Factor 1), whose transcript is strongly upregulated in Arabidopsis thaliana flowers under copper deficiency. We also found that CITF1 regulates copper uptake into roots and delivery to flowers and that anthers of flowers accumulate the most copper. CITF1 acts together with a master regulator of copper homeostasis, SPL7 (Squamosa Promoter Binding Protein like7), and the function of both is required for Cu delivery to anthers and pollen fertility. Loss of function of SPL7 and CITF1 in the citf1 spl7 double mutant leads to seedling lethality and pollen infertility. CITF1 and SPL7 also regulate the biosynthesis of jasmonic acid (JA), a plant hormone involved in stamen development, and JA is needed for normal plant growth under copper deficiency. We now focus on establishing the mechanism by which CITF1 contributes to copper homeostasis and identifying the precise sites of copper action in pollen development and plant fertility, the transport systems responsible for copper delivery to reproductive organs, and the sites of interaction between copper and the jasmonate metabolic pathway. This work is supported by the NSF-IOS award  #1656321

Relevant publications:

Transcriptional Regulation of Copper Homeostasis in Cereals and its Relationship to Fertility and Yield

Global food security and the demand for high-yielding grain crops necessitate the use of marginal lands for agriculture purposes. These soils are often deficient in essential mineral nutrients such as copper, causing reduced crop growth, infertility and consequently low yield and even total crop failure. The total grain yield is directly linked to crop and soil fertility. In this regard, limited copper availability in the soil causes copper deficiency in crop plants, a condition that leads to plant infertility and consequently low yields; however, total crop failure can be expected under acute copper deficiencies. However, the physiological, molecular and genetic mechanisms underlying this trait are unknown. This project is motivated by our findings that two transcription factors, AtSPL7 and AtCITF1 regulate copper homeostasis and pollen fertility in  Arabidopsis thaliana by controlling the expression of genes involved in the uptake of copper into roots and subsequent delivery to anthers.  Wheat is one of the most important staple food crops, which is also regarded as most sensitive to copper deficiency. Which wheat genes are responsible for the uptake of copper from the soil and delivery to the reproductive organs, and which wheat genes regulate these transport processes, is unknown.  This project uses physiological, functional genomic approaches and the state-of-the-art synchrotron x-ray technologies, to study copper homeostasis and its regulation in wheat, Triticum aestivum and a wheat proxy, Brachypodium distachyon.  This project is funded by the USDA-NIFA award and in part by The Schwartz Research Fund for Women in Life Sciences. Mark Sorrells (Section of Plant Breeding and Genetics) and Matthew Willmann (Cornell Plant Transformation Facility) are also project participants.

Relevant publications:

Sustainable Approaches to Increase the Yield and Nutritional Value of Wheat         

Hand-in-hand with the above-described projects is a collaborative effort with our colleagues from The Ivan Franko National University of Lviv, Ukraine, Olga Terek and Natalya Romanyuk, we are evaluating wheat genotypes from the State Register of Plant Varieties Suitable for Dissemination in Ukraine. with the aim of developing breeding strategies for boosting yield and grain mineral content. This project is funded by the CRDF-GLOBAL U.S.-Ukraine Competition OISE-9531011.  Mark Sorrells (Section of Plant Breeding and Genetics), Murray McBride (Section of Soil and Crop Sciences), Zhangjun Fei (USDA-ARS, Boyce Thompson Institute), and Arthur Woll and Rong Huang (Cornell High Energy Synchrotron Source) are also project participants.

Shoot-to-root Signaling of Iron Deficiency

Iron is essential for the growth and development of all organisms but can be toxic to cells in excess. To preclude iron deficiency while avoiding toxicity, plants have evolved sophisticated mechanisms to sense and respond to the fluctuation of iron availability in the immediate root environment and the needs of the developing shoot. Despite significant progress in the understanding of how plants acquire iron from the soil and how iron is mobilized within the plant, not much is known about how shoots communicate their iron status to the root. Iron deficiency signaling mutants in A. thaliana provide a useful tool to address the question of the nature of systemic iron deficiency signal(s), its interactions with sensors in different tissues and cell types as well as the signal propagation to root epidermal cells to trigger iron deficiency response.

Relevant publications:

 

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