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Marcela Rojas-Pierce

Associate Department Head

Professor

Partners Building III 227

Bio

The vacuole is the major storage compartment in plant cells and has important implications for the nutritional value of agricultural crops. Our research is focused on identifying the molecular mechanisms that regulate the biogenesis of the vacuole and the delivery of tonoplast proteins to the vacuolar membrane. We use chemical and classical genetic approaches to characterize these mechanisms in the model plant Arabidopsis thaliana.

Plant vacuoles have additional functions in growth and development. Dynamics of vacuole fusion are also important for critical physiological functions such as the regulation of stomata closing during water deficit and gravitropism. Our lab is starting to elucidate molecular mechanisms of vacuole dynamics that may contribute to responses of plants to these environmental cues.

Courses Taught:

  • PB 780 Plant Molecular Biology (Fall)

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Education

Ph.D. Botany University of California 2003

B.S. Biology Universidad de los Andes, Colombia 1997

Area(s) of Expertise

Cell Biology, Vesicle Trafficking, Vacuole Biogenesis

Publications

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Grants

Date: 08/01/19 - 7/31/23
Amount: $999,883.00
Funding Agencies: National Science Foundation (NSF)

The plant vacuole is the most predominant organelle in plant cells, is essential, and can occupy up to 90% of the cell volume. Vacuole fusion is a dynamic process in cellular movements such as the opening of stomata. Stomata are pores on the leaf surface that regulate gas exchange and their movement can have large implications to carbon fixation, water loss and ultimately yield. Guard cell vacuoles are highly dynamic changing from a single large organelle in open stomata to a highly convoluted and sometimes fragmented vacuole in closed stomata. The proposed research will take advantage of available mutants with incomplete complements of SNARE and HOPS complexes to identify the rules that govern vacuole fusion control during stomata opening. An integrative systems biology approach combining genetics, biochemistry, quantitative microscopy and mathematical modeling will be used to develop a model of vacuole membrane dynamics during stomata movements.

Date: 04/01/19 - 3/31/23
Amount: $299,922.00
Funding Agencies: National Science Foundation (NSF)

The aim of this exploratory EAGER is to generate the first plant-compatible inducible degron tool for inactivation of protein targets in plants. This system is urgently needed for analyses of cellular processes that are controlled by essential proteins, and to improve temporal resolution in protein knockdown experiments. Systems for the control of protein activity by protein degrons are revolutionizing animal and yeast cell biology, but they have so far been out of reach for plant biologists. The proposed system utilizes targeted ubiquitination and protein degradation via the proteasome and is inducible via a glucocorticoid receptor-Dexamethasome system. If successful, this system could be used to study the loss of any plant protein with high temporal resolution (e.g. within hours or minutes), which is not possible with any genetic tool available today. This system will also enable the characterization of essential proteins, for which the only genetic tool available today is induced RNA silencing. A fast, inducible system to control protein abundance in plants will be useful for plant biologists from any discipline to query the function of their favorite protein in real time.

Date: 10/29/18 - 10/28/22
Amount: $330,101.00
Funding Agencies: National Aeronautics & Space Administration (NASA)

This proposal will study the contribution f membrane contact sites to gravity sensing in Arabidopsis.

Date: 02/17/20 - 6/30/22
Amount: $457,188.00
Funding Agencies: Game-Changing Research Incentive Program for Plant Sciences (GRIP4PSI)

Enabling the next generation of sustainable farms requires a paradigm shift in resource management of the two most critical agricultural inputs for food production: water and nitrogen (N) - based fertilizer. Inefficient management of these resources increases food production costs, decreases productivity, and impacts the environment. An integrated approach is needed to improve the sustainability and efficiency throughout the production chain. Emerging (bio)electrochemical (BEC) technologies offer alternatives to conventional, fossil-fuel intensive N fertilizer production. Recently our team has demonstrated two game-changing BEC technologies: 1) microbial conversion of nitrogen gas into ammonium, and 2) plasma generation of N species (e.g., nitrate, nitrite) and other reactive species in water for fertilization and anti-pathogen benefits. We will integrate these technologies to produce BEC, N-based fertilizer, and with advanced sensor and delivery systems, we will precisely supply fertilizers for sustainable precision agriculture. Our proposed approach focuses on the development of a novel “BEC fertigation on demand system” by using sensor-driven data and molecular analyses to investigate BEC fertigation impact on the plants’ growth, adaptation, and microbiome; its impact on food safety and quality, and its economic feasibility for on-farm deployment.

Date: 09/01/16 - 8/31/20
Amount: $539,132.00
Funding Agencies: National Science Foundation (NSF)

North Carolina State University faculty lack access to confocal microscopes that incorporate the latest technical advances for quantitative imaging, and this hampers their ability to provide valuable research training and education opportunities to undergraduate and graduate students and makes them less competitive in securing research funding. To train a well-prepared, knowledgeable workforce and to conduct world-class research, NCSU needs quantitative fluorescence microscopy applications such as 3-D Raster Image Correlation Spectroscopy and single molecule counting that cannot be accurately performed with existing equipment. In addition, NCSU has no super-resolution capability. The requested instrument will impact research and training programs across six NCSU colleges and numerous disciplines, including Cell and Molecular Biology, Biochemistry, Animal and Plant Developmental Biology, Plant Pathology, and Bio-Engineering, among others. The Zeiss LSM880 with Airyscan will enable NCSU faculty and students to 1) perform measurements with increased sensitivity and discrimination, 2) obtain fast temporal and spatial data, and 3) image live biological samples for longer times with reduced phototoxicity. The Zeiss LSM880 with Airyscan located within the Cellular and Molecular Imaging Facility (CMIF), a core research facility at NCSU, will provide training opportunities to students at all levels. In the past five years, 116 graduate students, 47 post docs, and 54 undergraduates as well as researchers from neighboring institutions (North Carolina Central University) and local industries have trained on the current confocal microscope, resulting in numerous publications and student poster presentations at international meetings and undergraduate research symposia. The new LSM880 with Airyscan will build on this success and expose students to state-of-the-art imaging applications. An innovative Light Microscopy Workshop will serve under-represented students from local Historically Black Colleges and Universities and a local women’s college.


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