Robert Franks

We are using the diversity of Mimulus (Monkey Flower) species to identify the molecular mechanisms of reproductive isolation and speciation. Our work will significantly contribute of our understanding of the molecular, ecological and evolutionary bases of speciation and biodiversity generation.

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.

Here we propose to determine the evolutionary genetic basis underlying species divergence in endosperm development and embryogenesis and their consequences for hybrid seed lethality, a principal isolating barrier in the Mimulus guttatus sp. complex [1]. We focus on two diploid species, the serpentine endemic M. nudatus and the widespread M. guttatus, which do not hybridize in the wild despite their coexistence and shared pollinators. Controlled interspecific crosses yield two hybrid seed types: hybrid seed that exhibit early arrested endosperm development and hybrid seed with relatively normal early endosperm development but late endosperm deficiency. We integrate molecular and developmental experiments, RNA sequencing, and high-throughput genome mapping to elucidate the genetic mechanisms contributing to seed abortion in M. guttatus x M. nudatus crosses.

The coordination of spatial patterning cues and cellular proliferation underlies diverse processes from cancerous growth to reproductive development. A long-term objective of my research program is to understand how proliferative cues are coordinated with spatial information during organogenesis. In Arabidopsis thaliana this coordination of patterning and proliferation is necessary within the carpel margin meristem (CMM) to generate ovules that when fertilized will become seeds. The CMM is a vital meristematic structure with a unique pattern of organ initiation, and novel mechanisms of meristematic development that are not yet well characterized. In the previous funding period we demonstrated that the SEUSS (SEU) and AINTEGUMENTA (ANT) transcription factors regulate patterning events within the gynoecium that are critical for carpel margin meristem and ovule development. Our genetic analysis demonstrates that SEU and ANT share a partially redundant and overlapping function essential for proper CMM development. As SEU and ANT do not share sequence similarity, the molecular basis for this redundancy is not understood. We propose that the SEU and ANT activities synergistically converge at key transcriptional nodes. A node in this sense is a gene or a set of related genes that requires the combined activities of SEU and ANT for its proper expression. Our recently published transcriptomic analysis identified many putative nodes encoding known transcriptional regulators. By studying these candidate nodes we hope to better understand the transcriptional hierarchies that control CMM development and uncover the mechanistic basis of the synergistic action of SEU and ANT. Our transcriptomics study cannot determine if these nodes are directly or indirectly regulated by SEU or ANT activity. However, even if these node genes are indirectly controlled by SEU and ANT activity, their expression within the developing CMM suggests they may still play a critical functional role during CMM development. Furthermore, having now identified a set of genes that are enriched for CMM expression we are in a position to study the cis-regulatory elements that support gene expression within the CMM and the medial gynoecial domain. Here we propose to: 1) Identify direct targets of SEU regulation within the CMM to further refine the transcriptional hierarchy required for CMM development; 2) Develop a protoplast sorting protocol for gynoecial cells to enable a systems-biological analysis of developmental events within the CMM; 3) Determine the functional role of one of our high priority candidate genes during CMM development; and 4) Identify evolutionarily conserved cis-regulatory elements that support the expression of our candidate genes in the CMM. Intellectual Merit: Understanding the coordination of cellular proliferation and spatial patterning during organogenesis is of broad interest to scientists working in a diversity of fields. Completion of these specific aims will move us toward this future goal by illuminating the mechanistic basis for the overlapping functions of SEU and ANT during carpel margin meristem and ovule development. Additionally, we expect that by elucidating the molecular mechanisms of the synergistic action of SEU and ANT upon key transcriptional nodes, we will engender a greater understanding of the molecular underpinnings of non-additivity within transcriptional networks and the complexity of developmental programs. Past NSF funding for this project (IOS-0821896) has resulted in the publication of five articles in well-respected journals (two in Plant Physiology, and one each in Developmental Biology, PLoS One, and BMC Plant Biology). Broader impacts: I ensure a broad societal impact from my program by integrating my research efforts with my teaching and training responsibilities and by widely disseminating materials and results. Furthermore, I organize an outreach group that presents hands-on science demonstrations at local North Carolina middle schools. Additionally, our work on the mechanisms of CMM development may lea

The coordination of spatial patterning cues and cellular proliferation underlies diverse processes from cancerous growth to reproductive development. In Arabidopsis thaliana this coordination of patterning and proliferation is necessary within the carpel margin meristem to generate ovules that when fertilized will become seeds. In the previous funding period we demonstrated that the SEUSS (SEU) and AINTEGUMENTA (ANT) transcription factors regulate critical patterning events that support carpel margin meristem and ovule development. Our genetic analysis demonstrates that SEU and ANT share a partially redundant and overlapping function essential for proper seed formation. As SEU and ANT do not share sequence similarity, the molecular basis for this redundancy is not understood.

This project will examine the development of the soybean gynoecium/seed pod with a focus on ovule/seed development. The interest is to characterize the normal developmental processes so that efforts to understand varieties that generate higher numbers of ovules/seeds can be understood.

Project Summary The survival of seed plants, and thus the security of humankind?s food supply, requires the development of ovules that when fertilized will develop into seeds. In flowering plants the ovules develop within the gynoecium, the female reproductive structure. In Arabidopsis thaliana the gynoecium is made up of two carpels that are fused along their edges or margins to form a tube-like structure. Ovules arise on the inner surface of the gynoecial tube from specialized meristematic regions known as the Carpel Margin Meristems (CMMs). Genetic mutations that disrupt the development of the CMM result in a reduction of seed formation. Thus proper development of the CMMs is critical for female fertility in Arabidopsis and agricultural productivity in many crop plants. The main objective of the proposed research is to generate an understanding of the molecular mechanisms of early CMM development. Regional specification within the developing gynoecium refers to the assignment of different positional identities to different parts of the structure. Regional specification is critical for the development of the CMM. Specifically, adaxial (or inner) identity and margin identity must be properly specified to ensure CMM formation and thus ovule development. Experimental data indicates that three key regulatory genes, SEUSS, LEUNIG and AINTEGUMENTA, play a crucial role in the early development of the CMM. Dr Franks proposes a bipartite model in which 1) the SEUSS, LEUNIG and AINTEGUMENTA genes are required for the expression of the adaxial identity marker PHABULOSA within the developing gynoecium and 2) PHABULOSA expression is critical for the early development of the CMM. He proposes a variety of molecular genetic experiments to thoroughly test this model: 1) specific molecular markers will be used to follow regional specification during gynoecial development in mutant plants in which the activity of one or more of above-mentioned key regulators (SEUSS, LEUNIG and AINTEGUMENTA) is compromised; 2) the expression patterns of the SEUSS and LEUNIG gene products within the developing gynoecium will be determined; 3) the significance of adaxial identity specification during CMM development by the PHABULOSA, PHAVULOTA and REVOLUTA genes will be investigated; 4) and a unique genetic modifier screen will be utilized to identify novel regulators of CMM development. In many crop plants the development of the CMM is critical for agricultural productivity. By generating an enhanced molecular understanding of the regulation and control of CMM development, the proposed research may enable methods to engineer agricultural varieties with enhanced yield and thus meet the growing global demand for food. Additionally, the PI will enhance the societal benefits of his research program by fully integrating his scientific research efforts with his graduate and undergraduate teaching and training responsibilities. Materials and research results will be widely dispersed through publication in scientific journals and through web-based vehicles to interested scientists and all levels of educators. Furthermore, Dr. Franks will organize interested graduate students to prepare and present demonstrations at local elementary schools that will help to encourage an interest in scientific studies from this early age.

Variation in inflorescence architectures of flowering plants affects the success of plant reproduction and the yield of a crop by influencing seed number and dispersal/harvest ability. During angiosperm evolution, innovation of inflorescences has repeatedly occurred in different lineages. Despite the importance of inflorescence innovation in angiosperm evolution and crop production, we know little about the genetic basis of inflorescence development and the molecular changes that have altered inflorescence constructions in different plant lineages. This is partly due to the complexity of inflorescence development pathway and partly due to the lack of comparative studies between closely related species from an evolutionary perspective. Identifying genes responsible for heritable phenotypic differences between species represents the central challenge in evolutionary developmental genetics (EDG), a subdiscipline in biology that is among the most rapidly growing. It requires the use of diverse research strategies and a combination of technical advances from multidisciplines, from phylogenetics, developmental biology to molecular genetics and molecular biology. Previous EDG studies in plants often lacked data from one or more of these areas due to the lack of expertise in the multidisciplines of a single investigator, which hampered a clear understanding of the causal molecular changes of morphological evolution. The proposed study will combine the strength of three young faculty members with expertise in the following areas: plant developmental genetics (Franks), molecular biology, tissue culture, and transformation (Xie), and evolutionary biology, molecular systematics and evolution of dogwoods (Xiang), to unravel what changes in what genes have contributed to the condensation and petaloid bracts of inflorescences in different dogwood species. The dogwood genus Cornus L., containing our state flower C. florida, is a common element in eastern US forests, critically important to forest ecology and horticulture. The genus is an excellent model for EDG study of inflorescence due to the striking differences of inflorescence architectures displayed among species. Identification of genetic changes leading to the condensation and origin of petal-like bracts of inflorescences in Cornus will not only increase our understanding of inflorescence development and evolution at the molecular level in flowering plants, but also hold a promise in bioengineering of dogwoods to produce plants with novel inflorescence forms for ornamental purposes.

Reproduction in higher plants requires the formation of ovules that develop into seeds. During development, ovules arise on the inner surface of the gynoecium from specialized meristematic regions known as the Carpel Margin Meristems (CMM). Proper development of the CMM is critical for female fertility and for agricultural productivity in many crop plants. The long-term goal of my research program is to understand at the molecular level the development of the CMM. Arabidopsis thaliana provides a unique opportunity to reveal mechanisms that coordinate the development of this important reproductive meristem. This proposal focuses on identifying novel genetic components critical for CMM development by screening for genetic modifiers of the seuss mutant. Our initial pilot screen has yielded eight interesting seuss-modifier (sum) mutants that enhance the seuss carpel phenotype. This proposal asks for funding to further characterize these mutants and to continue our screening