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Orm Expression Alters Sphingolipid Homeostasis And Differentially Affects Ceramide Synthase Activity, Athen N. Kimberlin, Gongshe Han, Kyle D. Luttgeharm, Ming Chen, Rebecca E. Cahoon, Julie M. Stone, Jennifer E. Markham, Teresa M. Dunn, Edgar B. Cahoon

Center for Plant Science Innovation: Faculty and Staff Publications

Sphingolipid synthesis is tightly regulated in eukaryotes. This regulation in plants ensures sufficient sphingolipids to support growth while limiting the accumulation of sphingolipid metabolites that induce programmed cell death. Serine palmitoyltransferase (SPT) catalyzes the first step in sphingolipid biosynthesis and is considered the primary sphingolipid homeostatic regulatory point. In this report, Arabidopsis (Arabidopsis thaliana) putative SPT regulatory proteins, orosomucoidlike proteins AtORM1 and AtORM2, were found to interact physically with Arabidopsis SPT and to suppress SPT activity when coexpressed with Arabidopsis SPT subunits long-chain base1 (LCB1) and LCB2 and the small subunit of SPT in a yeast ( …

Transcriptome Response Of Cassava Leaves Under Natural Shade, Zehong Ding, Yang Zhang, Yi Xiao, Fangfang Liu, Minghui Wang, Xinguang Zhu, Peng Liu, Qi Sun, Wenquan Wang, Ming Peng, Tom Brutnell, Pinghua Li

Center for Plant Science Innovation: Faculty and Staff Publications

Cassava is an important staple crop in tropical and sub-tropical areas. As a common farming practice, cassava is usually cultivated intercropping with other crops and subjected to various degrees of shading, which causes reduced productivity. Herein, a comparative transcriptomic analysis was performed on a series of developmental cassava leaves under both full sunlight and natural shade conditions. Gene expression profiles of these two conditions exhibited similar developmental transitions, e.g. genes related to cell wall and basic cellular metabolism were highly expressed in immature leaves, genes involved in lipid metabolism and tetrapyrrole synthesis were highly expressed during the transition stages, and …

Rna-Seq Based Analysis Of Population Structure Within The Maize Inbred B73, Zhikai Liang, James C. Schnable

Center for Plant Science Innovation: Faculty and Staff Publications

Recent reports have shown than many identically named genetic lines used in research around the world actually contain large amounts of uncharacterized genetic variation as a result of cross contamination of stocks, unintentional crossing, residual heterozygosity within original stocks, or de novo mutation. 27 public, large scale, RNA-seq datasets from 20 independent research groups around the world were used to assess variation within the maize (Zea mays ssp. mays) inbred B73, a four decade old variety which served as the reference genotype for the original maize genome sequencing project and is widely used in genetic, genomic, and phenotypic research. Several …

Dedicated Industrial Oilseed Crops As Metabolic Engineering Platforms For Sustainable Industrial Feedstock Production, Li-Hua Zhu, Frans Krens, Mark A. Smith, Xueyuan Li, Weicong Qi, Elbertus N. Van Loo, Tim Iven, Ivo Feussner, Tara J. Nazarenus, Dongxin Huai, David C. Taylor, Xue-Rong Zhou, Allan G. Green, Jay Shockey, K. Thomas Klasson, Robert T. Mullen, Bangquan Huang, John M. Dyer, Edgar B. Cahoon

Center for Plant Science Innovation: Faculty and Staff Publications

Feedstocks for industrial applications ranging from polymers to lubricants are largely derived from petroleum, a non-renewable resource. Vegetable oils with fatty acid structures and storage forms tailored for specific industrial uses offer renewable and potentially sustainable sources of petrochemical-type functionalities. A wide array of industrial vegetable oils can be generated through biotechnology, but will likely require non-commodity oilseed platforms dedicated to specialty oil production for commercial acceptance. Here we show the feasibility of three Brassicaceae oilseeds crambe, camelina, and carinata, none of which are widely cultivated for food use, as hosts for complex metabolic engineering of wax esters for lubricant …

Ginkgo And Welwitschia Mitogenomes Reveal Extreme Contrasts In Gymnosperm Mitochondrial Evolution, Wenhu Guo, Felix Grewe, Weishu Fan, Gregory J. Young, Volker Knoop, Jeffrey D. Palmer, Jeffrey P. Mower

Center for Plant Science Innovation: Faculty and Staff Publications

Mitochondrial genomes (mitogenomes) of flowering plants are well known for their extreme diversity in size, structure, gene content, and rates of sequence evolution and recombination. In contrast, little is known about mitogenomic diversity and evolution within gymnosperms. Only a single complete genome sequence is available, from the cycad Cycas taitungensis, while limited information is available for the one draft sequence, from Norway spruce (Picea abies). To examine mitogenomic evolution in gymnosperms, we generated complete genome sequences for the ginkgo tree (Ginkgo biloba) and a gnetophyte (Welwitschia mirabilis). There is great disparity in size, …

A Bacterial Effector Co-Opts Calmodulin To Target The Plant Microtubule Network, Ming Guo, Panya Kim, Guangyong Li, Christian Elowsky, James R. Alfano

Center for Plant Science Innovation: Faculty and Staff Publications

The bacterial pathogen Pseudomonas syringae depends on effector proteins secreted by its type III secretion system for the pathogenesis of plants. The majority of these effector proteins are known suppressors of immunity, but their plant targets remain elusive. Using Arabidopsis thaliana as a model host, we report that the HopE1 effector uses the host calcium sensor, calmodulin (CaM), as a co-factor to target the microtubule- associated protein 65 (MAP65), an important component of the microtubule network. HopE1 interacted with MAP65 in a CaMdependent manner, resulting in MAP65-GFP dissociation from microtubules. Transgenic Arabidopsis expressing HopE1 had reduced secretion of the immunity …

Screen Of Non-Annotated Small Secreted Proteins Of Pseudomonas Syringae Reveals A Virulence Factor That Inhibits Tomato Immune Proteases, Takayuki Shindo, Farnusch Kaschani, Fan Yang, Judit Kovács, Fang Tian, Jiorgos Kourelis, Tram Ngoc Hong, Tom Colby, Mohammed Shabab, Rohini Chawla, Selva Kumari, Muhammed Ilyas, Anja C. Hörger, James R. Alfano, Renier A. L. Van Der Hoorn

Center for Plant Science Innovation: Faculty and Staff Publications

Pseudomonas syringae pv. tomato DC3000 (PtoDC3000) is an extracellular model plant pathogen, yet its potential to produce secreted effectors that manipulate the apoplast has been under investigated. Here we identified 131 candidate small, secreted, non-annotated proteins from the PtoDC3000 genome, most of which are common to Pseudomonas species and potentially expressed during apoplastic colonization. We produced 43 of these proteins through a custom-made gateway-compatible expression system for extracellular bacterial proteins, and screened them for their ability to inhibit the secreted immune protease C14 of tomato using competitive activity-based protein profiling. This screen revealed C14-inhibiting protein-1 (Cip1), which contains …

Identification Of Homogentisate Dioxygenase As A Target For Vitamin E Biofortification In Oilseeds, Minviluz G. Stacey, Rebecca E. Cahoon, Hanh T. Nguyen, Yaya Cui, Shirley Sato, Cuong T. Nguyen, Nongnat Phoka, Kerry M. Clark, Yan Liang, Joe Forrester, Josef Batek, Phat Tien Do, David A. Sleper, Thomas E. Clemente, Edgar B. Cahoon, Gary Stacey

Center for Plant Science Innovation: Faculty and Staff Publications

Soybean (Glycine max) is a major plant source of protein and oil and produces important secondary metabolites beneficial for human health. As a tool for gene function discovery and improvement of this important crop, a mutant population was generated using fast neutron irradiation. Visual screening of mutagenized seeds identified a mutant line, designated MO12, which produced brown seeds as opposed to the yellow seeds produced by the unmodified Williams 82 parental cultivar. Using forward genetic methods combined with comparative genome hybridization analysis, we were able to establish that deletion of the GmHGO1 gene is the genetic basis of …

Evolutionary Dynamics Of The Plastid Inverted Repeat: The Effects Of Expansion, Contraction, And Loss On Substitution Rates, Andan Zhu, Wenhu Guo, Weishu Fan, Jeffrey P. Mower

Center for Plant Science Innovation: Faculty and Staff Publications

• Rates of nucleotide substitution were previously shown to be several times slower in the plastid inverted repeat (IR) compared with single-copy (SC) regions, suggesting that the IR provides enhanced copy-correction activity.

• To examine the generality of this synonymous rate dependence on the IR, we compared plastomes from 69 pairs of closely related species representing 52 families of angiosperms, gymnosperms, and ferns.

• We explored the breadth of IR boundary shifts in land plants and demonstrate that synonymous substitution rates are, on average, 3.7 times slower in IR genes than in SC genes. In addition, genes moved from the SC into the …

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Residues Responsible For The Selectivity Of Α-Conotoxins For Ac-Achbp Or Nachrs, Bo Lin, Shi-Hua Xiang, Mengsen Li

Center for Plant Science Innovation: Faculty and Staff Publications

Nicotinic acetylcholine receptors (nAChRs) are targets for developing new drugs to treat severe pain, nicotine addiction, Alzheimer disease, epilepsy, etc. α-Conotoxins are biologically and chemically diverse. With 12–19 residues and two disulfides, they can be specifically selected for different nAChRs. Acetylcholine-binding proteins from Aplysia californica (Ac-AChBP) are homologous to the ligand-binding domains of nAChRs and pharmacologically similar. X-ray structures of the α-conotoxin in complex with Ac-AChBP in addition to computer modeling have helped to determine the binding site of the important residues of α-conotoxin and its affinity for nAChR subtypes. Here, we present the various α-conotoxin residues that are selective …

Screen Of Non-Annotated Small Secreted Proteins Of Pseudomonas Syringae Reveals A Virulence Factor That Inhibits Tomato Immune Proteases, Takayuki Shindo, Farnusch Kaschani, Fan Yang, Judit Kovács, Fang Tian, Jiorgos Kourelis, Tram Ngoc Hong, Tom Colby, Mohammed Shabab, Rohini Chawla, Selva Kumari, Muhammed Ilyas, Anja C. Hörger, James R. Alfano, Renier A. L. Van Der Hoorn

Center for Plant Science Innovation: Faculty and Staff Publications

Pseudomonas syringae pv. tomato DC3000 (PtoDC3000) is an extracellular model plant pathogen, yet its potential to produce secreted effectors that manipulate the apoplast has been under investigated. Here we identified 131 candidate small, secreted, non-annotated proteins from the PtoDC3000 genome, most of which are common to Pseudomonas species and potentially expressed during apoplastic colonization. We produced 43 of these proteins through a custom-made gateway-compatible expression system for extracellular bacterial proteins, and screened them for their ability to inhibit the secreted immune protease C14 of tomato using competitive activity-based protein profiling. This screen revealed C14-inhibiting protein-1 (Cip1), which contains motifs of …

Snrna 3' End Processing By A Cpsf73- Containing Complex Essential For Development In Arabidopsis, Yunfeng Liu, Shengjun Li, Yuan Chen, Athen N. Kimberlin, Edgar B. Cahoon, Bin Yu

Center for Plant Science Innovation: Faculty and Staff Publications

Uridine-rich small nuclear RNAs (snRNAs) are the basal components of the spliceosome and play essential roles in splicing. The biogenesis of the majority of snRNAs involves 3’ end endonucleolytic cleavage of the nascent transcript from the elongating DNA-dependent RNA ploymerase II. However, the protein factors responsible for this process remain elusive in plants. Here, we show that DEFECTIVE in snRNA PROCESSING 1 (DSP1) is an essential protein for snRNA 3’ end maturation in Arabidopsis. A hypomorphic dsp1-1 mutation causes pleiotropic developmental defects, impairs the 3’ end processing of snRNAs, increases the levels of snRNA primary transcripts (pre-snRNAs), and alters …

Limited Mitogenomic Degradation In Response To A Parasitic Lifestyle In Orobanchaceae, Weishu Fan, Andan Zhu, Melisa Kozaczek, Neethu Shah, Natalia Pabón-Mora, Favio González, Jeffrey P. Mower

Center for Plant Science Innovation: Faculty and Staff Publications

In parasitic plants, the reduction in plastid genome (plastome) size and content is driven predominantly by the loss of photosynthetic genes. The first completed mitochondrial genomes (mitogenomes) from parasitic mistletoes also exhibit significant degradation, but the generality of this observation for other parasitic plants is unclear. We sequenced the complete mitogenome and plastome of the hemiparasite Castilleja paramensis (Orobanchaceae) and compared them with additional holoparasitic, hemiparasitic and nonparasitic species from Orobanchaceae. Comparative mitogenomic analysis revealed minimal gene loss among the seven Orobanchaceae species, indicating the retention of typical mitochondrial function among Orobanchaceae species. Phylogenetic analysis demonstrated that the mobile cox1 …