Digital Commons Network^™

Oil-Producing Metabolons Containing Dgat1 Use Separate Substrate Pools From Those Containing Dgat2 Or Pdat, Anushobha Regmi, Jay Shockey, Hari Kiran Kotapati, Philip D. Bates

Faculty Publications

© 2020 American Society of Plant Biologists. All rights reserved. Seed triacylglycerol (TAG) biosynthesis involves a metabolic network containing multiple different diacylglycerol (DAG) and acyl donor substrate pools. This network of pathways overlaps with those for essential membrane lipid synthesis and utilizes multiple different classes of TAG biosynthetic enzymes. Acyl flux through this network ultimately dictates the final oil fatty acid composition. Most strategies to alter seed oil composition involve the overexpression of lipid biosynthetic enzymes, but how these enzymes are assembled into metabolons and which substrate pools are used by each is still not well understood. To understand the …

Comparative Analysis Of Rhizosphere Microbiomes Of Southern Highbush Blueberry (Vaccinium Corymbosum L.), Darrowâs Blueberry (V. Darrowii Camp), And Rabbiteye Blueberry (V. Virgatum Aiton), Jiangang Li, Olga V. Mavrodi, Jinfeng Hou, Chazden Blackmon, Ebrahiem M. Babiker, Dmitri V. Mavrodi

Faculty Publications

Plants are inhabited by millions of parasitic, commensal, and mutualistic microorganisms that coexist in complex ecological communities, and profoundly affect the plant’s productivity, health, and capacity to cope with environmental stress. Therefore, a better understanding of the rhizosphere microbiome may open a yet untapped avenue for the rational exploitation of beneficial plant–microbe interactions in modern agriculture. Blueberries encompass several wild and cultivated species of shrubs of the genus Vaccinium that are native to North America. They are grown commercially for the production of fruits, which are considered a health food due to the rich content of minerals, trace elements, and …

Evaluation Of Detached Strawberry Leaves For Anthracnose Disease Severity Using Image Analysis And Visual Ratings, Melinda A. Miller-Butler, Barbara J. Smith, Kenneth J. Curry, Eugene K. Blythe

Faculty Publications

Inoculation of detached strawberry leaves with Colletotrichum species may provide an accurate, rapid, nondestructive method of identifying anthracnose-resistant germplasm. The purpose of this study was to statistically compare two methods (visual and image analysis) of evaluating disease severity of strawberry germplasm screened for anthracnose resistance. Detached leaves of 77 susceptible and resistant strawberry clones were inoculated with one Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. and two C. fragariae A. N. Brooks isolates. Anthracnose disease symptoms on each leaf were assessed quantitatively via computer-based image analysis to determine percentage lesion area and qualitatively by two independent raters using a visual disease …

Rhizosphere Microbial Communities Of Spartina Alternifloa And Juncus Roemerianus From Restored And Natural Tidal Marshes On Deer Island, Mississippi, Olga Mavrodi, Carina M. Jung, Jed O. Eberly, Samuel Hendry, Sanchirmaa Namijilsuren, Patrick D. Biber, Karl J. Indest, Dmitri V. Mavrodi

Faculty Publications

The U. S. Gulf of Mexico is experiencing a dramatic increase in tidal marsh restoration actions, which involves planting coastal areas with smooth cordgrass (Spartina alterniflora) and black needlerush (Juncus roemerianus) for erosion control and to provide habitat for fish and wildlife. It can take decades for sedimentary cycles in restored marshes to approach reference conditions, and the contribution of the sediment microbial communities to these processes is poorly elucidated. In this study, we addressed this gap by comparing rhizosphere microbiomes of S. alterniflora and J. roemerianus from two restored marshes and a natural reference marsh located at Deer Island, …

The Effect Of Light Conditions On Interpreting Oil Composition Engineering In Arabidopsis Seeds, Nischal Karki, Philip D. Bates

Faculty Publications

Arabidopsis thaliana is the most developed and utilized model plant. In particular, it is an excellent model for proof‐of‐concept seed oil engineering studies because it accumulates approximately 37% seed oil by weight, and it is closely related to important Brassicaceae oilseed crops. Arabidopsis can be grown under a wide variety of conditions including continuous light; however, the amount of light is strongly correlated with total seed oil accumulation. In addition, many attempts to engineer novel seed oil fatty acid compositions in Arabidopsis have reported significant reductions in oil accumulation; however, the relative reduction from the nontransgenic controls varies greatly within …

Long-Term Irrigation Affects The Dynamics And Activity Of The Wheat Rhizosphere Microbiome, Dmitri V. Mavrodi, Olga Mavrodi, Liam D.H. Elbourne, Sasha Tetu, Robert F. Bonsall, James Parejko, Mingming Yang, Ian T. Paulsen, David M. Weller, Linda S. Thomashow

Faculty Publications

The Inland Pacific Northwest (IPNW) encompasses 1. 6 million cropland hectares and is a major wheat-producing area in the western United States. The climate throughout the region is semi-arid, making the availability of water a significant challenge for IPNW agriculture. Much attention has been given to uncovering the effects of water stress on the physiology of wheat and the dynamics of its soilborne diseases. In contrast, the impact of soil moisture on the establishment and activity of microbial communities in the rhizosphere of dryland wheat remains poorly understood. We addressed this gap by conducting a three-year field study involving wheat …

Leaf Herbivory Induces Resistance Against Florivores In Raphanus Sativus, Andrew C. Mccall, Samantha Case, Kelsy Espy, Grant Adams, Stephen J. Murphy

Student Publications

Florivory can have significant negative effects on plant fitness, driving selection for resistance traits in flowers. In particular, herbivory to leaves may induce resistance in flowers because herbivores on leaves often become florivores on flowers as plant ontogeny proceeds. The literature on inducible resistance in floral tissues is limited, so we used a series of experiments to determine whether prior leaf damage by Spodoptera exigua (Hübner) caterpillars affected florivore preference and performance on wild radish (Raphanus sativus L.). We found that Spodoptera exigua larvae preferred petals from control plants versus petals from plants exposed to prior leaf damage, and …

Lentic And Lotic Habitats As Templets For Fungal Communities: Traits, Adaptations, And Their Significance To Litter Decomposition Within Freshwater Ecosystems, Kevin A. Kuehn

Faculty Publications

Decomposition of plant matter is a key ecosystem process and considerable research has examined plant litter decay processes in freshwater habitats. Fungi are common inhabitants of the decomposer microbial community and representatives of all major fungal phyla have been identified within freshwater systems. Development and application of quantitative methods over the last several decades have firmly established that fungi are central players in the decomposition of plant litter in freshwaters and are important mediators of energy and nutrient transfer to higher trophic levels. Despite the critical roles that fungi play in carbon and nutrient cycling in freshwater ecosystems, there are …

Contribution Of Surface Leaf-Litter Breakdown And Forest Composition To Benthic Oxygen Demand And Ecosystem Respiration In A South Georgia Blackwater River, Andrew S. Mehring, Kevin A. Kuehn, Cynthia J. Tant, Catherine M. Pringle, R. Richard Lowrance, George Vellidis

Faculty Publications

Many North American blackwater rivers exhibit low dissolved O₂ (DO) that may be the result of benthic respiration. We examined how tree species affected O₂ demand via the quantity and quality of litter produced. In addition, we compared areal estimates of surface leaf-litter microbial respiration to sediment O₂ demand (SOD) and ecosystem respiration (ER) in stream and swamp reaches of a blackwater river to quantify contributions of surface litter decomposition to O₂ demand. Litter inputs averaged 917 and 678 g m⁻² y⁻¹ in the swamp and stream, respectively. Tree species differentially affected O_{2 …}

Priming In The Microbial Landscape: Periphytic Algal Stimulation Of Litter-Associated Microbial Decomposers, Kevin A. Kuehn, Steven N. Francoeur, Robert H. Findlay, Robert K. Neely

Faculty Publications

Microbial communities associated with submerged detritus in aquatic ecosystems often comprise a diverse mixture of autotrophic and heterotrophic microbes, including algae, bacteria, protozoa, and fungi. Recent studies have documented increased rates of plant litter mass loss when periphytic algae are present. We conducted laboratory and field experiments to assess potential metabolic interactions between natural autotrophic and heterotrophic microbial communities inhabiting submerged decaying plant litter of Typha angustifolia and Schoenoplectus acutus. In the field, submerged plant litter was either exposed to natural sunlight or placed under experimental canopies that manipulated light availability and growth of periphytic algae. Litter was collected …

Visual And Electronic Evaluations Of Detached Strawberry Leaves Inoculated With Colletotrichum Species, M. A. Miller-Butler, K. J. Curry, B. R. Kreiser, B. J. Smith

Faculty Publications

Inoculation of detached strawberry leaves with Colletotrichum species may provide an accurate, rapid, non-destructive method of identifying anthracnose resistant germplasm. Two assessments of anthracnose disease severity were compared on detached strawberry leaves inoculated with Colletotrichum fragariae and C. gloeosporioides: a quantitative assessment made via computer-based image analysis and a visual assessment made by two independent raters. The image analysis provided a precise measurement of percent lesion area of infected leaves. There was a strong positive correlation between percent lesion area and the visual disease scores of the raters.

Nucleosome Structure Incorporated Histone Acetylation Site Prediction In Arabidopsis Thaliana, Chen Zhao, Hui Liu, Youping Deng, Tieliu Shu

Faculty Publications

Background

Acetylation is a crucial post-translational modification for histones, and plays a key role in gene expression regulation. Due to limited data and lack of a clear acetylation consensus sequence, a few researches have focused on prediction of lysine acetylation sites. Several systematic prediction studies have been conducted for human and yeast, but less for Arabidopsis thaliana.

Results

Concerning the insufficient observation on acetylation site, we analyzed contributions of the peptide-alignment-based distance definition and 3D structure factors in acetylation prediction. We found that traditional structure contributes little to acetylation site prediction. Identified acetylation sites of histones in Arabidopsis thaliana …

Global Protein Interactome Exploration Through Mining Genome-Scale Data In Arabidopsis Thaliana, Feng Xu, Guang Li, Chen Zhao, Yuhua Li, Peng Li, Jian Cui, Youping Deng, Tieliu Shi

Faculty Publications

Background

Many essential cellular processes, such as cellular metabolism, transport, cellular metabolism and most regulatory mechanisms, rely on physical interactions between proteins. Genome-wide protein interactome networks of yeast, human and several other animal organisms have already been established, but this kind of network reminds to be established in the field of plant.

Results

We first predicted the protein protein interaction in Arabidopsis thaliana with methods, including ortholog, SSBP, gene fusion, gene neighbor, phylogenetic profile, coexpression, protein domain, and used Naïve Bayesian approach next to integrate the results of these methods and text mining data to build a genome-wide protein interactome …

Water Uptake Threshold Of Rabbiteye (Vaccinium Ashei) Blueberries And Its Influence On Fruit Splitting, Donna A. Marshall-Shaw, James M. Spiers, Kenneth J. Curry

Faculty Publications

Split-resistant and split-susceptible rabbiteye blueberry fruit were evaluated at all stages of development to determine ''water uptake thresholds'' by soaking in distilled water. Weight increase after soaking was measured, and percent weight gain was calculated to take into consideration the weight increase of the fruit from development. The ratio of percent increase in volume to weight increase resulting from water uptake was calculated. Ratios of percent water uptake to weight increase between splitsusceptible 'Tifblue' and split-resistant 'Premier' blueberries were found to be similar. The split-susceptible 'Tifblue' had a 1.6 g/50 fruit increase with a 1.7% water uptake and a ratio …

Evaluation Of Cay-1, An Experimental, Natural Fungicide, For Control Of Strawberry Pathogens, Kenneth J. Curry, Maritza Abril, Anthony J. Delucca, Stephen M. Boue, Barbara J. Smith, David E. Wedge

Faculty Publications

CAY-1 is an experimental, natural product being tested as a potential fungicide. This saponin isolated from Capsicum frutescens interacts with membrane sterols causing leakage of cell components and ultimately cell death in a variety of fungi. CAY-1 and the commercial fungicide captan were tested in an in vitro doseresponse dilution-broth assay. They caused at least 85% growth inhibition of the fungal pathogens Colletotrichum acutatum, C fragariae and C. gloeosporioides when tested at 3.0 μM. Even though CAY-1 strongly reduced the growth of these fungal pathogens in laboratory assays and prevented anthracnose development in detached leaf assays, it did not …

Variation Of Morphology And Elemental Concentrations In The California Nickel Hyperaccumulator Streptanthus Polygaloides (Brassicaceae), Robert S. Boyd, Michael A. Wall, Scott R. Santos, Michael A. Davis

Faculty Publications

The Ni hyperaccumulator Strepthanthus polygaloides (Brassicaceae) is one of a handful of Ni hyperaccumulators known from continental North America. Surveys have revealed four distinctive morphs of this species, relying primarily on floral traits (sepal color and shape): a purple sepal morph (P), a yellow sepal morph (Y), a morph in which sepals start yellow and mature to purple (Y/P), and a morph with light yellow undulate sepals (U). In this study, we raised plants from ten populations (five Y, three P, one Y/P, and one U) under uniform greenhouse conditions to determine if morphs varied in morphology and elemental concentrations …

Survey Of Blueberry (Vaccinium Spp.) Problems In The Gulf South, Melinda A. Miller-Butler, Kenneth J. Curry, Barbara J. Smith, Jeffrey S. Braswell

Faculty Publications

The blueberry (Vaccinium) industry in Mississippi has been steadily increasing since the early 1980s, but some plants in older fields are now in decline. The root rot pathogen, Phytophthora cinnamomi, is endemic in the southeastern United States and has caused severe losses to blueberries in North Carolina and Arkansas. Because the warm, humid climate of Mississippi, with periods of high precipitation, provides a favorable environment for Phytophthora root rot disease, it was suspected to be the cause of plant decline in older blueberry fields. Members of the Gulf South Blueberry Growers Association were mailed surveys to determine …

Laboratory Method To Estimate Rain-Induced Splitting In Cultivated Blueberries, Donna A. Marshall-Shaw, James M. Spiers, Stephen J. Stringer, Kenneth J. Curry

Faculty Publications

Preharvest rainfall that occurs when fruit are fully ripe or approaching full ripeness can result in detrimental fruit splitting in rabbiteye and southern highbush blueberries. This study was initiated to develop a laboratory method to model rain-related incidence of splitting in cultivated blueberries with the goal of predicting the incidence of splitting in blueberry cultivars and selections. Multiyear field surveys of rabbiteye and southern highbush cultivars show that the incidence of rain-related splitting is strongly cultivar-dependent. Laboratory values for forced splitting and naturally occurring rain-related field splitting data show a strong correlation indicating that the incidence of fruit splitting can …

Measuring The Effects Of Salinity Stress In The Red Mangrove, Rhizophora Mangle L., Patrick D. Biber

Faculty Publications

The mangrove habitat exhibits many unique physical features, one of the most important of which is a salinity gradient. Photosynthetic rates, as measured by leaf stomatal conductance and leaf chlorophyll fluorescence induction, were tested as indicators of salinity stress in seedlings of the red mangrove, Rhizophora mangle, grown under five different salinity levels: 0, 15, 30, 45, and 60 parts per thousand. Photosynthetic gas exchange (measured by stomatal conductance), as well as the light reaction of photosynthesis (measured by chlorophyll fluorescence) were found to decrease as salinity increased. The use of leaf stomatal conductance and chlorophyll fluorescence as a …

Phylogeny And Androecial Evolution In Schisandraceae, Inferred From Sequences Of Nuclear Ribosomal Dna Its And Chloroplast Dna TrnL-F Regions, Zhong Liu, Gang Hao, Yi-Bo Luo, Leonard B. Thien, Samuel W. Rosso, An-Ming Lu, Zhi-Duan Chen

Faculty Publications

Sequences of nuclear ribosomal DNA ITS and chloroplast trnL‐F regions were used to construct a phylogeny of Schisandraceae. The results show that there are two major clades in Schisandraceae. One is composed entirely of Schisandra species; the other contains a mixture of Schisandra and Kadsura species. Molecular data place Smith’s sect. Sphaerostema of Schisandra prominently within Kadsura, and thus neither Schisandra nor Kadsura is monophyletic, refuting the traditional division of the family into two genera based on morphological characters of mature fruits. The sister relationship between S. glabra (North America) and S. bicolor (China) and the monophyly of …

Strawberry Anthracnose: Histopathology Of Colletotrichum Acutatum And C. Fragariae, Kenneth J. Curry, Maritza Abril, Jana B. Avant, Barbara J. Smith

Faculty Publications

Ontogeny of the invasion process by Colletotrichum acutatum and C. fragariae was studied on petioles and stolons of the strawberry cultivar Chandler using light and electron microscopy. The invasion of host tissue by each fungal species was similar; however, each invasion event occurred more rapidly with C. fragariae than with C. acutatum. Following cuticular penetration via an appressorium, subsequent steps of invasion involved hyphal growth within the cuticle and within the cell walls of epidermal, subepidermal, and subtending cells. Both species of fungi began invasion with a brief biotrophic phase before entering an extended necrotrophic phase. Acervuli formed once …

Osmophores, Floral Features, And Systematics Of Stanhopea (Orchidaceae), Kenneth J. Curry, Lorraine M. Mcdowell, Walter S. Judd, William Louis Stern

Faculty Publications

The floral fragrance glands (osmophores) of 18 species of Stanhopea and Sievekingia were examined through a series of developmental studies at light and electron microscope levels including late bud stages through postanthesis. Various characters were identified to be of potential systematic value and were recorded for each species. These characters included: texture of the osmophore surface, number of distinct cell layers comprising the osmophore, nature of lipid inclusions in osmophore cells, and presence or absence of plastoglobuli in osmophore amyloplasts. These characters were combined with traditional features of floral lip morphology for cladistic analysis. Sievekingia was the postulated outgroup. Stanhopea …

Initiation Of Terpenoid Synthesis In Osmophores Of Stanhopea Anfracta (Orchidaceae): A Cytochemical Study, Kenneth J. Curry

Faculty Publications

The terpenoid component of the osmophore fragrance in Stanhopea species is composed of isoprene units synthesized via the mevalonic acid pathway. Localization of hydroxymethylglutaryl CoA synthase in the pathway was achieved using a technique which elicits the formation of an electron- dense precipitate of uranyl ferrocyanide at the point where an acetyl group from acetyl CoA is transferred to acetoacetyl CoA, releasing free CoA-SH. Applying this technique to cells of the osmophore of S. anfracta resulted in a precipitate between the inner and outer mitochondrial membranes, in the smooth endoplasmic reticulum, and, to a lesser extent, on the outer surface …

Osmophores Of Stanhopea (Orchidaeceae), William Louis Stern, Kenneth J. Curry, Alec M. Pridgeon

Faculty Publications

Species of the Neotropical orchid genus Stanhopea produce a fragrance comprising terpenoids and aromatics which attracts euglossine bee pollinators. The secretory tissue, called an osmo- phore, is located in the adaxial region of a sac formed near the proximal portion of the floral lip. This region is easily recognized in Stanhopea oculata and S. wardii because it is papillate. The osmophore in these two species includes all the cells of the papillae and those directly below, that grade into fundamental tissue. Osmophore cells are more densely cytoplasmic than cells in the adjacent tissue. Numerous amyloplasts and mitochondria are seen in …