Plant Pathology Commons^™

Breeding For Resistance In California Strawberry To Verticillium Dahliae, Zachary Christman

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

This article focuses on breeding resistant strawberries to the fungus Verticillium dahliae, common name Verticillium wilt. This is a serious fungal disease that can result in a loss of 50% or more of a strawberry harvest when grown in infested soil. The main goal is to provide an example of how a cultivar can be made more resistant to a plant pathogen with the use of plant breeding methods.

Since 1930 the University of California, Davis, has been developing strawberry cultivars that are adapted to the agricultural industry and regional farms. Developing cultivars that require fewer inputs are of …

Cop1, A Negative Regulator Of Photomorphogenesis, Positively Regulates Plant Disease Resistance Via Double-Stranded Rna Binding Proteins, Gah-Hyun Lim, Timothy Hoey, Shifeng Zhu, Marion Clavel, Keshun Yu, Duroy Navarre, Aardra Kachroo, Jean-Marc Deragon, Pradeep Kachroo

Plant Pathology Faculty Publications

The E3 ubiquitin ligase COP1 (Constitutive Photomorphogenesis 1) is a well known component of the light-mediated plant development that acts as a repressor of photomorphogenesis. Here we show that COP1 positively regulates defense against turnip crinkle virus (TCV) and avrRPM1 bacteria by contributing to stability of resistance (R) protein HRT and RPM1, respectively. HRT and RPM1 levels and thereby pathogen resistance is significantly reduced in the cop1 mutant background. Notably, the levels of at least two double-stranded RNA binding (DRB) proteins DRB1 and DRB4 are reduced in the cop1 mutant background suggesting that COP1 affects HRT stability via its effect …

Flowering Dogwood Infections With Macrophomina Phaseolina, Margaret T. Mmbaga, Lucas A. Mackasmiel, Frank A. Mrema

Agricultural and Environmental Sciences Faculty Research

Macrophomina phaseolina was isolated from the crown region and roots of mature flowering dogwood (Cornus florida L.) trees in the landscape and nursery plantings. Although this pathogen has been reported in Cornus species, its occurrence and impact on C. florida has not been reported. Pathogenicity tests were conducted on dogwood seedlings, and all inoculated seedlings developed root necrotic lesions and no small lateral roots, whereas the non-inoculated control seedlings remained disease-free and developed numerous small roots. Seedlings inoculated with M. phaseolina exhibited numerous microsclerotia, but non-inoculated seedlings did not. In greenhouse experiments, plants inoculated on the stems near the soil …

2018 Barley Variety Fact Sheets For Western Australia, Blakely Paynter, Georgia Trainor, Raj Malik, Jeremy Curry, Sanjiv Gupta, Sarah Collins, Daniel Huberli, Harmohinder Dhammu, Geoff Thomas, Ben Biddulph

Bulletins 4000 -

This bulletin is designed as a reference to help determine which barley variety to grow in your region. It provides market feedback, relative grain yield comparisons, disease ratings, agronomic information and herbicide tolerance ratings for all malt barley varieties segregated in Western Australia (WA) and selected feed varieties.

The decision whether to grow barley with a malt or feed classification depends on five main factors:

(1) Premium paid for different varieties when segregated.

(2) Relative grain yield of malt and feed grade barley varieties.

(3) Differences in input costs due to their agronomic and disease characteristics.

(4) Likelihood that grain …

Proceedings Of The 45th Annual Meeting Of The Southern Soybean Disease Workers (March 7-8, 2018, Pensacola Beach, Florida), Heather M. Kelly, Terry Spurlock, Carl Bradley, Danise Beadle, Patricia Bollich, Trey Price, Tom Allen

Southern Soybean Disease Workers: Conference Proceedings

Contents

List of SSDW Officers

Agenda for March 7-8, 2018

Abstracts for contributed/presented papers

Retrospective analyses regarding the impact of soybean diseases in the USA .TW Allen, PD Esker, and CA Bradley

Diaporthe (Phomopsis) species on soybean: current status in the United States. Febina Mathew, Kristina Petrovic, Lisa Castlebury, Tom Allen, Gary Bergstrom, John Bonkowski, Carl Bradley, James Buck, Emmanuel Byamukama, Martin Chilvers, Anne Dorrance, Nicholas Dufault, Loren Giesler, Nancy Gregory, Heather Kelly, Nathan Kleczewski, Trey Price, Dean Malvick, Sam Markell, Daren Mueller, Damon Smith, Terry Spurlock, Kiersten Wise, and Marina Johnson

New insights into the genetic underpinnings …

Characterization Of Botrytis Cinerea Resistance To Fungicides In California Strawberry Production, Scott D. Cosseboom

Master's Theses

Gray mold of strawberry, caused by Botrytis cinerea, is a very destructive pre- and post-harvest fruit rot. Outside of California, fungicide resistance in B. cinerea has been reported to every site-specific chemical class labeled for use against gray mold. One objective of this study was to characterize the resistance of 888 isolates of B. cinerea from California strawberry fields to ten active ingredients. Isolates were collected from the same planting block in 47 fields during the early-season (0 to 8 fungicide applications) and late-season (16 to 26 fungicide applications) of 2016. Sensitivity of each isolate was determined using the …

Gene Flow Between Divergent Cereal- And Grass-Specific Lineages Of The Rice Blast Fungus Magnaporthe Oryzae, Pierre Gladieux, Bradford Condon, Sebastien Ravel, Darren Soanes, Joao Leodato Nunes Maciel, Antonio Nhani, Li Chen, Ryohei Terauchi, Marc-Henri Lebrun, Didier Tharreau, Thomas Mitchell, Kerry F Pedley, Barbara Valent, Nicholas J. Talbot, Mark L. Farman, Elisabeth Fournier

Plant Pathology Faculty Publications

Delineating species and epidemic lineages in fungal plant pathogens is critical to our understanding of disease emergence and the structure of fungal biodiversity and also informs international regulatory decisions. Pyricularia oryzae (syn. Magnaporthe oryzae) is a multihost pathogen that infects multiple grasses and cereals, is responsible for the most damaging rice disease (rice blast), and is of growing concern due to the recent introduction of wheat blast to Bangladesh from South America. However, the genetic structure and evolutionary history of M. oryzae, including the possible existence of cryptic phylogenetic species, remain poorly defined. Here, we use whole-genome sequence …

Mac3a And Mac3b, Two Core Subunits Of The Mos4-Associated Complex, Positively Influence Mirna Biogenesis, Shengjun Li, Kan Liu, Bangjun Zhou, Mu Li, Shuxin Zhang, Lirong Zeng, Chi Zhang, Bin Yu

Center for Plant Science Innovation: Faculty Publications

MAC3A and MAC3B are conserved U-box containing proteins in eukaryotes. They are subunits of the MOS4-associated complex (MAC) that plays essential roles in plant immunity and development in Arabidopsis. However, their functional mechanisms remain elusive. Here we show that Arabidopsis thaliana MAC3A and MAC3B act redundantly in microRNA (miRNA) biogenesis. Lack of both MAC3A and MAC3B in the mac3b mac3b double mutant reduces the accumulation of miRNAs, causing elevated transcript levels of miRNA targets. mac3a mac3b also decreases the levels of primary miRNA transcripts (pri-miRNAs). However, MAC3A and MAC3B do not affect the promoter activity of genes encoding miRNAs ( …

A New Toolset For Protein Expression And Subcellular Localization Studies In Citrus And Its Application To Citrus Tristeza Virus Proteins, Amit Levy, Choaa El-Mochtar, Chunxia Wang, Michael M. Goodin, Vladimir Orbovic

Plant Pathology Faculty Publications

Background

Transient gene expression is a powerful tool to study gene function in plants. In citrus, Agrobacterium transformation is the method of choice for transient expression studies, but this method does not work efficiently with many gene constructs, and there is a need for a more robust transient expression system in citrus leaves. Biolistic particle delivery is an alternative to Agrobacterium transformation, and in some plants, such as Arabidopsis, gives higher transformation rates in leaf tissues than Agrobacterium.

Results

Here we describe an improved method for gene expression in epidermal cells of citrus leaves, using the Bio-Rad Helios gene-gun. …

Reactive Oxygen Species Metabolism And Plant-Fungal Interactions, Lauren M. Segal, Richard A. Wilson

Department of Plant Pathology: Faculty Publications

Fungal interactions with plants can involve specific morphogenetic developments to access host cells, the suppression of plant defenses, and the establishment of a feeding lifestyle that nourishes the colonizer often—but not always—at the expense of the host. Reactive oxygen species (ROS) metabolism is central to the infection process, and the stage-specific production and/or neutralization of ROS is critical to the success of the colonization process. ROS metabolism during infection is dynamic—sometimes seemingly contradictory—and involves endogenous and exogenous sources. Yet, intriguingly, molecular decision-making involved in the spatio-temporal control of ROS metabolism is largely unknown. When also considering that ROS demands are …

Evaluation Of Bacillus Strains For Plant Growth Promotion And Predictability Of Efficacy By In Vitro Physiological Traits, Rufus J. Akinrinlola, Gary Y. Yuen, Rhae A. Drijber, Anthony O. Adesemoye

Department of Plant Pathology: Faculty Publications

Bacilli are commonly used as plant growth-promoting agents but can be limited in effectiveness to certain crop and soil environments. The objectives of this study were to (1) identify Bacillus strains that can be consistent in promoting the growth of corn, wheat, and soybean and (2) determine whether physiological traits expressed in vitro can be predictive of growth promotion efficacy/consistency and be used for selecting effective strains. Twelve Bacillus strains isolated from wheat rhizospheres were evaluated in greenhouse pot tests with nonsterile soil for their effects on the growth of corn, soybean, and wheat. The strains also were assessed in …

Biophysical Approaches To Solve The Structures Of The Complex Glycan Shield Of Chloroviruses, Cristina De Castro, Garry Duncan, Domenico Garozzo, Antonio Molinaro, Luisa Sturiale, Michela Tonetti, James L. Van Etten

James Van Etten Publications

The capsid of Paramecium bursaria chlorella virus (PBCV-1) contains a heavily glycosylated major capsid protein, Vp54. The capsid protein contains four glycans, each N-linked to Asn. The glycan structures are unusual in many aspects: (1) they are attached by a β-glucose linkage, which is rare in nature; (2) they are highly branched and consist of 8–10 neutral monosaccharides; (3) all four glycoforms contain a dimethylated rhamnose as the capping residue of the main chain, a hyper-branched fucose residue and two rhamnose residues ''with opposite absolute configurations; (4) the four glycoforms differ by the nonstoichiometric presence of two monosaccharides, l-arabinose and …

Repeated Translocation Of A Gene Cassette Drives Sex-Chromosome Turnover In Strawberries, Jacob A. Tennessen, Na Wei, Shannon C.K. Straub, Rajanikanth Govindarajulu, Aaron Liston, Tia-Lynn Ashman

Faculty & Staff Scholarship

Turnovers of sex-determining systems represent important diversifying forces across eukary- otes. Shifts in sex chromosomes—but conservation of the master sex-determining genes— characterize distantly related animal lineages. Yet in plants, in which separate sexes have evolved repeatedly and sex chromosomes are typically homomorphic, we do not know whether such translocations drive sex-chromosome turnovers within closely related taxo- nomic groups. This phenomenon can only be demonstrated by identifying sex-associated nucleotide sequences, still largely unknown in plants. The wild North American octoploid strawberries (Fragaria) exhibit separate sexes (dioecy) with homomorphic, female heteroga- metic (ZW) inheritance, yet sex maps to three different chromosomes in …

Clean Low-Biomass Procedures And Their Application To Ancient Ice Core Microorganisms, Zhi-Ping Zhong, Natalie E. Solonenko, Maria C. Gazitua, Donald V. Kenny, Ellen Mosley-Thompson, Virginia I. Rich, James L. Van Etten, Lonnie G. Thompson, Matthew B. Sullivan

Department of Plant Pathology: Faculty Publications

Microorganisms in glacier ice provide tens to hundreds of thousands of years archive for a changing climate and microbial responses to it. Analyzing ancient ice is impeded by technical issues, including limited ice, low biomass, and contamination. While many approaches have been evaluated and advanced to remove contaminants on ice core surfaces, few studies leverage modern sequencing to establish in silico decontamination protocols for glacier ice. Here we sought to apply such “clean” sampling techniques with in silico decontamination approaches used elsewhere to investigate microorganisms archived in ice at ~41 (D41, ~20,000 years) and ~49 m (D49, ~30,000 years) depth …

Field Evaluation Of Commercially Available Small Unmanned Aircraft Crop Spray Systems, Wayne Woldt, D. Martin, M. Latheef, Greg Kruger, Robert J. Wright, Justin Mcmechan, Christopher A. Proctor, Tamra Jackson-Ziems

Department of Plant Pathology: Faculty Publications

Agricultural research and development on small unmanned aircraft systems (UAS) has been directed toward UAS enabled sensing to detect features of interest. While compelling, there is an immediate need to increase the breadth and depth of UAS-based research, to move beyond sensing, and explore active intervention in agricultural production systems. This paper is focused on the concept of crop protection through ultra-precise, unmanned aerial application systems, and seeks to initiate research discussion in this important area of opportunity. Toward this end, two different, commercially available, small Unmanned Aerial Application Systems (sUAAS - defined as less than 55 lbs. maximum take-off …

Development Of Ifox-Hunting As A Functional Genomic Tool And Demonstration Of Its Use To Identify Early Senescence-Related Genes In The Polyploid Brassica Napus, Juan Ling, Renjie Li, Chinedu Charles Nwafor, Junluo Cheng, Maoteng Li, Qing Xi, Jian Wu, Lu Gan, Qingyong Yang, Chao Liu, Ming Chen, Yongming Zhou, Edgar B. Cahoon, Chunyu Zhang

Center for Plant Science Innovation: Faculty Publications

Functional genomic studies of many polyploid crops, including rapeseed (Brassica napus), are constrained by limited tool sets. Here we report development of a gain-of-function platform, termed ‘iFOX (inducible Full-length cDNA OvereXpressor gene)-Hunting’, for inducible expression of B. napus seed cDNAs in Arabidopsis. A Gateway-compatible plant gene expression vector containing a methoxyfenozide-inducible constitutive promoter for transgene expression was developed. This vector was used for cloning of random cDNAs from developing B. napus seeds and subsequent Agrobacterium-mediated transformation of Arabidopsis. The inducible promoter of this vector enabled identification of genes upon induction that are otherwise lethal when constitutively overexpressed and …

Conventional And Hyperspectral Time-Series Imaging Of Maize Lines Widely Used In Field Trials, Zhikai Liang, Piyush Pandey, Vincent Stoerger, Yuhang Xu, Yumou Qiu, Yufeng Ge, James C. Schnable

Center for Plant Science Innovation: Faculty Publications

Background: Maize (Zea mays ssp. mays) is 1 of 3 crops, along with rice and wheat, responsible for more than one-half of all calories consumed around the world. Increasing the yield and stress tolerance of these crops is essential to meet the growing need for food. The cost and speed of plant phenotyping are currently the largest constraints on plant breeding efforts. Datasets linking new types of high-throughput phenotyping data collected from plants to the performance of the same genotypes under agronomic conditions across a wide range of environments are essential for developing new statistical approaches and computer …

Single-Molecule Sequencing And Optical Mapping Yields An Improved Genome Of Woodland Strawberry (Fragaria Vesca) With Chromosome-Scale Contiguity, Patrick P. Edger, Robert Vanburen, Marivi Colle, Thomas J. Poorten, Ching Man Wai, Chad E. Niederhuth, Elizabeth I. Alger, Shujun Ou, Charlotte B. Acharya, Jie Wang, Pete Callow, Michael R. Mckain, Jinghua Shi, Chad Collier, Zhiyong Xiong, Jeffrey P. Mower, Janet P. Slovin, Timo Hytonen, Ning Jiang, Kevin L. Childs, Steven J. Knapp

Center for Plant Science Innovation: Faculty Publications

Background: Although draft genomes are available for most agronomically important plant species, the majority are incomplete, highly fragmented, and often riddled with assembly and scaffolding errors. These assembly issues hinder advances in tool development for functional genomics and systems biology. Findings: Here we utilized a robust, cost-effective approach to produce high-quality reference genomes.We report a near-complete genome of diploid woodland strawberry (Fragaria vesca) using single-molecule real-time sequencing from Pacific Biosciences (PacBio). This assembly has a contig N50 length of ~7.9 million base pairs (Mb), representing a ~300-fold improvement of the previous version. The vast majority (>99.8%) …

Identification Of Bottlenecks In The Accumulation Of Cyclic Fatty Acids In Camelina Seed Oil, Xiao-Hong Yu, Rebecca E. Cahoon, Patrick J. Horn, Hai Shi, Richa R. Prakash, Yuanheng Cai, Maegan Hearney, Kent D. Chapman, Edgar B. Cahoon, Jorg Schwender, John Shanklin

Center for Plant Science Innovation: Faculty Publications

Modified fatty acids (mFA) have diverse uses; for example, cyclopropane fatty acids (CPA) are feedstocks for producing coatings, lubricants, plastics and cosmetics. The expression of mFA-producing enzymes in crop and model plants generally results in lower levels of mFA accumulation than in their natural-occurring source plants. Thus, to further our understanding of metabolic bottlenecks that limit mFA accumulation, we generated transgenic Camelina sativa lines co-expressing Escherichia coli cyclopropane synthase (EcCPS) and Sterculia foetida lysophosphatidic acid acyltransferase (SfLPAT). In contrast to transgenic CPA-accumulating Arabidopsis, CPA accumulation in camelina caused only minor changes in seed weight, germination rate, oil accumulation and seedling …

Integrating Phylogenetic And Network Approaches To Study Gene Family Evolution: The Case Of The Agamous Family Of Floral Genes, Daniel Santana De Carvalho, James C. Schnable, Ana Maria R. Almeida

Center for Plant Science Innovation: Faculty Publications

The study of gene family evolution has benefited from the use of phylogenetic tools, which can greatly inform studies of both relationships within gene families and functional divergence. Here, we propose the use of a network-based approach that in combination with phylogenetic methods can provide additional support for models of gene family evolution. We dissect the contributions of each method to the improved understanding of relationships and functions within the well-characterized family of AGAMOUS floral development genes. The results obtained with the two methods largely agreed with one another. In particular, we show how network approaches can provide improved interpretations …

Functional Modeling Of Plant Growth Dynamics, Y. Xu, Y. Qiu, James C. Schnable

Center for Plant Science Innovation: Faculty Publications

Recent advances in automated plant phenotyping have enabled the collection of time series measurements from the same plants of a wide range of traits at different developmental time scales. The availability of time series phenotypic datasets has increased interest in statistical approaches for comparing patterns of change among different plant genotypes and different treatment conditions. Two widely used methods of modeling growth with time are pointwise analysis of variance (ANOVA) and parametric sigmoidal curve fitting. Pointwise ANOVA yields discontinuous growth curves, which do not reflect the true dynamics of growth patterns in plants. In contrast, fitting a parametric model to …

Gipc Glcnac Glycosyltransferase, Toshiki Ishikawa, Lin Fang, Emilie A. Rennie, Julien Sechet, Jingwei Yan, Beibei Jing, William Moore, Edgar B. Cahoon, Henrik V. Scheller, Maki Kawai-Yamada, Jenny C. Mortimer

Center for Plant Science Innovation: Faculty Publications

Glycosylinositol phosphorylceramides (GIPCs), which have a ceramide core linked to a glycan headgroup of varying structure, are the major sphingolipids in the plant plasma membrane. Recently, we identified the major biosynthetic genes for GIPC glycosylation in Arabidopsis thaliana, and demonstrated that the glycan headgroup is essential for plant viability. However, the function of GIPCs and the significance of their structural variation are poorly understood. Here, we characterized the Arabidopsis glycosyltransferase GLUCOSAMINE INOSITOLPHOSPHORYLCERAMIDE TRANSFERASE1 (GINT1) and showed that it is responsible for the glycosylation of a subgroup of GIPCs found in seeds and pollen that contain N-acetylglucosamine (GlcNAc) and glucosamine …

Sma1, A Homolog Of The Splicing Factor Prp28, Has A Multifaceted Role In Mirna Biogenesis In Arabidopsis, Shengjun Li, Ran Xu, Aixia Li, Kan Liu, Liqing Gu, Mu Li, Hairui Zhang, Yueying Zhang, Shangshang Zhuang, Quanhui Wang, Gang Gao, Na Li, Chi Zhang, Yunhai Li, Bin Yu

Center for Plant Science Innovation: Faculty Publications

MicroRNAs (miRNAs) are a class of small non-coding RNAs that repress gene expression. In plants, the RNase III enzyme Dicer-like (DCL1) processes primary miRNAs (pri-miRNAs) into miRNAs. Here, we show that SMALL1 (SMA1), a homolog of the DEADbox pre-mRNA splicing factor Prp28, plays essential roles in miRNA biogenesis in Arabidopsis. A hypomorphic sma1-1 mutation causes growth defects and reduces miRNA accumulation correlated with increased target transcript levels. SMA1 interacts with the DCL1 complex and positively influences primiRNA processing. Moreover, SMA1 binds the promoter region of genes encoding pri-miRNAs (MIRs) and is required for MIR transcription. Furthermore, SMA1 also …

Generation And Evaluation Of Modified Opaque-2 Popcorn Suggests A Route To Quality Protein Popcorn, Ying Ren, Abou Yobi, Leandra Marshall, Ruthie Angelovici, Oscar Rodriguez, David R. Holding

Center for Plant Science Innovation: Faculty Publications

Introducing traits from dent corn to popcorn is challenging because it is difficult to recover adequate popping characteristics. QPM (Quality Protein Maize) is a dent corn variety carrying the opaque-2 (o2) mutation, specifying increased amounts of normally limiting essential amino acids, and modifier genes which restore the wild type vitreous kernel phenotype. In this study, we introgressed o2 and selected for endosperm modification using vitreousness and high 27-kD gamma zein content. In this way, we recovered high-lysine, fully poppable Quality Protein Popcorn (QPP). BC₂F₄ individuals with vitreous kernels were confirmed to be o2 mutants by …

Molecular Tools Enabling Pennycress (Thlaspi Arvense) As A Model Plant And Oilseed Cash Cover Crop, Michaela Mcginn, Winthrop B. Phippen, Ratan Chopra, Sunil Bansal, Brice A. Jarvis, Mary E. Phippen, Kevin M. Dorn, Maliheh Esfahanian, Tara J. Nazarenus, Edgar B. Cahoon, Timothy P. Durrett, M. David Marks, John C. Sedbrook

Center for Plant Science Innovation: Faculty Publications

Thlapsi arvense L. (pennycress) is being developed as a profitable oilseed cover crop for the winter fallow period throughout the temperate regions of the world, controlling soil erosion and nutrients run-off on otherwise barren farmland. We demonstrate that pennycress can serve as a user-friendly model system akin to Arabidopsis that is well-suited for both laboratory and field experimentation. We sequenced the diploid genome of the spring-type Spring 32-10 inbred line (1C DNA content of 539 Mb; 2n = 14), identifying variation that may explain phenotypic differences with winter-type pennycress, as well as predominantly a one-to-one correspondence with Arabidopsis genes, …

Lycophyte Plastid Genomics: Extreme Variation In Gc, Gene And Intron Content And Multiple Inversions Between A Direct And Inverted Orientation Of The Rrna Repeat, Jeffrey P. Mower, Peng-Fei Ma, Felix Grewe, Alex Taylor, Todd P. Michael, Robert Vanburen, Yin-Long Qiu

Center for Plant Science Innovation: Faculty Publications

Lycophytes are a key group for understanding vascular plant evolution. Lycophyte plastomes are highly distinct, indicating a dynamic evolutionary history, but detailed evaluation is hindered by the limited availability of sequences. Eight diverse plastomes were sequenced to assess variation in structure and functional content across lycophytes. Lycopodiaceae plastomes have remained largely unchanged compared with the common ancestor of land plants, whereas plastome evolution in Isoetes and especially Selaginella is highly dynamic. Selaginella plastomes have the highest GC content and fewest genes and introns of any photosynthetic land plant. Uniquely, the canonical inverted repeat was converted into a direct repeat (DR) …

The Role Of Type Iii Effectors From Xanthomonas Axonopodis Pv. Manihotis In Virulence And Suppression Of Plant Immunity, Cesar Augusto Medina, Paola Andrea Reyes, Cesar Augusto Trujillo, Juan Luis Gonzalez, David Alejandro Bejarano, Nathaly Andrea Montenegro, Jonathan M. Jacobs, Anna Joe, Silvia Restrepo, James R. Alfano, Adriana Bernal

Center for Plant Science Innovation: Faculty Publications

Xanthomonas axonopodis pv. manihotis (Xam) causes cassava bacterial blight, the most important bacterial disease of cassava. Xam, like other Xanthomonas species, requires type III effectors (T3Es) for maximal virulence. Xam strain CIO151 possesses 17 predicted T3Es belonging to the Xanthomonas outer protein (Xop) class. This work aimed to characterize nine Xop effectors present in Xam CIO151 for their role in virulence and modulation of plant immunity. Our findings demonstrate the importance of XopZ, XopX, XopAO1 and AvrBs2 for full virulence, as well as a redundant function in virulence between XopN and XopQ in susceptible cassava plants. We tested their role …

Xanthomonas Oryzae Pv. Oryzae Tale Proteins Recruit Ostfiiaγ1 To Compensate For The Absence Of Ostfiiaγ5 In Bacterial Blight In Rice, Wenxiu Ma, Lifang Zou, Zhiyuan Ji, Xiameng Xu, Zhengyin Xu, Yangyang Yang, James R. Alfano

Center for Plant Science Innovation: Faculty Publications

Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial blight (BB) of rice, uses transcription activator-like effectors (TALEs) to interact with the basal transcription factor gamma subunit OsTFIIAγ5 (Xa5) and activates the transcription of host genes. However, how OsTFIIAγ1, the other OsTFIIAγ protein, functions in the presence of TALEs remains unclear. In this study, we show that OsTFIIAγ1 plays a compensatory role in the absence of Xa5. The expression of OsTFIIAγ1, which is activated by TALE PthXo7, increases the expression of host genes targeted by avirulent and virulent TALEs. Defective OsTFIIAγ1 rice lines show reduced expression of the TALE-targeted …

Assessing Spatio-Temporal Patterns Of Forest Decline Across A Diverse Landscape In The Klamath Mountains Using A 28-Year Landsat Time-Series Analysis, Drew S. Bost

Cal Poly Humboldt theses and projects

Rates of tree mortality in California and the Pacific Northwest have greatly increased in recent years, driven largely by pest and pathogen outbreaks as well as the effects of hotter, warmer droughts. While there have been a multitude of regional-scale assessments of mortality and forest decline, landscape-level studies are necessary to better identify forests that are most vulnerable to decline and to anticipate future changes. This need is particularly notable in the remote and little-studied mountains of northwest California, which are renowned for their diverse, heterogeneous vegetation types. A recent observation of elevated levels of Shasta red fir (Abies …

Characterization Of Neofabraea Actinidiae And N. Brasiliensis As Causal Agents Of Apple Bull’S-Eye Rot In Southern Brazil, Amauri Bogo, Carla C. Comparin, Rosa M. Valdebenito Sanhueza, Patricia Ritschel, Ricardo T. Casa, Fábio N. Silva, Sydney E. Everhart

Department of Plant Pathology: Faculty Publications

The causal agents of apple bull’s-eye rot in southern Brazil have recently been described as Neofabraea actinidiae and N. brasiliensis. Isolates of both species were evaluated for response of mycelial growth index (MGI) to different temperatures, enzyme production, mycelial growth inhibition and effective concentrations (EC₅₀ and EC₁₀₀) of the fungicides triflumizole, pyrimethanil and thiophanate methyl, as well as aggressiveness on fruits of ‘Fuji’ hybrid and ‘Pink Lady’. There was significantly lower mycelium growth in N. brasiliensis compared with N. actinidiae at all temperatures tested. Neither species grew at 3 and 32°C. There were minor differences in …