We are glad that you are interested in the speakers for our 2021 WSU Plant Science Symposium. Below you will find information related to our 6 incredible keynote speakers and 4 featured speakers for this event.
Dr. Sarathi Weraduwage
Research Assistant Professor at Michigan State University
Dr. Simon Gilroy
Professor at the University of Wisconsin-Madison
Dr. Morgan Halane
Biologist from Great Ecology
Dr. Lyudmila Sidorenko
Principal Research Scientist at Corteva AgriSciences
Dr. Satyanarayana Tatineni
Research Plant Pathologist, USDA-ARS Plains Area Research Center
Dr. Jay Shockey
Research Geneticist, USDA-ARS Southern Regional Research Center
Dr. Gazala Ameen
Postdoctoral Research Associate – Washington State University
Wall- Associated Kinases in Plant Immunity
Plant biotrophic pathogen disease resistances rely on immunity receptor-mediated programmed cell death (PCD) responses, but specialized necrotrophic/hemi-biotrophic pathogens hijack these mechanisms to colonize the resulting dead tissue in their necrotrophic phase. Thus, immunity receptors can become necrotrophic pathogen dominant susceptibility targets but resistance mechanisms that resist necrotroph manipulation are recessive resistance genes. The barley rcs5 QTL imparts recessive resistance against the disease spot blotch caused by the hemi-biotrophic fungal pathogen Bipolaris sorokiniana. The rcs5 genetic interval was delimited to ~0.23 cM, representing an ~234 kb genomic region containing four wall-associated kinase (WAK) genes, designated HvWak2, Sbs1, Sbs2 (susceptibility to Bipolaris sorokiniana 1&2), and HvWak5. Post-transcriptional gene silencing of Sbs1&2 in susceptible barley cultivars resulted in resistance showing dominant susceptibility function. Allele analysis of Sbs1&2 from resistant and susceptible barley cultivars identified sequence polymorphisms associated with phenotypes in their primary coding sequence and promoter regions, suggesting differential transcriptional regulation may contribute to susceptibility. Transcript analysis of Sbs1&2 showed nearly undetectable expression in resistant and susceptible cultivars prior to pathogen challenge; however, upregulation of both genes occurred specifically in susceptible cultivars post-inoculation with a virulent isolate. Apoplastic wash fluids collected from barley infected with a virulent isolate induced Sbs1, suggesting regulation by an apoplastic-secreted effector. Thus, Sbs1&2 function as B. sorokiniana susceptibility targets and non-functional alleles or alleles that resist induction by the pathogen mediate rcs5-recessive resistance. The sbs1&2 alleles underlying the rcs5 QTL that the pathogen is unable to manipulate are the first resistance genes identified against spot blotch.
Cellulose nanocrystal dispersions protect tree fruits from cold damage
Cold damage to reproductive buds or flowers is a perennial concern to tree fruit producers. Indeed, cold damage has caused more economic losses to crops in the US than any other weather hazard. The potential losses (yield reductions to complete crop failure) from cold damage are predicted to increase with variable weather patterns resulting from climate change. Cellulose nanocrystals (CNC) represents a new generation of renewable nano-biomaterials, with many unique physical and chemical properties, including their low thermal conductivity. Our team has developed a process for creating CNC dispersions that can be sprayed onto trees, forming a thin (ca. 25µm-40µm) and durable insulating film around the surface of the buds. Thermal image analyses revealed that apple (Malus domestica Borkh) and sweet cherry (Prunus avium L.) flower buds treated with 3% CNC dispersions lose 16.5% less thermal energy into the environment in cold conditions than untreated buds. Analyses of internal freezing events in apple with digital scanning calorimetry showed that buds coated in 3% CNC exhibited lethal freezing at a temperature 3.2°C and 5.5°C lower than the untreated control 1 and 3 days after application, respectively. Large-scale field trials using commercially available electrostatic sprayers showed that CNC-treated (2.5%) reproductive buds were hardier by ca. 5.8°C, a level of protection that lasted up to 7 days post application. The results of this work suggest that CNC dispersions can effectively protect reproductive buds from cold damage and may represent a novel means for fruit growers worldwide to reduce losses.
Brent Arnoldussen
Graduate Student – Washington State University, Prosser IAREC
Erica Casagrande Biasuz
Graduate Student – Washington State University, Wenatchee: WSU-Tree Fruit Research and Extension Center
Honeycrisp apple trees water relations are affected by rootstock vigor
Dwarfing rootstocks are root system trees grafted on different apple scions with the aim of reducing canopy volume and improving apple productivity. It is believed that dwarfing rootstocks dwarf the scion via hydraulic resistance in xylem vessels, thus, more efficient water usage per plant. This research focuses on developing a physiological understanding of how rootstocks affect plant water relations which may offer a great opportunity to develop improved rootstocks in the future. Here, we analyze anatomical traits and physiological manipulation of water status to understand the approach of plant hydraulic conductivities on the water uptake dynamics in the soil-plant-atmosphere continuum. Water status will be measured as leaf transpiration, stomatal conductance, and midday stem water potential. Subsequently, the anatomy of trunk, shoots and leaves will be analyzed. Carbon and oxygen isotope composition were used as proxy technique associated with stomatal control due to its connection with carbon dioxide and water exchange with the atmosphere. It was observed that dwarfing rootstock affected scion shoot growth (P <0.001), stomatal conductance (P< 0.01) and stem water potential (P <0.001). Plant growth was positively correlated with stomatal conductance (r= 0.38; P <0.01) and stem water potential (r2= 0.55; P <0.001). Rootstocks with low vegetative vigor showed lower stomatal conductance and enriched leaf δ13C and δ18O isotope composition. Rootstocks affected plant water status and net gas exchange.
Efficiency of self-protection mechanisms for drought resiliency
Drought resiliency encompasses responses at the whole-organism, cellular, and molecular levels. Here we take a systems approach to analysis drought response in two drought adapted spring wheat (Triticum aestivum) genotypes, Drysdale and Hollis. Apart from increasing water use efficiency by reducing stomatal conductance, drought responses differed between the genotypes. Drysdale dissipated excess of harvested light energy through non-photochemical quenching (NPQ) and sustained higher Fv/Fm and ⏀PSII. Hollis, in constrast, maintained NPQ constant, whereas Fv/Fm and ⏀PSII declined, and electron donors of the electron transport chain were in the oxidized state. ROS homeostasis parameters of peroxisome abundance, catalase transcription and translation, and enzymatic activity of catalase were higher in Hollis than in Drysdale. Transcription of catalase and PEROXIN11 genes were reliable markers of peroxisome proliferation. Hollis also exploited autophagic flux to a greater extent than Drysdale. Measuring transcription level of autophagy flux marker ATG8 demonstrated that out of four T. aestivum ATG8 genes, ATG8.4 was upregulated more in Hollis than in Drysdale under drought. Furthermore, the flowering time was shorter and roots growth was suppressed under drought in Hollis, but not Drysdale. We conclude that lower photosynthetic activity under drought can be compensated by cellular self-protection traits.
Kathleen Hickey
PhD Candidate – Washington State University