Surpassing the Performance of Phenolate-derived Ionic Liquids in CO2 Chemisorption by Harnessing the Robust Nature of Pyrazolonates.

Superbase-derived ionic liquids (SILs) are promising sorbents to tackle the carbon challenge featured by tunable interaction strength with CO2 via structural engineering, particularly the oxygenate-derived counterparts (e. g., phenolate). However, for the widely deployed phenolate-derived SILs, unsolved stability issues severely limited their applications leading to unfavorable and diminished CO2 chemisorption performance caused by ylide formation-involved side reactions and the phenolate-quinone transformation via auto-oxidation. In this work, robust pyrazolonate-derived SILs possessing anti-oxidation nature were developed by introducing aza-fused rings in the oxygenate-derived anions, which delivered promising and tunable CO2 uptake capacity surpassing the phenolate-based SIL via a carbonate formation pathway (O-C bond formation), as illustrated by detailed spectroscopy studies. Further theoretical calculations and experimental comparisons demonstrated the more favorable reaction enthalpy and improved anti-oxidation properties of the pyrazolonate-derived SILs compared with phenolate anions. The achievements being made in this work provides a promising approach to achieve efficient carbon capture by combining the benefits of strong interaction strength of oxygenate species with CO2 and the stability improvement enabled by aza-fused rings introduction.

Survival of Isolates of the US-22, US-23, and US-24 Clonal Lineages of Phytophthora infestans by Asexual Means in Tomato Seed at Cold Temperatures.

Survival of Phytophthora infestans, causal agent of potato and tomato late blight, is thought to be negligible when exposed to freezing conditions typical of a Wisconsin winter. However, the persistence of relatively new P. infestans clonal lineages US-22, US-23, and US-24 within a production region during 2010 to 2014 warranted further investigation. We used tomato seed as a culture medium to determine the survival of P. infestans isolates representing the three lineages under temperatures of 18, 4, 0, -3, and -5°C for 11 time points (1 to 112 days postincubation). Survival varied interactively with temperature, duration of time at a temperature, and clonal lineage of the P. infestans isolate. US-22, -23, and -24 isolates survived for 112 days at 18 and 4°C, 84 days at 0°C, and 14 days at -3°C. US-23 survived longer at -3 and -5°C than did US-22 or US-24. The vigor of US-22 and US-24 isolates decreased with increasing exposure to cold temperatures, a trend that was not observed for the US-23 isolate. By calculating the length of time needed to kill the lineage isolates on infested tomato seed at five temperatures, we predicted that P. infestans would survive in 5% of tomato seed for 99, 25, and 16 days at 0, -3, and -5°C, respectively. We further applied a degree-day model to our empirical data to describe P. infestans survival as a function of cooling degree-day accumulations using archived soil temperatures at 5- and 10-cm depths at four Wisconsin locations over 27 years. The model indicated that survival of P. infestans in 5% of infested tomato seed would occur at 35 and 39% of the location-year combinations at 5- and 10-cm soil depths, respectively. Together, these data suggested that P. infestans has the potential to survive over the winter season by asexual means in infested tomato seed in Wisconsin and other Northern latitudes. Our cooling degree-day model for late blight in the tomato production system offers a tool for anticipating and mitigating disease based on integrated pest management concepts previously utilized for insects.

Efficacy of Organic and Conventional Fungicides and Impact of Application Timing on Control of Tomato Late Blight Caused by US-22, US-23, and US-24 Isolates of Phytophthora infestans.

Late blight, caused by Phytophthora infestans, is one of the most economically important diseases of potato and tomato worldwide. Repeated preventative application of fungicides is the primary means of control on susceptible solanaceous host crops. For organic production, fungicide choices are limited, and little efficacy data on noncopper options is available on which to base control recommendations. Twelve fungicides, including organic and conventional selections, were evaluated for both preventative and postinfection control of a single infection cycle of late blight caused by isolates representing three recently identified P. infestans clonal lineages (US-22, US-23, and US-24) using a detached tomato leaf assay. A subset of the most effective fungicides was also tested for preventative control of a single infection cycle of late blight caused by an isolate of US-23 on potted whole tomato plants under laboratory conditions. Fungicide applications made 2 days after inoculation failed to significantly control late blight on detached leaves in all treatments, with the exception of Bravo Ultrex (US-23 only) and Phostrol (US-22 only). Preventative fungicide applications of Bravo Ultrex, Ridomil Gold SL, Revus, Zonix, and low and high rates of EF400 significantly controlled late blight caused by US-22, -23, and -24 isolates. Additionally, preventative application of Phostrol significantly controlled late blight caused by the US-22 isolate; and Phostrol, low rate of Mycostat, and high rate of Champ significantly controlled late blight caused by the US-23 isolate. Late blight caused by the US-24 isolate was significantly reduced compared with US-22 and US-23 isolates for all fungicide treatments applied after inoculation, as well as for all preventative fungicide treatments, with the exception of Bravo, Ridomil, and Revus. In whole-potted-plant assays with the US-23 isolate, late blight was significantly controlled by preventative application of Bravo Ultrex, Ridomil Gold SL, and high rate of EF400; disease was not significantly controlled by Zonix, low rate of EF400, Phostrol, or low and high rates of Champ. Based on these results, it is anticipated that currently available fungicides with suitability to conventional and organic systems can effectively control late blight caused by new clonal lineages of P. infestans when applied preventatively and that late blight caused by the US-24 clonal lineage may require less fungicide use than US-22 or US-23 to mitigate disease.

Effect of Temperature on Growth and Sporulation of US-22, US-23, and US-24 Clonal Lineages of Phytophthora infestans and Implications for Late Blight Epidemiology.

Epidemics of late blight, caused by Phytophthora infestans (Mont.) de Bary, have been studied by plant pathologists and regarded with great concern by potato and tomato growers since the Irish potato famine in the 1840s. P. infestans populations have continued to evolve, with unique clonal lineages arising which differ in pathogen fitness and pathogenicity, potentially impacting epidemiology. In 2012 and 2013, the US-23 clonal lineage predominated late blight epidemics in most U.S. potato and tomato production regions, including Wisconsin. This lineage was unknown prior to 2009. For isolates of three recently identified clonal lineages of P. infestans (US-22, US-23, and US-24), sporulation rates were experimentally determined on potato and tomato foliage and the effect of temperature on lesion growth rate on tomato was investigated. The US-22 and US-23 isolates had greater lesion growth rates on tomato than US-24 isolates. Sporulation rates for all isolates were greater on potato than tomato, and the US-23 isolates had greater sporulation rates on both tomato and potato than the US-22 and US-24 isolates. Experimentally determined correlates of fitness were input to the LATEBLIGHT model and epidemics were simulated using archived Wisconsin weather data from four growing seasons (2009 to 2012) to investigate the effect of isolates of these new lineages on late blight epidemiology. The fast lesion growth rates of US-22 and US-23 isolates resulted in severe epidemics in all years tested, particularly in 2011. The greater sporulation rates of P. infestans on potato resulted in simulated epidemics that progressed faster than epidemics simulated for tomato; the high sporulation rates of US-23 isolates resulted in simulated epidemics more severe than simulated epidemics of isolates of the US-22 and US-24 isolates and EC-1 clonal lineages on potato and tomato. Additionally, US-23 isolates consistently caused severe simulated epidemics when lesion growth rate and sporulation were input into the model singly or together. Sporangial size of the US-23 isolates was significantly smaller than that of US-22 and US-24 isolates, which may result in more efficient release of sporangia from the tomato or potato canopy. Our experimentally determined correlates of fitness and the simulated epidemics resulting from their incorporation into the LATEBLIGHT model suggest that US-23 isolates of P. infestans may have the greatest fitness among currently prevalent lineages and may be the most likely lineage to persist in the P. infestans population. The US-23 clonal lineage has been documented as the most prevalent lineage in recent years, indicating its overall fitness. In our work, US-23 had the highest epidemic potential among current genotypes. Given that epidemic potential is a component of fitness, this may, in part, explain the current predominance of the US-23 lineage.

Novel Resistance in Heirloom Tomatoes and Effectiveness of Resistance in Hybrids to Phytophthora infestans US-22, US-23, and US-24 Clonal Lineages.

Late blight, caused by the oomycete Phytophthora infestans, causes serious losses in tomato production worldwide. Application of fungicides is the primary means of management but cultivar resistance, primarily through Ph resistance genes from Solanum pimpinellifolium, can provide a cost-effective and environmentally sound approach to an overall disease management program. Due to highly adaptable pathogen populations, cultivar resistance against late blight is often short lived and continual assessment of disease response to new pathogen types is necessary. We evaluated the disease response of 11 tomato cultivars to one isolate from each of three clonal lineages (US-22, US-23, and US-24) of P. infestans novel to the United States to determine the efficacy of currently deployed Ph genes in hybrid cultivars and the validity of claims of resistance in heirloom cultivars. Lesion length and pathogen growth were reduced on tomato genotypes 'Plum Regal' (Ph-3) and 'Legend' (Ph-2) compared with the susceptible control 'Brandywine Red' following inoculation with one isolate (US-23) but were not significantly different from the control with an isolate of US-22. 'Mountain Magic' (Ph-2 and Ph-3) and three heirloom cultivars ('Wapsipinicon Peach', 'Matt's Wild Cherry,' and 'Pruden's Purple') had reduced lesion length and pathogen growth to all three isolates. Although the genetics of resistance are not fully understood for many of these, the heirloom cultivars may be useful for future tomato late blight breeding efforts. All of the cultivars investigated in this work are currently available and use of cultivars exhibiting reduced disease development may limit losses to late blight and reduce reliance on fungicides. Resistant cultivars also limit the production of inoculum, reducing overall late blight risk and spread in tomato and potato crops.

Investigating the Host Range of the US-22, US-23, and US-24 Clonal Lineages of Phytophthora infestans on Solanaceous Cultivated Plants and Weeds.

Phytophthora infestans causes late blight, one of the most important diseases of potato and tomato worldwide. Recently in the United States, three newly identified clonal lineages, US-22, US-23, and US-24, have become widespread. While potato and tomato are the most commonly infected solanaceous hosts for P. infestans, new lineages may have a broader or different host range. Under controlled conditions, we determined the host range of isolates representing US-22, US-23, and US-24 genotypes of P. infestans on detached tissues of cultivated solanaceous plants and solanaceous weeds common to the upper midwestern production region. None of the isolates representing the clonal lineages produced late blight symptoms or signs on foliage of selected cultivars of eggplant, pepper, tomatillo, or ground cherry in a detached leaf assay. Symptoms and signs were evident on the potato and tomato cultivars tested, although with the US-24 isolate, infection on tomato was limited. None of the isolates sporulated on the common weed black nightshade, but some sporulation and necrosis was observed with all representatives of the lineages on bittersweet nightshade and petunia. Hairy nightshade supported abundant sporulation and symptoms, and sporangial production was not significantly different than that on tomato for each of the isolates representing the three lineages, indicating the potential for this weed to be a source of inoculum and contribute substantially to late blight epidemics. Interestingly, black nightshade had the highest incidence of sporulation on berries, but the lowest on leaves, suggesting the importance of testing multiple plant organs when determining susceptibility of a species. Our results update knowledge of the host range of the ever-changing P. infestans populations and will help to improve late blight management strategies by targeting these additional hosts.