Dairy Effluent-Saturated Biochar's Short-Term Effects on Vigna unguiculata and Cynodon dactylon Performance and Soil Properties.

We compared the effects of wood-, manure-, and blend-derived biochar (BC) saturated/unsaturated with dairy effluents on Vigna unguiculata and Cynodon dactylon performance and soil characteristics in a greenhouse pot study. Plant samples were assayed for herbage and root dry weight and N and C percentages. Soil samples were assayed for nutrients, pH, and conductivity. Variance analysis, Tukey's tests, Pearson's correlations, and multiple regression analysis were performed. The performance of C. dactylon was not affected. V. unguiculata's herbage and root production responded negatively to manure BC and 2% of any BC, respectively, which is mainly explained by the conductivity and soil P increase, respectively. When V. unguiculata was grown, BC inclusion decreased NO3-N and increased the soil P content. When C. dactylon was grown, only P was altered (increased) when manure or the blend BC were applied. The soil total C increased as the BC loading rate increased. The application of high BC rates was detrimental for V. unguiculata, but showed a neutral effect for C. dactylon. To improve dairy waste recycling, saturated 1% blend BC and saturated 2% blend or manure BC could be applied to V. unguiculata and C. dactylon, respectively, with no short-term negative impacts. Only wood BC avoided soil P build-up. BC application increased the soil total C, showing potential for C sequestration.

Biochar and Dairy Manure Amendment Effects on Cynodon dactylon Performance and Soil Properties.

Studies have determined the separate effects of biochar (BC) and manure application on forage species and soil, but few examined the effects of BCs made from different feedstock applied along with dairy manure. We compared the effect of wood- and manure-derived feedstock BC as well as dairy manure amendment application on Cynodon dactylon performance and soil properties in sandy loam and clay loam soils in a greenhouse pot study. Plant samples were assayed for herbage and root dry weight as well as herbage and root N and C percent and yield. Soil samples were assayed for macronutrients, micronutrients, metals, pH and conductivity. Data analyses involved variance analysis and Tukey's tests using R in RStudio (the IDE). In general, C. dactylon yields or mineral content were not affected by either manure or BC. However, an increase in the total herbage dry weight (30%) and in herbage N% (55%) was observed for clay loam and sandy loam soil, respectively, due to manure amendment application. There were no alterations in clay loam NO3-N and P due to any treatment; however, in sandy loam, these nutrients were not altered only when wood BC was applied. In sandy loam soil, NO3-N and P increased when manure BC along with dairy manure and when manure BC alone were applied, respectively. Thus, wood BC application should be considered to avoid these nutrient buildups when dairy manure is used as a soil amendment. This research shows a neutral (BC) or positive (dairy manure amendment) impact on C. dactylon performance. BC incorporation increases soil total C, showing potential for C sequestration. Long-term field trials could corroborate plant performance and soil parameters.

Quantitative assessment of Naegleria fowleri and Escherichia coli concentrations within a Texas reservoir.

Previous presence/absence studies have indicated a correlation between the presence of the pathogenic amoeba Naegleria fowleri and the presence of bacteria, such as the fecal indicator Escherichia coli, in environmental surface waters. The objective of this study was to use quantitative real-time polymerase chain reaction (qPCR) methodologies to measure N. fowleri and E. coli concentrations within a Texas reservoir in late summer, and to determine if concentrations of N. fowleri and E. coli were statistically correlated. N. fowleri was detected in water samples from 67% of the reservoir sites tested, with concentrations ranging up to an estimated 26 CE (cell equivalents)/100 mL. E. coli was detected in water samples from 60% of the reservoir sites tested, with concentrations ranging up to 427 CE/100 mL. In this study, E. coli concentrations were not indicative of N. fowleri concentrations.

Probe-based real-time PCR method for multilocus melt typing of Xylella fastidiosa strains.

Epidemiological studies of Pierce's disease (PD) can be confounded by a lack of taxonomic detail on the bacterial causative agent, Xylella fastidiosa (Xf). PD in grape is caused by strains of Xylella fastidiosa subsp. fastidiosa, but is not caused by other subspecies of Xf that typically colonize plants other than grape. Detection assays using ELISA and qPCR are effective at detecting and quantifying Xf presence or absence, but offer no information on Xf subspecies or strain identity. Surveying insects or host plants for Xf by current ELISA or qPCR methods provides only presence/absence and quantity information for any and all Xf subspecies, potentially leading to false assessments of disease threat. This study uses a series of adjacent-hybridizing DNA melt analysis probes that are capable of efficiently discriminating Xf subspecies and strain relationships in rapid real-time PCR reactions.

Coincident light and clock regulation of pseudoresponse regulator protein 37 (PRR37) controls photoperiodic flowering in sorghum.

Optimal flowering time is critical to the success of modern agriculture. Sorghum is a short-day tropical species that exhibits substantial photoperiod sensitivity and delayed flowering in long days. Genotypes with reduced photoperiod sensitivity enabled sorghum's utilization as a grain crop in temperate zones worldwide. In the present study, Ma(1), the major repressor of sorghum flowering in long days, was identified as the pseudoresponse regulator protein 37 (PRR37) through positional cloning and analysis of SbPRR37 alleles that modulate flowering time in grain and energy sorghum. Several allelic variants of SbPRR37 were identified in early flowering grain sorghum germplasm that contain unique loss-of-function mutations. We show that in long days SbPRR37 activates expression of the floral inhibitor CONSTANS and represses expression of the floral activators Early Heading Date 1, FLOWERING LOCUS T, Zea mays CENTRORADIALIS 8, and floral induction. Expression of SbPRR37 is light dependent and regulated by the circadian clock, with peaks of RNA abundance in the morning and evening in long days. In short days, the evening-phase expression of SbPRR37 does not occur due to darkness, allowing sorghum to flower in this photoperiod. This study provides insight into an external coincidence mechanism of photoperiodic regulation of flowering time mediated by PRR37 in the short-day grass sorghum and identifies important alleles of SbPRR37 that are critical for the utilization of this tropical grass in temperate zone grain and bioenergy production.

High-throughput DNA isolation method for detection of Xylella fastidiosa in plant and insect samples.

We report an inexpensive, high-throughput method for isolating DNA from insect and plant samples for the purpose of detecting Xylella fastidiosa infection. Existing methods often copurify inhibitors of DNA polymerases, limiting their usefulness for PCR-based detection assays. When compared to commercially available kits, the method provides enhanced pathogen detection at a fraction of the cost.

Black soldier fly (Diptera: Stratiomyidae) larvae reduce Escherichia coli in dairy manure.

Escherichia coli labeled with a green fluorescent protein was inoculated into sterile dairy manure at 7.0 log cfu/g. Approximately 125 black soldier fly larvae were placed in manure inoculated and homogenized with E. coli. Manure inoculated with E. coli but without black soldier fly larvae served as the control. For the first experiment, larvae were introduced into 50, 75, 100, or 125 g sterilized dairy manure inoculated and homogenized with E. coli and stored 72 h at 27 degrees C. Black soldier fly larvae significantly reduced E. coli counts in all treatments. However, varying the amount of manure provided the black soldier fly larvae significantly affected their weight gain and their ability to reduce E. coli populations present. For the second experiment, larvae were introduced into 50 g manure inoculated with E. coli and stored for 72 h at 23, 27, 31, or 35 degrees C. Minimal bacterial growth was recorded in the control held at 35 degrees C and was excluded from the analysis. Black soldier fly larvae significantly reduced E. coli counts in manure held at remaining temperatures. Accordingly, temperature significantly influenced the ability of black soldier fly larvae to develop and reduce E. coli counts with greatest suppression occurring at 27 degrees C.

Transcriptional profiling of sorghum induced by methyl jasmonate, salicylic acid, and aminocyclopropane carboxylic acid reveals cooperative regulation and novel gene responses.

We have conducted a large-scale study of gene expression in the C4 monocot sorghum (Sorghum bicolor) L. Moench cv BTx623 in response to the signaling compounds salicylic acid (SA), methyl jasmonate (MeJA), and the ethylene precursor aminocyclopropane carboxylic acid. Expression profiles were generated from seedling root and shoot tissue at 3 and 27 h, using a microarray containing 12,982 nonredundant elements. Data from 102 slides and quantitative reverse transcription-PCR data on mRNA abundance from 171 genes were collected and analyzed and are here made publicly available. Numerous gene clusters were identified in which expression was correlated with particular signaling compound and tissue combinations. Many genes previously implicated in defense responded to the treatments, including numerous pathogenesis-related genes and most members of the phenylpropanoid pathway, and several other genes that may represent novel activities or pathways. Genes of the octadecanoic acid pathway of jasmonic acid (JA) synthesis were induced by SA as well as by MeJA. The resulting hypothesis that increased SA could lead to increased endogenous JA production was confirmed by measurement of JA content. Comparison of responses to SA, MeJA, and combined SA+MeJA revealed patterns of one-way and mutual antagonisms, as well as synergistic effects on regulation of some genes. These experiments thus help further define the transcriptional results of cross talk between the SA and JA pathways and suggest that a subset of genes coregulated by SA and JA may comprise a uniquely evolved sector of plant signaling responsive cascades.