Arabidopsis PHOSPHATE TRANSPORTER1 genes PHT1;8 and PHT1;9 are involved in root-to-shoot translocation of orthophosphate

In plants, the uptake from soil and intercellular transport of inorganic phosphate (Pi) is mediated by the PHT1 family of membrane-spanning proton : Pi symporters. The Arabidopsis thaliana AtPHT1 gene family comprises nine putative high-affinity Pi transporters. While AtPHT1;1 to AtPHT1;4 are involved in Pi acquisition from the rhizosphere, the role of the remaining transporters is less clear

Nitrogen fertilizer rate but not form affects the severity of Fusarium wilt in banana

Nitrogen (N) fertilizers are routinely applied to bananas (Musa spp.) to increase production but may exacerbate plant diseases like Fusarium wilt of banana (FWB), which is the most economically important disease. Here, we characterized the effects of N rate and form on banana plant growth, root proteome, bacterial and fungal diversity in the rhizosphere, the concentration of Fusarium oxysporum f.sp. cubense (Foc) in the soil, and the FWB severity. Banana plants (Musa subgroup ABB) were grown under greenhouse conditions in soil with ammonium or nitrate supplemented at five N rates, and with or without inoculation with Foc. The growth of non-inoculated plants was positively correlated with the N rate. In bananas inoculated with Foc, disease severity increased with the N rate, resulting in the Foc-inoculated plant growth being greatest at intermediate N rates. The abundance of Foc in the soil was weakly related to the treatment conditions and was a poor predictor of disease severity. Fungal diversity was consistently affected by Foc inoculation, while bacterial diversity was associated with changes in soil pH resulting from N addition, in particular ammonium. N rate altered the expression of host metabolic pathways associated with carbon fixation, energy usage, amino acid metabolism, and importantly stress response signaling, irrespective of inoculation or N form. Furthermore, in diseased plants, Pathogenesis-related protein 1, a key endpoint for biotic stress response and the salicylic acid defense response to biotrophic pathogens, was negatively correlated with the rate of ammonium fertilizer but not nitrate. As expected, inoculation with Foc altered the expression of a wide range of processes in the banana plant including those of defense and growth. In summary, our results indicate that the severity of FWB was negatively associated with host defenses, which was influenced by N application (particularly ammonium), and shifts in microbial communities associated with ammonium-induced acidification. Copyright © 2022 Orr, Dennis, Wong, Browne, Cooper, Birt, Lapis-Gaza, Pattison and Nelson

Nitrogen fertilizer rate but not form affects the severity of Fusarium wilt in banana

Nitrogen (N) fertilizers are routinely applied to bananas (Musa spp.) to increase production but may exacerbate plant diseases like Fusarium wilt of banana (FWB), which is the most economically important disease. Here, we characterized the effects of N rate and form on banana plant growth, root proteome, bacterial and fungal diversity in the rhizosphere, the concentration of Fusarium oxysporum f.sp. cubense (Foc) in the soil, and the FWB severity. Banana plants (Musa subgroup ABB) were grown under greenhouse conditions in soil with ammonium or nitrate supplemented at five N rates, and with or without inoculation with Foc. The growth of non-inoculated plants was positively correlated with the N rate. In bananas inoculated with Foc, disease severity increased with the N rate, resulting in the Foc-inoculated plant growth being greatest at intermediate N rates. The abundance of Foc in the soil was weakly related to the treatment conditions and was a poor predictor of disease severity. Fungal diversity was consistently affected by Foc inoculation, while bacterial diversity was associated with changes in soil pH resulting from N addition, in particular ammonium. N rate altered the expression of host metabolic pathways associated with carbon fixation, energy usage, amino acid metabolism, and importantly stress response signaling, irrespective of inoculation or N form. Furthermore, in diseased plants, Pathogenesis-related protein 1, a key endpoint for biotic stress response and the salicylic acid defense response to biotrophic pathogens, was negatively correlated with the rate of ammonium fertilizer but not nitrate. As expected, inoculation with Foc altered the expression of a wide range of processes in the banana plant including those of defense and growth. In summary, our results indicate that the severity of FWB was negatively associated with host defenses, which was influenced by N application (particularly ammonium), and shifts in microbial communities associated with ammonium-induced acidification

Promoting physical activity among older women living in socio-economically disadvantaged areas: Development of a community-based intervention

<p><b>The effect of P treatment and C:N ratio applied on (a) plant growth, (b) plant P content, (c) soil Colwell P, and (d) soil mineral N.</b> Dashed lines represent no P, grey lines represent rock P and solid lines represent solution P amendment—triangles represent the application of a C:N ratio of 12.5:1 and circles represent the application of a C:N ratio of 50:1. Standard error of means is shown (n = 3).</p

Distance-based multivariate multiple regression showing relationships between environmental variables and bacterial community structure.

<p>Distance-based multivariate multiple regression showing relationships between environmental variables and bacterial community structure.</p

Distance-based redundancy analysis (dbRDA) of variation in bacterial community profiles as explained by environmental variables.

<p>Vectors represent correlations of variables with community structure along the first two dbRDA axes. No P amendment is represented by black symbols, rock P amendment is represented by open symbols and solution P amendment is represented by grey symbols. Application of a C:N ratio of 12.5:1 is represented by triangles and application of a C:N ratio of 50:1 is represented by circles. The values in parentheses indicate the percentages of the fitted and total variations explained by each axis.</p

Apportionment of P in soil, accumulated plant biomass and microbial biomass pools quantified at the end of the 20-week pot trial and expressed as percentages and P content (mg P kg^–1 soil) in parentheses.

<p>Apportionment of P in soil, accumulated plant biomass and microbial biomass pools quantified at the end of the 20-week pot trial and expressed as percentages and P content (mg P kg^–1 soil) in parentheses.</p

Change in soil P forms over the course of the experiment.

<p>(1) white bars represent P fractions prior to commencement of the experiment but after P treatments had been applied (2) black bars represent P fractions after the 20-week incubation where a C:N ratio of 12.5:1 was applied continuously and (3) grey bars represent P fractions after the 20-week incubation where a C:N ratio of 50:1 was applied continuously. Soil P forms were further grouped based on perceived plant P availability (readily-available P, moderately-available P and sparingly-available P). Standard error of means are shown (n = 3). Significant differences (<i>P</i> < 0.05) are indicated by different lowercase letters while those not statistically significant (<i>P</i> > 0.05) are indicated by the same lowercase letters. Different superscript letters indicate significant difference (P<0.05) in P fractions after 20 weeks following the two C:N treatments compared to initial levels as assessed by ANOVA followed by Fisher’s least significant difference (LSD).</p