MICROBIOME COMPARISON POST-INOCULATION WITH PHYTOPATHOGENIC XANTHOMONAS AND ANTIBIOTIC-PRODUCING ISOLATES

Xanthomonas oryzae pv oryzae (Xoo) and Xanthomonas oryzae pv oryzicola (Xoc) are notable phytopathogens that cause tremendous harm to the rice industry by causing bacterial leaf blight and leaf streak in rice, respectively. We aimed to investigate the impact of Xoo and Xoc on soil microbiomes by utilizing safe relatives inoculated into soil. We further investigated the effects of Xanthomonas-inhibiting, antibiotic-producing isolates inoculated into the soil microbiome in isolation and the presumed post-Xanthomonas inoculation. Microcosms were designed containing garden soil, which was inoculated with designated bacteria, and samples were taken for DNA extraction every week; the V4 region of the 16s rRNA was utilized for microbiome analysis. The Xanthomonas did not establish in the soil, and antibiotic-producing inoculations were not found to alter the microbiome alpha or beta diversity. The addition of the antibiotic-producing isolates was also found not to significantly to alter the microbiome. However, significant differences were found in the beta diversity when antibiotic-producing isolates were introduced post-Xanthomonas. The soil microbiome is known to impact the course of disease development in plants and act as a defense against the establishment of pathogens. Due to the high competition for resources within soil microbiomes, pathogen establishment can be deterred by previous soil occupants. When soil is found to resist invasion with pathogens, it can be considered disease suppressive

Evaluating the impact of tree provenance, tree phenotype and emergent disease on microbial and insect populations in tree ecosystems

Trees host complex microhabitats, supporting a wide diversity of organisms. This study focuses on two of these communities: the insect herbivores and the microbial endophytes. Studies in the field of community genetics have demonstrated that intraspecific genetic variation in a foundation species can have cascading effects on the composition and diversity of associated communities. Using a provenance trial, which excludes confounding environmental factors, the effects of tree phenotypic traits on the insect herbivore and microbial endophytic community were tested, in the first instance, using the Quercus study system. A leaf morphometric analysis allowed for accurate differentiation of the two native oak species, Quercus robur and Q. petraea. Interspecific variation in the composition of insect herbivore species and in the composition of bacterial and fungal endophyte species were recorded in the two oak species for the first time. The plant vigour hypothesis, which states that insect herbivores would preferentially feed on the most vigorous plant, was supported by the galling and mining insect feeding guilds in this study system but had varying effects on the endophytic species. Tree budburst phenology, another phenotypic trait, also had varying effects on the abundance of insects and endophytes. Quercus trees in the UK are expected to experience profound changes in climate. In an effort to maintain oak species, assisted migration schemes may be implemented, which involves the planting of seed stock from exotic provenances that match the predicted climate of the planting site in 50-100 years. This study considers the effect of this approach on the associated biodiversity. Insect and endophyte composition, richness and diversity were not strongly correlated with tree provenance, so it seems unlikely that climate matching strategies would strongly negatively impact these associated communities. As the UK climate warms, walnut trees (Juglans spp.) may become a more commercially viable source of hardwood timber. This study characterised the endophytic community of two introduced walnut trees in the UK: Juglans nigra and J. regia. A number of latent pathogenic fungi and bacteria were associated with asymptomatic tissues of both Quercus and Juglans, these species have the potential to cause disease if the tree is subjected to stress such as climate change and should therefore be monitored. Finally, the effect of a decline syndrome, Acute Oak Decline (AOD) which causes bleeding cankers among other symptoms on native oak species in the UK, on the endophytic community of oak was recorded. Bacterial endophyte communities did not differ between symptomatic and asymptomatic trees. However, differences in the fungal endophytic community associated with the inner bark of trees showing symptoms of AOD were significantly different from asymptomatic trees. This result suggests that (1) there could be a fungal component(s) to AOD that has not been reported or (2) asymptomatic trees harbour beneficial fungal endophytes that protect against AOD

Aplicación de Pseudomonas como agente biorreductor del cromo hexavalente de los efluentes de las curtiembres del distrito El Porvenir, 2022

El objetivo del presente estudio es analizar la aplicación de Pseudomonas para la biorremediación del cromo hexavalente presente en los efluentes de las curtiembres del distrito El Porvenir. Para esto, se hicieron dos búsquedas bibliográficas: la primera en repositorios nacionales, seleccionándose estudios que describieran las condiciones fisicoquímicas en las que se encuentran los efluentes; y la segunda en bases de datos como NCBI, ScienceDirect, SpringerLink y ResearchGate, seleccionándose artículos que detallaran Pseudomonas con la facultad de biorreducir el Cr(VI) a Cr(III). Se encontró que los efluentes no cumplen los límites máximos permisibles del MINAM, encontrándose altos niveles de Cr(VI) y de otros parámetros. Además, de las 8 especies encontradas en 15 artículos, se determinó que P. putida es la especie idónea para la biorreducción debido a su baja patogenicidad, susceptibilidad moderada a antibióticos, fácil identificación y a sus características de crecimiento (30°C, pH 5-10). Asimismo, se logró plantear un sistema de biorremediación de bajo costo económico en base al uso de biorreactores Airlift. Se concluye que la aplicación de P. putida como propuesta técnica-ambiental es viable y factible para su implementación y puede llegar a disminuir los niveles de Cr(VI) en los efluentes de las curtiembres del distrito El Porvenir

Application of Plant Growth Promoting Microorganism and Plant Growth Regulators in Agricultural Production and Research

Plant growth-promoting microorganisms (PGPM) are groups of rhizosphere microorganisms capable of colonizing the root environment. Some of the microbes that inhabit this zone are bacteria and fungi that are capable of efficiently colonizing roots and rhizosphere soil. These microorganisms can be used as biofertilizers for improving agricultural production even under stressful environmental conditions. In contrast to PGPM, plant growth regulators (PGR) are chemical compounds that significantly affect the growth and differentiation of plant cells and tissues. They function as chemical messengers for intercellular communication and play a vital role in plant signaling networks as they are involved in the plant developmental process and a wide range of biotic and abiotic stress responses. The application of PGPM and plant growth regulators/hormones or the synthesis of PGR and signal transduction, perception, and cross-talk creates a complex network that plays an essential role in the regulation of plant physiological processes. A better understanding of the mechanism of action of PGPM and PGR and their roles in plant growth and development, interaction and independence in their action, and hormonal crosstalk under stresses is essential for agricultural production and research. Therefore, this book has contributions in the form of research and review papers from eminent scientists worldwide and discusses the role of PGPM and PGR in agriculture production and research, their potentials as biocontrol agents, their effects on physicochemical properties of soil, innovation for sustainable agriculture, their role in seed transplanting, and their role in mitigating biotic and abiotic stresses