Role of microbes in alleviating abiotic stress in plants

The leading threat to agricultural productivity is the recurrent variations in environmental conditions. A battery of abiotic stresses namely flooding, salinity, temperature, drought, heavy metal toxicities, nutrient deficiencies and oxidative stress causes irreversible damage resulting in loss of plant’s vigor and yield. The relationship between plants and microorganisms is a highly dynamic system. The plant microbiome consists of plant growth-promoting bacteria and fungi. In the last decade, many microbes that give hosts the ability to withstand abiotic stress have been characterized in detail. Their beneficial association with plants enables the plant to endure different stresses imposed on them thereby enhancing the plant's sustainability and productivity. For sustainable agriculture, it is very significant to comprehend microbiome-assisted mechanisms for mitigating abiotic stress. This review will shed light on the current knowledge about the roles of various microorganisms in mitigating against abiotic stresses. The understanding of these mechanisms will help to increase the yield of plants and meet the food demands of the expanding population

Effects of foliar application of gibberellic acid, boric acid and sucrose on noni (M. citrifolia L.) fruit growth and quality

Noni juice processing industry depends explicitly on the quality of noni fruits and its juice together with increased production of fruits. This study evaluated the effects of chemical treatments on noni’s fruiting capacity, fruit yield and the fruit antioxidant properties. Noni plants in fruiting stage were foliar fed with boric acid (BA) at a concentration of 100 ppm or 200 ppm, gibberellic acid (GA3) at 20 ppm or 40 ppm and sucrose solution at 5 or 20% and water (control). Changes in fruiting numbers, fruit growth rates, fruit yield, total soluble solids (TSS), fruit antioxidant capacity and total phenolic content of fruits were determined after the foliar treatments. Fruiting, fruit growth rate and yield were significantly increased in BA, GA3 and sucrose treated plants when compared to the control treatment. Fruit TSS, antioxidant capacity and total phenol content were not affected. Sucrose 20% and BA treatments (100 ppm and 200 ppm) produced the highest fruit yields

Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation

Photosynthetic rate and biochemical composition of green algae Ulva flexuosa (Wulfen) J. Agardh as potential indicators of environmental stress in the intertidal zones

Photosynthetic rate and biochemical composition total chlorophyll (TC), total soluble protein (TSP) and total soluble carbohydrates (TSC) were determined for Ulva flexuosa, a green marine algae collected from Nasese, Lami and Laucala Beach areas in Suva, Fiji Islands. Ulva flexuosa from Laucala Beach area had the highest photosynthetic rates, TC and TSP content, while algae from Nasese area had the highest amount of TSC. Algae from Lami area had the lowest amount of photosynthesis rate, TC, TSP and TSC. High photosynthetic rate and biochemical content were mainly due to the presence of high levels of nitrogen in the area. Algae thrived in Laucala Beach and Nasese area where nitrogen content was high. Low photosynthetic rate and biochemical composition were recorded in algae from the Lami area, which was apparently the most polluted area. It appeared that conditions in Lami area were intolerable to U. flexuosa. Algae collected from the three sites differed in the measured parameters with respect to the differences in the pH, temperature and nitrogen levels indicating that physiological responses of algae could be used as indicators to monitor the environmental quality of the intertidal zones

Egg deposition by Spiralling whiteflies (Aleurodicus dispersus) strongly influences the stomatal conductance of Manihot esculenta

Whiteflies are considered a most damaging pest in all cassava-producing regions, as they are responsible for transmitting plant viruses and directly damaging plants via heavy infestation. Aleurodicus dispersus Russell (Hemiptera: Aleyrodidae) commonly known as Spiralling whitefly, a native to the Caribbean region and Central America. Over 300 plant species from approximately 77 families have been recorded as hosts of Aleurodicus dispersus Russell, worldwide, and the species is known to have widely spread over North America, South America, Asia, Africa, Australia and in several Pacific Island Countries (PIC). In the South Pacific it is known from Majuro (1986) (Marshall Is), Cook Islands (1984), Fiji (1985), Nauru (1987), Papua New Guinea (1987), Kiribati (June 1988), Tokelau (late 1988) and Tonga (November 1988

Evaluation of decision support system for agrotechnology transfer SUBSTOR potato model (v4.5) under tropical conditions

Decision Support System for Agrotechnology Transfer (DSSAT) SUBSTOR Potato model (v4.5) was calibrated using Desiree variety. DSSAT SUBSTOR Potato model simulates on a daily basis the development and growth of potatoes using inputs such as climate, soil and crop management. The experiment was conducted in Banisogosogo, Fiji Islands, during the potato growing season of 2012. Fresh and dry weights of belowground plant component (tubers) were taken during progressive harvests. The DSSAT SUBSTOR Potato model was calibrated using experimental field data, soil and weather data of the growing season. The manual calibration steps involved recalculation of soil water content and the adjustments of genetic co-efficient to suit the temperature and daylength regime similar to the experimental conditions. Tuber dry weight was used as the main parameter to evaluate the model. The R2 values of the observed and simulated model outputs before calibration for replicate plot 1, replicate plot 2 and replicate plot 3 were 0.52, 0.49 and 0.61 respectively. After calibration, the R2 values for tuber dry yield for replicate plot 1, replicate plot 2 and replicate plot 3 were 0.88, 0.66 and 0.92 respectively indicating a strong positive relationship between the simulated and the observed yield

Interaction of immune checkpoint PD-1 and chemokine receptor 4 (CXCR4) promotes a malignant phenotype in pancreatic cancer cells.

Despite recent therapeutic advances, pancreatic ductal adenocarcinoma (PDAC) remains a devastating disease with limited therapeutic options. Immune checkpoint inhibitors (ICIs) have demonstrated promising results in many cancers, but thus far have yielded little clinical benefit in PDAC. Based on recent combined targeting of programmed cell death protein-1 (PD-1) and C-X-C chemokine receptor 4 (CXCR4) in patient-derived xenografts (PDXs) and a pilot clinical trial, we sought to elucidate potential interactions between PD-1 and CXCR4. We observed concomitant expression and direct interaction of PD-1 and CXCR4 in PDAC cells. This interaction was disrupted upon CXCR4 antagonism with AMD3100 and led to increased cell surface expression of PD-1. Importantly, CXCR4-mediated PDAC cell migration was also blocked by PD-1 inhibition. Our work provides a possible mechanism by which prior studies have demonstrated that combined CXCR4 and PD-1 inhibition leads to decreased tumor growth. This is the first report investigating PD-1 and CXCR4 interactions in PDAC cells and our results can serve as the basis for further investigation of combined therapeutic targeting of CXCR4 and PD-1

Rhizobacteriome: Plant Growth - Promoting Traits and Its Functional Mechanism in Plant Growth, Development, and Defenses

The rhizomicrobiome comprises a wide variety of microorganisms that are essential for microbial colonization and root development in a wide variety of plants. A plant’s growth, development, and defense mechanisms would be impossible without the rhizomicrobiome’s microbes. In order to develop and operate properly, roots are essential to plants because they give structural support and aid in the intake of water and nutrients. This rhizobacteriome, a diverse bacterial population with particular roles that affect plant health, may be found in plant root exudates due to the complex variety of elements present. There are several metabolites produced by the plant-growth-promoting rhizobacteria (PGPR) in the rhizosphere near the plant roots that stimulate the plant’s development. Many PGPRs have the ability to solubilize phosphate, fix N2, produce biosynthesis of hydrolytic enzymes (hydrolase), produce phytohormones (phytoestrogens), produce siderophores (antibiotics), and more. Climate change, population growth, and the use of herbicides and insecticides have all had a significant influence on crop productivity in recent decades. Studies show that PGPR can boost plant growth and yield in a variety of species. As a result, PGPR dynamic microorganisms can be used as biofertilizers or biopesticides in agricultural techniques, which is critical to alleviating the urgent call for sustainable production. Rhizobacteriome, in particular PGPR found in the rhizosphere, and their many strategies for enhancing plant production are summarized in this chapter

Endogenous Pancreatic Cancer Cell PD-1 Activates MET and Induces Epithelial-Mesenchymal Transition to Promote Cancer Progression

We recently demonstrated that immune checkpoint PD-1 was endogenously expressed in pancreatic ductal adenocarcinoma (PDAC) cells. Our data indicated that PD-1 proteins are not exclusive to immune cells and have unrecognized signal transduction cascades intrinsic to cancer cells. Building on this paradigm shift, we sought to further characterize PD-1 expression in PDAC. We utilized a phospho-explorer array to identify pathways upregulated by PD-1 signaling. We discovered PD-1-mediated activation of the proto-oncogene MET in PDAC cells, which was dependent on hepatocyte growth factor (MET ligand) and not secondary to direct protein interaction. We then discovered that the PD-1/MET axis in PDAC cells regulated growth, migration, and invasion. Importantly, the PD-1/MET axis induced epithelial-to-mesenchymal transition (EMT), a well-established early oncogenic process in PDAC. We observed that combined targeting of PDAC cell PD-1 and MET resulted in substantial direct tumor cell cytotoxicity and growth inhibition in PDAC cell lines, patient-derived organoids, and patient-derived xenografts independent of cytotoxic immune responses. This is the first report of PDAC-endogenous PD-1 expression regulating MET signaling, which builds upon our growing body of work showing the oncogenic phenotype of PD-1 expression in PDAC cells is distinct from its immunogenic role. These results highlight a paradigm shift that the tumor-specific PD-1 axis is a novel target to effectively kill PDAC cells by antagonizing previously unrecognized PD-1-dependent oncogenic pathways