Biology subjects

Ghani, A.

Publications and source records attributed to Ghani, A..

7 recordsLinked to original sources

bioRxiv2025

United we stand: Plants that physically touch each other are more resilient to stress

Plants use sophisticated signaling networks to communicate with each other. While this process is thought to support the overall health and resilience of plant communities, it could also reflect eavesdropping between plants used for competition. Here we reveal that plants that physically touch each other aboveground are more resilient to excess light stress, and that this phenomenon is dependent on the ability of plants to exchange aboveground electric and H2O2 signals with each other. Using a mutant that is unable to transfer Ca2+/reactive oxygen species (ROS) signals but can transfer electric signals (hpca1), as a mediator/connector between different plants, we further separate electric from Ca2+/ROS plant-to-plant signals and transcriptional landscapes, and show that the transfer of Ca2+/ROS signals, as well as the function of several Ca2+/ROS-dependent transcripts, is required for excess light stress acclimation. Our study reveals that plants that live together and physically touch each other establish an aboveground community-wide signaling network that enhances their collective resilience to stress. TeaserPlants that physically touch and exchange aboveground signals with each other are more resilient to excess light stress.

plant biology↗

bioRxiv2025

bHLH35 mediates specificity in plant responses to multiple stress conditions

How biological systems respond to stress is a fundamental question in biology, primarily addressed using the reductionist approach of applying one stress condition at a time. In nature, however, organisms experience a multitude of stresses, simultaneously or sequentially, questioning the validity of the reductionist approach for predicting plant responses to stress under natural conditions. Here, we reveal that in the flowering plant Arabidopsis thaliana, the transcriptional regulator bHLH35 is required for plant survival under a specific set of stress conditions that includes a combination of salinity, excess light, and heat, occurring simultaneously (but not for each of these stresses applied individually or in any other combination). Under these conditions, bHLH35 interacts with NAC069 and binds the promoter of LBD31, also specifically required for survival under the 3-stress combination. Our findings uncover a high degree of specificity in the response of organisms to stress, a specificity that would not have been revealed using the reductionist approach, and one that should be taken into consideration when developing agronomically important crops with heightened resilience to climate change.

plant biology↗

bioRxiv2025

Transcriptomic and physiological responses of soybean plants subjected to a combination of water deficit and heat stress under field conditions

Water deficit, heat stress, and a combination of water deficit and heat stress are highly disruptive to crop yield worldwide. Unfortunately, the frequency and intensity of these conditions is gradually increasing due to climate change. Previous studies of water deficit and heat stress combination were primarily conducted under controlled growth conditions, revealing that the combination of water deficit and heat stress resulted in the activation of unique stress responses and acclimation pathways. However, whether similar responses to stress combination occur in the field remained largely unknown. Here we report on a two-year field study in which the transcriptomic and physiological responses of vegetative and reproductive tissues of soybean (Glycine max) to water deficit, heat treatment and their combination were studied. Our findings reveal that the transcriptomic responses of soybeans grown in the field are different from those grown under controlled growth chamber conditions. These differences were especially noticeable in plants subjected to the heat or water deficit treatments, and less in plants subjected to the stress combination. In addition, we report that differential transpiration between leaves and pods, that was originally discovered in plants grown under controlled growth conditions, occurs in field grown soybeans in response to heat stress, as well as heat stress combined with water deficit. We hope that the transcriptomic datasets generated by our study will contribute to future studies of crop responses to different stresses in the field, as well as highlight the need for more omics studies of plants grown under field conditions.

plant biology↗

bioRxiv2025

Integrative analysis of plant responses to a combination of water deficit, heat stress and eCO2 reveals a role for OST1 and SLAH3 in regulating stomatal responses

The frequency, intensity and duration of global change factors and/or environmental stressors, such as droughts, heat waves, floods, and pollution, are increasing due to anthropogenic activities, subjecting plants to compound conditions of Global Change Factor combination (GCFc), or stress combination. These can have contrasting or additive effects on plant physiological performance and impact different ecosystems and agro-ecosystems worldwide. Using an integrative physiological, genetic, hormonal, and transcriptomic analysis, we studied the response of Arabidopsis thaliana (L.) Heynh to a combination of water deficit (WD), heat stress (HS) and/or elevated levels of CO2 (eCO2). Our findings reveal high specificity in plant responses to GCFc. We further reveal that stomatal aperture regulation under conditions of GCFc is controlled by a blend of unique and shared regulators, that together determine the specific aperture size under each different set of GCFc conditions. Under a combination of WD, HS, and eCO2 (WD+HS+eCO2), for example, stomatal closure required the function of nitric oxide, OPEN STOMATA 1 and the S-type anion channel SLAH3, but not the S-type anion channel SLAC1, or many other regulators typically found to control stomatal aperture under less complex conditions, including HS+WD. Our findings highlight the complexity of plant physiological and molecular responses to conditions of stress combination and open the way for future studies of plant responses to stress combination, crucial to our understanding of how GCFc impacts different ecosystems and agro-ecosystems worldwide. In addition, our study provides an initial definition for a stomatal hierarchical stress code that could apply to future studies.

plant biology↗

bioRxiv2024

The potential of gene drive releases in malaria vector species to reduce the malaria burden in different African environments

Gene drive technologies are a promising means of malaria control with the potential to cause widespread and sustained reductions in transmission. In real environments, however, gene drive impacts will depend on local ecological and epidemiological factors. We develop a data-driven model to investigate the impacts of a gene drive that causes vector population suppression. We apply the model to sixteen [~]12,000km2 areas of west Africa that span variation in vector ecology and malaria prevalence. We simulate gene drive releases targeting different vector species combinations, and estimate reductions in vector abundance, malaria prevalence and clinical cases in children. Average reductions in vector abundance ranged from 77.3%-99.1% across areas when the gene drive releases targeted all major vector species (Anopheles gambiae, An. coluzzii, An. arabiensis, and An. funestus). Impacts on malaria depended strongly on which vector species were targeted. Consistently strong impacts required releases targeting all vector species, which reduced prevalence by over 90% in all areas. When the major vector species An. gambiae and An. coluzzii were targeted, average reductions in prevalence ranged from no reduction to 72% across areas, and reductions in cumulative clinical cases ranged from zero to 57%. When other new interventions including RTS,S vaccination and pyrethroid-PBO bednets were in place, at least 60% more clinical cases were averted when gene drives were added, demonstrating the benefits of integrated interventions. Our results give new insights into the factors determining the impacts of gene drives on malaria across different African settings.

genetics↗

bioRxiv2019

Variation in the Prevalence of Submicroscopic Malaria Infections: Historical Transmission Intensity and Age as Key Determinants

Molecular detection of Plasmodium falciparum infection has revealed large numbers of individuals with low-density (yet transmissible) infections undetectable by microscopy. Here we present an updated systematic review of cross-sectional malaria surveys to explore the prevalence and drivers of these submicroscopic infections and define where they are likely to be relevant to malaria control efforts. Our results show that submicroscopic infections predominate in low transmission settings, but also reveal marked geographical variation in their prevalence, being highest in South American surveys and lowest in West African studies. Whilst current transmission levels partly explain these results, we find that historical transmission intensity also represents a crucial determinant of the size of the submicroscopic reservoir. Submicroscopic infection was more likely in adults than children, although we did not observe a statistically significant influence of seasonality. Our results suggest that the contribution of submicroscopic infections to transmission likely varies substantially across settings, potentially warranting different approaches to their targeting in the approach to elimination.

epidemiology↗

bioRxiv2018

Estimating parasite load dynamics to reveal novel resistance mechanisms to human malaria

Improved methods are needed to identify host mechanisms which directly protect against human infectious diseases in order to develop better vaccines and therapeutics1,2. Pathogen load determines the outcome of many infections3, and is a consequence of pathogen multiplication rate, duration of the infection, and inhibition or killing of pathogen by the host (resistance). If these determinants of pathogen load could be quantified then their mechanistic correlates might be determined. In humans the timing of infection is rarely known and treatment cannot usually be withheld to monitor serial changes in pathogen load and host response. Here we present an approach to overcome this and identify potential mechanisms of resistance which control parasite load in Plasmodium falciparum malaria. Using a mathematical model of longitudinal infection dynamics for orientation, we made individualized estimates of parasite multiplication and growth inhibition in Gambian children at presentation with acute malaria and used whole blood RNA-sequencing to identify their correlates. We identified novel roles for secreted proteases cathepsin G and matrix metallopeptidase 9 (MMP9) as direct effector molecules which inhibit P. falciparum growth. Cathepsin G acts on the erythrocyte membrane, cleaving surface receptors required for parasite invasion, whilst MMP9 acts on the parasite. In contrast, the type 1 interferon response and expression of CXCL10 (IFN-{gamma}-inducible protein of 10 kDa, IP-10) were detrimental to control of parasite growth. Natural variation in iron status and plasma levels of complement factor H were determinants of parasite multiplication rate. Our findings demonstrate the importance of accounting for the dynamic interaction between host and pathogen when seeking to identify correlates of protection, and reveal novel mechanisms controlling parasite growth in humans. This approach could be extended to identify additional mechanistic correlates of natural- and vaccine-induced immunity to malaria and other infections.

systems biology↗