RESEARCH

My research

My research aims to identify plant genes that generate beneficial microbial associations in roots, such as mycorrhizal fungi and plant growth-promoting bacteria. This will help harness plant nutrition-boosting natural biotic associations. This will reduce the need for inorganic fertilizers in biofuel feedstock sorghum and other important agricultural crops.

ROLE OF THE PLANT MICROBIOME, AND ITS INTERACTION WITH PLANTS UNDER STRESS.

My goal is to improve our understanding of plant adaptation to rapid environmental changes by integrating plant-microbiota relationships into community ecology concept. The microbiomes of plants remained relatively diminutive and concealed within their substrates for over 450 million years and have regrettably lagged behind plants and animals in terms of progress of their ecological comprehension. Considering this extensive historical association between microorganisms and their respective host plants, it is plausible to assert that harnessing the plant microbiome holds significant promise in facilitating the host's ability to withstand a diverse array of environmental constraints. Microbial ecologists have been actively engaged in an ongoing debate about the reality of the Anthropocene for quite some time. For instance, “How do global environmental changes affect plant-associated microbial community assembly, coexistence and succession?” and "How does this alteration impact the realm of plant biology and development?". Based on a comprehensive analysis of various primary research articles, it is anticipated that global change variables will exert an influence on the assembly and functioning of plant microbiome communities. This influence can be attributed to a multitude of mechanisms, either directly or indirectly, which are mediated by the host organism and/or environmental factors. However, accurately determining the underlying mechanisms involved is a substantial issue, especially when seeking to understand the complex dynamics or assembly of taxa with obvious parallels in their resource needs. Microbial communities have the ability to transmit thermotolerance to plants and enhance their resilience to warming. This is supported by extensive research, which demonstrates that the host can rapidly adapt to stress through its microbiota. Despite the advancements in ecological theory, this particular subfield has undergone independent development. My previous study revealed that there was no discernible impact of nitrogen fertilisation and decreased watering practices on the temporal dynamics of arbuscular mycorrhizal (AM) community fungi, which are essential for their survival and adaptation in stress environments (Babalola et al., 2022). Given the fundamental importance of microbial process in plant adaptation, ongoing and future research efforts will contribute to our understanding of the mechanisms that govern the dynamics, composition, assembly, and co-occurrence patterns of microbial communities with a focus on three primary aims. Firstly, we will conduct a comprehensive examination of the interactions between plants and microbes in various habitats. Specifically, we will analyze the dynamics, composition, assembly, and co-occurrence patterns of these plant-microbe interactions in habitats that are characterized by significant factors such as increased levels of carbon dioxide (CO2), drought conditions, soil warming, salinity, and the application of fertilizers. Secondly, we will integrate the mechanisms of microbial and plant adaptation at different levels, and lastly, culminating in a comprehensive framework that can forecast plant-microbe interactions under diverse circumstances.

Themes for research

Exploring how common agricultural practices affect plant microbiome dynamics.

Understanding plant-arbuscular mycorrhizal fungus dynamics and interactions is essential for predicting biodiversity changes and optimizing plant microbiomes. As a sustainable fertilizer option, AMF's symbiotic interaction with plants is attracting attention. The current view is that limited nutrient availability may explain natural ecosystems' higher AMF abundance. Chemical fertilizers also alter AMF composition in undisturbed grassland. The patterns have prompted most microbial ecologists to believe that AMF helps plant to transfer immobile nutrients through their hyphae in return for carbon. So, AMF are useful in sequestering carbon in soil. Direct observations of this phenomenon in an intense agricultural ecology are less well-known. The findings of my research indicate that the life-history strategy of AMF is dependent on the preferential allocation of carbon by plants and a reciprocal control mechanism. The aforementioned objective was accomplished by conducting experimental manipulation of chemical fertilisation and implementing water reduction techniques in a Chinese wheat field.

First, I designed and conducted a controlled experiment in a semi-arid agricultural region to learn how decreasing irrigation affects AMF hyphae. Reduced watering reduced AM fungal hyphae, according to my investigation. My observation was linked to a decrease in photosynthetic activity and nonstructural carbohydrates, which drive field AMF growth (Babalola et al., 2022). I conducted a field experiment to determine how agricultural practices affect AMF species' temporal dynamics in the northern China plain. The study found that AM fungal community composition's temporal dynamics were resilient to nitrogen fertilisation and reduced watering regimes throughout wheat's lifespan. In particular, host plants can preferentially allocate more photosynthate to beneficial partners. This selective reward distribution can stabilize AM fungi community temporal dynamics (Babalola et al., 2022). An analysis of bacterial, pathogenic, and saprotrophic fungi showed that nitrogen fertilisation affected the temporal dynamics of these important microbes (Babalola et al., in review). My findings revealed a previously undiscovered link between conventional agricultural practices and microbial species' temporal dynamics and increased our understanding of agricultural practices' ecological consequences on soil ecosystems, specifically AM fungi's ecological service.

Root microbiota community assembly and stability

My postdoctoral researcher, my work examines the relative relevance of resource environment and other factors on sorghum root microbiome assembly and co-occurrence. Ecologists have directed their attention towards comprehending community assembly and species coexistence through the utilization of various ecological theories. However, certain aspects of this theory, particularly the niche theory, are insufficient in explaining the process of community assembly in ecosystems characterized by low species diversity, such as the community assembly observed in intensive agroecosystems. Although the host filtration mechanism has a significant impact, there may be other processes that affect community assembly structure without filtering the microbiome. Further research in this understudied area may reveal more surprising correlations. I'm using high-throughput molecular methods to compare deterministic and stochastic assembly processes in multiple resource environments and initial microbial species pools from Georgia's piedmont uplands and Arizona's Sonoran Desert. This data will determine if specific factors dominate root AMF community assembly. I expect core assemblages to be more impacted by host genotype and resource environment than the initial microbiome species pool. This investigation will quantify the relative importance of other unknown community assembly and co-occurrence mechanisms and by addressing these questions, we can effectively manage AM fungi by acquiring essential knowledge that can inform sustainable practices.

Studying how nitrogen fertilisation affects microbial biomass and community interactions

The "law of the minimum" in plant science asserts that the most restrictive nutrient controls plant growth and productivity.  Johnson's 2010 functional equilibrium model explains how plants with less nutritional constraints allocate less carbon to AMF. This carbon allocation determines AMF-host plant mutualism. With the CAS-TWAS fellowship award fellowship during my PhD in China, I sampled and analyzed root and soil samples from an intensive wheat field. The main goal was to assess how agricultural management practices affect microbial biomass and composition. The examination used microscopy, spectrophotometry, and Illumina MiSeq sequencing of 16S and 18S rDNA. My findings show that soil AMF communities responded strongly to nitrogen (N) fertilisation than those in roots (Babalola et al., 2022). Conversely, N fertilisation considerably influenced saprotrophic and pathogenic fungi and bacteria in soil and roots (Babalola et al., under review).This suggests that ecological and evolutionary factors shaping AM fungal community in roots are different from those shaping other microbial communities in the same root. My research shows that N fertilisation increases dominant microbial families and decreases rare families. This suggests that species interaction may vary depending on context, including reciprocal regulation between host plants and microbes, ecological stoichiometry (N: P ratio), species dependence, plant carbon allocation, and soil environment changes (Babalola et al.,2022). I am developing unique analytical methods to integrate the above next-generation microbial datasets to understand how well dominant microbes respond to common stresses like drought and excessive chemical fertilisation.

Future paths

The field of microbial ecology aims to elucidate phenomena that are imperceptible and currently inexplicable, along with establishing overarching principles or concepts that are applicable to all microorganisms in diverse habitats. These postulates are subsequently subjected to experimental scrutiny. Two aspects of microbial ecology that drives my future research directions is the potential impact of the current global change-induced perturbations on microbial populations. 1) I am particularly interested in understanding whether these perturbations will have significant consequences on plant health, plant distribution, and the ability of plants to adapt to stress and 2) to what extent beneficial microorganisms may alleviate stress conditions due to climate change. According to the findings of my research, it has been observed that a decrease in carbon allocation by the host plant can result in the disturbance of rhizosphere fungal biomass dynamics (Babalola et al., 2022). An ideal location to conduct future research projects that aim to understand how microbial assembly and activities would be a long-term research site such as Piedmont Uplands in Georgia or the Sonoran Desert in Arizona.

My postdoctoral research examines how the resource environment, initial microbial species pool from piedmont uplands in Georgia and Sonoran Desert in Arizona affect root microbiome formation. My present research will be expanded to investigate the interactions between plants and microbes, with a focus on elucidating the elements that contribute to community assembly and dynamics. My future endeavor aims to further our comprehension of the mechanisms via which plants can derive advantages from their associations with microbial organisms. Using controlled greenhouse experiments, I will assess core sorghum microbiome and track their community assembly over time. My identification of sorghum genotypes that efficiently recruits and utilize beneficial AM fungi symbiosis under variable environmental conditions mitigate issues such as biodiversity loss. Given the escalating environmental changes, it is imperative to extend this investigation to other plant species over multiple generations. This endeavor aims to forecast plant adaptation, as the principles governing sorghum-AM fungi-environment interactions may not be universally relevant to other plant-microbiome interactions. Conducting field and greenhouse experiments to investigate other plant-microbe interactions under varying abiotic conditions, such as soil fertility, temperature, precipitation, and fire, is a valuable opportunity for students and plays a crucial role in advancing our comprehension of the potential responses of plant and microbial populations to future environmental changes.

References

Babalola BJ, Li J, Willing CE, Zheng Y, Wang YL, Gan HY, Li XC, Wang C, Adams CA, Gao C. 2022. Nitrogen fertilisation disrupts the temporal dynamics of arbuscular mycorrhizal fungal hyphae but not spore density and community composition in a wheat field. New Phytologist 234(6): 2057-2072.

Johnson NC. 2010. Resource stoichiometry elucidates the structure and function of arbuscular mycorrhizas across scales. New Phytologist 185(3): 631-647.

Scroll down to read the research projects I have been involved in