Editorial: Exploring Pollen Microbiome: Implications for Plant Physiology, Crop Improvement and Human Allergies

NAGARAJU YALAVARTHI^1*Triveni Sodimalla²Thati Srinivas³Massimiliano Cardinale⁴

• ¹Central Sericultural Research and Training Institute Berhampore, Berhampore, India
• ²Professor Jayashankar Telangana State Agricultural University College of Home Science, Hyderabad, India
• ³Acharya N G Ranga Agricultural University, Guntur, India
• ⁴Universita del Salento, Lecce, Italy

The successful establishment begins with the attachment to pollen grains, which provide an initial substrate and favourble habitat for microbial colonization. Pollen morphological features significantly influence the diversity and persistence of pollen-associated microbes. The degree of surface ornamentation, ranging from smooth to highly reticulate or spiny exines, shapes microbial interactions by offering microhabitats where bacteria and fungi can attach and evade desiccation (Herrera et al., 2013). The survival of genera such as Acinetobacter sp., Pseudomonas sp., Sphingomonas sp., and Methylobacterium sp., are facilitated by their metabolic versatility, while others like Bacillus sp., and Staphylococcus sp., persist through endospore formation or biofilm production (Ambika Manirajan et al., 2016).Considering both, the critical role of pollen for plant biology and the recognized importance of the plant-associated microbiome for the plant fitness, we decided to propose this research topic on pollen microbiome. The idea behind was to stimulate the research on the topic as well as the genesis of new concepts about structure and function of the pollen microbiome, its role on plant ecology and crop productivity, and its contribution to human allergies. This research topic received seven manuscripts, four of which were accepted for publication. However, despite the limited number of manuscript (which may be due to the highly specific topic), the Research topic had already ~16,000 views and ~3,700 downloads at the time that the Topic Editors wrote this editorial paper. This demonstrates a notable interest for this new and relevant specific topic within the context of the broader plant microbiome research.Two research articles and two opinion articles were published, inmdicating that both scopes were fulfilled (new research/studies and new ideas/concepts). One research article (Khalaf et al., 2023) interestingly compared different high-throughput technologies to characterize the maize pollen microbiome (which was never analyzed before) and could finally identify the most probable main inhabitant: the Pantoea genus (especially the species ananatis). This is a very interesting discovery, in light of the fact that Pantoea is among the taxa that were found previously identified as stable cereal seed colonizers (Rahman ert al., 2018), and were recently demonstrated to be transmitted from seeds to the seeds of the next plant generation by inoculation of GFP-tagged strains in wheat (Sanz-Puente et al., 2025). This evidence point out the possibility that a link between the pollen microbiome and the seed microbiome exists, as discussed in the opinion paper of Cardinale and Schnell, 2023.The pollen microbiome acts as a double-edged sword, providing essential ecological functions while posing significant risks to plant, pollinator, and human health. Beneficial microbial taxa facilitate plant-pollinator interactions, enhance pollen viability, and contribute to ecosystem resilience. However, under specific environmental stresses or agricultural practices, these microbial communities can shift toward pathogenicity, leading to adverse outcomes. Several plant pathogens exploit pollen as a transmission vector, compromising plant reproductive efficiency and yield. For example, Erwinia amylovora, the causal agent of fire blight in both Malus domestica (apple) and Pyrus communis (pear), has been documented to use insect-mediated pollen dispersal to infect flowers (Rivest et al., 2024). Interestingly, Shrestha et al., 2024 demonstrated that pollen-associated microbiome acts as an effective biocontrol agents against the Fusarium pathogen causing agent of the Gibberella ear rot (GER). Therefore, it appears evident how we still lack a real comprehension of the complex interactions governing and driving the ecology of pollen microbiomes. More research will be needed to define clear evidences that will enhable us to place the pollen-associated microbes in the correct position within the one-health/one-bosecurity frameworks, to sustainably link agricultural applications, environmental safety and animal/ human health (Sherman et al., 2025).