Unique distribution of cyanobacterial podoviruses and their potential hosts in a paddy field of northeast China

Virome Analysis of Paddy Floodwater in Two Cropping Seasons

Paddy fields include two interconnected ecosystems-soil and floodwater. Microbes and viruses are an integral component of these ecosystems, yet the viral communities have not been extensively studied. We present an analysis of the viromes of paddy floodwater collected during the two cropping seasons in India, the kharif and rabi seasons respectively. The overall taxonomic and functional characteristics appeared to be similar in both seasons, suggesting stability of the viral community. Taxonomically, the families of tailed bacteriophages dominated. The predominance of functional roles related to lytic phages further confirmed this. We reconstructed two complete and several partial viral genomes from the assembled data. The genomes did not align with any known sequences, thus representing novel viruses of the floodwater ecosystem.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-024-01292-9.

Novel groups and unique distribution of phage phoH genes in paddy waters in northeast China

Although bacteriophages are ubiquitous in various environments, their genetic diversity is primarily investigated in pelagic marine environments. Corresponding studies in terrestrial environments are few. In this study, we conducted the first survey of phage diversity in the paddy ecosystem by targeting a new viral biomarker gene, phoH. A total of 424 phoH sequences were obtained from four paddy waters generated from a pot experiment with different soils collected from open paddy fields in northeast China. The majority of phoH sequences in paddy waters were novel, with the highest identity of ≤70% with known phoH sequences. Four unique groups (Group α, Group β, Group γ and Group δ) and seven new subgroups (Group 2b, Group 3d, Group 3e, Group 6a, Group 6b, Group 6c and Group 6d) were formed exclusively with the clones from the paddy waters, suggesting novel phage phoH groups exist in the paddy ecosystem. Additionally, the distribution proportions of phoH clones in different groups varied among paddy water samples, suggesting the phage community in paddy fields is biogeographically distributed. Furthermore, non-metric multidimensional scaling analysis indicated that phage phoH assemblages in paddy waters were distinct from those in marine waters.