Roseobacteraceae, often referred to as the marine roseobacter clade (MRC), are pivotal constituents of bacterial communities in coastal and pelagic marine environments. During the past two decades, 75 roseophages that infect various Roseobacteraceae lineages have been isolated. The N4-like roseophage clade, which encompasses 15 members, represents the largest clade among these roseophages. N4-like phages form a monophyletic group, classified as family Schitoviridae. And all N4-like roseophages form a unique clade within Schitoviridae and has been classified as the Rhodovirinae subfamily. In this study, we isolated a novel roseophage, vB_DshP-R7L, that infects Dinoroseobacter shibae DFL12 from Xiamen Bay in the East China Sea. Conserved genes of Schitoviridae have been identified in the genome of vB_DshP-R7L, and following phylogenetic analysis suggests that the newly isolated phage is a member of the Rhodovirinae subfamily and represents the sole member of a novel genus, Gonggongvirus. The genome of vB_DshP-R7L harbors six auxiliary metabolic genes (AMGs), most of which potentially enhance DNA de novo synthesis. Additionally, a gene encoding ribosomal protein was identified. Comparative genomic analysis of AMG content among Rhodovirinae indicates a distinct evolutionary history characterized by independent ancient horizontal gene transfer events. Read-mapping analysis reveals the prevalence of vB_DshP-R7L and other Rhodovirinae roseophages in estuarine waters. Our work illustrates the genomic features of a novel roseophage clade among the subfamily Rhodovirinae. The AMG content of vB_DshP-R7L is under severe purification selection, which reveals their possible ecological importance. We also demonstrated that vB_DshP-R7L and other Rhodovirinae roseophages are only detected in estuaries. Our isolation and characterization of this novel phage expands the understanding of the phylogeny, gene transfer history, and biogeography of Rhodovirinae infecting marine Roseobacteraceae.

China has assumed a leadership position in global kelp cultivation and export. However, the kelp harvesting process in China still relies primarily on manual labor, with only limited adoption of semi-mechanized devices. This dependence results in suboptimal efficiency and elevated labor intensity. The industry now faces an acute labor shortage driven by an aging workforce and rising labor costs, highlighting the urgent need for a fully mechanized harvesting solution. This paper comprehensively reviews current research on mechanized kelp harvesting devices for raft cultivation systems in China. It compares domestic and international practices in kelp seedling cultivation, cultivation models, and harvesting devices, with particular emphasis on the technical challenges hindering harvesting device development in China. Based on this analysis, we propose several recommendations, including the simultaneous advancement of cultivation model optimization and harvesting device innovation, the development of harvesting technologies aligned with specific downstream processing requirements, and the design of modular and multifunctional kelp harvesting vessels. Looking ahead, future research should prioritize integrating automation and intelligent systems, reflecting evolving trends in China’s marine aquaculture. Furthermore, to support China’s “dual carbon” goals, future harvesting systems should incorporate carbon-reduction features.

Background: Roseobacteraceae , often referred to as the marine roseobacter clade (MRC), are pivotal constituents of bacterial communities in coastal and pelagic marine environments. During the past two decades, 75 roseophages that infect various Roseobacteraceae lineages have been isolated. The N4-like Rhodovirinae subfamily, which encompasses 15 members, represents the largest clade among these roseophages. Results: In this study, we isolated a novel roseophage, vB_DshP-R7L, that infects Dinoroseobacter shibae DFL12 from Xiamen Bay in the East China Sea. Conserved genes of Schitoviridae have been identified in the genome of vB_DshP-R7L, and following phylogenetic analysis suggest that the newly isolated phage is a member of the Rhodovirinae subfamily and is indicative of a newly proposed genus, Xianganvirus . The genome of vB_DshP-R7L harbors six auxiliary metabolic genes (AMGs), most of which potentially enhance DNA de novo synthesis. Additionally, a gene encoding ribosomal protein was identified. Comparative genomic analysis of AMG content among Rhodovirinae indicates a distinct evolutionary history characterized by independent ancient horizontal gene transfer events. Read-mapping analysis reveals the prevalence of vB_DshP-R7L and other Rhodovirinae roseophages in estuarine waters. Conclusions: Our work illustrates the genomic features of a novel roseophage clade among N4-like Rhodovirinae . The AMG content of vB_DshP-R7L are under severe purification selection, which revealed their possible ecological importance. We also demonstrated that vB_DshP-R7L and other Rhodovirinae roseophages are restrictively distributed in estuaries. Our isolation and characterization of this novel phage expand the understanding of the phylogeny, gene transfer history and biogeography of N4-like Rhodovirinae infecting marine Roseobacteraceae .

Erythrobacter, an aerobic anoxygenic photoheterotrophic bacterial genus, plays a vital role in carbon and energy cycling in marine environments. However, their phage predators remain poorly understood, with only two strains previously reported. This study isolated and characterized two novel Erythrobacter phages, vB_EauS-R34L1 (R34L1) and vB_EauS-R34L2 (R34L2), from coastal seawater. Both phages exhibit long-tailed, icosahedral morphologies and relatively narrow but slightly different host ranges. One-step growth curve analysis revealed a 160-min latent period and burst sizes of 81 and 91 PFU/cell for R34L1 and R34L2, respectively. Genomic analysis showed that the phages possess dsDNA genomes of 56,415 bp (R34L1) and 54,924 bp (R34L2), with G+C contents of 61.60% and 61.19%, respectively. Both phages harbor a suite of unique genes, including GapR and GH19, which are crucial for host interaction and ecological functionality. Blastn analysis indicated a 99.73% genome similarity between them. Taxonomic and phylogenetic analyses positioned them in a novel viral genus cluster, Eausmariqdvirus, under the family Casjensviridae, indicating a distant evolutionary relationship with known phages. Metagenomic queries suggested that R34L1- and R34L2-like phages are exclusively abundant in temperate and tropical epipelagic zones. This study expands our understanding of Erythrobacter phages and provides insights into their ecological roles in marine ecosystems.

The current study was conducted to evaluate whether gamma (γ)‐irradiation improves the efficacy of defatted Hermetia illucens larvae (HIL) meal as the fishmeal protein substitute in Litopenaeus vannamei . The reference diet (diet R) contained 400 g/kg fishmeal, while two experimental diets replaced 50% of fishmeal with either nonirradiated (diet HIL) or γ‐irradiated defatted HIL meal (diet HIL5). Compared to group R, both average final body weight (FBW) and weight gain exhibited an increasing trend with the inclusion of defatted HIL meal, particularly with γ‐irradiated HIL. Lower feed intake and feed conversion ratio (FCR) while increased retention efficiencies of carbon (CRE), nitrogen, and phosphorus were observed in groups HIL and HIL5 than the R group. Additionally, with the incorporation of either γ‐irradiated or nonirradiated defatted HIL meal, significantly decreased malondialdehyde (MDA), carbon waste, nitrogen waste, phosphorus waste, relative usage of fishmeal and fish oil, and the ratio of fish‐in to fish‐out, whereas increased economic conversion ratio, economic profitability index, and profitability were observed compared to the shrimp fed a fishmeal‐based diet. Microbial analysis revealed a trend toward increased Pseudomonadota ( Ruegeria and Vibrio ) and decreased Bacillota ( Streptococcus ), though no statistical differences in alpha diversity or microbial community structure were observed. No adverse effects were detected in body components, digestive enzyme activities, or hepatopancreatic antioxidant capacity (AOC). These results demonstrate that γ‐irradiated defatted HIL meal can effectively replace 50% of dietary fishmeal (from 400 to 200 g/kg) without compromising growth performance, antioxidant status, or intestinal health in L. vannamei . Moreover, this substitution improves feed utilization, economic viability, and environmental sustainability by reducing waste output and fishery dependence.