## 3 Discussion  
Bacterial spot caused by _Xanthomonas_ is a devastating disease, causing significant losses. Several studies have demonstrated that using lytic bacteriophages as treatments for controlling pathogenic bacteria is a promising strategy to overcome ineffective disease management and reduce the environmental impacts caused by chemical compounds [1]. Here, we isolated and characterized two novel jumbo phages specifically infecting _Xanthomonas vesiatoria_ strains. The XaC1 and XbC2 phages have genome sizes of 348,967 nt and 367,901 bp, respectively, and were classified as jumbo phages due to possessing genomes larger than 200 kbp [34]. Both phages were lacking integrases or CI-like repressors, suggesting both phages are virulent, consistent with the formation of clear plaques onto top agar (Figure 1). Interestingly, the XaC1 and XbC2 phages possess long DTRs of 32,031 bp and 17,581 bp in length, respectively, suggesting the DTR packaging mechanism where the DTR is extended by synthesis of staggered nicks at the 3'ends [35]. Long DTRs have been found in several phages with lengths ranging from over hundred bases, such as the Tsamsa phage, at 284 bp [36], to several kilobases, such as the _Xanthomonas_ phage XacN1, which shows a DTR length of 65,875 bp [21]. On the other hand, both phages were found to encode several tRNAs; in particular, XbC2 encodes 34 tRNAs, a feature shared with similar phages that we used for genomic comparisons, such as the _Pectobacterium_ phage vB_PcaM_CBB (27 tRNAs), _Ervinia_ phage pEa_SNUABM_50 (34 tRNAs), _Ervinia_ phage pEa_SNUABM_47 (35 tRNAs), _Cronobacter_ phage vB_CsaM_GAP32 (26 tRNAs) and _Serratia_ phage BF (31 tRNAs). Generally, it has been proposed that phages encode tRNAs to compensate for codon usage, supplementing those codons essential for the phage but less commonly utilized by the host [37]. This can be supported by the fact that several XaC1 and XbC2 phage-encoded tRNAs showed a higher codon usage than the host (Tables S7 and S8). Moreover, other studies suggested that phage-encoded tRNAs can be positively selected because they are not sensitive to host anticodon nucleases [38] or used to evade retro-mediated bacterial immunity [39]. The genomic analysis of XaC1 and XbC2 revealed a relatively conserved modular arrangement compared with similar phages, identified by BLASTn and VIRIDIC, infecting _Ervinia_, _Serratia_, _Cronobacter_ and _Cronobacterium_. Despite that a similar distribution of collinear blocks was observed using MAUVE alignment, the XaC1 phage showed a lower similarity to the other analyzed phages. Comparative genomics revealed that the XaC1 and XbC2 phages belong to different genera when they were compared with the best matches obtained by BLAST analysis, and, in fact, the XaC1 phage may represent a member of a novel family, broadening the diversity of phages known to date. Meanwhile, XbC2 is grouped as a member of the _Zobellviridae_ family, where the additional phages analyzed for comparative genomics belonged to this same family. According to these results, we propose the two novel genera, \"_Lururavirus_\" and \"_Villivirus_\", for the XaC1 and XbC2 phages described in this study, respectively. On the other hand, the XaC1 and XbC2 phages contain a significant number of ORFs remains as ORFans encoding hypothetical proteins. Additionally, both phages harbor genes encoding methyltransferases, which may mediate phage protection against endonuclease activity of restriction-modification systems (Table S7) [40]. The phage XbC2 was found to encode Cas4 and Sir2-like proteins, which play roles in bacterial immunity. Cas4 is a DNA endonuclease implicated in the selection of a new spacer during CRISPR expansion [41]. Cas4 has been found in phages, including those that infect _Xanthomonas_ species [40]. In _Campylobacter jejuni_, CRISPR systems lack Cas4 proteins. Still, phage-encoded Cas4 promotes the acquisition of new spacers of host origin, suggesting that acquiring self-spacers employs the bacterial genome as a decoy to prevent phage DNA acquisition [42].