Complete Genome Sequence of Robbsia sp. KACC 23696 with Two Distinct Type III Secretion System Gene Clusters

The genus Robbsia was established in 2017 with R. andropogonis as the type species and currently comprises two validly published species, R. andropogonis and R. betulipollinis.However, genomic resources for this genus remain limited.Here, we report the complete genome sequence of Robbsia sp.KACC 23696 to expand the genomic resources available for the genus.Robbsia sp.KACC 23696 was isolated from the flower of Coreopsis lanceolata L. collected in the Republic of Korea and cultured aerobically on Reasoner's 2A agar (R2A; BD Difco, USA) at 28℃ for 48 h.High-molecular-weight genomic DNA was extracted using the MagAttract HMW DNA Kit (Qiagen, Germany) according to the manufacturer's instructions.Complete genome sequenc-ing was performed using the PacBio Sequel IIe platform (Pacific Biosciences, USA) and the Illumina NovaSeq 6000 platform (Illumina, USA).PacBio HiFi reads were assembled using the Flye assembler (version 2.8.3) [1] implemented in the microbial assembly application of SMRT Link (version 13.1; PacBio).Illumina reads were quality-filtered and adapter-trimmed using Trimmomatic (version 0.39) [2], and the resulting reads were used to polish the assembly with Pilon (version 1.24) [3].PacBio HiFi reads provided approximately 162-fold coverage, and Illumina short reads provided approximately 370fold coverage.The final assembly consisted of three circular replicons, confirmed by the connection of the 5′ and 3′ ends.The genome comprised one circular chromosome and two circular secondary replicons, designated chromid 1 and chromid 2, with sizes of 3,518,780 bp, 1,581,533 bp, and 1,220,225 bp and G+C contents of Robbsia sp.KACC 23696 was isolated from the flower of Coreopsis lanceolata L. in the Republic of Korea.Its complete genome comprises one circular chromosome and two circular chromids.In total, the genome encodes 5,086 protein-coding sequences, four rRNA operons, 56 tRNA genes, four non-coding RNA genes and 150 pseudogenes.Functional annotation revealed that transcription-and metabolism-related genes were the predominant functional categories in both chromids.Comparative genome analysis identified two putative type III secretion system (T3SS) gene clusters encoded on different replicons, exhibiting distinct gene organizations and protein compositions.