Assis Renata A B, Varani Alessandro M, Sagawa Cintia H D, Patané José S L, Setubal João Carlos, Uceda-Campos Guillermo, da Silva Aline Maria, Zaini Paulo A, Almeida Nalvo F, Moreira Leandro Marcio, Dandekar Abhaya M
Center of Research in Biological Science, Federal University of Ouro Preto, Ouro Preto, MG, Brazil; Department of Plant Sciences, University of California, Davis, CA, USA.
Faculty of Agricultural and Veterinary Sciences of Jaboticabal (FCAV), Universidade Estadual Paulista (UNESP), Department of Technology, Jaboticabal, SP, Brazil.
Genomics. 2021 Jul;113(4):2513-2525. doi: 10.1016/j.ygeno.2021.06.003. Epub 2021 Jun 3.
Xanthomonas arboricola pv. juglandis (Xaj) is the most significant aboveground walnut bacterial pathogen. Disease management uses copper-based pesticides which induce pathogen resistance. We examined the genetic repertoire associated with adaptation and virulence evolution in Xaj. Comparative genomics of 32 Xaj strains reveal the possible acquisition and propagation of virulence factors via insertion sequences (IS). Fine-scale annotation revealed a Tn3 transposon (TnXaj417) encoding copper resistance genes acquired by horizontal gene transfer and associated with adaptation and tolerance to metal-based pesticides commonly used to manage pathogens in orchard ecosystems. Phylogenomic analysis reveals IS involvement in acquisition and diversification of type III effector proteins ranging from two to eight in non-pathogenic strains, 16 to 20 in pathogenic strains, besides six other putative effectors with a reduced identity degree found mostly among pathogenic strains. Yersiniabactin, xopK, xopAI, and antibiotic resistance genes are also located near ISs or inside genomic islands and structures resembling composite transposons.
核桃细菌性溃疡病菌（Xanthomonas arboricola pv. juglandis，Xaj）是核桃树最重要的地上部细菌病原体。病害管理使用铜基农药，这会诱导病原体产生抗性。我们研究了与Xaj适应性和毒力进化相关的基因库。对32个Xaj菌株进行比较基因组学分析，揭示了通过插入序列（IS）可能获得和传播毒力因子的情况。精细注释显示，一个Tn3转座子（TnXaj417）编码通过水平基因转移获得的铜抗性基因，该基因与果园生态系统中用于管理病原体的金属基农药的适应性和耐受性相关。系统发育基因组学分析表明，IS参与了III型效应蛋白的获得和多样化，非致病菌株中有2至8个，致病菌株中有16至20个，此外，在大多数致病菌株中还发现了另外6个同一性程度降低的假定效应蛋白。耶尔森菌素、xopK、xopAI和抗生素抗性基因也位于IS附近或基因组岛及类似复合转座子的结构内部。
