Table 2_Analysis of causal pathogens of mulberry bacterial blight in samples collected from eight provinces of China using culturomics and metagenomic sequencing methods.docx

Mulberry bacterial blight (MBB) is a complex and one of the devastating diseases of mulberry that causes serious reduction in the yield and quality of mulberry. In recent years, the transformation of sericulture industry, mulberry production system, and increasing seedling trade have resulted in the spread of MBB to different parts of China, posing a major economic threat to the farmers and industry. This study investigated the occurrence of MBB in eight provinces of China during years 2023 and 2024. The MBB disease samples were collected and the composition of the MBB pathogenic microbiome was analyzed by combining culturomics and metagenomic sequencing methods. A total of 498 bacterial strains were isolated and identified through culturomics, and then 109 suspected pathogen strains were preliminarily screened based on metagenomic sequencing data. Finally, 10 pathogens including, Pseudomonas syringae, P. fulva, P. fluorescens, Pantoea ananatis, Pectobacterium parvum, P. carotovorum, Flavobacterium fluviale, Citrobacter portucalensis, Klebsiella grimontii, Stenotrophomonas maltophilia, were identified through Koch’s postulates. Based on the distribution pattern of pathogens and the changes in the microbiome community of mulberry following infection with P. syringae, we infer that P. syringae, and P. fulva are important pathogens of MBB. In addition, based on the analysis of meteorological data, different bacteria showed adaptability to different environments, leading to differences in the pathogens of MBB under different climate conditions and latitudes. The data presented herein provides a foundation for understanding the occurrence, spatial distribution and pathogenic mechanism of MBB and its major pathogens.

桑细菌性枯萎病（Mulberry bacterial blight, MBB）是一类复杂且极具破坏性的桑树病害，会严重降低桑叶的产量与品质。近年来，随着蚕桑产业、桑树生产体系的转型以及苗木贸易规模的扩大，桑细菌性枯萎病已扩散至中国多个区域，对种植户与蚕桑产业造成了严重的经济威胁。本研究于2023至2024年间，针对中国8个省份的桑细菌性枯萎病发生情况开展了调查。研究人员采集了该病的病样，并结合培养组学与宏基因组测序技术，分析了桑细菌性枯萎病的病原微生物组组成。通过培养组学方法，共分离并鉴定出498株细菌；随后基于宏基因组测序数据，初步筛选得到109株疑似病原菌株。最终通过科赫法则（Koch's postulates）鉴定出10种病原菌，包括：丁香假单胞菌（Pseudomonas syringae）、黄褐假单胞菌（P. fulva）、荧光假单胞菌（P. fluorescens）、菠萝泛菌（Pantoea ananatis）、小型果胶杆菌（Pectobacterium parvum）、胡萝卜软腐果胶杆菌（P. carotovorum）、河流黄杆菌（Flavobacterium fluviale）、葡萄牙柠檬酸杆菌（Citrobacter portucalensis）、格里蒙克雷伯菌（Klebsiella grimontii）以及嗜麦芽窄食单胞菌（Stenotrophomonas maltophilia）。结合病原菌分布特征以及桑树感染丁香假单胞菌后的微生物组群落变化，本研究推断丁香假单胞菌与黄褐假单胞菌是桑细菌性枯萎病的重要致病菌。此外，通过对气象数据的分析发现，不同病原菌对环境的适应性存在差异，进而导致不同气候条件与纬度区域下的桑细菌性枯萎病病原菌组成有所不同。本研究所得数据可为阐明桑细菌性枯萎病及其主要致病菌的发生规律、空间分布特征与致病机制提供理论支撑。