Abstract:

The bacterial wilt disease has a significant impact on the agricultural soil environment. In order to investigate the relationship among different types of texture of latosols and their bacterial communities in cropland in Hainan, this study selected six treatment groups (sand control, sand+inoculated with Ralstonia solanacearum, loam control, loam+inoculated with R.solanacearum, clay control, and clay+inoculated with R. solanacearum) from latosols experimental fields of three different types of texture, selected root injury inoculation method, and collected diseased plants and soil samples regularly to count plant incidence rate and to test soil physical and chemical properties and microbial diversity. The results showed that (1) tomato plants all showed symptoms of bacterial wilt after inoculation with R. solanacearum, with disease incidences of 52.3%, 77.9%, and 95.1%, respectively, and disease indexes of 20.2, 52.1, and 83.2, respectively, from loam, sand, and clay; (2) the pH value of loam soil in diseased plants was much lower than that of sand and clay, the pH value of sandy soil and loam soil was significantly and negatively correlated with the incidence rate (P<0.05), and the content of soil organic matter and available phosphorus in all test soils was negatively correlated with the incidence rate; (3) the α diversity index of soil bacteria in the diseased plants' rhizosphere was lower than that in healthy plants' rhizosphere, the relative abundance of Bacillus in the sand was higher than that in loam and clay, the relative abundance of Ralstonia, Devosia, Mesorhizobium, Bradyrhizobium, Nitrospira, unclassified_Gemmatimonadaceae and Haliangium genus in clay was higher than that in sand and loam, Bryobacter and Terrabacter were related to soil nutrients, and the relative abundance of Bryobacter and Terrabacter in loam was higher than in sand and clay. In summary, the incidence rates of tomato bacterial wilt in different types of latosols in cropland in Hainan are different, and the soil pH value is the key factor affecting the incidence rate. The occurrence of tomato bacterial wilt may lead to the loss of soil organic matter and available phosphorus and may reduce the soil bacterial diversity.

Key words: bacterial wilt, latosol, physicochemical properties, bacterial diversity

摘要：

青枯病对农田土壤环境的影响深远。为探究海南砖红壤质地和细菌群落与番茄青枯病发生的关系，为农业防治青枯病提供参考依据，以海南农田砖红壤为对象，番茄为茄科模式作物，采用大田试验，分别在3种不同质地砖红壤试验田设置了6个处理组（砂土对照、砂土+接种青枯菌、壤土对照、壤土+接种青枯菌、黏土对照与黏土+接种青枯菌），采用伤根接种法，通过定期采集发病植株和土壤样品，统计植株发病率、测定土壤理化性质和微生物多样性。结果表明：（1）接种青枯菌后番茄植株均出现青枯病症状，壤土、砂土、黏土发病率分别为：52.3%、77.9%、95.1%，病情指数分别为：20.3、52.1、83.2；（2）患病植株中壤土pH值远低于砂土和黏土；砂土和壤土pH值与发病率显著负相关（P<0.05），土壤有机质、有效磷含量均与发病率呈负相关；（3）发病植株所在土壤细菌α多样性指标比健康植株所在土壤更低，砂土芽孢杆菌属（Bacillus）相对丰度高于壤土和黏土，黏土中雷尔氏菌属（Ralstonia）、德沃斯氏菌属（Devosia）、中慢生根瘤菌属（Mesorhizobium）、慢生根瘤菌属（Bradyrhizobium）、硝化螺菌属（Nitrospira）、unclassified_Gemmatimonadaceae属与Haliangium属相对丰度比砂土和壤土高；壤土中与土壤养分有关的苔藓杆菌属（Bryobacter）、地杆菌属（Terrabacter）相对丰度均高于砂土和黏土。综上说明海南农田不同质地砖红壤番茄青枯病发病率不同，且土壤pH值是影响发病率的关键因素，番茄青枯病的发生会导致土壤有机质和有效磷的流失，同时会降低土壤细菌多样性。

关键词: 青枯病, 砖红壤, 理化性质, 细菌多样性