水肥菌一体化番茄基质栽培系统青枯病病株和健株根际微生物群落结构的差异

Difference of rhizobacterial community structure between bacterial wilt infected and healthy tomato plants in a substrate culture system

摘要:

【目的】探究水肥菌一体化基质栽培系统番茄青枯病害发生与根际群落结构的相互关系。【方法】通过田间病情调查,统计番茄青枯病发病率和病情指数,进而利用高通量测序技术比较分析感染青枯病和健康番茄植株根际基质细菌群落结构多样性和组成。【结果】番茄植株在生殖生长期(移栽后60 d)的发病率(6.17%)和病情指数(5.11)均大于营养生长期(移栽后30 d)(分别为2.5%和1.25)。青枯雷尔氏菌在发病初期(1级和2级)植株根际分布数量显著大于发病后期(3级和4级)。病株根际基质Chao1指数和Shannon指数均显著低于健株根际基质。与健株根际基质相比,病株根际基质中变形菌门(Proteobacteria)的相对含量极显著增加,放线菌门(Acidobacteria)和蓝细菌门(Cyanobacteria)的相对含量极显著降低(P<0.01),罗纳杆菌属(Rhodanobacter)和病原菌所在雷尔氏菌属(Ralstonia)相对含量显著增高,冗余分析(redundancy analysis,RDA)显示其与青枯雷尔氏菌的分布数量呈正相关,而慢生根瘤菌属(Bradyrhizobium)、粒状胞菌属(Granulicella)、海管菌属(Haliangium)和德沃斯氏菌属(Devosia)含量显著降低(P<0.05),RDA分析显示其与青枯雷尔氏菌的分布数量呈负相关。【结论】番茄感染青枯病后根际基质微生物多样性和有益菌群数量显著降低,因此,可以通过添加有益菌,调控土壤微生物群落组成来抵御土传青枯病害。

Abstract:

[Objective] To investigate the relationship between rhizobacterial community structure and bacterial wilt occurrence of tomato plants in a substrate culture system with the integration of water,fertilizers,and biocontrol agents.[Methods] After the field survey,the disease incidence (DI) and disease severity index (DSI) of bacterial wilt were calculated.Furthermore,the high-throughput sequencing technology was adopted to compare the rhizobacterial diversity and composition between infected and healthy tomato plants.[Results] The DI (6.17%) and DSI (5.11) of tomato plants at the reproductive stage were significantly higher than those at the vegetative stage (DI of 2.5% and DSI of 1.25,respectively).The number of Ralstonia solanacearum in the rhizosphere of diseased tomato plants at the early infection stage (grades 1 and 2) was much higher than that at the later infection stage (grades 3 and 4).Both Chao 1 and Shannon indexes of bacteria in the rhizosphere of diseased tomato plants were significantly lower than those in the rhizosphere of health plants.Compared with that in the rhizosphere of healthy plants,the relative abundance of Proteobacteria increased while that of Acidobacteriota and Cyanobacteria decreased (P<0.01);the relative abundance of Rhodanobacter and Ralstonia significantly increased,which was positively correlated with the number of R. solanacearum as demonstrated by redundancy analysis;the relative abundance of Bradyrhizobium,Granulicella,Haliangium,and Devosia significantly decreased (P<0.05),which was negatively correlated with the number of R. solanacearum.[Conclusion] Compared with those in the rhizosphere of healthy plants,the bacterial diversity and beneficial bacteria in the rhizosphere of tomato plants infected with bacterial wilt significantly reduced.Therefore,the addition of beneficial bacteria to change rhizobacterial community structure would be an efficient method to control tomato bacterial wilt.