Cao Yi, Yang Zhi-Xiao, Yang Dong-Mei, Lu Ning, Yu Shi-Zhou, Meng Jian-Yu, Chen Xing-Jiang
Guizhou Academy of Tobacco Science, Guiyang, China.
Front Microbiol. 2022 Feb 9;13:807057. doi: 10.3389/fmicb.2022.807057. eCollection 2022.
The root-knot nematode (RKN) is an important pathogen that affects the growth of many crops. Exploring the interaction of biocontrol bacteria-pathogens-host root microbes is the theoretical basis for improving colonization and controlling the effect of biocontrol bacteria in the rhizosphere. Therefore, 16S and 18S rRNA sequencing technology was used to explore the microbial composition and diversity of tobacco roots (rhizosphere and endophytic) at different growth stages in typical tobacco RKN-infected areas for 2 consecutive years. We observed that RKN infection changed the α-diversity and microbial composition of root microorganisms and drove the transformation of microorganisms from bacteria to fungi. The abundance of decreased significantly from 18% to less than 3%, while the abundance of increased from 4 to 15% at the early growth stage during the first planting year, and it promoted the proliferation of at the late growth stage in rhizosphere microorganisms with the highest abundance of 17%. The overall trend of rhizosphere microorganisms changed in the early growth stage with increasing growth time. The specific results were as follows: (1) and increased rapidly after 75 days, became the main abundant bacteria in the rhizosphere microorganisms. (2) The dominant flora in fungi were and . (3) Comparing the root microbes in 2017 and 2018, RKN infection significantly promoted the proliferation of and in both the rhizosphere and endophytes during the second year of continuous tobacco planting, increasing the relative abundance of from 2 to 25%. was determined to play an important role in plant pest control. Finally, a total of 32 strains of growth-promoting bacteria were screened from tobacco rhizosphere bacteria infected with RKN through a combination of 16S rRNA sequencing and life-promoting tests. The results of this research are helpful for analyzing the relationship between RKNs and bacteria in plants, providing reference data for elucidating the pathogenesis of RKNs and new ideas for the biological control of RKNs. GRAPHICAL ABSTRACT.
根结线虫（RKN）是一种影响多种作物生长的重要病原体。探索生防细菌 - 病原体 - 宿主根际微生物之间的相互作用是改善定殖并控制生防细菌在根际作用效果的理论基础。因此，连续两年运用16S和18S rRNA测序技术，对典型烟草根结线虫感染地区不同生长阶段烟草根（根际和内生）的微生物组成和多样性进行了探究。我们观察到，根结线虫感染改变了根际微生物的α多样性和微生物组成，并促使微生物从细菌向真菌转变。在第一个种植年的早期生长阶段，[未提及的细菌名称1]的丰度从18%显著降至3%以下，而[未提及的细菌名称2]的丰度从4%增至15%，并且在根际微生物后期生长阶段促进了[未提及的细菌名称3]的增殖，其丰度最高达17%。随着生长时间增加，根际微生物在早期生长阶段呈现出总体变化趋势。具体结果如下：（1）[未提及的细菌名称4]和[未提及的细菌名称5]在75天后迅速增加，成为根际微生物中的主要优势细菌。（2）真菌中的优势菌群为[未提及的真菌名称1]和[未提及的真菌名称2]。（3）比较2017年和2018年的根际微生物，在连续种植烟草的第二年，根结线虫感染显著促进了根际和内生菌中[未提及的细菌名称6]和[未提及的细菌名称7]的增殖，使[未提及的细菌名称6]的相对丰度从2%增至25%。[未提及的细菌名称6]被确定在植物害虫防治中发挥重要作用。最后，通过16S rRNA测序和促生试验相结合，从感染根结线虫的烟草根际细菌中筛选出32株促生细菌。本研究结果有助于分析植物中根结线虫与细菌之间的关系，为阐明根结线虫的发病机制提供参考数据，并为生防根结线虫提供新思路。图形摘要。
