喀斯特石漠化治理区钙果种植年限对根内细菌群落的影响

Planting years affect endophytic bacterial community of Cerasus humilis (Bge.) Sok. from karst rocky desertification control areas

摘要:

存在于健康植物根中的内生细菌不但能够与宿主植物建立共生关系，而且还具有促进植物生长、提升植物对营养元素摄取能力等功能，从而对维持陆地生态平衡、提升喀斯特石漠化综合治理成效具有重要的意义。【目的】探究宿主植物根中的内生细菌群落结构，为深入认识宿主植物-内生细菌的互作机制提供理论依据。【方法】以被引种到喀斯特断陷盆地石漠化综合治理区不同种植年限钙果根中的内生细菌和根际土为研究对象，分析根内生细菌群落特征和根际土理化性质。【结果】钙果种植年限对研究区土壤质量整体有着直接、显著的影响，并间接影响根内生细菌群落。根内生细菌群落以共生互作为主，通过共网络结构识别出种植第一年和第三年的前三位优势属为链霉菌属(Streptomyces)、卡氏伯克霍尔德菌属(Burkholderia-Caballeronia- Paraburkholderia)和噬几丁质菌属(Chitinophaga)，种植第五年的前三位优势属为Streptomyces、Chitinophaga和海无柄孢囊黏细菌属(Haliangium)。根内生细菌群落的形成主要由随机性过程中的生态漂变所主导。【结论】不同生长阶段钙果根内生细菌群落结构的差异是由于随机性过程赋予了微生物物种多样化。内生细菌群落的共生互作关系以及优势菌具有生防功能，可增强钙果定殖能力和生长，进而提升钙果在喀斯特断陷盆地石漠化综合治理区的生态效益和经济效益。

Abstract:

Endophytic bacteria in the roots of a healthy plant not only form a symbiotic relationship with the host plant but also promote plant growth and enhance plant uptake of nutrients, being of importance for maintaining terrestrial ecological balance and improving the comprehensive management of karst rocky desertification. [Objective] To explore the endophytic bacterial communities in the roots of host plants and provide a theoretical basis for deeply understanding the interaction mechanisms between host plants and endophytic bacteria. [Methods] The community structures of endophytic bacteria and physicochemical properties of rhizosphere soil of Cerasus humilis (Bge.) Sok. introduced for the control of rocky desertification in the karst graben basin with different years were studied. [Results] Planting years of C. humilis had a direct and significant influence on the rhizosphere soil quality and an indirect effect on the bacterial community in the roots. The endophytic bacterial community was mainly characterized by symbiotic interactions. The top three dominant bacterial genera identified by the co-occurrence network in the first year and third year were Streptomyces, Burkholderia-Caballeronia-Paraburkholderia and Chitinophaga, and the top three dominant bacterial genera in the fifth year were Streptomyces, Chitinophaga and Haliangium, which had biocontrol effects. The endophytic bacterial community was shaped by stochastic ecological drift processes. [Conclusion] The differences of endophytic bacterial communities along the planting year gradient are due to the microbial diversity endowed by stochastic processes. The interactions among endophytic bacteria and the dominant bacteria with biocontrol effects could promote the colonization and growth of C. humilis, thereby enhancing the ecological and economic benefits of C. humilis for the comprehensive control of rocky desertification in the karst graben basin.