Kaushik Rishabh, Pandit Maharaj K, Meyerson Laura A, Chaudhari Diptaraj S, Sharma Meesha, Dhotre Dhiraj, Shouche Yogesh S
Department of Environmental Studies, University of Delhi, Delhi, 110007, India.
Centre for Interdisciplinary Studies of Mountain & Hill Environment, University of Delhi, Delhi, 110007, India.
Curr Microbiol. 2021 May;78(5):2051-2060. doi: 10.1007/s00284-021-02473-1. Epub 2021 Apr 10.
Invasive plants are known to alter the soil microbial communities; however, the effects of co-occurring native and invasive congeners on the soil bacterial diversity and their predictive metabolic profiles are not known. Here, we compared the rhizosphere bacterial communities of invasive Prosopis juliflora and its native congener Prosopis cineraria using high-throughput sequencing of the 16S rRNA gene. Unweighted Pair Group Method with Arithmetic mean (UPGMA) based dendrogram revealed significant variation in the communities of these co-occurring Prosopis species. Additionally, Canonical Correspondence Analysis (CCA) based on microbial communities in addition to the soil physiochemical parameters viz. soil pH, electrical conductivity, moisture content and sampling depth showed ~ 80% of the variation in bacterial communities of the rhizosphere and control soil. We observed that Proteobacteria was the predominant phylum of P. juliflora rhizosphere and the control soil, while P. cineraria rhizosphere was dominated by Cyanobacteria. Notably, the invasive P. juliflora rhizosphere showed an enhanced abundance of bacterial phyla like Actinobacteria, Chloroflexi, Firmicutes and Acidobacteria compared to the native P. cineraria as well as the control soil. Predictive metagenomics revealed that the bacterial communities of the P. juliflora rhizosphere had a higher abundance of pathways involved in antimicrobial biosynthesis and degradation, suggesting probable exposure to enemy attack and an active response mechanism to counter it as compared to native P. cineraria. Interestingly, the higher antimicrobial biosynthesis predicted in the invasive rhizosphere microbiome is further corroborated by the fact that the bacterial isolates purified from the rhizosphere of P. juliflora belonged to genera like Streptomyces, Isoptericola and Brevibacterium from the phylum Actinobacteria, which are widely reported for their antibiotic production ability. In conclusion, our results demonstrate that the co-occurring native and invasive Prosopis species have significantly different rhizosphere bacterial communities in terms of composition, diversity and their predictive metabolic potentials. In addition, the rhizosphere microbiome of invasive Prosopis proffers it a fitness advantage and influences invasion success of the species.
已知入侵植物会改变土壤微生物群落；然而，共生的本地同属植物和入侵同属植物对土壤细菌多样性及其预测代谢谱的影响尚不清楚。在此，我们使用16S rRNA基因的高通量测序比较了入侵性牧豆树（Prosopis juliflora）及其本地同属植物灰叶牧豆树（Prosopis cineraria）的根际细菌群落。基于算术平均的非加权配对组方法（UPGMA）构建的树状图显示，这些共生牧豆树物种的群落存在显著差异。此外，基于微生物群落以及土壤理化参数（即土壤pH值、电导率、含水量和采样深度）的典范对应分析（CCA）表明，根际和对照土壤中细菌群落约80%的变异。我们观察到，变形菌门是牧豆树根际和对照土壤中的优势菌门，而灰叶牧豆树根际则以蓝细菌为主。值得注意的是，与本地灰叶牧豆树以及对照土壤相比，入侵性牧豆树根际中放线菌门、绿弯菌门、厚壁菌门和酸杆菌门等细菌门的丰度有所增加。预测宏基因组学表明，牧豆树根际的细菌群落中参与抗菌生物合成和降解的途径丰度更高，这表明与本地灰叶牧豆树相比，它可能面临敌人攻击并具有积极的应对机制。有趣的是，从牧豆树根际纯化的细菌分离物属于放线菌门的链霉菌属、异节杆菌属和短杆菌属等属，这些属因具有抗生素生产能力而被广泛报道，这进一步证实了入侵根际微生物组中预测的更高抗菌生物合成。总之，我们的结果表明，共生的本地和入侵牧豆树物种在根际细菌群落的组成、多样性及其预测代谢潜力方面存在显著差异。此外，入侵牧豆树的根际微生物组为其提供了适应性优势，并影响该物种的入侵成功。
