西瓜连作根际土壤微生物群落演替特征

doi:10.3864/j.issn.0578-1752.2023.21.009

摘要/Abstract

摘要：

【目的】研究连作对西瓜根际土壤中细菌、真菌群落构建和潜在功能的影响，明确根际微生物对环境变化的适应性，为西瓜连作障碍的生态防治和农田土壤的健康保持提供理论基础。【方法】以未连作（对照）、连作2茬和连作 6茬的西瓜根际土壤为研究对象，利用16S rRNA和ITS高通量测序技术解析西瓜连作对根际土壤细菌、真菌群落特征和演替的影响。【结果】随着连作茬次的增加，西瓜根际土壤中细菌多样性指数呈现先下降后上升趋势，真菌多样性指数显著下降。在细菌属水平，多茬次的连作降低了西瓜根际土壤中鞘氨醇单胞菌属（Sphingomonas）和溶杆菌属（Lysobacter）的相对丰度；在真菌属水平，镰刀菌属（Fusarium）相对丰度随连作茬次增加呈增加趋势。与对照相比，连作的网络复杂度更高，但网络结构稳定性低。此外，相比于对照，连作6茬显著减少有害物质的生物降解途径以及氨基酸的代谢途径的相对丰度，并且在连作6茬后真菌群落中病原真菌相对丰度显著增多。在群落演替过程中，随机性过程主导连作下西瓜根际细菌群落构建，而确定性过程主导连作下西瓜根际真菌群落构建。【结论】连作引起根际细菌和真菌的群落特征、功能组成和演替过程变化，细菌群落关键功能的减少、病原真菌相对丰度的增加以及微生物群落网络稳定性的减小可能是导致西瓜连作障碍发生的重要因素。

关键词: 西瓜, 连作土壤, 根际微生物群落, 功能预测, 群落演替

Abstract:

【Objective】The aim of this study was to investigate the effects of continuous cropping on the construction and potential functions of bacterial and fungal communities in the rhizosphere soil of watermelon, and to clarify the adaptability of rhizosphere microorganisms to environmental changes, so as to provide a theoretical basis for ecological control of watermelon continuous cropping obstacles and healthy maintenance of farmland.【Method】In this study, the rhizosphere soil of watermelon without continuous cropping (CK), continuous cropping for 2 times and continuous cropping for 6 times was used as the research object. 16S rRNA and ITS high-throughput sequencing were used to analyze the effects of continuous cropping on the bacterial and fungal communities of rhizosphere soil of watermelon.【Result】With the increasing continuous cropping times, the bacterial diversity index in the rhizosphere soil of watermelon showed a trend of first decreasing and then increasing, while the fungal diversity index decreased significantly. At the bacterial genus level, multiple times of continuous cropping decreased the relative abundance of Sphingomonas and Lysobacter in watermelon rhizosphere soil; at the fungal genus level, the relative abundance of Fusarium increased with the continuous cropping times. Compared with CK, the network complexity of continuous cropping was higher, but the stability of network structure was lower. In addition, compared with CK, the relative abundance of biodegradation pathways of harmful substances and metabolic pathways of amino acids could be significantly reduced after continuous cropping for 6 times; the relative abundance of pathogenic fungi significantly increased in the fungal community after continuous cropping for 6 times. During community succession, the stochastic processes dominated rhizosphere bacterial community construction in watermelon under continuous cropping, while the deterministic processes dominated rhizosphere fungal community construction in watermelon.【Conclusion】Continuous cropping caused changes in community characteristics, functional composition and succession process of rhizosphere bacteria and fungi. The decrease of key functions of bacterial community, the increase of pathologic fungi and the decrease of stability of microbial community network might be the important factors leading to occurrence of watermelon continuous cropping obstacles.

Key words: watermelon, continuous cropping soil, rhizosphere microbial community, function prediction, community succession

郭晗玥, 王东升, 阮杨, 乔亦铸, 张芸滔, 李玲, 黄启为, 郭世伟, 凌宁, 沈其荣. 西瓜连作根际土壤微生物群落演替特征[J]. 中国农业科学, 2023, 56(21): 4245-4258.

GUO HanYue, WANG DongSheng, RUAN Yang, QIAO YiZhu, ZHANG YunTao, LI Ling, HUANG QiWei, GUO ShiWei, LING Ning, SHEN QiRong. Characteristics and Succession of Rhizosphere Soil Microbial Communities in Continuous Cropping Watermelon[J]. Scientia Agricultura Sinica, 2023, 56(21): 4245-4258.

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https://www.chinaagrisci.com/CN/Y2023/V56/I21/4245

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	连作茬次 Cropping times	节点数 Total nodes	边数 Total links	平均度 Average degree	网络直径 Network diameter	模块化 Modularity	平均聚类系数 Average clustering coefficient	正相关 Positivity (%)	负相关 Negative (%)
细菌 Bacterial	总网络 Total	380	552	2.905	16	0.833	0.291	45.83	54.17
	对照组 CK	316	384	2.43	15	0.860	0.314	48.70	51.30
	连作2茬 CC2	309	395	2.557	16	0.815	0.321	56.20	43.80
	连作6茬 CC6	358	522	2.916	15	0.820	0.299	45.98	54.02
真菌 Fungal	总网络 Total	202	615	6.089	15	0.468	0.253	46.67	53.33
	对照组 CK	127	196	3.087	14	0.766	0.234	58.67	41.33
	连作2茬 CC2	188	575	6.117	10	0.425	0.252	48.52	51.48
	连作6茬 CC6	171	528	6.175	12	0.405	0.306	44.70	55.30