不同轮作模式对马铃薯根际土壤真菌群落的影响

【目的】揭示不同轮作模式对马铃薯根际土壤真菌群落的影响，为土壤健康管理及维持马铃薯可持续生产提供科学依据。【方法】分别对旱地轮作和水旱轮作模式下的马铃薯健康植株及发生细菌性软腐病植株的根际土壤样品进行采集，将旱地轮作和水旱轮作模式下健康植株根际土壤样品分别记为HD.J和SH.J，将旱地轮作和水旱轮作模式下发生细菌性软腐病植株根际土壤样品分别记为HD.B和SH.B。利用Illumina高通量测序平台，分析真菌核糖体DNA内转录间隔区1（ITS1）的序列，比较在2种轮作模式下马铃薯根际土壤真菌群落特征的差异。【结果】马铃薯健康植株的根际土壤真菌群落组成和多样性特征在2种轮作模式下相似，主坐标分析也显示HD.J和SH.J的距离很接近。HD.J和SH.J在门水平已知的真菌类群中均以子囊菌门和担子菌门为优势菌门，子囊菌门的相对丰度分别为33.0%和30.0%，担子菌门的相对丰度分别为3.8%和9.6%；HD.J和SH.J的门水平未知真菌丰度分别为63.0%和60.0%。HD.J和SH.J的共有优势目是子囊菌门的肉座菌目、柔膜菌目、格孢腔菌目和粪壳菌目及担子菌门的伞菌目，推测是马铃薯根际土壤真菌群落的核心类群。2种轮作模式下的马铃薯根际土壤真菌群落Alpha多样性依次为HD.B>；SH.J>；HD.J>；SH.B。HD.B和SH.B中担子菌门的相对丰度明显高于HD.J和SH.J，其中SH.B中担子菌门的地星目真菌丰度高达82.8%，HD.B中担子菌门的银耳目丰度为18.6%；HD.B中还有2个优势属分别是可引起马铃薯黄萎病的轮枝孢属和引起水稻菌核杆腐病的双曲孢属，丰度分别为6.8%和5.9%。通过比对FUNGuild数据库预测根际土壤真菌营养型，发现HD.J只有病原营养型真菌相对丰度较高（20.6%），HD.B的病原营养型真菌、腐生营养型真菌和病原—腐生—共生营养型真菌的相对丰度分别为15.4%、18.8%和21.4%；SH.J和SH.B的腐生营养型真菌相对丰度分别为28.2%和10.2%，其他营养型真菌的相对丰度总和分别为4.6%和4.9%。【结论】马铃薯根际土壤真菌优势类群在2种轮作模式下保持稳定，推测是马铃薯根际土壤真菌群落的核心类群，对维持马铃薯健康生长具有重要意义。旱地轮作模式可能更有利于根际土壤中病原营养型真菌的富集，发病马铃薯可能更有利于根际土壤中腐生营养型真菌生长，导致土壤微生态平衡被破坏，及时清理发病植株残体可加快恢复土壤健康。

Effects of different crop rotation modes on fungal community in potato rhizosphere soil

【Objective】The purpose of this study was to reveal the distribution features of fungi in potato rhizosphere soil when bacterial disease occurred or not in paddy-upland rotation mode and upland rotation mode, respectively, so as to provide reference for soil health management and sustainable potato production.【Method】The rhizosphere soil samples of healthy potato plants/plants with bacterial disease were collected in upland rotation and paddy-upland rotation modes, respectively. The rhizosphere soil samples of healthy potato plants in upland rotation and paddy-upland rotation were labeled as HD.J and SH.J, respectively, and those of plants with bacterial disease in upland rotation and paddy-upland rotation were labeled as HD.B and SH.B, respectively. Using Illumina high-throughput sequencing platform, the fungal ribosomal DNA internal transcribed spacer 1(ITS1) was analyzed to compare the distribution characteristics of fungal communities in rhizosphere soil in two rotation modes.【Result】The composition and diversity of fungal community in rhizosphere soil of healthy potato plants were similar in the two rotation patterns. Principal coordinate analysis also showed that the distance between the fungal community structure of HD.J and SH.J was close. For known phyla of HD.J and SH.J, Ascomycota and Basidiomycota were the dominant phyla. Among the known fungal communities, the relative abundance of Ascomycota was 33.0% and 30.0%, and that of Basidiomycota was 3.8% and 9.6% in HD.J and SH.J, respectively. The phyla of HD.J and SH.J were mainly unknown fungi, accounting for 63.0% and 60.0%, respectively. Hypocreales, Helotiales, Pleosporales and Sordariales belonging to Ascomycota and Agaricales belonging to Basidiomycota were the common dominant orders of both HD.J and SH.J, which might be the core group of potato rhizosphere soil fungal community. When potato bacterial disease occurred, the fungal community Alpha-diversity of the two rotation patterns was HD.B>SH.J>HD. J>SH.B. The relative abundances of Basidiomycota of HD.B and SH.B were higher than those of HD.J and SH.J. Among them, the abundance of Geastrales was up to 82.8% in SH.B while the abundance of Tremellales was 18.6% in HD.B. Two dominant genera in HD.B were Verticillium, which could cause Verticillium wilt of potato, and Nakataea, which could cause sclerotinia and stalk rot of rice, with abundance of 6.8% and 5.9% respectively. Using FUNGuild database for prediction of fungal trophic modes, comparing that there was only one trophic mode, pathotroph, was dominant in HD.J (20.6% relative abundance), there were dominant modes, pathotroph, saprotroph, and pathotroph-saprotroph-symbiotroph in HD.B(with 15.4%, 18.8% and 21.4% of relative abundance, respectively). The relative abundances of saprotroph in SH.J and SH.B were 28.2% and 10.2%, respectively, and the total abundances of other trophic modes were 4.6% and 4.9%.【Conclusion】The dominant fungal populations in potato rhizosphere soil in the two rotation patterns remain stable, which suggests that they may be the core group of rhizosphere fungi and they are of great significance to maintain the healthy growth of potato. Upland rotation mode may be more conducive to the accumulation of pathotroph fungi. Diseased potato may be more conducive to the accumulation of saprotroph fungi. It is important to remove diseased plant residues in time in order to restore the microecosystem balance of soil.