健康与患病刺梨植株可培养叶际真菌菌群差异比较

本研究比较了健康与患叶斑病刺梨植株叶际真菌群落特征差异,以期探索病原菌的潜在来源,为人工构建具拮抗功能群落和刺梨叶斑病的生物防控提供参考。通过可培养方法对不同健康状况的刺梨叶际真菌进行分离培养,结合形态学和分子系统学对菌株进行综合鉴定;利用FUNGuild平台对真菌进行功能注释;结合根际、根部真菌作拆分网络分析探索病原菌的潜在来源。本研究结果表明：1）刺梨叶际真菌具有丰富的多样性。从刺梨叶际8个样品中共分离到真菌266株,其隶属于3门、6纲、13目、30科、46属中的61个种。其中,健康植株叶际内生真菌（LHE）包括8属10种27株,附生真菌（LHS）包括33属37种77株。患病叶际内生真菌（LDE）分离到7属10种38株;附生真菌（LDS）分离到31属35种124株。2）不同样品的真菌优势属和特有类群有差异。不同健康状况下叶际附生真菌的优势属均为拟盘多毛孢属Pestalotiopsis,但二者的相对多度存在差异,LHS为11.49%,LDS为32.26%;内生真菌优势属二者均为链格孢属Alternaria,但相对多度各异,LHE为33.33%,LDE为63.16%。其中,LHE特有类群为盘长孢状刺盘孢 Colletotrichum gloeosporioides和果生刺盘孢Colletotrichum fructicola等8种;LDE特有类群为茄链格孢 Alternaria solani和Didymella sinensis 等8种;LHS特有类群是草酸青霉Penicillium oxalicum和Peniophora crassitunicata等21种;LDS特有类群是尖孢镰刀菌Fusarium oxysporum、赭绿青霉Penicillium ochrochloron和易脆毛霉Mucor fragilis等19种。3）不同样品叶际真菌功能不同。经FUNGuild解析表明,LHS、LHE和LDE的叶际真菌功能群主要以腐生型为主,LDS则主要以植物病原菌群为主。本研究结果初步揭示刺梨植株健康与患叶斑病叶际间真菌多样性、群落组成及营养功能群存在差异,植株健康状况与其真菌群落特征密切相关;叶斑病病原菌主要源于刺梨叶际的附生微生物群。

Comparison of culturable phyllosphere fungal flora between healthy and diseased Rosa roxburghii

Phyllospere fungal flora of R. roxburghii was investigated, and the differences in the characteristics of phyllosphere fungal communities between healthy and diseased leaves of R. roxburghii were compared. The phyllosphere fungi on the leaves with different health conditions were isolated and cultured, and the isolates were comprehensively identified by combining morphology and molecular phylogeny. The fungi were functionally annotated by using the FUNGuild platform. In combination with the rhizosphere and root fungi, the potential sources of pathogenic fungi were explored by splitting network analysis. The results indicated that there were rich fungal diversity in phyllosphere of R. roxburghii. A total of 266 fungal isolates was obtained from 8 samples of R. roxburghii phyllosphere, belonging to 61 species in 3 phyla, 6 classes, 13 orders, 30 families and 46 genera. Among them, phyllosphere endophytic fungi of healthy plants (LHE) totalled 27 isolates of 10 species in 8 genera, and the epiphytic fungi of healthy plants (LHS) totalled 77 isolates of 37 species in 33 genera. Endophytic fungi in diseased leaves (LDE) totalled 38 isolates belonging to 10 species in 7 genera. Epiphytic fungi in diseased leaves (LDS) totalled 124 isolates belonging to 35 species in 31 genera. The dominant genus of epiphytic fungi was Pestalotiopsis in both healthy and diseased leaves, and the relative abundance was 11.49% for LHS and 32.26% for LDS. The dominant genus of endophytic fungi was Alternaria, and the relative abundance was 33.33% for LHE and 63.16% for LDE. There were 8 unique taxa in LHE such as Colletotrichum gloeosporioides and Colletotrichum fructicola, 8 unique taxa in LDE including Alternaria solani and Didymella sinensis, 21 unique taxa in LHS including Penicillium oxalicum and Peniophora crassitunicata and 19 unique taxa in LDS including Fusarium oxysporum, Penicillium ochrochloron and Mucor fragilis. FUNGuild analysis showed that the phyllosphere fungal functional groups in LHS, LHE and LDE were mainly saprophytic, while those in LDS mainly phytopathogenic. The fungal diversity, community composition, and trophic functional groups between healthy and diseased leaves of R. roxburghii were different, and plant health state was closely related to the fungal community characteristics; the pathogens of leaf spot diseases mainly came from epiphytic microbiota.