红树林叶片感染真菌后可能会向非健康状态变化,为了比较三种红树林植物海漆、秋茄和桐花树健康与非健康叶片真菌类群,明确其中真菌类群的差异,该研究从广西茅尾海红树林自然保护区采集海漆、秋茄和桐花树健康与非健康叶片,对叶片中真菌分离纯化并进行形态学鉴定,提取真菌的DNA,采用RAPD多样性、ITS序列对真菌进行分子鉴定.经过初步分析,从海漆、秋茄和桐花树中共分离到157株真菌,经过形态学和RAPD分析,可能为19种不同的真菌.采用真菌ITS序列对19种真菌代表性菌株进行分析,结果表明:19种真菌都属于子囊菌门,有15株与已有的真菌ITS序列相似性在97%以上;有4株相似性低于95%,可能为新种.海漆健康和非健康叶片分别分离到真菌7种和5种,健康叶片含了非健康叶片中所有真菌;秋茄健康和非健康叶片分离到真菌1种和9种,且健康叶片中分离到的内生真菌Dothiorella aegiceri也包含于非健康叶片分离的真菌中;桐花树健康和非健康叶片分离到真菌1种和3种,且桐花树分离的内生真菌也是Dothiorella aegiceri,其包含于非健康叶片中分离到的真菌.该研究证明,海漆内生真菌同时也可能是植物病原菌,内生真菌与植物病原菌没有明显界限;另一方面,该研究发现秋茄和桐花树叶片的病变是由外部的病原真菌感染引起,感染的原因可能是昆虫叮咬红树林植物后留下了创口,这些创口有利于真菌的感染.%Mangrove may become unhealthy after infected by fungi.In order to compare the fungi in healthy and unhealthy leaves of mangrove plants, the healthy and unhealthy leaves of Excoecaria agallocha, Kandelia candel and Aegiceras corniculata were collected from Maowei Sea National Mangrove Reserve, including 82, 82 and 81 of them from healthy leaves, and 90, 86 and 90 from healthy leaves respectively.The fungi were isolated and purified from leaves and identified by morphological characters, then the DNA of fungi were extracted and analysed by RAPD and ITS sequence.After preliminary analysis, 157 strains of endophytic fungi were isolated, and they were classified into nineteen kinds through morphology and RAPD analysis.The nineteen strains of fungi were analysed by ITS sequence.The results showed that nineteen strains belonged to Ascomycetes, and the similarity between fifteen isolates and the existed ITS sequences in GenBank was more than 97%.Among them, the ITS sequences of four endophytic fungi shared less than 95% similarity with the ITS sequences available in GenBank, so they may belong to new species.Seven species of fungi were isolated from healthy leaves of Excoecaria agallocha, and five from unhealthy leaves, and the fungi of unhealthy leaves was included in the fungi from healthy leaves.One fungus was isolated from healthy leaves of Kandelia candel, and nine from unhealthy leaves, and the fungus of unhealthy leaves was included in the fungi from healthy leaves, and Dothiorella aegiceri was both isolated in healthy and unhealthy leaves;One fungus was isolated from healthy leaves of Aegiceras corniculata, and three from unhealthy leaves, and Dothiorella aegiceri was both isolated in healthy and unhealthy leaves too.Our result is interesting.Firstly, our research demonstrated that the discriminate between fungi pathogen and endophytic fungi was not very clear in some plants, because the endophytic fungi of Excoecaria agallocha developed into plants pathogens;secondly, we found that the pathological changes in Kandelia candel and Aegiceras corniculata was caused by external fungi pathogen, and this was followed by biting of insect on leaves, and the wound were in favor of infections of fungi pathogen.
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