Page 6 - 《广西植物》2023年第6期
P. 6

9 9 2                                  广  西  植  物                                         43 卷
                  ( 1. Agricultural College/ Peony Collegeꎬ Henan University of Science and Technologyꎬ Luoyang 471023ꎬ Henanꎬ Chinaꎻ 2. Orchid
                    Conservation & Research Center of Shenzhen and the National Orchid Conservation Center of Chinaꎬ Shenzhen Key Laboratory
                          for Orchid Conservation and Utilizationꎬ Key Laboratory of National Forestry and Grassland Administration
                                  for Orchid Conservation and Utilizationꎬ Shenzhen 518114ꎬ Guangdongꎬ China )

                 Abstract: Holcoglossum kimballianum is a rare and endangered orchidꎬ and its wild populations are in urgent need of
                 conservation. Endophytic fungi and bacteria are important to the growth and development of orchids. In order to assess the
                 diversity of H. kimballianum endophytes and the impact of sampling methods on the endophytesꎬ high ̄throughput
                 sequencing technology was used to study the diversity of endophytes in fresh and silica gel ̄dried roots of H. kimballianum

                 in ex ̄situ conservation. The results were as follows: (1) The species compositions of endophytic fungi and endophytic
                 bacteria were distinctly different in fresh and silica gel ̄dried roots of H. kimballianum. There were total of 6 phyla 46
                 families 51 genera of endophytic fungi and 15 phyla 105 families 178 genera of endophytic bacteria annotated in the roots
                 of the H. kimballianum. After silica gel ̄driedꎬ the endophytic fungi of the H. kimballianum had total of 6 phylaꎬ 88
                 familiesꎬ 116 generaꎬ and the endophytic bacteria had total of 21 phylaꎬ 154 familiesꎬ 336 genera. (2) Endophytes in
                 the roots of H. kimballianum in ex ̄situ conservation were of richness and diversity of endophytic bacterial community was
                 much higher than that of endophytic fungal community. After silica gel ̄driedꎬ the α diversity indices of endophytic fungi
                 increased and the β diversity indices decreasedꎬ while the α diversity indices of endophytic bacteria decreased and the β
                 diversity indices increased. (3) Significantly different fungi Psathyrella candolleana and Colletotrichum tofieldiae only
                 existed in the endophytic fungal communities of fresh roots. The significantly different bacteria in roots of fresh
                 Hocoglossum kimballianum was Marseillaꎬ and the significantly different bacteria in the silica gel ̄dried roots included
                 Beijerinckiaceaeꎬ Xanthobacteraceae and Bradyrhizobium. ( 4) Co ̄occurrence network analysis revealed that the
                 dominant species and interaction patterns in the endophytic communities of the roots of Hocoglossum kimballianum were
                 changed after silica gel ̄dried. In summaryꎬ different sampling treatments can affect the community structure of the
                 endophytes in the roots of H. kimballianumꎬ and it is advisable to use fresh root samples when studying the endophytes of
                 orchids. The results provide an endophytic data basis for wild populations conservation and artificial cultivation of
                 H. kimballianumꎬ and also provide a reference for sampling methods of endophytic microorganisms in orchids.
                 Key words: Holcoglossum kimballianumꎬ endophytic fungiꎬ endophytic bacteriaꎬ freshꎬ silica gel ̄driedꎬ diversity



                生态系统中ꎬ植物与大量微生物相互作用ꎬ这                           (Ceratobasidium)ꎬ将该菌株与手参种子进行共培
            些微生物在地下和地上植物器官的内部和外表面                              养ꎬ发现它能明显促进手参种子原球茎的形成且最

            都有 定 殖 ( Compant et al.ꎬ 2019ꎻ Escudero et al.ꎬ    终分化成幼苗ꎮ 杨文科(2020) 通过迁地共生萌发
            2019)ꎬ这些与植物相关的微生物群落统称为植物                           从白旗兜兰(Paphiopedilum spicerianum)原球茎中分
            微生物群(Marchesi et al.ꎬ 2015)ꎮ 细菌和真菌是植               离出胶膜菌属(Tulasnella)ꎬ它能有效促进其种子萌
            物微生物群的主要组成部分ꎬ它们对植物微生态系                             发直到幼苗阶段ꎮ 这都表明内生真菌在兰科植物
            统的平衡起到重要作用ꎮ 植物中的内生菌是指其                             的生长发育中具有极大的促进作用ꎮ 据不完全统
            生活史的一定阶段或全部阶段ꎬ生活于健康植物中                             计ꎬ已报道的常见兰科植物菌根真菌有 69 属ꎬ分别

            的各种组织和器官的细胞间隙或细胞内的菌类ꎮ                              隶 属 于 担 子 菌 门 ( Basidiomycota )、 子 囊 菌 门
            内生真菌对兰科植物非常重要ꎬ兰科菌根真菌属于                             (Ascomycota)及毛霉门(Mucoromycota)的 50 科(王
            内生真菌ꎬ它们是兰科植物生长发育各个阶段不可                             美娜等ꎬ2021)ꎮ
            或缺的关键因素ꎬ能直接参与兰科植物根系甚至整                                 此外ꎬ兰科植物的内生菌中还存在大量有益的
            个植株的生理代谢活动ꎬ从而保障兰科植物的生                              内生细菌ꎬ这些有益的内生细菌对兰科植物的生长
            长、个体间竞争以及对病原体的防御( 盖雪鸽等ꎬ                            发育 也 发 挥 着 积 极 的 促 进 作 用ꎬ Tsavkelove 等
            2014ꎻ Li et al.ꎬ 2021 )ꎮ 高 越 等 ( 2019 ) 从 手 参      (2007)研究表明内生细菌能促进兰科植物种子萌
            (Gymnadenia conopsea) 根 系 中 分 离 出 角 担 菌 属          发、光合形态建成、缓解非生物胁迫及生长发育等ꎮ
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