Subterranean gametophytic axes in the primitive liverwort Haplomitrium harbour a unique type of endophytic association with aseptate fungi
Subterranean gametophytic axes in the primitive liverwort Haplomitrium harbour a unique type of endophytic association with aseptate fungi
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DOI：
10.1046/j.1469-8137.2003.00849.x
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发表时间：
2003-10-01
期刊：
影响因子：
9.4
通讯作者：
Ligrone, R
中科院分区：
文献类型：
--
作者：
Carafa, A;Duckett, JG;Ligrone, R
Haplomitrium是一种原始的苔类，与其他苔类只有遥远的亲缘关系，发育根状地下轴，藏有内生真菌。在这里，我们报告的真菌协会在H。gibbsiae和H.地下轴的表皮细胞分泌丰富的粘液，其中含有无隔的真菌菌丝。该真菌穿透表皮细胞并形成由宿主细胞质包围的细胞内丛枝。感染仅限于表皮细胞在H。gibbsiae，而H.卵叶真菌也感染紧邻的皮层细胞，在那里它形成突出的团块（“肿块”）。In H.在表皮细胞中沿着有丛枝形成类似于gibbsiae的真菌孢子。在这两个物种的肿块进行细胞质变性和崩溃，表现出较短的寿命比arbuscules.The真菌感染Haplomitrium提出的亲和共生协会与肾小球真菌在高等植物（丛枝菌根）和叶状苔。然而，在单藓属真菌形态建成的模式是没有先例的bratites，也没有在高等植物中。考虑到球囊菌门作为最古老的谱系的菌根真菌，和单藓属作为基础的陆地植物菌根真菌，这里描述的协会可能是最原始的陆地植物真菌共生记录的日期。
Haplomitrium, a primitive liverwort taxon with only remote affinities to other liverwort groups, develops root-like subterranean axes harbouring fungal endophytes. Here we report on the fungal association in H. gibbsiae and H. ovalifolium, using light and electron microscopy.The epidermal cells of subterranean axes secrete abundant mucilage that harbours aseptate fungal hyphae. The fungus penetrates the epidermal cells and forms intracellular arbuscules invested by the host cytoplasm. Infection is restricted to epidermal cells in H. gibbsiae, whereas in H. ovalifolium the fungus also infects the cortical cells immediately adjacent, where it forms prominent swellings ('lumps'). In H. gibbsiae similar fungal swellings are formed in the epidermal cells along with arbuscules. In both species the lumps undergo cytoplasmic degeneration and collapse, showing a shorter lifespan than the arbuscules.The fungal infection in Haplomitrium presents affinities with symbiotic associations with glomeromycotean fungi in higher plants (arbuscular mycorrhizas) and thalloid liverworts. However, the pattern of fungal morphogenesis in Haplomitrium has no precedent in bryophytes nor in higher plants.Considering the Glomeromycota as the most ancient lineage of mycorrhizal fungi, and Haplomitrium as basal in land plant phylogenies, the association described here may be the most primitive land plant-fungal symbiosis documented to date.