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目的研究假鹰爪(Desmos chinensis Lour.)茎、叶组织中内生真菌的分布及其rDNA ITS序列系统发育。方法采用石蜡永久制片法观察鹰爪茎、叶组织显微结构,细胞化学法确定内生真菌的分布,平板分离法分离培养内生真菌,对分离菌株进行rDNA ITS区PCR扩增和测序,通过rDNA ITS序列进行内生真菌的分类鉴定及系统发育分析。结果假鹰爪茎中的内生真菌主要分布在韧皮部薄壁细胞,叶中主要分布主脉上方厚角细胞以内的薄壁细胞、栅栏组织、海绵组织。共分离14株内生真菌,分属于拟茎点霉属(Phomopsis)、刺盘孢属(Colletotrichum)和球座菌属(Guignardia),其中拟茎点霉(P.spp.)占总菌株数的57.1%,其次为胶孢刺盘孢(C.gloeosporioides)和芒果球座菌(G.mangiferae)。结论内生真菌在假鹰爪茎、叶组织中均有分布,无明显组织特异性;rDNA ITS序列系统发育较好的揭示了假鹰爪内生真菌的系统进化关系。
Objective To study the distribution of endophytic fungi in stems and leaves of Desmos chinensis Lour. And the phylogenetic relationship of rDNA ITS sequences. Methods The paraffin wax was used to observe the microstructure of the stem and leaf tissue of eagle’s paw. The distribution of endophytic fungi was determined by cytochemical method. Endophytic fungi were isolated and cultured by plate separation method. The isolates were amplified by PCR and sequenced. Identification and phylogenetic analysis of endophytic fungi by rDNA ITS sequences. Results The endophytic fungi in the stems and leaves of pseudacorn claw were mainly distributed in the phloem parenchyma cells. The main distribution of parenchymatous cells, palisade tissue and spongy tissue in the leaf was mainly in the thick angle cells above the main vein. A total of 14 strains of endophytic fungi were isolated, belonging to Phomopsis, Colletotrichum and Guignardia, of which P.spp. Followed by 57.1% of C. gloeosporioides and G. mangiferae. Conclusion Endophytic fungi are distributed in the stem and leaf tissue of the falcon claw without obvious tissue specificity. The systematic phylogenetic relationship of rDNA ITS sequences reveals the phylogenetic relationship of endophytic fungi.