Inhibition of sporulation and ultrastructural alterations of grapevine downy mildew by the endophytic fungus Alternaria alternata
Inhibition of sporulation and ultrastructural alterations of grapevine downy mildew by the endophytic fungus Alternaria alternata
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DOI：
10.1094/phyto-96-0689
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发表时间：
2006-07-01
期刊：
影响因子：
3.2
通讯作者：
Pertot, I.
中科院分区：
文献类型：
--
作者：
Musetti, R.;Vecchione, A.;Pertot, I.
从葡萄叶片中分离出126株内生微生物，并将其接种于葡萄叶盘上进行霜霉病生防试验。在126个菌株中，只有5个菌株能完全抑制葡萄疫霉的产孢，经鉴定均为链格孢（Alternaria alternata）。利用透射电镜观察了葡萄生疫霉与A. alternata在葡萄藤叶组织中的分布。细胞学观察表明，即使不与A.在Alternata中，葡萄生疫霉菌丝体表现出严重的超微结构改变，例如存在增大的液泡或含有电子致密沉淀物的液泡。吸器坏死，形状不规则或被胼胝质样物质包裹。因此。A的毒性作用。alternata对葡萄褐斑病菌的致病性。目的：研究A.交替通过薄层层析和质子磁共振波谱分析真菌液体培养物。内生菌产生的主要低分子量代谢产物为三种二酮哌嗪类化合物：环（L-丙氨酰丙氨酸-反式-4-羟基-L-脯氨酸）。环（L-亮氨酸-反式-4-羟基-L-脯氨酸）和环（L-丙氨酸-反式-4-羟基-L-脯氨酸）。当以不同浓度施用于葡萄叶盘和温室植物时，三种二酮哌嗪的混合物在Linlitilo P. viticola sponilation中非常有效。
One hundred twenty-six endophytic microorganisms isolated from grapevine leaves showing anomalous symptoms of downy mildew were tested on grapevine leaf disks as biocontrol agents against Plasmopara viticola. Among the 126 microorganisms, only five fungal isolates completely inhibited the sporulation of P. viticola; all of them were identified as Alternaria alternata. Ultrastructural analyses were carried out by transmission electron microscopy to observe cellular interactions between P. viticola and A. alternata in the grapevine leaf tissue. Cytological observations indicated that, even without close contact with A. alternata, the P. viticola mycelium showed severe ultrastructural alterations, such as the presence of enlarged vacuoles or vacuoles containing, electron-dense precipitates. Haustoria appeared necrotic and irregularly shaped or were enclosed in callose-like substances. Therefore. a toxic action of A. alternata against P. viticola was hypothesized. To examine the production of toxic low-molecular-weight metabolites by A. alternata. we analyzed the fungal liquid culture by thin layer chromatography and proton magnetic resonance spectroscopy. The main low-molecular-weight metabolites produced by the endophyte were three diketopiperazines: cyclo(L-pllenylalanine-trans-4-hydroxy-L-proline). cyclo(L-leucine-trans-4-hydroxy-L-proline), and eyclo(L-alanine-trans-4-hyclroxy-L-proline). When applied at different concentrations to both grapevine leaf disks and greenhouse plants, a mixture of the three diketopiperazities was very efficacious in linlitiilo P. viticola sponilation.