The goal of the present research was to ascertain the potential root endophytic fungi against Dematophora necatrix, Hartig, the causal pathogen of white root rot in apples; however, it has an expanded range of hosts across different fruit trees. Out of 36 endophytic fungi segregated from symptomless roots of apple, wheat, maize, marigold, cherry, and garlic plants, only 9 isolates showed inhibitory effect during preliminary screening and were further assayed under in vitro, pot, and field conditions against the white root rot pathogen/disease. Under in vitro conditions, maximum mycelial inhibition of 81.48% was obtained with the isolate Aspergillus aculeatus strain C2. Microscopic studies on interaction between fungal endophyte with hyphal tips of D. necatrix revealed various morphological abnormalities in the hyphae. In glasshouse conditions, seed treatment pursued by soil application with Crinipellis tabtim strain M8 isolate was highly effective and exhibited 93.55% disease control. Similarly, under field conditions, the overall maximum disease control was exhibited by Crinipellis tabtim strain M8 (84.95%). The most promising root endophytes that were identified rely on morphological and ITS sequence analysis. Root colonization assay was performed which revealed maximum endosphere and rhizosphere colonization with Crinipellis tabtim strain M8. Additionally, confocal microscopic illustrations of transverse sections of root cells tenanted by fungal endophytes as compared to untreated control suggested the persistence and establishment of endophytes in the endosphere of apple seedlings. These findings present the first report on colonization of apple roots by fungal root endophytes suggesting an alternative and sustainable approach for management of white root rot disease.

中文翻译：

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反对根瘤菌（Dematophora necatrix）的真菌根内生菌的筛选，鉴定和定殖：果树无处不在的病原体

本研究的目的是确定针对苹果白根腐病病原体Dematophora necatrix，Hartig的潜在根内生真菌。但是，它在不同果树上的寄主范围有所扩大。从苹果，小麦，玉米，万寿菊，樱桃和大蒜植物的无症状根系中分离出来的36种内生真菌中，只有9种分离物在初步筛选期间显示出抑制作用，并在体外，盆栽和田间条件下针对白根进行了进一步测定腐烂病原体/疾病。在体外条件下，分离的棘孢曲霉菌株C2获得的最大菌丝抑制率为81.48％。真菌内生菌与D. necatrix菌丝尖端之间相互作用的显微镜​​研究揭示了菌丝中的各种形态异常。在温室条件下，通过应用Crinipellis tabtim菌株M8分离物在土壤中进行的种子处理非常有效，并具有93.55％的病害控制能力。类似地，在田间条件下，总体上最大的疾病控制表现为Crinipellis tabtim菌株M8（84.95％）。确定的最有希望的根内生菌依赖于形态学和ITS序列分析。进行了根定植测定​​，揭示了用crinipellis tabtim菌株M8最大的内球和根际定植。此外，与未经处理的对照相比，被真菌内生菌租用的根细胞横切面的共聚焦显微镜插图表明，内生菌在苹果幼苗的内层球体内持久存在。