Piriformospora indica?rescues growth diminution of rice seedlings during high salt stress

Piriformospora indica association has been reported to increase biotic as well as abiotic stress tolerance of its host plants. We analyzed the beneficial effect of P. indica association on rice seedlings during high salt stress conditions (200 and 300 mM NaCl). The growth parameters of rice seedlings such as root and shoot lengths or fresh and dry weights were found to be enhanced in P. indica-inoculated rice seedlings as compared with non-inoculated control seedlings, irrespective of whether they are exposed to salt stress or not. However, salt-stressed seedlings performed much better in the presence of the fungus compared with non-inoculated control seedlings. The photosynthetic pigment content [chlorophyll (Chl) a, Chl b, and carotenoids] was significantly higher in P. indica-inoculated rice seedlings under high salt stress conditions as compared with salt-treated non-inoculated rice seedlings, in which these pigments were found to be decreased. Proline accumulation was also observed during P. indica colonization, which may help the inoculated plants to become salt tolerant. Taken together, P. indica rescues growth diminution of rice seedlings under salt stress.     

Isolation and Molecular Identification of Fungi with Magnesite Enrichment Potential from KÜMAŞ Quarries in Turkey

Abstract

Magnesite is an important raw material used in various industrial applications, especially the production of high-temperature resistant materials. Due to its high reactant nature, magnesite ore is not found in pure form and it contains a great variety of pollutants such as calcium compounds, which restrict its use when exceeding 1% of the ore. Thus, the development of efficient strategies for the removal of pollutants remains a crucial step for magnesite utilization. In this regard, our present work was conducted to isolate and identify active fungal strains that remove calcium pollutants without changing the main magnesium content of the ore. For this aim, magnesite ore samples were collected from two quarries (Turanoca?? and Ortaocak) of KÜMA? Magnesite Inc. and fungal isolation studies were done by using the ore’s flora. Active isolates were chosen according to their CaCO₃ and MgCO₃ dissolving capabilities and identified by using conventional light microscopy and molecular characterization techniques. 71 fungal isolates were obtained from the isolation step and 14 of them were chosen as active isolates that solve calcium compounds while not affecting the magnesium component. The data of the microscopic examination and 18S rDNA gene sequence analysis showed that 14 active strains with magnesite enrichment potential grouped in Aspergillus alliaceus (3), Aspergillus flavus (2), Aspergillus leporis (1), Aspergillus nomius (1), Fusarium tricinctum (2), Penicillium chrysogenum (1) and Penicillium sp. (4).     

一株侵染豌豆蚜的昆虫病原真菌的分离及鉴定

【目的】从采集到的自然染菌的豌豆蚜Acyrthosiphon pisum虫尸分离纯化得到一株病原真菌,定名为TF-2。本研究旨在确定该菌株的分类地位,为豌豆蚜生物防治提供真菌资源。【方法】对自然染菌的豌豆蚜虫尸上寄生真菌TF-2进行回接试验,分离纯化出致病菌株TF-2;在显微镜下配制TF-2菌株不同浓度孢子悬浮液,采用浸渍法和离体叶片饲养法测定其对豌豆蚜成虫的毒力;利用光学显微镜观察菌株形态学特征。PCR扩增TF-2的rDNA-ITS序列并测序,构建系统发育树对TF-2菌株进行分子鉴定。【结果】毒力测定结果表明,TF-2菌株对豌豆蚜成虫表现出很强的致病力,1×10^7孢子/mL处理6 d后豌豆蚜成虫校正死亡率达到100%。TF-2在PDA培养基上菌落呈圆形,白色或淡黄色毡状,菌落背面呈奶油色;菌株孢梗呈瓶状,在菌丝上单生或侧生2~3个,大小为(19-42)μm×(1.1-2.5)μm,基部较粗至尖端逐渐变细,分生孢子长椭圆形,大小为(4.2-11.8)μm×(1.6-2.6)μm。菌丝体产生晶体呈八面体。该菌株的rDNA-ITS序列与长孢蜡蚧菌Lecanicillium longisporum(GenBank登录号:KX426564)的rDNA-ITS核苷酸序列一致性达99%,位于系统发育树的同一分支。【结论】菌株TF-2被鉴定为豌豆蚜的病原真菌长孢蜡蚧菌L.longisporum,对豌豆蚜的生物防治具有潜在的应用价值。     

ZBP1 promotes fungi-induced inflammasome activation and pyroptosis,apoptosis, and necroptosis (PANoptosis)

Candida albicans and Aspergillus fumigatus are dangerous fungal pathogens with high morbidity and mortality, particularly in immunocompromised patients. Innate immune-mediated programmed cell death (pyroptosis, apoptosis, necroptosis) is an integral part of host defense against pathogens. Inflammasomes, which are canonically formed upstream of pyroptosis, have been characterized as key mediators of fungal sensing and drivers of proinflammatory responses. However, the specific cell death pathways and key upstream sensors activated in the context of Candida and Aspergillus infections are unknown. Here, we report that C. albicans and A. fumigatus infection induced inflammatory programmed cell death in the form of pyroptosis, apoptosis, and necroptosis (PANoptosis). Further, we identified the innate immune sensor Z-DNA binding protein 1 (ZBP1) as the apical sensor of fungal infection responsible for activating the inflammasome/pyroptosis, apoptosis, and necroptosis. The Zα2 domain of ZBP1 was required to promote this inflammasome activation and PANoptosis. Overall, our results demonstrate that C. albicans and A. fumigatus induce PANoptosis and that ZBP1 plays a vital role in inflammasome activation and PANoptosis in response to fungal pathogens.     

真菌组蛋白赖氨酸甲基转移酶的研究进展

甲基化修饰是蛋白翻译后修饰的主要方式之一。真菌中,多种赖氨酸甲基转移酶能够执行组蛋白特定位点上赖氨酸的甲基化。组蛋白上赖氨酸的甲基化与真菌DNA的复制、转录以及异染色质的形成相关。甲基化参与了多种生物学过程,如真菌发育、昼夜节律调节、次级代谢基因簇表达、水解酶合成、致病真菌毒力形成。本文结合笔者工作,对目前真菌中已经发现的组蛋白赖氨酸甲基转移酶的命名、分类、结构域特征、催化域的三维结构以及它们所执行的甲基化在各种真菌中的作用进行了总结,提出了目前研究的不足并对未来的研究方向和内容进行了展望。     

植物病原真菌的自噬

作为真核生物中普遍存在的现象,自噬不但实现了对细胞内物质的降解和回收利用,而且与植物病原真菌早期侵染阶段的附着胞发育、膨压升高、菌丝体形成、完成侵染等一系列过程密切相关,并且发挥了重要的作用。本文归纳了植物病原真菌自噬的相关基因和自噬过程;总结了自噬对病原真菌生长发育、致病力的调控和影响;概括了病原真菌自噬所涉及的信号通路;阐明了自噬影响植物病原真菌侵染过程的主要分子机制。为今后以自噬相关基因或蛋白作为靶点来筛选抑制病原真菌侵染的新型药物提供新的策略和思路。     

Mycorrhizal preference promotes habitat invasion by a native Australian orchid: Microtis media

Background and Aims

Mycorrhizal specialization has been shown to limit recruitment capacity in orchids, but an increasing number of orchids are being documented as invasive or weed-like. The reasons for this proliferation were examined by investigating mycorrhizal fungi and edaphic correlates of Microtis media, an Australian terrestrial orchid that is an aggressive ecosystem and horticultural weed.

Methods

Molecular identification of fungi cultivated from M. media pelotons, symbiotic in vitro M. media seed germination assays, ex situ fungal baiting of M. media and co-occurring orchid taxa (Caladenia arenicola, Pterostylis sanguinea and Diuris magnifica) and soil physical and chemical analyses were undertaken.

Key Results

It was found that: (1) M. media associates with a broad taxonomic spectrum of mycobionts including Piriformospora indica, Sebacina vermifera, Tulasnella calospora and Ceratobasidium sp.; (2) germination efficacy of mycorrhizal isolates was greater for fungi isolated from plants in disturbed than in natural habitats; (3) a higher percentage of M. media seeds germinate than D. magnifica, P. sanguinea or C. arenicola seeds when incubated with soil from M. media roots; and (4) M. media–mycorrhizal fungal associations show an unusual breadth of habitat tolerance, especially for soil phosphorus (P) fertility.

Conclusions

The findings in M. media support the idea that invasive terrestrial orchids may associate with a diversity of fungi that are widespread and common, enhance seed germination in the host plant but not co-occurring orchid species and tolerate a range of habitats. These traits may provide the weedy orchid with a competitive advantage over co-occurring orchid species. If so, invasive orchids are likely to become more broadly distributed and increasingly colonize novel habitats.     

Effect of Kocide and Ridomil plus fungicides on the mycoflora of tomato plant in Upper Egypt

Kocide 101 (77% cupric hydroxide) and Ridomil plus (15% metalaxyl and 35% copper oxychloride) were used in the treatment of tomato plants in the field. Generally, the two fungicides exhibited an inhibitive effect on the total and individual counts of glucophilic fungi after different periods of treatment except in some cases, the counts were not affected or promoted compared with the control. Fungal genera and species associated with roots and shoots of tomato plants were isolated from untreated plants as control and then compared with those isolated from plants treated with different doses of fungicides. The most common fungal species recovered from soil and different parts of plants were Alternaria alternata, Aspergillus flavus, A. fumigatus, A. niger, A. terreus, Cochliobolus spicifer, Emericella nidulans, E. nidulans var. lata, Fusarium oxysporum, Gibberella fujikuroi, Mycosphaerella tassiana, Nectria haematococca, Penicillium chrysogenum, P. funiculosum, P. oxalicum, Stachybotrys chartarum and Rhizopus stolonifer.     

Herbal remedies for the management of seed-borne fungal pathogens by an edible plant Decalepis hamiltonii (Wight & Arn)

Abstract

Antifungal activity-guided assay of solvent extracts of Decalepis hamiltonii (Wight & Arn) (Asclepiadaceae) against important phytopathogenic fungi, known to cause diseases in sorghum, maize and paddy proved to be highly significant. Among the five solvent extracts tested, Petroleum ether extract showed highly significant antifungal activity. Phytochemical analysis revealed that the antifungal active principle is a phenolic compound. TLC separation of the phenolic fraction using chloroform as an eluting solvent revealed the presence of seven bands but the antifungal activity was observed only in band five with R_f value 0.77. The antifungal active compound is identified as 2-hydroxy-4-methoxybenzaldehyde based on Nuclear Magnetic Resonance (NMR) and mass spectral analysis. The Minimal inhibitory concentration (MIC) varied between 200 μg ml^?1 and 700 μg ml^?1 depending on the fungal species. Seed treatment of the active principle significantly increased seed germination and seed vigour with a corresponding decrease in seed mycoflora. The antifungal active compound was effective against all the 24 fungal species tested suggesting broad-spectrum antifungal activity. Comparative evaluation of the active principle with the synthetic fungicides revealed that the antifungal activity of the active principle obtained from the plant is better than that of synthetic fungicide. This plant being an edible one can be exploited in the management of seed-borne pathogenic fungi and the prevention of biodeterioration of grains and mycotoxin elaboration during storage.