Evaluation of characteristics of Simplicillium lanosoniveum on pathogenicity to aphids and in vitro antifungal potency against plant pathogenic fungi
Abstract
This study aimed to evaluate the aphidicidal and antifungal activities of Simplicillium lanosoniveum in laboratory conditions . S. lanosoniveum isolate Cs0701 shown to be pathogenic to the aphid s, Aphis gossypii , Ceratovacuna lanigera and Hysteroneura setariae . The data showed that isolate Cs0701 exudates had greater mycelial growth -inhibiting effects on plant pathogenic fungi, Scleroti um rolfsii, Alternaria brassicicola and Rhizoctonia solani , in cellophane paper antibiosis test. In addition, mycelial growth of Cochliobolus miyabeanus, Curvularia lunata and Fusarium sp. were partially inhibited by isolate Cs0701 exudates . The culture fi ltrates of isolate Cs0701 were screened for their antifungal activity against the plant pathogenic fungi. The results revealed that A. brassicicola, Cochliobolus miyabeanus and Curvularia lunata conidial germination was inhibit ed by isolate Cs0701. The culture filtrate was also able to inhibit conidial germination of jasmine orange (Murraya paniculata) powdery mildew, Oidium murrayae . However , plant host range tests showed that isolate Cs0701 was not pathogenic to Pistia stratiotes , Eichhornia crassipes , Lemma perpusilla and Glycine max. Taken together, these findings provide convincing experimental evidence that S. lanosoniveum isolate Cs0701 is biologically active against both aphids and plant pathogenic fungi including powdery mildew. Pot and field trials are necessary to con firm efficacy of S. lanosoniveum against aphids and plant pathogenic fungi.
Keywords
Download Options
Introduction
Salvinia auriculata Aublet (eared salvinia) and S. molesta Mitchell (giant salvinia) are two exotic floating ferns sold at local flower markets and aquarium shops. Brown Spot of S. auriculata and S. molesta caused by Simplicillium lanosoniveum (J.F.H. Beyma) Zare & Gams 2001 was reported in Taiwan (Chen et al., 2008). Studies of tested isolate of S. lanosoniveum grown on potato dextrose agar plates at different temperatures showed that optimum temperature for mycelial growth, conidial germination and sporulation was 25°C (unpublished data). Simplicillium, was associated with ticks, nematodes, and scale insects as well as rusts, such as Aecidium elaeagni-latifoliae, Hemileia vastatrix (coffee rust) and Uromyces pencanus (Gams and Zare, 2003; Bischoff and White, 2004; Polar et al., 2005; Baiswar et al., 2014). S. lanosoniveum was a mycoparasite of soybean rust caused by Phakopsora pachyrhizi in Louisiana and Florida, USA. It was found coiling within sori and around urediniospores and showed a trophic attraction to rust sori, extending from sorus to sorus. The mycophilic and disease-suppressive nature of S. lanosoniveum on P. pachyrhizi, the soybean rust pathogen was recently documented. However, S. lanosoniveum did not cause lesions or necrosis on soybean (Ward et al., 2011; 2012). S. chinense F. Liu & L. Cai was reported as pathogens of plant parasitic nematodes (Liu and Cai, 2012; Zhao et al., 2013). Lecanicillium and Simplicillium (both formerly Verticillium spp.) are included in the family Cordycipitaceae, which also includes the anamorphic genera Beauveria and Isaria (Zare and Gams, 2001; Sung et al., 2007). Lecanicillium spp. were reported as pathogens of aphids, scale insects, ticks, nematodes, and whiteflies (Pirali-Kheirabadi et al., 2007; Cuthbertson et al., 2008; Arevalo et al., 2009; Liu et al., 2009).
Fungal phytopathogens pose serious problems worldwide in the cultivation of economically important crops, especially in the subtropical and tropical regions. Microbial antagonists are widely used for the biocontrol of fungal plant diseases due to their perceived increased level of safety and minimal environmental impacts. Fungal biological control agents have several mechanisms of action including mycoparasitism, production of antibiotics or enzymes, competition for nutrients and the induction of plant defense responses that allow them to control pathogens (Brimner and Boland, 2003). The development of new biocontrol products against plant diseases required the process involves screening of high numbers of candidate antagonists and to fulfill many different requirements (Köhl et al., 2011).
S. lanosoniveum has recently been discovered as a dual pathogen of aquatic ferns, Salvinia spp., and soybean rust, P. pachyrhizi (Chen et al., 2008; Ward et al., 2012). The objectives of this study were to examine the pathogenicity of S. lanosoniveum to plants and aphids and the in vitro antifungal activity of S. lanosoniveum culture filtrates on plant pathogenic fungi.
