Transformation of the endophytic fungus Acremonium implicatum with GFP and evaluation of its biocontrol effect against Meloidogyne incognita

• Published in: World journal of microbiology & biotechnology 2015-04, Vol.31 (4), p.549-556
• Main Authors: Yao, Yu-Rong, Tian, Xue-Liang, Shen, Bao-Ming, Mao, Zhen-Chuan, Chen, Guo-hua, Xie, Bing-Yan
• Format: Article
• Language: English
• Subjects: Acremonium; Acremonium - genetics; Acremonium - growth & development; Acremonium - physiology; Analysis; Animals; Antibiosis; Applied Microbiology; Biochemistry; Biological control; Biomedical and Life Sciences; Biotechnology; Confocal; confocal laser scanning microscopy; egg shell; Eggs; endophytes; Endophytes - genetics; Endophytes - growth & development; Endophytes - physiology; Environmental Engineering/Biotechnology; Enzymes; Experiments; Fungi; Green Fluorescent Proteins - genetics; Green Fluorescent Proteins - metabolism; Hatching; Host plants; hyphae; Hyphae - genetics; Hyphae - growth & development; Hyphae - physiology; Life Sciences; Lycopersicon esculentum; Lycopersicon esculentum - parasitology; Meloidogyne incognita; Microbiology; Microscopy; mortality; mutants; nematicidal properties; Nematoda; Nematodes; Original Paper; Parasitism; Parasitology; Pest Control, Biological - methods; Plant Diseases - parasitology; Plant tissues; Plants (organisms); protoplasts; roots; Shells; Studies; Symbiosis; Tomatoes; toxicity; Transformation, Genetic; Transformations; Tylenchoidea - microbiology; Tylenchoidea - physiology; Worms; xylem
• ISSN: 0959-3993; 1573-0972
• DOI: 10.1007/s11274-014-1781-2

Acremonium implicatum is an endophytic fungus with biocontrol potential against Meloidogyne incognita based on its opportunistic egg-parasitic, hatching inhibition, and toxic properties. To understand its mode of plant endophytism and opportunistic egg parasitism, GFP-tagged A. implicatum was constructed by PEG-mediated protoplast transformation. By laser scanning confocal microscopy (LSCM), we evaluated the endophytism and opportunistic egg parasitism of a stable gfp transformant (Acr-1). Acr-1 could colonize epidermal tissue, cortical tissue, and xylem of roots and form a mutualistic symbiosis with tomato host plants. LSCM of Acr-1 infecting M. incognita eggs revealed that hyphae penetrated the shell and grew inside eggs to form trophic hyphae. A large number of hyphae enveloped parasitized eggs. In addition, the egg shell integrity was destroyed by fungal penetration. The percentage of egg parasitism was 33.8 %. There were no marked differences between the wild type and mutant in nematode second-stage juvenile mortality and egg hatching and in fungal control efficiency in a pot experiment. In conclusion, gfp-transformation did not change the nematicidal activity of A. implicatum and is a tool to examine the mode of plant endophytism and opportunistic egg parasitism of A. implicatum.