China Animal Husbandry and Veterinary Medicine ›› 2024, Vol. 51 ›› Issue (2): 709-718.doi: 10.16431/j.cnki.1671-7236.2024.02.027

• Preventive Veterinary Medicine • Previous Articles     Next Articles

Effects of Different Environmental and Nutritional Conditions on Growth Characteristics,Spore Production and Chitinase Expression of Nematode-trapping Fungi Arthrobotrys conoides

SUN Dianming1, ZHANG Huimei1, LI Ningxing1, SUN Yansen1, LI Ruobing1, QIAO Jun1, CAI Xuepeng2, MENG Qingling1   

  1. 1. College of Animal Science and Technology, Shihezi University, Shihezi 832003, China;
    2. China Institute of Veterinary Drug Control, Beijing 100081, China
  • Received:2023-06-25 Online:2024-02-05 Published:2024-01-29
  • Contact: 国家自然科学基金(32260888、32060801);新疆自治区研究生科研创新计划项目(XJGRI2015038)
  • Supported by:
    The project was supported by the National Key Research and Development Program of China (2019YFC1905301);National Natural Science Foundation of China (22078115,21776108,21690083,22008078).

Abstract: 【Objective】 This experiment was conducted to understand the effects of temperature, pH and different nutritional conditions on the growth and spore production of the nematode-trapping fungi Arthrobotrys conoides (A. conoides), analyse the expression level of chitinase-encoding genes under carbon and nitrogen starvation, and optimise the culture conditions to provide a basis for the expansion culture of the fungi.【Method】 The hyphae of A. conoides AC-shz1 were inoculated at different temperatures (15, 20, 25, 30 and 35 ℃), pH (5.0, 5.5, 6.0, 6.5, 7.0, 7.5 and 8.0), carbon resource (fructose, galactose, glucose, sucrose, maltose, lactose, starch, cellulose and chitin), nitrogen resource (glycine, phenylalanine, peptone, yeast powder, ammonium sulphate and urea) and carbon-nitrogen ratio (1∶1, 5∶1, 10∶1, 20∶1 and 40∶1) of YPSSA medium, and the growth rate and morphology were observed and recorded, and its sporulation capacity was measured.The expression levels of four chitinase-encoding genes was also analyzed by Real-time quantitative PCR under carbon and nitrogen starvation.【Result】 The results showed that A.conoides could grow at a temperature of 15-30 ℃, among which hyphae grew the fastest and had the strongest sporulation capacity at 25 ℃.When the pH was 6.5-7.5, the hyphae growth was the better and the sporulation capacity was the stronger at pH 7.0.It was found that the most suitable sources for hyphae growth and spore production were glucose medium and sucrose medium, among which glucose medium spore production was the highest.The most suitable nitrogen sources were yeast powder and peptone, among which yeast powder medium had the highest spore yield, and the optimal carbon-nitrogen ratio with glucose and yeast powder as carbon and nitrogen sources was 5∶1.Compared with control group, under carbon starvation, the transcript levels of the chitinase of the nematode-trapping fungi A. conoides-14 (AC-14, P<0.01) and chitinase of the nematode-trapping fungi A. conoides-190 (AC-190, P>0.05) genes were up-regulated, the chitinase of the nematode-trapping fungi A. conoides-379 (AC-379, P>0.05) and chitinase of the nematode-trapping fungi A. conoides-483 (AC-483, P<0.01) genes were down-regulated.Under nitrogen starvation, the transcript levels of all four chitinase-encoding genes were extremely significantly down-regulated (P<0.01).【Conclusion】 The optimum temperature for hyphae growth and spore production was 25 ℃, the optimum pH was 7.0, and the optimum carbon-nitrogen sources were glucose and yeast powder, respectively, the optimum carbon-nitrogen ratio of 5∶1, which laid the foundation for the further development of highly effective nematode-trapping fungal biocontrol agents.

Key words: nematode-trapping fungi; Arthrobotrys conoides; temperature; pH; carbon-nitrogen resource; chitinase

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