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Acta Prataculturae Sinica ›› 2025, Vol. 34 ›› Issue (1): 135-150.DOI: 10.11686/cyxb2024122

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Effect of the Epichloë endophyte on the root morphology of Stipa purpurea infected by the hemiparasite Pedicularis kansuensis

Yuan LI1,2,3(), Si-yu MENG1(), Xiao-yun FENG1,2,3, Gen-sheng BAO1,2,3()   

  1. 1.Academy of Animal Science and Veterinary Medicine,Qinghai University,Xining 810003,China
    2.Qinghai Academy of Animal Science and Veterinary Medicine,Xining 810016,China
    3.Key Laboratory of Superior Forage Germplasm in the Qinghai-Tibetan Plateau,Xining 810016,China
  • Received:2024-04-10 Revised:2024-06-05 Online:2025-01-20 Published:2024-11-04
  • Contact: Gen-sheng BAO
  • About author:First author contact:These authors contributed equally to this work.

Abstract:

The root hemiparasite Pedicularis kansuensis derives nutrients from its host, Stipa purpurea, through structures known as haustoria, and this suppresses the growth of S. purpurea. Previous studies have shown that Epichlo? endophytes, microorganisms that form a symbiotic relationship with their host, are able to ameliorate the damage to S. purpurea caused by the hemiparasite P. kansuensis. The potential mechanism of this effect may be that Epichlo? positively regulates the root morphology of its host infected with the hemiparasite. In this study, we conducted a pot experiment to compare the root morphology between endophyte-infected (E+) and endophyte-free (E-) S. purpurea parasitized by P. kansuensis at different densities. Our results indicate that parasitism by P. kansuensis decreased both the shoot and root biomass of S. purpurea, and resulted in substantially decreased values of all the measured root morphological traits. The values of biomass and root morphological traits of S. purpurea sharply decreased with increasing density of P. kansuensis. The values of biomass and root morphological parameters of S. purpurea parasitized by P. kansuensis were higher in the E+ group than in the E- group. A structural equation model indicated that as the total length, surface area, and topological index of S. purpurea roots decreased, the biomass of S. purpurea decreased. The inhibitory effect of P. kansuensis on the growth of S. purpurea was positively related to the density of P. kansuensis. By contrast, the presence of the Epichlo? endophyte facilitated the accumulation of biomass of S. purpurea parasitized by P. kansuensis through altered root morphological traits including root total length and surface area, and the number of externally connected grass roots. In conclusion, Epichlo? endophytes are able to alleviate stress imposed by a hemiparasite upon P. kansuensis by facilitating change in its root morphological traits. Our findings reveal new information about the mutualistic relationship between Epichlo? endophytes and their hosts, and demonstrate that the introduction of the Epichlo? symbiont isan effective biological method to control hemiparasitic weeds.

Key words: Epichlo? endophyte, Stipa purpurea, Pedicularis kansuensis, root hemiparasite plant, root morphology