Effect of the Epichlo? endophyte on the root morphology of Stipa purpurea infected by the hemiparasite Pedicularis kansuensis
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 Epichloë 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 Epichloë 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 Epichloë 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,Epichloë 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 Epichloë endophytes and their hosts,and demonstrate that the introduction of the Epichloë symbiont is an effective biological method to control hemiparasitic weeds.
国家科技期刊平台
NSTL
万方数据
