The impacts of space mutation and host genotype on endophyte role in host perennial ryegrass stress tolerance

Abstract

Aims This study reveal if host genotype, endophyte or space mutation have effects on host stress resistance and select the best performance genotype.Methods Stress tolerance of 8 different perennial ryegrass genotypes including endophyte infected (E+) and endophyte free (E-) with and without space mutation were evaluated. Four different treatments were established which included control {CK, 45% of relatively soil moisture content (RSWC)}, drought stress (D, 15% RSWC), salt stress (S, 250 mmol NaCl with 45% RSWC) and drought combined with salt stress (DS, 250 mmol NaCl with 15% RSWC).Results The results showed that stress treatments significantly inhibited (P< 0.05) the growth of perennial ryegrass as plant height, tiller numbers and biomass of most plants significantly decreased (P<0.05). Under both control and stress treatments, host genotypes had significant (P<0.05) effects on plant growth, contents of phytohormones, ion and nutrient elements. However, there is no consistent performance for each host genotype. For plants both with and without space mutation, endophyte promoted host growth, regulated the rational distribution of ion content and nutrient elements in host plant. The space mutation had effects on plants performance as there was significant difference (P< 0.05) between mutation and without mutant for all of the tested indices except with plant height, aboveground biomass, CTK contents, underground Na+ and C/P, SK, Na, aboveground C.Conclusions The effects of host genotype on plant performance was much more pronounced and far greater than that of endophyte infection and mutation. Endophyte had effects on more indices of plants without mutant which suggest mutation may hide some effects of endophyte as its strong effects.