Response of Diploid Perennial Ryegrass to Fungal Endophyte AR29 Infections under Water Stress

Abstract

Asexual fungus Neotyphodium spp. are often associated with aboveground parts of different grasses. Perennial ryegrass (Lolium perenne L.), dominant cool-season grass species in New Zealand, is frequently infected by endophytic fungus (Neotyphodium lolli). To evaluate the growth, nutrient status, and avoidance to dehydration stress, clones of diploid perennial ryegrass either infected with Neotyphodium lolii AR29 endophyte (E+) or not infected (E−) were grown in a potted Andisol with intermittent wetting-drying cycles in a controlled growth chamber. Results showed that endophyte infection (E+) significantly reduced plant height, tiller number, shoot and root dry weights, and root volume with an associated increase in root/shoot ratios of ryegrass. The E+ plants showed a greater shoot and lower root avoidance to dehydration stress than the E− plants. The negative values of relative interaction intensity index between the diploid ryegrass and AR29 endophyte association suggested that these host-endophyte associations were parasitic under intermittent soil wetting-drying cycles. While the nitrogen (N) and phosphorus (P) concentration, plant production index, and water-use efficiency were significantly greater in E+ plant than in E− plants, the N and P efficiency ratios were greater in E− plants than in E+ plants. Results suggested that the endophyte mediation may have synergistic or antagonistic effects which depend on particular host genotype-endophyte combinations and environmental conditions to promote drought tolerance in grasses for degraded land restoration or forage production.

Fungal endophytes and a virus confer drought tolerance to Nicotiana benthamiana plants through modulating osmolytes, antioxidant enzymes and expression of host drought responsive genes

“…This result is in line with several other studies showing a neutral effect of fungal endophytes on shoot biomass under stress (Briggs et al, 2013;He L, 2017;Hesse et al, 2003Hesse et al, , 2005Hill et al, 1996;Jia et al, 2015;Kane, 2011;Khan et al, 2013;Oberhofer et al, 2014;Rudgers and Swafford, 2009). In contrast, certain endophytic strains were also reported to increase (Ghabooli et al, 2013;Gibert et al, 2012;Hill et al, 1996;Malinowski et al, 2005;Vazquez-de-Aldana et al, 2013;Zhang and Nan, 2007) or decrease (Assuero et al, 2006;He L, 2017;Rahman et al, 2015;Yang et al, 2014; plant shoot biomass under water stress. Previously, we reported increased shoot biomass increased of N. benthamiana plants under stress when inoculated with the same fungal strains that we used in the present study (Dastogeer et al, 2017a).…”

Role of Epichloë Endophytes in Improving Host Grass Resistance Ability and Soil Properties

“…However, plants respond to drought stress through physiological, biochemical, and morphological responses, culminating in stress tolerance. Many studies showed that the endophytes of the genus Epichloë play an important function in enhancing drought resistance in Epichloë-infected grasses through regulating the photosynthetic, osmotic adjustment, and antioxidant enzyme systems, water use efficiency, and nutrient accumulation. ,− , Studies with A. inebrians have demonstrated that E.…”

“…Many studies showed that the endophytes of the genus Epichloëplay an important function in enhancing drought resistance in Epichloe-infected grasses through regulating the photosynthetic, osmotic adjustment, and antioxidant enzyme systems, water use efficiency, and nutrient accumulation. 12,[22][23][24][25][26][27][28][29][30][31][32][33][34]56 Studies with A. inebrians have demonstrated that E. gansuensis infection (E+) increased proline accumulation and decreased superoxide dismutase (SOD) activity compared to plants without this E. gansuensis (E−) when under drought stress; however, photosynthetic capacity of E+ and E− A. inebrians plants does not differ when under drought stress. 57 The presence of an Epichloëspp.…”

“…Interestingly, Epichloë endophytes can enhance the resistance of host grasses to abiotic stresses, and the implications of this in forage grazing systems has been well-documented with ryegrass and tall fescue . With regard to abiotic stresses, increased resistance to salt stress, − drought stress, ,− waterlogging stress, ,,, cold stress, , heavy metal stress, ,− and low nitrogen stress − and increased tolerance to combined stresses ,, have been reported when grasses are host to the endophytes of genus Epichloë. In addition, a number of studies have confirmed that the presence of an Epichloë endophyte could affect soil microbial communities and soil properties. − In addition, one study has demonstrated that E.…”

The Inhibitory Effect of Endophyte-Infected Tall Fescue on White Clover Can Be Alleviated by Glomus mosseae Instead of Rhizobia

“…Mutual relationships have been found between endophytes and some important cultivated grasses such as tall fescue and perennial ryegrass [22][23][24]. The host plants can provide endophytic fungi with photosynthetic products, nutrients and habitats; moreover, secondary metabolites produced by endophytic fungi can promote the growth and development of host plants [25] and improve the host's resistance to biotic [26][27][28][29][30] and abiotic stresses [31][32][33] such as drought [34][35][36], nutrient deficiency [37], herbivory [38][39][40][41] and pathogens [25,42,43], Given the higher growth advantages of endophyte-infected (E+) over endophyte-free (E−) plants, E+ grasses are considered to be ideal plant species for artificial grasslands. However, endophyte infection could change the interspecific relationship between host grasses and neighboring plants [44].…”