Fungal endophytes enhance wheat heat and drought tolerance in terms of grain yield and second-generation seed viability.

ABSTRACT

AIMS: We evaluated the impact of fungal endophyte symbiosis on the growth, ecophysiological and reproductive success of wheat exposed to heat and drought. METHODS AND RESULTS: The resistance of pot-grown wheat to heat or drought stress was measured by quantifying efficiency of photosystem II (Fv /Fm), plant height, average seed weight (ASW), total seed weight (TSW), water-use efficiency (WUE) as well as time to 50% germination and percentage germination of second-generation seeds produced under heat stress, drought stress or well-watered conditions. The endophytic fungi tested increased wheat tolerance for drought and heat. Endophyte SMCD 2206 was the most beneficial, followed by SMCD 2210 and 2215. Surprisingly, second-generation seeds produced by drought-stressed wheat colonized by SMCD 2206, 2210 or 2215 had decreased WUE relative to those produced by endophyte-free, drought-stressed plants. However, these seeds germinated more rapidly than those produced by endophyte-free, stressed parental plants. CONCLUSIONS: The tested consortium of endophytes has the potential to improve wheat adaptation to heat and drought. SIGNIFICANCE AND IMPACT OF THE STUDY The capacity of endophytes to increase wheat tolerance for abiotic stress and to improved germination in endophyte-free second-generation seeds arising from stressed plants could be applicable to agriculture. The mechanisms by which intergenerational endophyte-mediated affects occurs warrant further research.