Mycorrhizal association between the desert truffle Terfezia boudieri and Helianthemum sessiliflorum alters plant physiology and fitness to arid conditions

Abstract

The host plant Helianthemum sessiliflorum was inoculated with the mycorrhizal desert truffle Terfezia boudieri Chatin, and the subsequent effects of the ectomycorrhizal relationship on host physiology were determined. Diurnal measurements revealed that mycorrhizal (M) plants had higher rates of photosynthesis (35%), transpiration (18%), and night respiration (49%) than non-mycorrhizal (NM) plants. Consequently, M plants exhibited higher biomass accumulation, higher shoot-to-root ratios, and improved water use efficiency compared to NM plants. Total chlorophyll content was higher in M plants, and the ratio between chlorophyll a to chlorophyll b was altered in M plants. The increase in chlorophyll b content was significantly higher than the increase in chlorophyll a content (2.58- and 1.52-fold, respectively) compared to control. Calculation of the photosynthetic activation energy indicated lower energy requirements for CO(2) assimilation in M plants than in NM plants (48.62 and 61.56 kJ mol(-1), respectively). Continuous measurements of CO(2) exchange and transpiration in M plants versus NM plants provided a complete picture of the daily physiological differences brought on by the ectomycorrhizal relationships. The enhanced competence of M plants to withstand the harsh environmental conditions of the desert is discussed in view of the mycorrhizal-derived alterations in host physiology.

Expression Analysis of Aquaporins from Desert Truffle Mycorrhizal Symbiosis Reveals a Fine-Tuned Regulation Under Drought

“…Similar results have been recently observed in the H. sessiliflorum/T. boudieri mycorrhiza, where the enhanced ability of M plants to survive in the harsh desert conditions was attributed to their higher CO 2 assimilation rates and water use efficiency which, in turn, are controlled by modification of hydraulic conductances (Turgeman et al 2011).…”

Two new Terfezia species from Southern Europe

“…These plants and their associated fungi play a major role in the maintenance of Mediterranean shrub lands and xerophytic grasslands, and thus in preventing erosion and desertification (Honrubia et al 2014). In fact, this mycorrhizal association is well adapted to semiarid climates through the physiological mechanism of drought avoidance (Morte et al 2000, Turgeman et al 2011. The soils of desert truffles show a remarkable variability that reflects the climatic conditions in which they form.…”

Ectomycorrhizae and tree seedling nitrogen nutrition in forest restoration

“…Inoculation with ECM fungi has also been shown to improve survival and growth of seedlings on arid sites (Turgeman et al 2011;Sebastiana et al 2013) where reduced nutrient availability compounds the effects of water stress. Nursery inoculation of cork oak (Quercus suber L.) with Pisolithus tinctorius (Mich.: Pers.)…”