dispersion of soil aggregates to break down; the increasing bulk density will make the soil morecompact and decrease total porosity, thereby hampering soil aeration and as a result, plants in salinesoils not only suffer from high Na+ levels, but are also affected by some degree of hypoxia [5].Tomatoes (Solanum lycopersicum L.) are among the most widely produced and consumedvegetables worldwide. The worldwide production has been estimated at 100 million t year1 witha total production area of about 4.2 million ha [7]. Although considered moderately tolerant to saltstress, tomato fruit yield decreases by about 10% for each unit of soil EC above a threshold value of2.5 dSm–1 [8]. Additionally to the development of salt-tolerant cultivars [1], three major cultivationtechniques have so far proved useful to attenuate the effects of excess soil salinity: (i) subjectingseedlings to water- or NaCl-stress can facilitate the adaptation of salt-stressed adult plants; (ii) mistapplication improves vegetative growth and yield of salt-stressed tomato plants grown underMediterranean conditions; and (iii) grafting tomato cultivars onto appropriate rootstocks can reducethe effects of salinity [3].Arbuscular mycorrhizal fungi (AMF) have been frequently reported to improve crop plants’tolerance to stressful abiotic environments such as saline soils. Although AMF can themselves benegatively affected by soil salinity [9,10], several studies report improved growth and performanceof mycorrhizal plants under salt stress [9,11–16]. The symbiosis of plants with AMF oftenresults in increased nutrient uptake, accumulation of osmoregulatory compounds, an increase inphotosynthetic rates, and an decrease in root respiration and water use, suggesting that salt stressalleviation by AMF results from a combination of effects ranging from nutritional to molecularlevels [11,17,18].