Inoculation with selenobacteria and arbuscular mycorrhizal fungi to enhance selenium content in lettuce plants and improve tolerance against drought stress

Abstract

This study evaluated the co-inoculation effect of the endophytic selenobacteria Bacillus sp., Klebsiella sp. or Acinetobacter sp. and the arbuscular mycorrhizal (AM) fungus Rhizophagus intraradices on lettuce plants grown under drought conditions. Plants inoculated with both microorganisms were able to enhance the Se content in their shoots (1 to 6 µg plant -1 ) and promote macro-and micronutrient uptake. Moreover, the inoculated plants showed significant tolerance to drought stress, as determined by their adaptation to physiological parameters (relative water content and stomatal conductance),increase in photosynthetic pigments (chlorophyll and carotenoids) and improvement inantioxidant enzyme levels (catalase, ascorbate peroxidase and glutathione reductase). The selenobacteria increased the Se content in lettuce plants and enhanced the effect of AM fungus in controlling the antioxidant systems that play a role as elicitors of plant drought responses and improving the nutritional quality and physiological and biochemical processes involved in plant drought tolerance.

Plant growth promoting rhizobacteria for improved water stress tolerance in wheat genotypes.

“…The highest dry matter content was obtained with the inoculation of a mixture of both strains (AG-70 + AG-54) (Figure 1), which agrees with the results obtained in previous studies that have described that soil beneficial bacteria would promote plant growth under abiotic stress. In this sense, Durán et al (2016) found similar results in lettuce inoculated with PGPR strains (Bacillus sp. and Klebsiella sp.…”

“…This agrees with our results as the bacterial strains under study promoted positive effects on the root system by increasing the production capacity of auxin, and thus promoting an increase in root length (Figure 3); this indicate that the inoculation with these strains can be a morphological strategy to increase tolerance to water stress. Glick (2014) Regarding stomatal conductance (Table 1) produce an improved rate of photosynthesis and, consequently, increase leaf water potential, which plays an important role in the tolerance of plants to water stress (Durán et al, 2016).…”

Heavy metals uptake and translocation by lettuce and spinach grown on a metal-contaminated soil

“…These results are in the same line with those of Rattan et al (2005) and Lone et al (2003). The prolonged application of treated and untreated wastewaters results in significant buildup of heavy metals in the soils (Khan et al, 2008;Ghosh et al, 2012;Durán et al, 2016) and grown vegetables and cereals which they subsequently transfer to the food chain causing potential health risk to consumers (Singh et al, 2010;Gupta et al, 2011). Heavy metals concentrations in plants grown on wastewater-irrigated soils were reported to be significantly higher than those grown on fresh water-irrigated soils (Khan et al, 2008;Singh et al, 2010;Gupta et al, 2011).…”

Volatile organic compounds stimulate plant growing and seed germination of Lactuca sativa

“…Until now, mycorrhiza associations have been studied intensively for decades by its role to tolerate biotic and abiotic stress, plant productivity, nutrients acquisition and plant productivity ( Van der Heijden et al, 2015). Specifically, a recent study performed by Durán et al (2016) …”