Effect of arbuscular mycorrhizal fungi (AMF) and water stress on growth, phenolic compounds, glandular hairs, and yield of essential oil in basil (Ocimum gratissimum L)

Abstract

Background: Water stress is one of the most adverse conditions that may affect growth, and synthesis of essential oils in aromatic and medicinal plants. To overcome these climatic conditions, mycorrhiza is an adaptation strategy developed by plants to help them cope with these adverse conditions. For this purpose, we studied the influence of mycorrhizal fungi (Glomus intraradices) and water stress on the growth of basil plants (Ocimum gratissimum L), the yield of essential oils, and the abundance of glandular hairs. Results: The analyses show that AMF increases the yield of oils with a maximum recorded in stressed mycorrhizal plants (0.33%) and the lowest in non-stressed non-mycorrhizal plants (0.22%). The contents of total phenolic compounds increase in non-mycorrhizal plants under stress (104% in leaves and 97% in the roots) unlike the mycorrhiza which did not stimulate the synthesis of these compounds, Moreover, the contents of chlorophyll pigments decrease with the application of stress in non-mycorrhizal plants (53%) and increase in mycorrhizal plants. The proline contents increased significantly with the application of water stress; this increase is more pronounced in non-mycorrhizal plants than mycorrhizal plants. Conclusions: Water stress limits the growth and leads to a decrease in morphological parameters, this reduction is accompanied by a synthesis of several molecules in particular proline and phenolic compounds, However, the AMF stimulates growth, and drives the water status in plants at an optimal level, thus confirming the role of mycorrhizal symbiosis in plant defense against biotic and abiotic stress.

Insights On the Impact of Arbuscular Mycorrhizal Symbiosis On Tomato Tolerance to Water Stress

“…Indeed, this trend was particularly observed in R. intraradices-colonized plants, under both NS and WS conditions, although these results were not always statistically significant (Table I). In agreement with previous studies (Bárzana et al, 2012;Hazzoumi et al, 2015), root colonization seemed not to be strongly affected by WS independently of the AM fungal species considered here. The proportion of AM root colonization was greater for R. intraradices, while the percentage of arbuscules in the colonized portion was significantly greater for F. mosseae, both in NS and WS conditions, suggesting a different colonization strategy adopted by the two fungi.…”

“…C leaf and g s ) or the extent (CCI) of these parameters in the presence of a specific AM fungal species, thus confirming that the plant response also depends on the plant/AM fungal species association, as suggested previously by Augé et al (2015). Under WS conditions, an increased PSII efficiency promoted by AM symbiosis was reported in stressed plants (Bárzana et al, 2012;Ruiz-Lozano et al, 2016), while Hazzoumi et al (2015) demonstrated an increased chlorophyll pigment level in basil (Ocimum gratissimum) colonized by an AM fungus. The positive impact of AM symbiosis on WS tolerance was further supported by the A N and, consequently, iWUE values obtained in this work.…”

Chemical composition and antioxidant activity of leaves of mycorrhized sea-buckthorn ( Hippophae rhamnoides L.)

“…During the establishment of the arbuscular mycorrhizal symbiosis, a range of chemical and biological parameters is affected in plants, including the pattern of secondary compounds (Karagiannidis et al, 2012). Previous studies confirm that arbuscular mycorrhizal fungi (AMF) affects the content of phenols (Hazzoumi et al, 2015). Higher content of flavonoids has been demonstrated in mycorrhizal roots of alfalfa (Medicago sativa L.) (Larose et al, 2002).…”

Effect of Mycorrhizal Association on Nodule Number, Mass, Leghaemoglobin and Free Proline Content in Macrotyloma uniflorum (Lam.) Verdc. Under PEG Induced Water Stress

“…However, the contents in the non mycorrhizal induced stress plants were slightly more compared to mycorrhizal plants. Proline accumulation correlates with drought resistance in various plant species (Parcel et al, 2003;Farahani et al, 2008;Bhosale and Shide 2011;Hazzoumi et al, 2015). Proline content in roots colonized by AM fungi is significantly less as compared to non AM fungi indicating osmotic adjustment thereby enhancing the ability of the host to cope up with the water stress (Porcel et al, 2003;Kohler et al, 2008).…”

“…RuizLozano et al (2001) have shown that drought induced nodule senescence in legume plants could be ameliorated by AM fungal association. It is now well established in various plant systems that AMF association can protect the host from adverse effects of drought (Allen and Allen 1986;Ruiz-Lozano et al, 1995;Goicoechea et al, 2005;Hazzoumi et al, 2015). Macrotyloma uniflorum, commonly known as horse gram, is highly nutritious and cultivated for the seeds.…”