Effect of symbiosis with arbuscular mycorrhizal fungi on salt stress tolerance in GF677 (peach×almond) rootstock

Abstract

Genus Prunus is of great importance for cultivation, mainly because its main species provide fruits and seeds, valuable ornamental qualities and timber. However, stone fruit trees and almonds, major cultivars of genus Prunus, are sensitive to salt stress. Such sensitivity causes losses in stone fruit and almond production (ca. 50% of regular yield at high salinity grounds). Having in mind that symbiosis with arbuscular mycorrhiza fungi (AMF) may improve plant tolerance to salt stress and that symbiosis effect should be tested in case-by-case approach, we tested salt stress response of AMF inoculated GF677 rootstock (Prunus dulcis × Prunus persica hybrid) in this study. Adding to that, we tested GF677 symbiosis with two AMF species R. intraradices and F. mosseae. Results showed that under salinity stress AMF inoculated GF677 plants displayed improved physiological parameters (chlorophyll, soluble sugars and proline content) and increased antioxidant enzymes activity in comparison to non-inoculated control plants. Comparison of two AMF species beneficial effects on tested parameters revealed that for total chlorophyll content inoculation with F. mosseae has prevailed, while for total soluble sugars and proline content R. intraradices has prevailed. Finally, GF677 in symbiosis with F. mosseae was selected for molecular studies of salinity response. Since many of plants’ genes involved in simultaneous response to salt stress and AMF colonization remained unidentified so far, we performed bioinformatics analysis of freely online available data to find differentially expressed genes common to these two responses. Upon GO classification and networking analysis of genes identified as common to both responses, we selected two most prominent ones (UDPGT73C6 and CYP707A3) and tested their expression profile in leaves and roots of F. mosseae inoculated GF677 rootstocks under salt stress. Even though specific roles of UDPGT73C6 and CYP707A3 are uncharacterized in Prunus tree species, results suggested their involvement in response to salt stress and AMF inoculation of GF677 plants, which is in concordance with a scarce knowledge on their roles in other plant species. Based on this study finding we may conclude that symbiosis of GF677 rootstocks with AMF increases plants tolerance to salinity stress, which should be considered in other Prunus tree species as well.