Induction of Phenolic Compounds in Pea (Pisum sativum L.) Inoculated by Rhizobium leguminosarum and Infected with Orobanche crenata

Abstract

Parasitic plants are among the most important problematic weeds, they are responsible of major losses of many crops. Early growth stages, such as seed germination stimulated by host root exudates and tubercle development, are key phases for these parasites development. Inhibition of these early phases could be a general strategic option for parasitic plants management. In our previous study, we have demonstrated that some Rhizobium leguminosarum strains decrease pea infection by Orobanche crenata and germinated seeds enhanced browning symptoms. These observations suggested the probability of toxic compounds accumulation such as gallic acid and naringenin used as a defence strategy by inoculated pea plants. In this study, we demonstrate that these two phenolic compounds cause severe physiological disorder of germination broomrape seeds. They inhibited germination of O. crenata seeds induced by strigol analogue GR 24 , and caused a browning reaction in germinated seeds.

Striga seed-germination activity of root exudates and compounds present in stems of Striga host and nonhost (trap crop) plants is reduced due to root colonization by arbuscular mycorrhizal fungi

“…Rhizobial inoculation of legumes reduces the seed-germination activity of root exudates on Orobanche (Mabrouk et al 2007). By mixing root exudates of a rhizobial pea plant with a GR-24 solution, Mabrouk et al (2007) showed that the reduced seed-germination activity of the root exudates of rhizobial pea plants on O. crenata is at least partially due to the presence of seed germination inhibitors in those exudates.…”

“…Rhizobial inoculation of legumes reduces the seed-germination activity of root exudates on Orobanche (Mabrouk et al 2007). By mixing root exudates of a rhizobial pea plant with a GR-24 solution, Mabrouk et al (2007) showed that the reduced seed-germination activity of the root exudates of rhizobial pea plants on O. crenata is at least partially due to the presence of seed germination inhibitors in those exudates. However, in our experiments, the combination of root exudates of nonmycorrhizal or mycorrhizal cowpea BR1 with water did not result in an increase in Striga seed germination, suggesting that mycorrhization did not lead to an increased production of compounds inhibitory to Striga seed germination.…”

“…Recently, by mixing pea root exudates with a solution of the synthetic strigolactone analog GR-24, it could be shown that a lower seed-germination activity of the root exudates of rhizobial pea plants on Orobanche is at least partially due to the presence of seed germination inhibitors in those exudates (Mabrouk et al 2007). However, it is not known yet whether root exudates of mycorrhizal plants exhibit an inhibitory effect on Striga seed germination or show a reduced stimulatory activity.…”

Insights to plant–microbe interactions provide opportunities to improve resistance breeding against root diseases in grain legumes

“…conceive root exudates of their host plants as a signal to germinate and subsequently infect the host. Mabrouk et al () assessed the interaction of rhizobia ( Rhizobium leguminosarum ), pea root exudates, and broomrape and found that the germination rate of broomrape seeds significantly decreases in the presence of root exudates collected from rhizobia inoculated peas. They identified marked changes in root exudate composition following inoculation with rhizobia, notably with significantly higher exudation of various phenolic compounds and flavonoids.…”

Biology and management of the fast‐emerging threat of broomrape in rapeseed–mustard

“…Mabrouk et al . () also have shown that some Rhizobium leguminosarum strains decrease O. crenata infections in pea by inducing systemic resistance.…”