ABSTRACT
The parasitic weed, Orobanche crenata, is one of the most devastating constraint for faba bean production in Mediterranean regions. Plant host defense induction was reported as one of the most appropriate control methods in many crops. The aim of this study was to elucidate the effect of salicylic acid (SA) and indole acetic acid (IAA) on the induction of faba bean resistance to O. crenata under the field and controlled experimental conditions. Both hormones were tested on two contrasting faba bean genotypes: Giza 843 (partially resistant to O. crenata) and Lobab (susceptible) at three different application methods (seed soaking, foliar spray, and the combination of both seed soaking and foliar spray). Soaking seeds in SA or IAA provided the highest protection levels reaching ~75% compared to the untreated control plants. Both elicitors limited the chlorophyll content decrease caused by O. crenata infestation and increased phenolic compound production in host plants. Phenylalanine ammonia lyase, peroxidase, and polyphenol oxidase activities were stimulated in the host plant roots especially in the susceptible genotype Lobab. The magnitude of induction was more obvious in infested than in non-infested plants. Histological study revealed that both SA and IAA decreased the number of attached O. crenata spikes which could be related to specific defense responses in the host plant roots.
ABSTRACT
Knowledge of genetic diversity and population structure is a crucial step for an efficient use of available material in a plant breeding program and for germplasm conservation strategies. Current study undertakes an assessment of the genetic variations and population structure of Moroccan lentil including nine landraces and eight released varieties using sequence-related amplified polymorphism (SRAP) and random amplified polymorphism DNA (RAPD) markers. Results revealed that the two markers used have a good efficiency to assess genetic diversity in lentil. A total of 115 and 90 bands were respectively scored for SRAP and RAPD, of which 98.3% and 93.3% were polymorphic. The polymorphic information content values were 0.350 with SRAP and 0.326 with RAPD. Analysis of molecular variance based on the combined data sets of both markers revealed lower variations within (35%) than among (65%) landraces (PhiPT = 0.652), implying significant genetic differentiation between landraces. Principal coordinate analysis and the ascendant hierarchical classification clustered samples into groups that were consistent with the geographical origin of the cultivars. Population structure corroborated the main groups and confirmed the high differentiation among them. Moroccan lentil germplasm showed a wide genetic diversity that might be conserved and assessed for tolerance to biotic and abiotic stresses.
ABSTRACT
BACKGROUND: Orobanche crenata represents a major biotic constraint to production of faba bean and lentil in Morocco. While this parasitic plant attacks both of these crops, the extent to which Orobanche biotypes specialise in parasitising specific crops is unknown. To address this question, we studied O. crenata that grew on different hosts and quantified their host specificity to faba bean and lentil. The virulence of O. crenata populations on each host was investigated through field trials, pot and Petri dishes assays. Genetic diversity of the parasite populations was also assessed through molecular analyses. RESULTS: The two legume species showed distinct patterns of specificity. Faba bean was more susceptible to both O. crenata populations, while the specificity for lentil by lentil-grown O. crenata was evident at the final stage of the parasite life cycle as shown by correspondence factorial analyses. Considerable internal variation (81%) within O. crenata populations parasitising both legume species was observed by molecular analyses, but significant divergence (19%; Ø = 0.189; P = 0.010) among the populations was detected. CONCLUSION: These results indicate that O. crenata can adapt to specific host species, which is important knowledge when developing integrated pest management practices for parasitic weed control. © 2017 Society of Chemical Industry.
