CHARACTERIZATION OF GRAIN LEGUME BIODIVERSITY FOR STRESS ADAPTATION AND INNOVATIVE INDUSTRIAL USES WITH LOW ENVIRONMENTAL INPUTS

This thesis focuses on the characterization of the biodiversity of grain legumes, pea (Pisum sativum L.) and lentil (Lens culinaris Medik.), with the aim of improving stress adaptation and promoting innovative industrial uses with low environmental inputs. Research activities were carried out at the Department of Soil, Plant and Food Sciences of the University of Bari “Aldo Moro”. A part of the work was conducted in collaboration with the industrial partner Innovaprot S.r.l. and the valuable support of Dr. Luigi Manfredi. After a general introduction (Chapter 1), Chapters 2 and 3 focus on the interaction between pea and the holoparasitic root plant Orobanche crenata (Oc), today representing one of the major biotic stresses affecting grain legumes cultivation in the Mediterranean area. Specifically, Chapter 2 reports experimental activities aimed at investigating the genetic basis of Oc resistance displayed by the pea breeding line ROR12. Quantitative trait loci (QTLs) associated with this trait were identified, and marker assays were developed to assist selection in breeding programs. Chapter 3 reports another experimental study aimed at investigating the relation between strigolactone (SL) exudation and field response to Oc in pea, using a global pea germplasm collection, SL biosynthetic mutants and a set of segregating RILs originating from ROR12 as resistant parent. Phenotypic screening, SLs quantification, and RNA-seq were used in this case as investigation methods. Chapter 4 reports a study, based on transcriptomics and hormonal quantification, carried out to investigate the physiological roles of SLs and the SL-biosynthetic enzymes Carotenoid Cleavage Dioxygenase (CCD)7 and 8. This led, among other, to the definition of association between SLs and response to multiple abiotic stresses (hydrogen peroxide and salt, oxidative and heat). In addition, hormonal cross-talks were identified between SLs and the stress-related hormones jasmonic acid and abscissic acid. Chapter 5 reports the characterization of a lentil germplasm collection for seed color, phenolic profile and antioxidant activity. Superior lines were identified, and association among traits were defined. Finally, Chapter 6 discusses the results of the thesis as a whole and provides a conclusion with future perspectives.