Seeds in the context of agricultural research: combining traditional and innovative approaches to boost seed quality

One of the challenges of the last few years is to provide conditions allowing to feed the overgrowing world population while also taking into consideration land availability and the global climate change. In this PhD thesis, different methods have been developed, useful to promote a sustainable agriculture. The experimental work focuses mainly on aspects related to Seed Technology, particularly the development of improved seed priming protocols, combined with the use of novel molecular hallmarks for seed germination. Besides this, efforts were also dedicated to develop genetic engineering methods useful to improve the complex trait of seed vigor, as a step to support both basic and translational research. Seed germination is a critical parameter for the successful development of sustainable agricultural practices. While germination is impaired by environmental constraints related to the climate change scenario, priming is a pre-sowing technique that promote germination and seedling robustness by managing a series of crucial parameters during seed imbibition. In particular, it enhances the antioxidant/DNA repair activities triggered during the pre-germinative metabolism. A hydropriming protocol was developed for Solanum melongena L. and its crop wild relatives Solanum torvum Swartz and Solanum villosum Miller, and for the first time the molecular dynamics of pre-germinative metabolism were explored in primed seeds. In a parallel work, hydropriming and biopriming have been applied to Medicago truncatula seeds to enhance germination on contaminated soil. Phenotypic parameters were monitored and compared to find the most appropriate treatment combinations. The expression profiles of specific genes were used as molecular indicators of seed quality, to investigate seedling fitness under the imposed treatments. Although genetic transformation has enabled fundamental insights into plant biology, unfortunately for most crops transformation and regeneration remain arduous. Genome editing techniques are an innovative and powerful strategy to introduce mutations or insert/substitute wide portion of DNA at a targeted site. These techniques have extremely important implications for agriculture and environment. Genome editing provides novel opportunities to enhance crop productivity if accompanied by an efficient transformation protocol. In this work, a novel vector for genome editing able to target the Tdp1β gene (tyrosyl-DNA phosphodiesterase 1β) in M. truncatula was developed. Aside being a cereal model plant, Oryza sativa is one of the worlds most important crops and a major staple food that feeds more than three billion people worldwide. Rice cultivation in Europe is restricted to a few southern countries, Italy is the major producer in terms of quantity and varieties. Some elite cultivars, such as Vialone Nano for example, are recalcitrant to genetic transformation are local varieties (from Lombardy and Veneto) very appreciated at a culinary level but they suffer severe susceptibility to diseases and/or pathogens. To safeguard this variety, an efficient genetic transformation protocol has been hereby developed, as an essential step for the targeted improvement of relevant agronomic traits.