Integrated analysis of regulatory networks modulating seed coat permeability in natural accessions
The European seed market is in constant expansion and improving seed quality is a key factor towards meeting the increase in demand. The seed coat is constituted from multi-cell layers that surround the embryo that will become the future plant. Seed coat properties and composition have a significant impact on seed quality. Notably, mutant seeds with permeable seed coats have defects in germination phenotypes such as lower dormancy, shorter longevity and reduced stress tolerance. The regulatory mechanisms that modulate seed coat permeability are, however, not well understood. The candidate has performed a genome-wide association study in Arabidopsis thaliana and identified ARR16 as a novel regulatory gene affecting permeability, this Arabidopsis thaliana response regulator (ARR) is a signaling component for the plant hormone, cytokinins (CKs).
	The project objective is to determine the transcriptional network involving ARR16 that controls permeability in natural accessions. In work package 1 (WP1), the spatio-temporal expression of ARR16 will be examined in seed tissues of permeable and non-permeable accessions with GFP reporter lines. Also, we will generate mutants with CRISPR/Cas9 gene edited haplotype copies, aiming to precisely define the cis-elements in the ARR16 promoter that determine seed permeability. Next, cytological analyses will be carried out on seed coats of ARR16 mutants to ascertain the composition and structural basis of the modified permeability (WP2). Finally, transcriptomes of mutant and wild-type seed coat cells isolated by laser microdissection will be analyzed, aiming to reveal CKs signaling networks mediated by ARR16 in seeds (WP3). The proposed project is feasible and appropriate for a Marie Skłodowska-Curie Individual Fellowship since the expected outcomes are innovative and generate knowledge for both fundamental and industrial research, while the candidate will improve his skills and knowledge of a specialized research area.