of the abscission process within the abscission zone and organ detachment……….……………...…… 27 1.3.2.4. Differentiation of a protective layer………………………….…. 1.4. The Arabidopsis abscission regulatory module INFLORESCENCE DEFICIENT IN ABSCISSION / HAESA-like receptor kinases………………………… 32 2. Aims and Design of the Present Study………………………………….………………….. 3. Materials and methods…………………………………………………….………….……….. 4. Identification and molecular analysis of INFLORESCENCE DEFICIENT IN ABSCISSION (IDA)-like genes and HAESA (HAE)-like receptor kinases in Solanaceae species of agronomic importance…………………………………...………. 4.1. The IDA-like gene family in the Solanaceae………………………………..……… 48 4.2. Phylogenetic relationship among IDA-like prepropeptides in Solanaceae…….... 4.3. Cis-acting regulatory elements in the promoter regions of the N. benthamiana IDA-like family…………………………..……………… 4.4. The HAE-like gene family in the Solanaceae………………………………..…….. 4.5. Phylogenetic relationship among HAE-like protein kinases in Solanaceae…….. 57 4.6. Amino acid residues involved in the interaction between IDA mature peptides and HAESA-like receptors………………………….…………….. 4.7. Expression patterns of IDA-like and HAE-like genes in Nicotiana benthamiana during growth and abscission……………...…………….……. 4.8. Expression patterns of IDA-like genes in Nicotiana benthamiana during water stress………………………………...…………… 68 4.9. Conclusions………………………………………………………………….………… 70 5. Silencing and overexpression of INFLORESCENCE DEFICIENT IN ABSCISSION and HAESA receptor kinase in flowers of Nicotiana benthamiana: effects on corolla abscission…………………..…......…….……. 5.1. Silencing and overexpression of IDA-like and HAE-like genes using a viral vector based on Citrus leaf blotch virus……………………….……….…. 73 5.2. The inoculation of clbv3'-NbenIDA and clbv3'-NbenHAE constructs arrests corolla abscission………………………...…………………...……… 79 5.3. Anatomy of the corolla tube base in flowers of plants inoculated with the control clbv3' vector and the clbv3'-NbenIDA construct…………..……….…. 5.4. Knockdown of target genes at the base of the corolla tube through inoculation with the clbv3'-NbenIDA and clbv3'-NbenHAE constructs…………….…. 84 5.5. Overexpression of NbenIDA1A decreases plant growth