Aspartic proteinases (APs) are a class of endopeptidases widely distributed among various taxa.

Plant APs are linked with reproductive processes such as cell wall components distribution in pollen tube

(PT), ovule development and zymogens activation during flower development. Among the 70 APs in

Arabidopsis, only AP1, AP2 and AP3 contain a 100 amino acid sequence called PSI (Plant Specific Insert);

therefore, they are called typical APs. The goal of this work is to understand the role of each typical APs

during plant development, particularly in reproduction. For this, two knockdown T-DNA insertion lines were

obtained (ap1, ap2), and phenotypical assays were performed along with gene expression analysis to

characterize the mutant reproductive performance and to understand the APs behaviour in these tissues.

The results obtained showed a slower vegetative development rate relative to wild-type, increased number

of aborted seeds and unfertilised ovules, in both lines. Importantly, ap2 had a slower PT growth rate,

indicating a putative role for this AP in PT guidance or loosening of transmitting tissue cells. Gene expression

analysis demonstrated that these APs are differentially expressed in flowers. These results points to distinct

roles of AP1 and AP2 during reproduction, representing a starting point for further studies.