GENOME WIDE ANALYSES OF ASPARTIC PROTEASES ON POTATO GENOME

NORERO N; D IPPÓLITO, SEBASTIAN; DECIMA ONETO, C; MASSA, G; FEINGOLD, S; GABRIELA, GUEVARA MARÍA

Salta

Congreso; SAIB PABMB 2019; 2019

SAIB

Aspartic proteases (AP) are proteolytic enzymes widely distributed on plants, animals, and microorganisms. They are involved in multiple functions related to protein recycling, immune response, biotic and abiotic stress, cell death, and others. They are the second largest group among proteases after serine proteases, but their specific functions are poorly understood. Some aspartic proteases have been purified from potato genome and have demonstrated to confer tolerance to Phytophthora infestans and diverse abiotic stresses. In addition, one of these proteases (AAT77954.1) has been associated with cell death. In this work, we characterize the aspartic protease family on the potato genome for the first time. We built a HMMER profile from 51 aspartic proteases from Arabidopsis thaliana L., and we performed a HMMER search on potato genome peptide database V4.1 (PGSC, 2011). We manually curated 121 proteins out of 150 sequences that included aspartic sites typical of AP, identifying 68 AP genes on potato genome (PGSC, DM V4.1). These genes were distributed on all 12 chromosomes with some preference for chromosomes VIII and VII. In several cases, tandem arrays were evidenced. Gene structural analyses showed a high proportion of intronless genes (30 out of 68). The phylogenetic study showed seven clusters named StAP1 to StAP7. The presence of aspartic proteases domains was analyzed distinguishing typical, atypical, and nucellin-like AP, previously described in Arabidopsis thaliana L. genome, on potato genome. A characteristic feature of some AP is the occurrence of an extra 100 amino acid long segment, known as plant-specific insert (PSI), which folds as an independent domain and generally is processed out during protein maturation. This domain was present only in proteins grouped in Cluster VII, which includes the homolog to AAT77954.1. Most aspartic proteases presented a signal peptide related to extracellular localization, and some of them presented TAXI_C and TAXI_N domains that could be related to pathogen defense. RNA-Seq expression data from double monoploid Solanum tuberosum group Phureja (PGSC, 2011), including libraries from different tissues, plant organs, biotic and abiotic stress conditions, reveals the expression of AP in all of them, without evident relation with cluster distribution. These analyses will help to unveil the structure and composition of the potato aspartic proteases family, providing insights for future studies.