Revisiting Vitis vinifera Subtilase Gene Family: A Possible Role in Grapevine Resistance against Plasmopara viticola

Abstract

Subtilisin-like proteases, also known as subtilases, are a very diverse family of serine peptidases present in many organisms. In grapevine, there are hints of the involvement of subtilases in defense mechanisms, but their role is not yet understood. The first characterization of the subtilase gene family was performed in 2014. However, simultaneously, the grapevine genome was re-annotated and several sequences were re-annotated or retrieved. We have performed a re-characterization of this family in grapevine and identified 82 genes coding for 97 putative proteins, as result of alternative splicing. All the subtilases identified present the characteristic S8 peptidase domain and the majority of them also have a pro-domain I9 inhibitor, a protease-associated (PA) domain, and a signal peptide for targeting to the secretory pathway. Phylogenetic studies revealed six subtilase groups denominated VvSBT1 to VvSBT6. As several evidences have highlighted the participation of plant subtilases in response to biotic stimulus, we have investigated subtilase participation in grapevine resistance to Plasmopara viticola, the causative agent of downy mildew. Fourteen grapevine subtilases presenting either high homology to P69C from tomato, SBT3.3 from Arabidopsis thaliana or located near the Resistance to P. viticola (RPV) locus were selected. Expression studies were conducted in the grapevine-P. viticola pathosystem with resistant and susceptible cultivars. Our results may indicate that some of grapevine subtilisins are potentially participating in the defense response against this biotrophic oomycete.

Subtilisin‐like proteases in plant defence: the past, the present and beyond

“…The first subtilase gene family to be described belonged to Lycopersicon esculentum (tomato) and consisted of 15 members (Meichtry et al ., ). After this work, subtilase gene families were also characterized in Arabidopsis thaliana , presenting 56 known genes (Rautengarten et al ., ), in Oryza sativa (rice) with 63 genes (Tripathi and Sowdhamini, ), in moss Physcomitrella patens with 23 genes, in Populus trichocarpa with 90 genes (Schaller et al ., ) and, more recently, in Vitis vinifera and Solanum tuberosum (potato), both with 82 known genes (Figueiredo et al ., ; Norero et al ., ).…”

“…When comparing resistant and susceptible grapevine genotypes, a subtilase presenting sequence similarity with tomato P69C was observed to be constitutively expressed in the resistant genotypes, increasing its expression after inoculation (Figueiredo et al ., ; Monteiro et al ., ). More recently, subtilase participation in the defence response against P. viticola was reinforced (Figueiredo et al ., ). In Vitis pseudoreticulata leaves infected with E. necator , an up‐regulation of several subtilase genes was also reported (Weng et al ., ).…”

From structure to function – a family portrait of plant subtilases

“…The two most distantly related enzymes, AtSBT6.1 and AtSBT6.2, are the orthologs of mammalian site‐1‐protease (S1P) and tripeptidyl peptidase II (TPP2), respectively, while all other family members in subgroups SBT1 to SBT5 appear to be plant‐specific. Large SBT gene families have also been identified in other plant species, comprising 63 pyrolysin genes in rice ( Oryza sativa ; Tripathi & Sowdhamini, ), 82 in grape ( Vitis vinifera ; Cao et al ., ; Figueiredo et al ., ), and 82 in potato ( Solanum tuberosum ; Norero et al ., ). As compared with the entire genome of Arabidopsis, 60% of which is contained in large duplicated segments, SBT family expansion has been driven predominantly by tandem gene duplications.…”

Genome-wide Study of SBT Genes in Eight Plant Species: Evolution and Expression Outlines for Development and Stress

“…Since then, in Arabidopsis thaliana, 56 known genes of this family was found (Rautengarten et al 2005), and 63 genes of this family in Oryza sativa (rice) was also indicated (Tripathi & Sowdhamini 2006). Besides, in the years that followed, the SBT family genes were explored in Physcomitrella patens (23 gene members), Populus trichocarpa (90 gene members), Vitis vinifera (82 gene members) and Solanum tuberosum (82 gene members), respectively (Figueiredo et al 2016, Schaller et al 2012, Sigrid Norero et al 2016.…”