Saccharum spontaneum transcriptome analysis for identification of the potential genes involved in receptor-mediated nonhost resistance

Nonhost resistance (NHR) protects plants against a wide range of non-adapted pathogens, which implicates a potential exploitation as a source for novel disease resistance strategies. Recently, promising strategies for developing durable resistant crops have been provided with the introduction of two gene groups to plants, including membranelocalized pattern-recognition receptors (PRRs) and nucleotide-binding LRR receptors (NLRs), both of which are associated with NHR. S. spontaneum (Sspon), the polyploidy progenitor of sugarcane, is considered a valuable resistance source to various stresses. However, little has been reported on the genes involved in the receptor-mediated NHR. With the aim of identifying potential genes, transcriptome data from the Saccharum project under di↵erent tissues and conditions was investigated. Amino acid sequences of known genes with grouped domains were used as queries in the search for gene homologs and analogs in Sspon transcriptome. Reverse alignments were performed using TBLASTN. Matching clusters were annotated in a non-redundant local database. The Expasy Translate Tool was used to predict the correct Open Reading Frames (ORF). Aiming to identify domain patterns, ORFs were submitted to RPS-BLAST against CDD database. Predictions of subcellular localization and transmembrane helix were inferred by TargetP and TMHMM servers. Results revealed at least seven classes of genes in Sspon. PRRs include five classes: class I with three domains ”Leucine Rich RepeatXII, Protein Kinase, Transmembrane” (EFR and XA۲۱ genes), class II ”LRRXI, PK, TM” (PEPR۲), class III ”Legume lectin, PK, TM” (LECRK IV.۱, IV.۲, IX.۱), class IV ”LRR, TM” (EIX۱, EIX۲), and class V ”LysM, PK, TM” (LYK). NLRs include two classes: class VI ”Toll/Interleukin ۱Receptor, TM” (TIR) and class VII ”NB-ARC, LRR” (RPS۲, RPP۱۳). These receptors, which are homologous to previously known resistance genes, are promising candidates for conferring NHR. In addition, novel combinations of gene domains were reported in Sspon, which might represent novel gene structures.

کلیدواژه ها:

Nonhost resistance ، Saccharum spontaneum ، Transcriptome analysis ، Receptors ، Protein domains