Structural and phylogenetic analysis of Pto-type disease resistance gene candidates in banana

Abstract

The tomato Pto gene encodes a serine/threonine kinase (STK) whose molecular characterization has provided valuable insights into the disease resistance mechanism of tomato and it is considered as a promising candidate for engineering broad-spectrum pathogen resistance in this crop. In this study, a pair of degenerate primers based on conserved subdomains of plant STKs similar to the tomato Pto protein was used to amplify similar sequences in banana. A fragment of approximately 550 bp was amplified, cloned and sequenced. The sequence analysis of several clones revealed 13 distinct sequences highly similar to STKs. Based on their significant similarity with the tomato Pto protein (BLASTX E value <3e-53), seven of them were classified as Pto resistance gene candidates (Pto-RGCs). Multiple sequence alignment of the banana Pto-RGC products revealed that these sequences contain several conserved subdomains present in most STKs and also several conserved residues that are crucial for Pto function. Moreover, the phylogenetic analysis showed that the banana Pto-RGCs were clustered with Pto suggesting a common evolutionary origin with this R gene. The Pto-RGCs isolated in this study represent a valuable sequence resource that could assist in the development of disease resistance in banana.

Molecular cloning and characterization of disease-resistance gene candidates of the nucleotide binding site (NBS) type from Cocos nucifera L

“…Phylogenetic analyses also classified CnRGCs within the subclass non-TIR-NBSeLRR and presented homology with R genes belonging to the same subclass. So far, the TIR domain has not been found in the structure of NBS-LRR genes of monocot plants, for example, the TIR domain is absent in the rice genome sequence [15,57,35] and has not been found in other monocot plants [30,31,58]. Our results are in agreement with the hypothesis that the TIR subclass is restricted to dicotyledonous species.…”

“…These percent identities were similar to those observed between RGCs or resistance genes from other plant species [26,30,32].…”

Molecular Cloning and Characterization of an Ortholog of NPR1 Gene from Dongguan Dajiao (Musa spp. ABB)

“…Genetic transformation has the potential to overcome these constraints by transferring agronomically important single genes. To date, there are few reports on the isolation of banana resistance gene (R gene) (Pei et al 2006;Santy et al 2007), and no full-length R gene has been isolated.…”

Isolation and characterization of nucleotide-binding site and C-terminal leucine-rich repeat-resistance gene candidates in bananas

“…Most of them are non-TIR (Toll/interleukin-1 receptor-like domain) NBS-LRR genes, amplified in Gongjiao, Xinyiyejiao, Zhongshandajiao, Fenjiao, and Williams (Pei et al, 2007). In other groups, R genes include cf orthologs amplified in landrace Zebrina GF (Wiame et al, 2000), pto family RGAs amplified in M. acuminata (Peraza-Echeverria et al, 2007) andM. ornate, M. schizocarpa, M. textilis, andM.…”