Non-TIR-NBS-LRR resistance gene analogs in apricot (Prunus armeniacaL.)

Abstract

Genes encoding for proteins with nucleotide-binding site and leucine-rich repeat motifs (NBS-LRR) have been suggested to play a general role in plant defence mechanism. In Prunus species, many TIR (Toll / Interleukin-1 Receptor), and only very few non-TIR sequences were identified, which was explained either by the unequal distribution of TIR/non-TIR sequences in the Prunus genome or by the incapability of primers in the amplification of non-TIR RGAs. The objective of this work was to check whether a new semi-nested PCR strategy can be developed for the targeted isolation of non-TIR-NBS-LRR Resistance Gene Analog (RGA) sequences from apricot. Three primers (CUB-P-loop F, CUB-Kin2 F and CUB-HD R) were designed, from which CUB-Kin2 F and CUB-HD R were constructed to anneal selectively to the non-TIR sequences. A colony Polymerase Chain Reaction (PCR) indicated that out of the 96 clones tested 28 showed amplification using the newly developed primers, while no amplification occurred when using the formerly described primers. Half of the 28 positive clones were sequenced and they turned out to represent 11 different non-TIR RGA sequences. A phylogenetic analysis was carried out based on an alignment containing 293 Rosaceae and 21 non-Rosaceaa sequences. A significantly higher ratio (91%) of non-TIR sequences were arranged in multi-genera clades than that of (57%) the TIR groups confirming that non-TIR sequences might be of more ancient origin than TIR sequences.

Resistance to root‐knot nematodes Meloidogyne spp. in woody plants

“…Genomic studies aiming to identify immune components have recently focused on woody plants, which constitute an important piece of the plant evolutionary puzzle. As in herbaceous plants, NLRs have been found in particular in poplar (Populus trichocarpa), grapevine, apricot and peach (Kohler et al, 2008;Kortekamp et al, 2008;Yang et al, 2008;Gutermuth et al, 2011;Verde et al, 2013). It has been shown that the NLR genes of four woody Rosaceae species, Malus domestica (apple), Pyrus bretschneideri (pear), P. persica and Prunus mume (mei), have undergone recent duplications, which have contributed to their…”