Link to home

Transcriptome analysis of cultivated and wild sweetpotato reveals differences in NB-LRR resistance gene repertoire

Camilo Parada Rojas: North Carolina State University

<div>Plants possess an innate immune system with disease resistance (R) genes encoding for proteins that recognize pathogen effectors during infection. An important class of resistance gene contains nucleotide-binding and leucine-rich repeat domains NB-LRRs. Sweetpotato (<em>Ipomoea batatas</em>) is an important staple crop worldwide that can become infected by several pathogens in the field and postharvest. Some of these pathogens, such as <em>Ceratocystis fimbriata,</em> secrete effectors and can be controlled through host resistance; nonetheless, little is known about the R gene repertoire of this crop. We performed a transcriptome motif based search of NB-LRR genes in the hexaploid <em>I. batatas</em> (Beauregard) and the diploid wild relatives <em>I. trifida</em> (NSP306) and <em>I. triloba</em> (NSP323). We identified 509 NB-LRR genes in the 77,919 <em>I. batatas</em> transcriptome, as well as 628 and 644 NB-LRRs in the transcriptomes of <em>I. trifida </em>and <em>I. triloba</em>, respectively. Wild relatives of sweetpotato harbored more NB-LRR genes compared to cultivated sweetpotato. From the predicted NB-LRR genes in <em>I. batatas,</em> 56 contain an N-terminal toll/interleukin 1 receptor (TIR) domain, and 295 contain an N-terminal coiled-coil (CNL) domain. The identified NB-LRR genes provide significant insight into the resistome of sweetpotato and a first step towards identifying <em>R</em> genes effective for control of <em>C. fimbriata,</em> the causal agent of black rot in sweetpotato.</div>