Gene Rpi-bt1 from Solanum bulbocastanum Confers Resistance to Late Blight in Transgenic Potatoes

Abstract

Phytophthora infestans, the causal agent of late blight is the most devastating pathogen of cultivated potato worldwide. Utilizing map based cloning; a genomic region containing a cluster of six nucleotide binding site-leucine-rich repeat resistance gene analogs was isolated from the wild potato species Solanum bulbocastanum. Four genes were pseudogenes, with coding sequences interrupted by either frame shift mutations or premature stop codons. However, neither of the two uninterrupted genes conferred resistance to P. infestans when introduced into susceptible potatoes. Specific primers for one of the pseudogenes were used to amplify an uninterrupted cDNA from P. infestans-infected S. bulbocastanum leaves. A corresponding gDNA was amplified from a late blight-resistant bulbocastanum-tuberosum introgression line (Rpi-bt1). The Rpi-bt1 gene under transcriptional control of the constitutive potato Ubi3 promoter was found to confer resistance to P. infestans in several transgenic potato lines in a whole plant greenhouse assay.Resumen Phytophthora infestans, el agente causal del tizón tardío, es el patógeno mas devastador de la papa cultivada en el mundo. Mediante la clonación basada en mapas, se aisló de la especie silvestre de papa Solanum bulbocastanum una región genómica que incluía un grupo de repetición con seis análogos de genes de resistencia de sitios de unión de nucleótidos ricos en leucina. Cuatro genes fueron pseudogenes, con secuencias de codificación interrumpidas ya fuera por mutaciones por cambio de marcos o por codones de terminación prematura. No obstante, ninguno de los dos genes sin interrupción confirió resistencia a P. infestans cuando se introdujeron a papas susceptibles. Se utilizaron iniciadores específicos para uno de los pseudogenes para amplificar un ADNc ininterrumpido de hojas de S. bulbocastanum infectadas con P. infestans. También se amplificó un ADNg correspondiente de una línea de introgresión (Rpi-bt1) de bulbocastanumtuberosum resistente al tizón tardío. Se encontró que el gen Rpi-bt1 bajo control transcripcional del promotor de papa Ubi3 confiere resistencia a P. infestans en varias líneas de papa transgénica en un ensayo con planta completa bajo invernadero.

Cloning and Characterization ofR3b; Members of theR3Superfamily of Late Blight Resistance Genes Show Sequence and Functional Divergence

“…I-2 like sequences from tomato were I-2 (AF118127), I2C-1 (AF004878), I2C-2 (AF004879), and I2C-5 (AF408704). Other SH sequences were identified in this study: SH159B22-b = EF638450; SH159B22-c = EF638451; SH27O14e = EF638455; SH27O14f = EF638456; SH27O14b = EF638454; SH96A7a = EF638458; SH96A7b = EF638464; SH193J21c = EF638453; EB70Ea = R3b = HQ437670; Rpi-blb1 and Rpi-sto1 = EU884421 and Rpi-pta1 = EU884422 (Vleeshouwers et al 2008); RB-ver = EF202329 (Liu and Halterman 2006); and Rpi-bt1 = FJ188415 (Oosumi et al 2009). Alignments were performed according to the Clustal W algorithm and the closest related gene family, founded by Rpi-blb1, was used as an outgroup.…”

DNA Markers for Selection of Late Blight Resistant Potato Breeding Lines

“…In this study, four P. infestans resistance genes named Rpi-blb1 [8], Rpi-blb2 [15], Rpi-blb3 [16] and Rpi-bt1 [17] were used based on prior publications.…”

Expression of biotic stress response genes to Phytophthora infestans inoculation in White Lady, a potato cultivar with race-specific resistance to late blight

“…Compared to this, race-nonspecific resistance is not correlated with hypersensitive response, and instead involves limiting pathogen spread in the host [10].…”