R/Avr gene expression study of Rpi-vnt1.1 transgenic potato resistant to the Phytophthora infestans clonal lineage EC-1

• Published in: Plant cell, tissue and organ culture tissue and organ culture, 2017-11, Vol.131 (2), p.259-268
• Main Authors: Roman, Maria Lupe, Izarra, Myriam, Lindqvist-Kreuze, Hannele, Rivera, Cristina, Gamboa, Soledad, Tovar, Jose Carlos, Forbes, Gregory A., Kreuze, Jan F., Ghislain, Marc
• Format: Article
• Language: English
• Subjects: AVR gene; Biomedical and Life Sciences; Blight; Comparative studies; Disease resistance; Gene expression; Genes; Genetic engineering; Genetic transformation; Host plants; Immunity; Inoculation; Late blight; Life Sciences; Low level; Original Article; Phytophthora infestans; Plant diseases; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Plant resistance; Plant Sciences; Potatoes; Transgenic plants; Vegetables
• ISSN: 0167-6857; 1573-5044
• DOI: 10.1007/s11240-017-1281-9

The Avr avirulence gene of Phytophthora infestans and R gene of the potato are the genetic components of the gene-for-gene interaction resulting in host plant resistance. This effector-triggered immunity has been recently exploited to generate extreme resistance to late blight in potato by genetic engineering. The choice of the R genes, their number forming a R gene stack, and the pathogen Avr gene diversity will likely determine how long this extreme resistance will last. Here, we report on a comparative study on the Rpi-vnt1.1 gene which originated from Solanum venturii , and was introduced in the potato variety ‘Desiree’ by genetic transformation, and the Avr-vnt1 gene from two isolates of the EC-1 lineage of P. infestans . EC-1 was reported previously as not expressing the Avr-vnt1 gene and, therefore, being virulent on Rpi-vnt1.1 transgenic plants. Unexpectedly, whole-plant resistance assays identified 5 out of 52 transgenic events as resistant to two isolates of P. infestans , POX067 and POX109, belonging to the EC-1 lineage. We demonstrated that in both isolates, the Avr-vnt1.1 gene was expressed at a low level. Expression of the Rpi-vnt1.1 gene was shown to be rapidly increased by two-fold and subsequently to have steady state expression for at least 5 days after the inoculation. The Rpi-vnt1.1 gene in addition to other R genes as a stack in farmers’ preferred varieties will confer extreme resistance to late blight disease and rotations of plants with different R -gene-stack in time is likely to last longer than plants with single R gene.