Identification of Powdery Mildew Susceptibility Genes in Solanaceae Plants

Specific genes of the Mildew Locus O (MLO) gene family are linked to susceptibility towards powdery mildew fungal disease, which causes economic losses in agricultural settings. To search for source of powdery mildew resistance, Michela Appiano from Wageningen University and colleagues developed a breeding strategy based on the selective inactivation of MLO susceptibility genes in different plants.

PCR-based methodologies were used to isolate MLO genes from eggplant, potato, and tobacco, which are common hosts for powdery mildew fungi. The researchers were able to isolate the genes, namely SmMLO1, StMLO1 and NtMLO1 from eggplant, potato, and tobacco, respectively. Genetic analyses showed that these genes came from a common ancestor with tomato SlMLO1 and pepper CaMLO2, previously shown to be important for powdery mildew pathogenesis.

Furthermore, tobacco NtMLO1 was characterized as powdery mildew susceptibility gene. Single nucleotide mutation of NtMLO1 also led to complete loss-of-function of the gene.

The results of the study are vital in understanding MLO gene evolution in Solanaceae and for molecular breeding approaches to develop powdery mildew resistance using reverse genetics.

Read the research article published at Transgenic Research.