Abstract:

The technologies of genechip microarray combined with RT-PCR were used to investigate the resistance mechanism of Haynaldia villosa to the powdery mildew. The transcriptome of uninoculated resistant H. villosa，wildtype resistant H. villosa and susceptible mutant inoculated with Blumeria graminis f. sp. tritici were obtained using barley genechip microarray. RT-PCR and comparison of the transcriptome in inoculated and uninoculated resistant H. villosa indicated that the genes involved in the salicylic acid and ethylene signal transduction pathways were upregulated by B. graminis inoculation in the resistant H. villosa. RT-PCR and transcriptome comparison in the inoculated wildtype resistant and susceptible mutant showed that the genes involved in the ethylene and jasmonic acid signal transduction pathways were upregulated by B. graminis inoculation in the susceptible mutant H. villosa, while the salicylic acid signal transduction pathway was not participated in the process. The endogenous SA concentration of wildtype and susceptible mutant H. villosa inoculated for different hours were measured. SA concentration in the resistant H. villosa increased dramatically after inoculated with B. graminis, while that in the susceptible mutant remained at very low level. Since genes in the ethylene signal pathway were induced in the resistant and mutant H. villosa and genes in the salicylic acid signal transduction pathway were induced only in the resistant H. villosa, the salicylic acid signal transduction pathway might be the major pathway involved in H. villosa resistance to the powdery mildew. Genes involved in the resistance to powdery mildew in the H. villosa were also identified, including pathogenesis related protein genes, defense genes, transcription factors, signal transduction components and resistance gene analogs.

Key words: Barley genechip, Haynaldia villosa, Signal transduction pathway, Defense response, Powdery mildew