| Popis: |
Background: Small heat shock proteins (sHSPs) belong to the class of molecular chaperones that respond to biotic and abiotic stresses in plants. Previous studies have identified strong induction of the GmHsp22.4 gene in response to Meloidogyne javanica nematode in resistant soybean genotypes compared to susceptible one. This study aimed to investigate the functional involvement of this small chaperone in response to M. javanica. First, it was evaluated the activation of the promoter region by nematode’s infection and the occurrence of polymorphisms between resistant and susceptible resequenced soybean accessions in the gene coding and promoter regions. Then functional analysis using Arabidopsis thaliana lines overexpressing the soybean GmHsp22.4 gene, and knocked out mutants were challenged to M. javanica’s infection.Results: High expression levels of the GFP gene marker in transformed A. thaliana plants revealed that the promoter region of GmHsp22.4 was strongly activated after nematode infection. However, structural analysis of the soybean resistant and susceptible genotypes did not detect any polymorphisms in the whole gene model, including the 2.0 kb promoter region. Moreover, the reproduction of the nematode was significantly reduced in plants overexpressing GmHsp22.4 gene in A. thaliana compared to the wild type. Additionally, the reproduction of M. javanica in the A. thaliana mutants was significantly increased and was related with the structural organization of heat shock cis element (HSE) in the promoter.Conclusions: The soybean chaperone GmHsp22.4 is involved in the defense response to root-knot nematode M. javanica’s infection in A. thaliana. The HSE in the promoter region close to the transcriptional start site (TSS) are important to GmHsp22.4 promoter activation after nematode infection. It was not possible to detect any polymorphisms occurrence in GmHsp22.4 gene between the M. javanica-resistant and susceptible soybean genotypes, so the resistance mechanism might not be related with the transcriptional regulation in the initiation process or based on sequence level on the TSS. |
