RESUMO
The wheat recombinant chromosome inbred line LDN(Dic-3A)10, obtained through introgression of a Triticum dicoccoides disomic chromosome 3A fragment into Triticum turgidum spp. durum var. Langdon, is resistant to fusarium head blight (FHB) caused by Fusarium graminearum. To identify genes involved in FHB resistance, we used a cDNA-AFLP approach to compare gene expression between LDN(Dic-3A)10 and the susceptible parental line LDN at different time points post-inoculation. In total, 85 out of the â¼ 500 transcript-derived fragments (TDFs) were found to be differentially expressed: 36 and 19% were upregulated in LDN(Dic-3A)10 and LDN, respectively, whereas 45% were induced in both genotypes. Several of the cloned TDFs showed similarity to proteins involved in specific recognition of plant pathogens or associated with early responses to infection. Some TDFs specific to the inoculation response did not show similarity to characterized proteins. The availability of T. aestivum genome sequences allowed the in silico mapping of 28 TDFs and the acquirement of the corresponding gene sequences and, in some cases, their regulatory regions. Analysis of promoter regions revealed the potential existence of shared transcription regulation mechanisms. For instance, three TDF-associated genes contained binding sites for WRKY transcription factors, which have been implicated in the regulation of genes associated with pathogen defense, and three for abscisic acid-responsive element (ABRE). Collectively, our results revealed specific pathogen recognition in the interactions of LDN and LDN(Dic-3A)10 with F. graminearum. Such recognition leads to changes in the expression of several transcripts, attributable to the presence of the wheat QTL Qfhs.ndsu-3AS.
Assuntos
Fusarium/crescimento & desenvolvimento , Perfilação da Expressão Gênica , Genes de Plantas , Interações Hospedeiro-Patógeno , Triticum/imunologia , Triticum/microbiologia , Análise do Polimorfismo de Comprimento de Fragmentos Amplificados , DNA Complementar/análise , Resistência à Doença , Regulação da Expressão Gênica de Plantas , Fatores de Tempo , Triticum/genéticaRESUMO
Eight isozyme systems were used in this study: acid phosphatase (ACP), alcohol dehydrogenase (ADH), esterase (EST), glutamate dehydrogenase (GDH), malate dehydrogenase (MDH), phosphoglucoisomerase (PGI), 6-phosphogluconate dehydrogenase (PGD), and phosphoglucomutase (PGM). The polymorphism of these enzyme systems was studied in 25 elite inbred lines. A total of 19 loci were identified, but only eight of them were polymorphic in the germplasm tested. The polymorphic index for the eight informative markers ranged from 0.08 to 0.57, with a mean value of 0.36. Five isozyme loci were mapped in F2:3 populations with existing RFLP data. Est-1, Gdh-2 and Pgi-2 were mapped to linkage groups 3, 14 and 9, respectively. As in previous reports, an ACP locus and a PGD locus were found to be linked, both located in linkage group 2 of the public sunflower map