Differentially expressed genes in dicamba-resistant and dicamba-susceptible biotypes

作者：Keith Barbara K; Kalinina Elena B; Dyer William E^*

来源：Weed Biology and Management, 2011, 11(4): 224-234.

DOI：10.1111/j.1445-6664.2011.00424.x

• auxinic herbicide
• gene expression
• herbicide resistance
• subtraction hybridization

In an ongoing effort to investigate the mechanism of auxinic herbicide resistance in Kochia scoparia (kochia), polymerase chain reaction-based cDNA suppression subtractive hybridization was used to identify genes that are differentially expressed between dicamba-resistant (HRd) and dicamba-susceptible (S1) kochia biotypes in response to herbicide treatment. Both the HRd and S1 adaptor-ligated cDNAs were used in separate hybridizations in order to generate biotype-specific clones. A total of 710 cDNAs, representing putative differentially expressed mRNAs, were isolated and subjected to further screening. The false-positive cDNAs were removed by conducting two colony hybridizations and at least one Northern hybridization. Differential or biotype-specific expression was confirmed for six clones each from the HRd and S1 plants. The S1-related genes were constitutively expressed at higher levels than in the HRd plants, but none had significant sequence similarity to known genes. Among the HRd-related genes, HRd-88 had 42% amino acid sequence identity to a conserved domain within thiol peptidases, which might be involved in auxin-regulated gene expression. The constitutively expressed and inducible (by the dicamba treatment) HRd-39 had 40% identity and 60% similarity to a domain from the Fe(II)/a-ketoglutarate-dependent hydroxylase superfamily. The HRd-39 gene product had the characteristics of an enzyme that is able to detoxify dicamba via oxidative hydroxylation and thus its overexpression might confer the dicamba resistance phenotype.

• 出版日期2011-12