1a. Objectives (from AD-416):
Increase resistance to fungal pathogens such as Fusarium oxysporum f. sp. vasinfectum and Verticillium dahliae by down regulating desoxyhemigossypol-O-methyltransferase (dHG-6-OMT).
1b. Approach (from AD-416):
We have over 100 independent Coker 312 callus lines transformed with an intron-containing hair-pin (ihp) construct of desoxyhemigossypol-6-O-methyltransferase (dHG-6-OMT) sequence from Coker 312 driven by the CaMV35S promoter to reduce the expression of dHG-6-OMT throughout the plant. We will generate transgenic cotton (G. hirsutum) plants from these transformed lines. We will confirm that the transgenic plants contain the RNAi construct by Southern hybridization and by quantitative Reverse Transcriptase PCR (q-RT-PCR) of dHG-6-OMT mRNA. We will determine if the dHG-6-OMT mRNA is significantly reduced as expected in root tip tissues of young seedlings of G. hirsutum and we expect that the dHG-6-OMT mRNA levels will to be even lower in mature glanded tissues. In addition, we will analyze root tissues for the presence of methylated phytoalexins; again, we expect a decrease of methylation to correlate with the RNAi suppression of dHG-6-OMT transcripts.
3. Progress Report:
This is a new project that replaced 6202-22000-031-27R and which is continuing and expanding upon the work of the precursor project. The goal of this project is to develop new technology to increase the cotton plant's resistance to soilborne pathogens that cause wilt. Project work in FY 2013 focused on 18 embryogenic independent callus lines that have been treated to produce the more potent protective compounds known as phytoalexins. Plants derived from these lines will allow us to test for resistance to wilt pathogenes. Project work, as it progresses, will provide foundational information to support efforts to develop cotton plants resistant to wilt and soilborne pathogens.