|WAGNER, TANYA - Texas A&M University|
|Bell, Alois - Al|
|MAGILL, CLINT - Texas A&M University|
Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Abstract Only
Publication Acceptance Date: 1/20/2023
Publication Date: 1/27/2023
Citation: Wagner, T.A., Puckhaber, L.S., Bell, A.A., Magill, C., Liu, J. 2023. Lessons from the introgression of G. hirsutum RNAi O-methyl transferase construct into G. barbadense. In: Proceedings of the National Cotton Council Beltwide Cotton Conferences, January 8-10, 2023, Austin, Texas. 2023:489.
Technical Abstract: Cotton species produce a unique set of terpenoid aldehydes that are toxic to fungi, bacteria, and insects. These are hemigossypolone, hemigossypols, gossypols, and heliocides. Depending on the species and in a tissue specific manner, these compounds can be methylated. For example, G. barbadense leaves have high levels of methylated terpenoid aldehydes, and the G. hirsutum leaves have only non-methylated compounds. In vitro toxicity assays have suggested that the methylated forms of the compounds are not as toxic as the non-methylated compounds. The enzyme desoxyhemigossypol O-methyl transferase is responsible for the methylation. We have knocked-down the expression of the desoxyhemigossypol O-methyl transferase in G. hirsutum via RNAi, such that these plants have no detectable methylation in root tissue (a tissue where methylated compounds are normally present in G. hirsutum). Here we describe our efforts to introgress the RNAi OMT construct into G. barbadense lines PS7, SBSI, and PS6. Through these efforts, we have learned that G. hirsutum has two repressors of the desoxyhemigossypol OMT in leaves. Also, the ratio of methylated to non-methylated terpenoid aldehyde compounds appears to be tightly controlled in G. barbadense leaves.