Diversity of α‐tubulin transcripts in Lolium rigidum. Issue 2 (10th October 2020) - Chen, Jinyi
Abstract: BACKGROUND: Tubulin, the target site of dinitroaniline herbicides, is encoded by small gene families in plants. To better characterize the mechanisms of target‐site resistance to dinitroaniline herbicides in the globally important weedy species Lolium rigidum, attempts were made to amplify and sequence α‐tubulin transcripts. RESULTS: Four α‐tubulin isoforms (TUA1, TUA2, TUA3 and TUA4) were identified in L. rigidum . Variations in the number and sequence of transcripts encoding these α‐tubulin proteins were found in individuals from the two L. rigidum populations examined. Within and among populations, differences in the 5′‐ and 3′‐untranslated regions of cDNA in TUA3 and TUA4 were identified. Furthermore, a novel double mutation, Arg‐390‐Cys+Asp‐442‐Glu, in the TUA3 transcript was identified and has the potential to confer dinitroaniline resistance. CONCLUSION: This research reveals the complexity of the α‐tubulin gene family in individuals/populations of the cross‐pollinated weedy species L. rigidum, and highlights the need for better understanding of the molecular architecture of tubulin gene families for detecting resistance point mutations. Although TUA4 is a commonly expressed α‐tubulin isoform containing most frequently reported resistance mutations, other mutant tubulin isoforms may also have a role in conferring dinitroaniline resistance. Abstract : In annual ryegrass, six α‐tubulin transcripts were identified in the susceptible population and five in the resistant one. A novel double mutation Arg‐390‐Cys+Asp‐442‐Glu was demonstrated to confer dinitroaniline resistance. © 2020 Society of Chemical Industry