Australian Herbicide Resistance Initiative, School of Agriculture and Environment, University of Western Australia, Perth, Western Australia, Australia.
Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI, USA.
Pest Manag Sci. 2021 Feb;77(2):970-977. doi: 10.1002/ps.6109. Epub 2020 Oct 10.
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.
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.
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.
作为二硝基苯胺类除草剂的靶标位点，微管蛋白是植物中小基因家族编码的。为了更好地描述全球重要杂草物种硬叶狗尾草中靶标位点对二硝基苯胺类除草剂抗性的机制，尝试扩增和测序α-微管蛋白转录本。
在硬叶狗尾草中鉴定出了 4 种α-微管蛋白同工型（TUA1、TUA2、TUA3 和 TUA4）。在所研究的两个硬叶狗尾草种群个体中，发现了编码这些α-微管蛋白的转录本数量和序列的变化。在种群内和种群间，TUA3 和 TUA4 的 cDNA 5'和 3'非翻译区存在差异。此外，还鉴定出 TUA3 转录本中的一个新的双重突变，Arg-390-Cys+Asp-442-Glu，具有赋予二硝基苯胺抗性的潜力。
本研究揭示了异花授粉杂草物种硬叶狗尾草个体/种群中α-微管蛋白基因家族的复杂性，并强调了更好地理解微管蛋白基因家族的分子结构以检测抗性点突变的必要性。虽然 TUA4 是一种普遍表达的α-微管蛋白同工型，包含最常报道的抗性突变，但其他突变微管蛋白同工型也可能在赋予二硝基苯胺抗性方面发挥作用。
