Giacomini Darci A, Umphres Alinna M, Nie Haozhen, Mueller Thomas C, Steckel Lawrence E, Young Bryan G, Scott Robert C, Tranel Patrick J
Department of Crop Sciences, University of Illinois, Urbana, IL, USA.
Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA.
Pest Manag Sci. 2017 Aug;73(8):1559-1563. doi: 10.1002/ps.4581. Epub 2017 May 16.
Resistance to herbicides that inhibit protoporphyrinogen oxidase (PPO) is a widespread and growing problem for weed managers across the midwestern and midsouthern United States. In Amaranthus spp., this resistance is known to be conferred by a glycine deletion at the 210 amino acid (ΔG210) in PPO2. Preliminary analysis indicated that the ΔG210 mutation did not fully account for observed resistance to PPO inhibitors in two Amaranthus palmeri populations from Tennessee and one from Arkansas.
Sequencing PPX2 cDNA from six resistant plants uncovered two new mutations at the R98 site (R98G and R98M), a site previously found to endow PPO-inhibitor resistance in Ambrosia artemisiifolia. Sequencing of this region from additional plants sprayed with 264 g fomesafen ha showed the presence of one or both R98 mutations in a subset of the resistant plants from all three populations. No plants sensitive to fomesafen contained either mutation. A derived cleaved amplified polymorphic sequence (dCAPS) assay to test for the presence of these mutations in A. palmeri was developed.
Two new mutations of PPX2 (R98G, R98M) likely confer resistance to PPO-inhibitors in A. palmeri, and can be rapidly identified using a dCAPS assay. © 2017 Society of Chemical Industry.
对抑制原卟啉原氧化酶（PPO）的除草剂产生抗性，是美国中西部和中南部杂草管理者面临的一个普遍且日益严重的问题。在苋属植物中，已知这种抗性是由PPO2中第210位氨基酸处的甘氨酸缺失（ΔG210）导致的。初步分析表明，ΔG210突变并不能完全解释田纳西州的两个糙果苋种群以及阿肯色州的一个糙果苋种群中观察到的对PPO抑制剂的抗性。
对六株抗性植株的PPX2 cDNA进行测序，在R98位点发现了两个新突变（R98G和R98M），该位点先前在豚草中被发现赋予PPO抑制剂抗性。对另外264克/公顷噁草酮处理植株的该区域进行测序，结果显示所有三个种群的抗性植株亚群中存在一个或两个R98突变。对噁草酮敏感的植株均未携带任何一种突变。开发了一种衍生的酶切扩增多态性序列（dCAPS）分析方法，用于检测糙果苋中这些突变的存在情况。
PPX2的两个新突变（R98G、R98M）可能赋予糙果苋对PPO抑制剂的抗性，并且可以使用dCAPS分析方法快速鉴定。© 2017化学工业协会。
