Zhang Xiao-Qi, Powles Stephen B
WA Herbicide Resistance Initiative, School of Plant Biology, University of Western Australia WA 6009, Australia.
New Phytol. 2006;172(4):636-45. doi: 10.1111/j.1469-8137.2006.01879.x.
The molecular basis of an acetyl-CoA carboxylase (ACCase) target-based resistant Lolium rigidum population (WLR 96) was studied here. The carboxyl-transferase domain of the plastidic ACCase gene from resistant individuals was amplified by PCR and sequenced. The DNA sequences were aligned and compared with a susceptible population. Six amino acid substitutions were identified in the resistant population. The substitution Ile-2041-Asn, known to confer resistance to ACCase-inhibiting herbicides aryloxyphenoxypropionate (APP) in Alopecurus myosuroides, was identified in most resistant plants but it is always linked with other amino acid substitutions. This was confirmed by a cleaved amplified polymorphism (CAP) marker and an allele-specific PCR. The sole amino acid substitution Ile-2041-Asn was not found in this population. It is likely this mutation evolved later among individuals already possessing the other substitutions. Three haplotypes were identified from the resistant population based on the six amino acid combinations, and two are linked with herbicide resistance in this population. The multiple amino acid substitutions including the Ile-2041-Asn form the molecular basis endowing a high degree of resistance to ACCase-inhibiting herbicides in this L. rigidum population.
本文研究了基于乙酰辅酶A羧化酶（ACCase）靶点的硬直黑麦草抗性种群（WLR 96）的分子基础。通过PCR扩增抗性个体质体ACCase基因的羧基转移酶结构域并进行测序。将DNA序列进行比对，并与一个敏感种群进行比较。在抗性种群中鉴定出6个氨基酸替换。在大多数抗性植株中鉴定出Ile-2041-Asn替换，已知该替换赋予黑麦草对ACCase抑制性除草剂芳氧苯氧丙酸酯（APP）的抗性，但它总是与其他氨基酸替换相关联。这通过酶切扩增多态性（CAP）标记和等位基因特异性PCR得到证实。在该种群中未发现单独的Ile-2041-Asn氨基酸替换。这种突变可能是在已经具有其他替换的个体中后来进化出来的。基于这6种氨基酸组合，从抗性种群中鉴定出3种单倍型，其中2种与该种群中的除草剂抗性相关联。包括Ile-2041-Asn在内的多个氨基酸替换构成了该硬直黑麦草种群对ACCase抑制性除草剂具有高度抗性的分子基础。
