College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Ministry of Education, China.
College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Ministry of Education, China.
Pestic Biochem Physiol. 2017 Nov;143:231-238. doi: 10.1016/j.pestbp.2017.08.009. Epub 2017 Aug 9.
Quinclorac, an auxin-type herbicide, is widely used to control barnyardgrass and some dicotyledon weeds. Echinochloa crus-galli var. zelayensis, a variety of E. crus-galli (L.) Beauv., is widespread in China and some populations have resistance to quinclorac. E. crus-galli var. zelayensis seeds with varying sensitivity to quinclorac were used in the present study. The expression of the ADP/ATP carrier protein (ANT) gene, which plays an important role in the maintenance of cellular energy balance, dramatically rose in the S biotype after exposure to quinclorac, while no change was found in two R biotypes. The activity of β-cyanoalanine synthase (β-CAS), which is the key enzyme for cyanide degradation, was higher in two R biotypes than in the S biotype before and after treatment with quinclorac. One single-nucleotide difference was detected in the EcCAS gene of two R biotypes compared with the S biotype. The nucleotide change, which caused one amino acid substitution, replacing Methionine (Met)-295 with Lysine (Lys)-295 in the two R biotypes, which are same as the rice β-CAS gene at this position. In addition, EcCAS gene expression was higher in the two R biotypes than in the S biotype. In conclusion, β-CAS may play a crucial role in the resistance of E. crus-galli var. zelayensis to quinclorac. EcCAS gene mutation and higher gene expression may enhance the activity of β-CAS to avoid the accumulation of toxic cyanide in resistant populations, thus contributing to the resistance mechanism of E. crus-galli var. zelayensis. to quinclorac.
精喹禾灵是一种生长素型除草剂，被广泛用于防治稗草和一些阔叶杂草。节节草是稗草（L.）Beauv.的一个变种，在中国广泛分布，有些种群对精喹禾灵具有抗性。本研究使用对精喹禾灵敏感性不同的节节草种子。ADP/ATP 载体蛋白（ANT）基因的表达在维持细胞能量平衡中起着重要作用，在接触精喹禾灵后，S 生物型中的表达显著增加，而在两个 R 生物型中没有发现变化。β-氰基丙氨酸合酶（β-CAS）的活性，作为氰化物降解的关键酶，在两个 R 生物型中比 S 生物型更高，在处理前后用精喹禾灵。与 S 生物型相比，两个 R 生物型的 EcCAS 基因检测到一个单核苷酸差异。核苷酸变化导致一个氨基酸取代，即在两个 R 生物型中由蛋氨酸（Met）-295取代赖氨酸（Lys）-295，与该位置的水稻β-CAS 基因相同。此外，EcCAS 基因在两个 R 生物型中的表达高于 S 生物型。总之，β-CAS 可能在节节草对精喹禾灵的抗性中起关键作用。EcCAS 基因突变和更高的基因表达可能增强β-CAS 的活性，以避免抗性种群中有毒氰化物的积累，从而有助于节节草对精喹禾灵的抗性机制。
