基于ALS基因突变猪殃殃抗/敏生物型的生态适合度差异机理

Tribenuron-methyl resistant catchweed bedstraw is competitive with wheat in China, where it exists as on-going and serious threat with a wide distribution. In previous work, we conduct investigations on the seed germination of catchweed bedstraw in a wide range of environmental conditions. In addition, the target-site Acetolactate synthase (ALS) gene mutation in the resistant catchweed bedstraw population conferred resistance to tribenuron-methyl. At this stage, tribenuron-methyl is the most widely used herbicide for controlling broad-leaf weeds in China. However, with the frequent use of tribenuron-methyl, resistance in catchweed bedstraw has become a serious problem in China. By now, little is known regarding the fitness costs in tribenuron-methyl resistant catchweed bedstraw. Therefore, we used five resistant/susceptible catchweed bedstraw biotypes possessing different target-site mutations of ALS gene, that had a consistent genetic background, and wheat cultivar Ningmai 22 as research materials. In this study, we aim to (1) evaluate the differences in biological characteristic parameters in life cycle under different treatments of tribenuron-methyl; (2) determine the biological characteristic parameters in life cycle under non-competition, intraspecific competition, and wheat co-cultured with catchweed bedstraw conditions, resepectively; (3) analyze the different ecological adaptation between different catchweed bedstraw biotypes in responses to herbicide stress and biotic stress; and (4) predict the developmental model of different tribenuron-methyl-resistant catchweed bedstraw biotypes. The expected results of this project will reveal the quantification of fitness differences between herbicide-resistant and herbicide-susceptible catchweed bedstraw biotypes and provide key information to the design of weed management strategies in winter wheat fields.

抗苯磺隆猪殃殃是严重威胁我国小麦安全生产的恶性杂草之一。申请者前期发现，猪殃殃的种子萌发生态适应性强，靶标酶ALS基因突变是其对苯磺隆产生抗性的主要原因，在苯磺隆大面积连续应用的现阶段，猪殃殃将在冬麦区持续严重危害。目前，关于抗性猪殃殃的生态适合度代价知之甚少。申请者以5个遗传背景一致、ALS蛋白保守区域氨基酸不同的猪殃殃抗性和敏感生物型及优质小麦宁麦22为研究材料，分析苯磺隆胁迫下，不同生物型间生命周期内生物学特征参数差异；然后在非竞争、种内竞争和小麦-猪殃殃共生生境中，测定供试材料的生物学特征参数，并结合苯磺隆胁迫，从生态学、生物化学和分子生物学角度解析其田间生态适应性差异，构建抗性猪殃殃发展预测模型。预期结果不仅可揭示猪殃殃抗/敏生物型的生态适合度差异机理，解析抗性发展规律，同时可为评估除草剂新品抗性风险，制定绿色精准治理优质小麦田抗性杂草新策略提供科学依据。

靶标酶ALS基因突变形成的抗苯磺隆猪殃殃是严重威胁我国小麦安全生产的恶性杂草之一。在苯磺隆大面积连续应用的现阶段，猪殃殃将在冬麦区持续严重危害。解析抗性猪殃殃的生态适宜性机理、预测其抗性发展趋势已成为亟待解决的科学问题。本项目以5个遗传背景一致、ALS蛋白保守区域氨基酸不同的猪殃殃抗性和敏感生物型及优质小麦宁麦22为研究材料，测定猪殃殃ALS蛋白保守区域氨基酸不同的生物型间应答温度、光照、pH、NACl、埋土深度胁迫的种子萌发生态学特性差异，调查不同生物型间生命周期内生物学特征参数差异，研究在非竞争、种内竞争和小麦-猪殃殃共生生境中，不同生物型的生物学特征参数差异，从生态学、生物化学和分子生物学角度分析不同生物型的田间生态适应性差异，预测了不同生物型的发展趋势。结果表明，Pro-197-Thr突变的GAJT-001种子对温度、光照、pH、NaCl及埋土深度胁迫的适应性较强，种子萌发的生态适应性强于敏感生物型及Pro-197-Ala的GASY-001、Pro-197-Ser的GASY-002、Trp-574-Leu的GAXH-002生物型。苯磺隆预处理后，存活的敏感生物型的株高、地上部分鲜重、结实量和千粒重始终略高于抗性生物型，敏感生物型的结实量显著高于抗性生物型，不同抗性生物型间无显著差异。非竞争条件下，敏感生物型的株高、地上部分鲜重和千粒重始终略高于抗性生物型，敏感生物型结实量显著高于抗性生物型，不同抗性生物型间无显著差异。种内竞争和猪殃殃-小麦竞争的条件下，敏感生物型的结实量明显高于抗性生物型，而抗性生物型GAJT-001、GASY-001、GASY-002间的株高、地上部分鲜重和结实量无显著差异，但均显著高于GAXH-002。敏感生物型与不同生物型共生，以与GAJT-001共生中Pro-197-Thr检出率最高，与GAXH-002共生Trp-574-Leu检出率最低；GAJT-001生物型与其他生物型共生的子代中，Pro-197-Thr检出率明显高于其他类型突变。不同生物型单独繁殖及其共生繁殖的子代均对氯氟吡氧乙酸敏感。GAJT-001的生态适应性、繁殖蔓延风险高于GASY-001、GASY-002，而GASY-001、GASY-002生态适应性、繁殖蔓延风险明显高于GAXH-002，轮换使用激素类除草剂可有效治理抗性猪殃殃蔓延。