Abstract：
This study unveils the detoxification potential of insecticide-tolerant plant beneficial bacteria (PBB), i.e., Ciceribacter azotifigens SF1 and Serratia marcescens SRB1, in spinach treated with fipronil (FIP), profenofos (PF) and chlorantraniliprole (CLP) insecticides. Increasing insecticide doses (25-400 μg kg-1 soil) significantly curtailed germination attributes and growth of spinach cultivated at both bench-scale and in greenhouse experiments. Profenofos at 400 μg kg-1 exhibited maximum inhibitory effects and reduced germination by 55%; root and shoot length by 78% and 81%, respectively; dry matter accumulation in roots and shoots by 79% and 62%, respectively; leaf number by 87% and leaf area by 56%. Insecticide application caused morphological distortion in root tips/surfaces, increased levels of oxidative stress, and cell death in spinach. Application of insecticide-tolerant SF1 and SRB1 strains relieved insecticide pressure resulting in overall improvement in growth and physiology of spinach grown under insecticide stress. Ciceribacter azotifigens improved germination rate (10%); root biomass (53%); shoot biomass (25%); leaf area (10%); Chl-a (45%), Chl-b (36%) and carotenoid (48%) contents of spinach at 25 μg CLP kg-1 soil. PBB inoculation reinvigorated the stressed spinach and modulated the synthesis of phytochemicals, proline, malondialdehyde (MDA), superoxide anions (O2•-), and hydrogen peroxide (H2O2). Scanning electron microscopy (SEM) revealed recovery in root tip morphology and stomatal openings on abaxial leaf surfaces of PBB-inoculated spinach grown with insecticides. Ciceribacter azotifigens inoculation significantly increased intrinsic water use efficiency, transpiration rate, vapor pressure deficit, intracellular CO2 concentration, photosynthetic rate, and stomatal conductance in spinach exposed to 25 μg FIP kg-1. Also, C. azotifigens and S. marcescens modulated the antioxidant defense systems of insecticide-treated spinach. Bacterial strains were strongly colonized to root surfaces of insecticide-stressed spinach seedlings as revealed under SEM. The identification of insecticide-tolerant PBBs such as C. azotifigens and S. marcescens hold the potential for alleviating abiotic stress to spinach, thereby fostering enhanced and safe production within polluted agroecosystems.
摘要：
这项研究揭示了耐杀虫剂的植物有益菌（PBB）的解毒潜力，即，用氟虫腈（FIP）处理的菠菜中的环孢菌氮杂异素SF1和粘质沙雷氏菌SRB1，profenofos（PF）和chloantraniliprole（CLP）杀虫剂。杀虫剂剂量的增加（25-400μgkg-1土壤）显着减少了在实验室规模和温室实验中种植的菠菜的发芽属性和生长。Profenofos在400μgkg-1时表现出最大的抑制作用，并使发芽减少了55％；根和芽长度分别减少了78％和81％，根和芽中的干物质积累分别增加79%和62%，叶数分别为87%和叶面积分别为56%。杀虫剂的应用导致根尖/表面的形态变形，氧化应激水平升高，菠菜中的细胞死亡。耐杀虫剂的SF1和SRB1菌株的应用减轻了杀虫剂压力，从而使在杀虫剂胁迫下生长的菠菜的生长和生理得到了整体改善。发芽率(10%);根生物量(53%);芽生物量(25%);叶面积(10%);Chl-a(45%),25μgCLPkg-1土壤中菠菜的Chl-b（36％）和类胡萝卜素（48％）含量。多溴联苯接种使胁迫下的菠菜恢复活力，并调节植物化学物质的合成，脯氨酸,丙二醛（MDA），超氧阴离子（O2·-），和过氧化氢（H2O2）。扫描电子显微镜（SEM）显示，用杀虫剂生长的PBB接种的菠菜的根尖形态和背面叶表面的气孔开口恢复。接种环化杆菌显着提高内在水分利用效率，蒸腾速率,蒸气压力不足，细胞内CO2浓度，光合速率，和暴露于25μgFIPkg-1的菠菜的气孔导度。此外，氮杂芽孢杆菌和粘质链球菌调节了经杀虫剂处理的菠菜的抗氧化防御系统。如SEM所示，细菌菌株强烈定植于杀虫剂胁迫的菠菜幼苗的根表面。对耐杀虫剂的多溴联苯的鉴定，如氮杂芽孢杆菌和粘质芽孢杆菌，具有减轻菠菜非生物胁迫的潜力，从而促进受污染的农业生态系统内的强化和安全生产。
