The present investigation deals with the comparative study of plant growth promoting rhizobacteria (PGPR), salicylic acid (SA), and Ag-nanoparticle (AgNPs) on the physiology, sugar metabolism and yield of two varieties of wheat V-1 (GA 2002) and V-2 (Inqalab-91), differing in sensitivity to yellow rust. The study was based on the hypothesis that bacteria from stressed habitat may have better biocontrol potential than that of the normal condition. Three PGPR strains Bacillus cereus, Bacillus spp., and Burkholderia sp. were used as bioinoculant. The former two were isolated from the rhizosphere of wheat previously infected with rust and powdery mildew respectively and Burkholderia sp. was isolated from the rhizosphere of uninfected wheat. The seeds were soaked for 2 h prior to sowing in the broth culture of PGPR strains and SA. The AgNPs were applied as foliar spray (60 days after sowing). Yellow rust was induced 68 days after sowing. The treatments with Bacillus cereus, AgNPs, and SA effectively reduced the yellow rust in wheat as measured by AUDPC (area under production curve). Bacillus cereus significantly stimulated phenylalanine ammonia lyase activity. The abscisic acid (ABA), SA, indole acetic acid (IAA), and gibberellin (GA), the chlorophyll, and carotenoids contents were also increased in the sensitive variety (infected with yellow rust) following PGPR application. PGPR further augmented the activities of antioxidant enzymes and proline content. The biological yield was significantly higher in plants inoculated with Bacillus cereus. Bacillus cereus appears to act synergistically with SA to increase grain size. The tolerance to yellow rust is mediated by increase in the activity of phenylalanine ammonia lyase (PAL) and superoxide dismutase (SOD) and ABA content. AgNPs delay maturity and have a greater impact on the accumulation of photosynthates. Bacillus cereus can act synergistically with SA to improve total sugar content of flag leaves + grain. The AgNPs can be supplemented with Bacillus cereus for enhanced sugar production and sugar translocation to grains. AgNps and Bacillus cereus exhibit similar biocontrol potential against yellow rust as evidenced by AUDPC and PAL activity, but the Bacillus cereus superseded on AgNPs with respect to production of phytohormones, effect being more pronounced in the sensitive variety Inqalab-91.

中文翻译：

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银纳米颗粒、水杨酸和植物促生长根际细菌对黄锈病小麦生理的交互作用

本研究涉及植物生长促进根际细菌 (PGPR)、水杨酸 (SA) 和纳米银颗粒 (AgNPs) 对两种小麦 V-1 的生理、糖代谢和产量的比较研究 (GA 2002)和 V-2 (Inqalab-91)，对黄锈病的敏感性不同。该研究基于以下假设：来自压力栖息地的细菌可能比正常条件下的细菌具有更好的生物防治潜力。三种 PGPR 菌株蜡样芽孢杆菌、芽孢杆菌和伯克霍尔德菌。用作生物接种剂。前两者分别从先前感染锈病和白粉病的小麦的根际和伯克霍尔德氏菌分离。从未感染小麦的根际分离。播种前将种子浸泡在 PGPR 菌株和 SA 的肉汤培养物中 2 小时。AgNPs 作为叶面喷雾施用（播种后 60 天）。播种后68天诱发黄锈病。根据 AUDPC（生产曲线下面积）测量，蜡样芽孢杆菌、AgNPs 和 SA 处理有效地减少了小麦的黄锈病。蜡样芽孢杆菌显着刺激苯丙氨酸解氨酶活性。在 PGPR 应用后，敏感品种（感染黄锈病）的脱落酸 (ABA)、SA、吲哚乙酸 (IAA) 和赤霉素 (GA)、叶绿素和类胡萝卜素的含量也有所增加。PGPR 进一步增强了抗氧化酶的活性和脯氨酸含量。接种蜡样芽孢杆菌的植物的生物产量显着更高。蜡样芽孢杆菌似乎与 SA 协同作用以增加晶粒尺寸。对黄锈病的耐受性是由苯丙氨酸解氨酶 (PAL) 和超氧化物歧化酶 (SOD) 的活性和 ABA 含量的增加介导的。AgNPs 延迟成熟并对光合产物的积累产生更大的影响。蜡样芽孢杆菌可与SA协同作用，提高旗叶+籽粒的总糖含量。AgNPs 可以补充蜡状芽孢杆菌，以提高糖产量和糖向谷物的转运。AgNps 和蜡状芽孢杆菌对黄锈病表现出相似的生物防治潜力，如 AUDPC 和 PAL 活性所证明的那样，但蜡样芽孢杆菌在植物激素的产生方面取代了 AgNP，其效果在敏感品种 Inqalab-91 中更为明显。AgNPs 延迟成熟并对光合产物的积累产生更大的影响。蜡样芽孢杆菌可与SA协同作用，提高旗叶+籽粒的总糖含量。AgNPs 可以补充蜡状芽孢杆菌，以提高糖产量和糖向谷物的转运。AgNps 和蜡状芽孢杆菌对黄锈病表现出相似的生物防治潜力，如 AUDPC 和 PAL 活性所证明的那样，但蜡样芽孢杆菌在植物激素的产生方面取代了 AgNP，其效果在敏感品种 Inqalab-91 中更为明显。AgNPs 延迟成熟并对光合产物的积累产生更大的影响。蜡样芽孢杆菌可与SA协同作用，提高旗叶+籽粒的总糖含量。AgNPs 可以补充蜡状芽孢杆菌，以提高糖产量和糖向谷物的转运。AgNps 和蜡状芽孢杆菌对黄锈病表现出相似的生物防治潜力，如 AUDPC 和 PAL 活性所证明的那样，但蜡样芽孢杆菌在植物激素的产生方面取代了 AgNP，其效果在敏感品种 Inqalab-91 中更为明显。AgNPs 可以补充蜡状芽孢杆菌，以提高糖产量和糖向谷物的转运。AgNps 和蜡状芽孢杆菌对黄锈病表现出相似的生物防治潜力，如 AUDPC 和 PAL 活性所证明的那样，但蜡样芽孢杆菌在植物激素的产生方面取代了 AgNP，其效果在敏感品种 Inqalab-91 中更为明显。AgNPs 可以补充蜡状芽孢杆菌，以提高糖产量和糖向谷物的转运。AgNps 和蜡状芽孢杆菌对黄锈病表现出相似的生物防治潜力，如 AUDPC 和 PAL 活性所证明的那样，但蜡样芽孢杆菌在植物激素的产生方面取代了 AgNP，其效果在敏感品种 Inqalab-91 中更为明显。