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Glucose-6-phosphate dehydrogenase (G6PDH), the rate-limiting enzyme of the pentose phosphate pathway (PPP), plays a pivotal role in plant stress responses. However, the function and mechanism of G6PDHs in crop plants challenged by fungal pathogens remain poorly understood. In this study, a wheat G6DPH gene responding to infection by <i>Puccinia striiformis</i> f. sp. <i>tritici</i> (<i>Pst</i>), designated <i>TaG6PDH2</i>, was cloned and functionally identified. <i>TaG6PDH2</i> expression was significantly upregulated in wheat leaves inoculated with <i>Pst</i> or treated with abiotic stress factors. Heterologous mutant complementation and enzymatic properties indicate that <i>TaG6PDH2</i> encodes a G6PDH protein. The transient expression of <i>TaG6PDH2</i> in <i>Nicotiana benthamiana</i> leaves and wheat protoplasts revealed that TaG6PDH2 is a chloroplast-targeting protein. Silencing <i>TaG6PDH2</i> via the barley stripe mosaic virus (BSMV)-induced gene silencing (VIGS) system led to compromised wheat resistance to the <i>Pst</i> avirulent pathotype CYR23, which is implicated in weakened H₂O₂ accumulation and cell death. In addition, TaG6PDH2 was confirmed to interact with the wheat glutaredoxin TaGrxS4. These results demonstrate that <i>TaG6PDH2</i> endows wheat with increased resistance to stripe rust by regulating reactive oxygen species (ROS) production.