Effects of Efficient Ethylene Remover on the Lignification of Fresh Faba Bean ( L.) during Storage.

Postharvest ethylene accumulation and lignification are significant issues affecting the storage quality of fresh faba beans, resulting in rapid quality decline. However, there is still a lack of effective preservation methods to preserve the quality of faba beans during storage. This study aimed to investigate the regulation of lignification in faba beans during storage using a high-efficiency ethylene remover (HEER), examining physiological responses, key enzyme activities, and transcriptomic changes. Results showed that the HEER treatment inhibited the lignification, reducing it by 45% and lowering the respiratory rate of fresh pods by 32.8% during storage. Additionally, the HEER treatment suppressed respiration rates and the activities of lignin synthesis-related enzymes, including phenylalanine ammonia-lyase (from 353.73 to 246.60 U/g), cinnamic acid-4-hydroxylase (from 635.86 to 125.00 U/g), 4-coumarate: coenzyme A ligase (from 1008.57 to 516.52 U/g), and cinnamyl-alcohol dehydrogenase (from 129.42 to 37.12 U/g), thus slowing lignin accumulation. During storage, the hardness of fresh faba bean increased by 9.79% from the initial period, being 1.44 times higher than that of HEER. On days 8 and 16 of storage, the respiratory rate of the treated beans decreased by 24.38% and 4.12%, respectively. Physiological and enzyme activity analyses indicated that HEER treatment-induced increase in hardness was associated with the phenylpropanoid metabolic pathway. Moreover, the HEER significantly down-regulated the expression of several key genes, namely , , and . This study helps to deepen the understanding of the inhibition of lignification by HEER and provide new insights for the development of preservation technology of faba bean.