Elucidating the relationship between ethylene biosynthesis and climacteric respiration in tomato

The study evaluated the quadruple mutant slaco1/3/6/7 and the quintuple mutant slaco1/3/4/6/7. While the quadruple mutant retained 2.3%–2.7% of wild-type (WT) peak ethylene production—sufficient to maintain respiratory levels comparable to WT—the quintuple mutant produced only 0.2%–0.3% of WT ethylene, exhibiting a strong suppression of climacteric respiration.

This respiratory suppression was accompanied by a broad downregulation of tricarboxylic acid (TCA) cycle genes, a significant drop in alternative oxidase SlAOX1a transcript abundance, and reduced mitochondrial Complex II activity in the fruit tissue.

Implications for postharvest storage

Despite severe metabolic constraints in fruits with drastically suppressed ethylene levels, cellular ATP contents remained largely unchanged. These findings demonstrate a clear quantitative ethylene threshold required for climacteric respiration stimulation, providing novel target strategies to regulate ripening and extend postharvest shelf life.

Source

Chen, H., Li, Z., Shi, Y., Li, D., & Chen, K. (2026). Threshold of ethylene for climacteric respiration during postharvest tomato ripening. Postharvest Biology and Technology, 243, 114718.  https://doi.org/10.1016/j.postharvbio.2026.114718

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