CLASS-II KNOX genes coordinate spatial and temporal ripening in tomato

Alexandra Keren-Keiserman, Amit Shtern, Matan Levy, Daniel Chalupowicz, Chihiro Furumizu, John Paul Alvarez, Ziva Amsalem, Tzahi Arazi, Sharon Alkalai-Tuvia, Idan Efroni, Naomi Ori, John L. Bowman, Elazar Fallik, Alexander Goldshmidt*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Fruits can be divided into dry and fleshy types. Dry fruits mature through senescence and fleshy fruits through ripening. Previous studies have indicated that partially common molecular networks could govern fruit maturation in these different fruit types. However, the nature of such networks remains obscure. CLASS-II KNOX genes were shown to regulate the senescence of the Arabidopsis (Arabidopsis thaliana) dry fruits, the siliques, but their roles in fleshy-fruit development are unknown. Here, we investigated the roles of the tomato (Solanum lycopersicum) CLASS-II KNOX (TKN-II) genes in fleshy fruit ripening using knockout alleles of individual genes and an artificial microRNA line (35S:amiR-TKN-II) simultaneously targeting all genes. 35S:amiR-TKN-II plants, as well as a subset of tkn-II single and double mutants, have smaller fruits. Strikingly, the 35S:amiR-TKN-II and tknII3 tknII7/ + fruits showed early ripening of the locular domain while their pericarp ripening was stalled. Further examination of the ripening marker-gene RIPENING INHIBITOR (RIN) expression and 35S:amiR-TKN-II rin-1 mutant fruits suggested that TKN-II genes arrest RIN activity at the locular domain and promote it in the pericarp. These findings imply that CLASS-II KNOX genes redundantly coordinate maturation in both dry and fleshy fruits. In tomato, these genes also control spatial patterns of fruit ripening, utilizing differential regulation of RIN activity at different fruit domains.

Original languageAmerican English
Pages (from-to)657-668
Number of pages12
JournalPlant Physiology
Issue number1
StatePublished - Sep 2022

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VC American Society of Plant Biologists 2022. All rights reserved.


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