Histone Deacetylase CpHDA3 Is Functionally Associated with CpERF9 in Suppression of and Genes during Papaya Fruit Ripening.

Histone deacetylase (HDAC) performs important functions in plant growth and development, including fruit ripening. As a complex biological process, fruit ripening involves the histone acetylation modification of ripening-associated genes. Histone deacetylase genes () have been well studied in and rice, but the biological functions of s in papaya are poorly understood. In the present work, three , belonging to the RPD3/HDA1 subfamily, were identified from papaya and named as , , and . and were induced by propylene, while was propylene-repressed. Moreover, CpHDA3 protein could physically interact with CpERF9 and enhance the transcriptional repression activities of CpERF9 to downstream genes , and . Histone acetylation levels of and were increased during fruit ripening. Taken together, these results suggested that CpERF9 recruits CpHDA3 to form a histone deacetylase repressor complex to mediate pectin methylesterase and polygalacturonase genes expression during papaya fruit ripening and softening.