Functional identification of the pepper(Capsicum annuum L.) mediator subunit MED21 in regulating pollen development

The involvement of multiple members of Mediator in regulating the growth and development of various plant tissues through diverse mechanisms has been well documented. In this study, a subunit of Mediator, CaMED 21 , was identified in pepper. Tissue-specific expression analysis showed that this subunit is expressed in leaves, flowers, and fruits, with notably high expression levels in flowers and fruits. Through virus-induced gene silencing, silencing of the CaMED 21 gene was found to result in reduced leaf size and decreased pollen viability in pepper. Conversely, overexpression of CaMED 21 in tomato led to increased plant height, larger leaves, enhanced pollen viability, and bigger fruits. Results from protein interaction analysis suggest that CaMED 21 may regulate plant morphogenesis through interactions with PR 3 and SlMED 18. The regulatory role of the CaMED 21 subunit in leaf morphology and pollen viability of pepper has been demonstrated. These results provide valuable insights for further exploration of the CaMED 21 subunit’s function and offer a novel perspective on the mechanisms governing pepper growth regulation.