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Article|01 Sep 2021|OPEN
LsAP2 regulates leaf morphology by inhibiting CIN-like TCP transcription factors and repressing LsKAN2 in lettuce
Chen Luo 1, Shenglin Wang1, Kang Ning1, Zijing Chen1, Yixin Wang1, Jingjing Yang1 & Qian Wang1,
1Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing 100193, China

Horticulture Research 8,
Article number: 184 (2021)
doi: 10.1038/hortres.2021.184
Views: 51

Received: 10 Jan 2021
Revised: 21 Apr 2021
Accepted: 20 May 2021
Published online: 01 Sep 2021

Abstract

Leaf size and flatness directly affect photosynthesis and are closely related to agricultural yield. The final leaf size and shape are coordinately determined by cell proliferation, differentiation, and expansion during leaf development. Lettuce (Lactuca sativa L.) is one of the most important leafy vegetables worldwide, and lettuce leaves vary in shape and size. However, the molecular mechanisms of leaf development in lettuce are largely unknown. In this study, we showed that the lettuce APETALA2 (LsAP2) gene regulates leaf morphology. LsAP2 encodes a transcriptional repressor that contains the conserved EAR motif, which mediates interactions with the TOPLESS/TOPLESS-RELATED (TPL/TPR) corepressors. Overexpression of LsAP2 led to small and crinkly leaves, and many bulges were seen on the surface of the leaf blade. LsAP2 physically interacted with the CINCINNATA (CIN)-like TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP) transcription factors and inhibited their transcriptional activation activity. RNA sequencing analysis showed that LsAP2 affected the expression of auxin- and polarity-related genes. In addition, LsAP2 directly repressed the abaxial identity gene KANADI2 (LsKAN2). Together, these results indicate that LsAP2 regulates leaf morphology by inhibiting CIN-like TCP transcription factors and repressing LsKAN2, and our work provides insights into the regulatory mechanisms of leaf development in lettuce.