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Multiple mechanisms explain how reduced KRP expression increases leaf size of Arabidopsis thaliana
Author(s) -
Sizani Bulelani L.,
Kalve Shweta,
Markakis Marios N.,
Domagalska Malgorzata A.,
Stelmaszewska Joanna,
AbdElgawad Hamada,
Zhao Xin'ai,
De Veylder Lieven,
De Vos Dirk,
Broeckhove Jan,
Schnittger Arp,
Beemster Gerrit T. S.
Publication year - 2019
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.15458
Subject(s) - endoreduplication , biology , cell cycle , arabidopsis thaliana , microbiology and biotechnology , arabidopsis , mitosis , cell division , meristem , transcriptome , mutant , cytokinesis , cell growth , embryo , genetics , botany , cell , gene , gene expression
Summary Although cell number generally correlates with organ size, the role of cell cycle control in growth regulation is still largely unsolved. We studied kip related protein ( krp) 4 , 6 and 7 single, double and triple mutants of Arabidopsis thaliana to understand the role of cell cycle inhibitory proteins in leaf development. We performed leaf growth and seed size analysis, kinematic analysis, flow cytometery, transcriptome analysis and mathematical modeling of G1/S and G2/M checkpoint progression of the mitotic and endoreplication cycle. Double and triple mutants progressively increased mature leaf size, because of elevated expression of cell cycle and DNA replication genes stimulating progression through the division and endoreplication cycle. However, cell number was also already increased before leaf emergence, as a result of an increased cell number in the embryo. We show that increased embryo and seed size in krp4/6/7 results from seed abortion, presumably reducing resource competition, and that seed size differences contribute to the phenotype of several large‐leaf mutants. Our results provide a new mechanistic understanding of the role of cell cycle regulation in leaf development and highlight the contribution of the embryo to the development of leaves after germination in general.