SHOEBOX Modulates Root Meristem Size in Rice through Dose-Dependent Effects of Gibberellins on Cell Elongation and Proliferation.
Little is known about how the size of meristem cells is regulated and whether it participates in the control of meristem size in plants. Here, we report our findings on shoebox (shb), a mild gibberellin (GA) deficient rice mutant that has a short root meristem size. Quantitative analysis of cortical cell length and number indicates that shb has shorter, rather than fewer, cells in the root meristem until around the fifth day after sowing, from which the number of cortical cells is also reduced. These defects can be either corrected by exogenous application of bioactive GA or induced in wild-type roots by a dose-dependent inhibitory effect of paclobutrazol on GA biosynthesis, suggesting that GA deficiency is the primary cause of shb mutant phenotypes. SHB encodes an AP2/ERF transcription factor that directly activates transcription of the GA biosynthesis gene KS1. Thus, root meristem size in rice is modulated by SHB-mediated GA biosynthesis that regulates the elongation and proliferation of meristem cells in a developmental stage-specific manner.
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.
Jintao
J
Li
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.
Yu
Y
Zhao
Department of Biological Sciences and NUS Centre for BioImaging Sciences, National University of Singapore, Singapore.
Huangwei
H
Chu
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.
Likai
L
Wang
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.
Yanru
Y
Fu
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan, China.
Ping
P
Liu
Plant Industry, Commonwealth Scientific and Industrial Research Organization, Canberra, Australia.
Narayana
N
Upadhyaya
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.
Chunli
C
Chen
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.
Tongmin
T
Mou
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan, China.
Yuqi
Y
Feng
Department of Biological Sciences and NUS Centre for BioImaging Sciences, National University of Singapore, Singapore.
Prakash
P
Kumar
Department of Biological Sciences and NUS Centre for BioImaging Sciences, National University of Singapore, Singapore.
Jian
J
Xu
D001483:Base Sequence; D001665:Binding Sites; D049109:Cell Proliferation; D048430:Cell Shape; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005875:Gibberellins / Q000502:physiology*; D018519:Meristem / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D012275:Oryza / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D010937:Plant Growth Regulators / Q000502:physiology; D010940:Plant Proteins / Q000502:physiology*; D018517:Plant Roots / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D050656:Transcription Factor AP-2 / Q000502:physiology*
D005875:Gibberellins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D050656:Transcription Factor AP-2