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Short Panicle 3 controls panicle architecture by upregulating APO2/RFL and increasing cytokinin content in rice
Author(s) -
Huang Yong,
Bai Xufeng,
Luo Meifang,
Xing Yongzhong
Publication year - 2019
Publication title -
journal of integrative plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.734
H-Index - 83
eISSN - 1744-7909
pISSN - 1672-9072
DOI - 10.1111/jipb.12729
Subject(s) - panicle , cytokinin , rice plant , horticulture , biology , agronomy , gene , genetics , auxin
Inflorescence architecture is a major determinant of spikelet numbers per panicle, a key component of grain yield in rice. In this study, Short Panicle 3 ( SP3 ) was identified from a short panicle 3 ( sp3 ) mutant in which T‐DNA was inserted in the promoter of SP3 , resulting in a knockdown mutation. SP3 encodes a DNA binding with one finger (Dof) transcriptional activator. Quantitative real time (qRT)‐PCR and RNA in situ hybridization assays confirmed that SP3 is preferentially expressed in the young rice inflorescence, specifically in the branch primordial regions. SP3 acts as a negative regulator of inflorescence meristem abortion by upregulating APO2/RFL . SP3 both up‐ and downregulates expression of genes involved in cytokinin biosynthesis and catabolism, respectively. Consequently, cytokinin concentrations are decreased in young sp3 panicles, thereby leading to small panicles having fewer branches and spikelets. Our findings support a model in which SP3 regulates panicle architecture by modulating cytokinin homeostasis. Potential applications to rice breeding, through gene‐editing of the SP3 promoter are assessed.