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Feng MQ, Lu MD, Long JM, Yin ZP, Jiang N, Wang PB, Liu Y, Guo WW, Wu XM. miR156 regulates somatic embryogenesis by modulating starch accumulation in citrus. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:6170-6185. [PMID: 35661206 DOI: 10.1093/jxb/erac248] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 06/02/2022] [Indexed: 05/17/2023]
Abstract
Somatic embryogenesis (SE) is a major regeneration approach for in vitro cultured tissues of plants, including citrus. However, SE capability is difficult to maintain, and recalcitrance to SE has become a major obstacle to plant biotechnology. We previously reported that miR156-SPL modules regulate SE in citrus callus. However, the downstream regulatory pathway of the miR156-SPL module in SE remains unclear. In this study, we found that transcription factors CsAGL15 and CsFUS3 bind to the CsMIR156A promoter and activate its expression. Suppression of csi-miR156a function leads to up-regulation of four target genes, SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (CsSPL) genes, and reduction of SE efficiency. In the short tandem target mimic (STTM)-miR156a overexpression callus (MIM156), the number of amyloplasts and starch content were significantly reduced, and genes involved in starch synthesis and transport were down-regulated. csi-miR172d was down-regulated, whereas the target genes, CsTOE1.1 and CsTOE1.2, which inhibit the expression of starch biosynthesis genes, were up-regulated. In our working model, CsAGL15 and CsFUS3 activate csi-miR156a, which represses CsSPLs and further regulates csi-miR172d and CsTOEs, thus altering starch accumulation in callus cells and regulating SE in citrus. This study elucidates the pathway of miR156-SPLs and miR172-TOEs-mediated regulation of SE, and provides new insights into enhancing SE capability in citrus.
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Affiliation(s)
- Meng-Qi Feng
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Meng-Di Lu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Jian-Mei Long
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Zhao-Ping Yin
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Nan Jiang
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Peng-Bo Wang
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Yue Liu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Wen-Wu Guo
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
- Hubei Hongshan Laboratory, Wuhan, China
| | - Xiao-Meng Wu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
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