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Ma X, Ying P, He Z, Wu H, Li J, Zhao M. The LcKNAT1- LcEIL2/3 Regulatory Module Is Involved in Fruitlet Abscission in Litchi. Front Plant Sci 2022; 12:802016. [PMID: 35126427 PMCID: PMC8813966 DOI: 10.3389/fpls.2021.802016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 12/15/2021] [Indexed: 06/12/2023]
Abstract
Large and premature organ abscission may limit the industrial development of fruit crops by causing serious economic losses. It is well accepted that ethylene (ET) is a strong inducer of organ abscission in plants. However, the mechanisms underlying the control of organ abscission by ET are largely unknown. We previously revealed that LcKNAT1, a KNOTTED-LIKE FROM ARABIDOPSIS THALIANA1 (KNAT1)-like protein, acted as a negative regulator in control of fruitlet abscission through suppressing the expression of ET biosynthetic genes in litchi. In this study, we further reported that LcKNAT1 could also directly repress the transcription of LcEIL2 and LcEIL3, two ETHYLENE INSENSITIVE 3-like (EIL) homologs in litchi, which functioned as positive regulators in ET-activated fruitlet abscission by directly promoting the expression of genes responsible for ET biosynthesis and cell wall degradation. The expression level of LcKNAT1 was downregulated, while LcEIL2/3 was upregulated at the abscission zone (AZ) accompanying the fruitlet abscission in litchi. The results of electrophoretic mobility shift assays (EMSAs) and transient expression showed that LcKNAT1 could directly bind to the promoters of LcEIL2 and LcEIL3 and repress their expression. Furthermore, the genetic cross demonstrated that the β-glucuronidase (GUS) expression driven by the promoters of LcEIL2 or LcEIL3 at the floral AZ was obviously suppressed by LcKNAT1 under stable transformation in Arabidopsis. Taken together, our findings suggest that the LcKNAT1-LcEIL2/3 regulatory module is likely involved in the fruitlet abscission in litchi, and we propose that LcKNAT1 could suppress both ET biosynthesis and signaling to regulate litchi fruit abscission.
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Affiliation(s)
- Xingshuai Ma
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in South China at Ministry of Agriculture and Rural Affair, Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Peiyuan Ying
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in South China at Ministry of Agriculture and Rural Affair, Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Zidi He
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in South China at Ministry of Agriculture and Rural Affair, Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Hong Wu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in South China at Ministry of Agriculture and Rural Affair, Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Jianguo Li
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in South China at Ministry of Agriculture and Rural Affair, Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Minglei Zhao
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in South China at Ministry of Agriculture and Rural Affair, Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, College of Horticulture, South China Agricultural University, Guangzhou, China
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Ma X, Yuan Y, Wu Q, Wang J, Li J, Zhao M. LcEIL2/3 are involved in fruitlet abscission via activating genes related to ethylene biosynthesis and cell wall remodeling in litchi. Plant J 2020; 103:1338-1350. [PMID: 32391616 DOI: 10.1111/tpj.14804] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 04/07/2020] [Accepted: 04/28/2020] [Indexed: 05/28/2023]
Abstract
Fruit crops are subject to precocious fruit abscission, during which the phytohormone ethylene (ET) acts as a major positive regulator. However, the molecular basis of ET-induced fruit abscission remains poorly understood. Here, we show that two ETHYLENE INSENSITIVE 3-like (EIL) homologs in litchi, LcEIL2 and LcEIL3, play a role in ET-activated fruitlet abscission. LcEIL2/3 were significantly upregulated in the fruit abscission zone (AZ) during the ET-induced fruitlet abscission in litchi. The presence of LcEIL2/3 in wild-type Arabidopsis and ein3 eil1 mutants can accelerate the floral organ abscission. Moreover, the electrophoretic mobility shift assay and dual luciferase reporter analysis illustrated that LcEIL2/3 directly interacted with the gene promoters to activate the expression of cell wall remodeling genes LcCEL2/8 and LcPG1/2, and ET biosynthetic genes LcACS1/4/7 and LcACO2/3. Furthermore, we showed that LcPG1/2 were expressed in the floral abscission zone of Arabidopsis, and constitutive expression of LcPG2 in Arabidopsis promoted the floral organ abscission. In conclusion, we propose that LcEIL2/3 are involved in ET-induced fruitlet abscission via controlling expression of genes related to ET biosynthesis and cell wall remodeling in litchi.
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Affiliation(s)
- Xingshuai Ma
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, China
- Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, 510642, China
| | - Ye Yuan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, China
- Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, 510642, China
| | - Qian Wu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, China
- Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, 510642, China
| | - Jun Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, China
- Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, 510642, China
| | - Jianguo Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, China
- Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, 510642, China
| | - Minglei Zhao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, China
- Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, 510642, China
- Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, College of Horticulture, South China Agricultural University, Guangzhou, 510642, China
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