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Guo WL, Chen BH, Guo YY, Chen XJ, Li QF, Yang HL, Li XZ, Zhou JG, Wang GY. Expression of Pumpkin CmbHLH87 Gene Improves Powdery Mildew Resistance in Tobacco. FRONTIERS IN PLANT SCIENCE 2020; 11:163. [PMID: 32318077 PMCID: PMC7147351 DOI: 10.3389/fpls.2020.00163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 02/03/2020] [Indexed: 06/11/2023]
Abstract
Powdery mildew (PM), caused by Podosphaera xanthii, is a major threat to the global cucurbit yield. The molecular mechanisms underlying the PM resistance of pumpkin (Cucurbita moschata Duch.) are largely unknown. A homolog of the basic helix-loop-helix (bHLH) transcription factor was previously identified through a transcriptomic analysis of a PM-resistant pumpkin. In this study, this bHLH homolog in pumpkin has been functionally characterized. CmbHLH87 is present in the nucleus. CmbHLH87 expression in the PM-resistant material was considerably downregulated by PM; and abscisic acid, methyl jasmonate, ethephon, and NaCl treatments induced CmbHLH87 expression. Ectopic expression of CmbHLH87 in tobacco plants alleviated the PM symptoms on the leaves, accelerated cell necrosis, and enhanced H2O2 accumulation. The expression levels of PR1a, PR5, and NPR1 were higher in the PM-infected transgenic plants than in PM-infected wild-type plants. Additionally, the chlorosis and yellowing of plant materials were less extensive and the concentration of bacteria at infection sites was lower in the transgenic tobacco plants than in the wild-type plants in response to bacterial wilt and scab pathogens. CmbHLH87 may be useful for genetic engineering of novel pumpkin cultivars in the future.
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Affiliation(s)
- Wei-Li Guo
- School of Horticulture Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
| | - Bi-Hua Chen
- School of Horticulture Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
| | - Yan-Yan Guo
- School of Horticulture Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
| | - Xue-Jin Chen
- School of Horticulture Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
| | - Qing-Fei Li
- School of Horticulture Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
| | - He-Lian Yang
- School of Horticulture Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
| | - Xin-Zheng Li
- School of Horticulture Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
| | - Jun-Guo Zhou
- School of Horticulture Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
| | - Guang-Yin Wang
- School of Horticulture Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
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Guo WL, Chen BH, Guo YY, Yang HL, Mu JY, Wang YL, Li XZ, Zhou JG. Improved Powdery Mildew Resistance of Transgenic Nicotiana benthamiana Overexpressing the Cucurbita moschata CmSGT1 Gene. FRONTIERS IN PLANT SCIENCE 2019; 10:955. [PMID: 31402923 PMCID: PMC6670833 DOI: 10.3389/fpls.2019.00955] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 07/09/2019] [Indexed: 05/27/2023]
Abstract
Powdery mildew (PM), which is mainly caused by Podosphaera xanthii, is a serious biotrophic pathogen disease affecting field-grown and greenhouse-grown cucurbit crops worldwide. Because fungicides poorly control PM, the development and cultivation of PM-resistant varieties is critical. A homolog of SGT1 (suppressor of the G2 allele of skp1), which encodes a key component of the plant disease-associated signal transduction pathway, was previously identified through a transcriptomic analysis of a PM-resistant pumpkin (Cucurbita moschata) inbred line infected with PM. In this study, we have characterized this SGT1 homolog in C. moschata, and investigated its effects on biotic stress resistance. Subcellular localization results revealed that CmSGT1 is present in the nucleus. Additionally, CmSGT1 expression levels in the PM-resistant material was strongly induced by PM, salicylic acid (SA) and hydrogen peroxide (H2O2). In contrast, SA and H2O2 downregulated CmSGT1 expression in the PM-susceptible material. The ethephon (Eth) and methyl jasmonate (MeJA) treatments upregulated CmSGT1 expression in both plant materials. The constitutive overexpression of CmSGT1 in Nicotiana benthamiana (N. benthamiana) minimized the PM symptoms on the leaves of PM-infected seedlings, accelerated the onset of cell necrosis, and enhanced the accumulation of H2O2. Furthermore, the expression levels of PR1a and PR5, which are SA signaling transduction markers, were higher in the transgenic plants than in wild-type plants. Thus, the transgenic N. benthamiana plants were significantly more resistant to Erysiphe cichoracearum than the wild-type plants. This increased resistance was correlated with cell death, H2O2 accumulation, and upregulated expression of SA-dependent defense genes. However, the chlorosis and yellowing of plant materials and the concentration of bacteria at infection sites were greater in the transgenic N. benthamiana plants than in the wild-type plants in response to infections by the pathogens responsible for bacterial wilt and scab. Therefore, CmSGT1-overexpressing N. benthamiana plants were hypersensitive to these two diseases. The results of this study may represent valuable genetic information for the breeding of disease-resistant pumpkin varieties, and may also help to reveal the molecular mechanism underlying CmSGT1 functions.
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Affiliation(s)
- Wei-Li Guo
- School of Horticulture Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
| | - Bi-Hua Chen
- School of Horticulture Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
| | - Yan-Yan Guo
- School of Horticulture Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
| | - He-Lian Yang
- School of Horticulture Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
| | - Jin-Yan Mu
- School of Horticulture Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
| | - Yan-Li Wang
- School of Horticulture Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
| | - Xin-Zheng Li
- School of Horticulture Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
| | - Jun-Guo Zhou
- School of Horticulture Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, China
- Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, China
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