Article Highlight | 7-Mar-2024

Deciphering the role of PoWRKY71 and PoCAB151 in enhancing drought tolerance in paeonia ostii

Nanjing Agricultural University The Academy of Science

Drought stress significantly impacts plant growth, leading to substantial agricultural economic losses, estimated at 30% or about US$30 billion annually. This environmental challenge prompts plants to adopt various adaptive mechanisms, including root system modification and early flowering, to mitigate its effects. Despite the understanding of physiological and molecular responses, such as the role of abscisic acid and specific metabolites in enhancing drought resistance, the regulatory mechanisms of WRKY transcription factors, particularly in stabilizing photosynthesis under drought conditions, remain inadequately explored.

In September 2023, Horticulture Research published a research entitled by “Telomere-to-telomere genome assembly of melon (Cucumis melo L. var. inodorus) provides a high-quality reference for meta-QTL analysis of important traits”. This research explored the roles of PoWRKY71 and PoCAB151 genes in enhancing drought tolerance in Paeonia ostii.

Initially, a drought triggered WRKY transcription factor PoWRKY71 was identified through transcriptome analysis and found to be specifically expressed in leaves on the 12th day after drought treatment.  Functional assays demonstrated that overexpressing PoWRKY71 in Nicotiana tabacum improved drought tolerance by maintaining higher chlorophyll content, photosynthetic rate, and lower oxidative stress levels compared to wild-type plants. Conversely, silencing PoWRKY71 in P. ostii increased sensitivity to drought stress, and downregulated the expression level of light-harvesting chlorophyll a/b-binding protein (CAB), indicating its positive regulatory role in drought resistance.

Further interaction assays revealed that PoWRKY71 can directly activate the transcription of PoCAB151 by targeting the W-box, demonstrating its crucial role in stabilizing photosynthesis and enhancing drought tolerance. PoCAB151 was shown to be a chloroplast protein involved in light capture and transfer, with its expression also upregulated in response to drought. Overexpression of PoCAB151 in tobacco led to improved physiological responses under drought conditions, such as higher water content, chlorophyll content, and photosynthetic efficiency, while silencing PoCAB151 resulted in decreased drought tolerance.

The study concluded that PoWRKY71 positively regulates drought resistance by directly activating the transcription of PoCAB151, which in turn stabilizes photosynthesis and promotes the accumulation of drought-resistant substances. This regulatory mechanism highlights the potential for genetic manipulation of WRKY transcription factors and their target genes to improve plant drought tolerance, offering new insights into the molecular basis of plant responses to drought stress.

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References

Authors

Yuting Luan1, Zijie Chen1, Ziwen Fang1, Xingqi Huang2, Daqiu Zhao1,* and Jun Tao1,3,*

Affiliations

1College of Horticulture and Landscape Architecture, Yangzhou University, Yangzhou 225009, China

2Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA

3Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou 225009, China

About  Jun Tao

Male, 1966-, Ph.D., Professor of College of Horticulture and Landscape Architecture, Yangzhou University, research interests: 1. floral physiology and molecular biology, 2. floral genetic physiology and germplasm innovation, 3. floral mining and exploitation of functional components.

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