Biotechnology Bulletin ›› 2023, Vol. 39 ›› Issue (10): 136-147.doi: 10.13560/j.cnki.biotech.bull.1985.2023-0339

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Functional Analysis of WRKY6 Gene in Tomato Under Low-phosphorus Stress

CHEN Hao-ting1(), ZHANG Yu-jing1, LIU Jie1, DAI Ze-min1, LIU Wei1, SHI Yu1, ZHANG Yi1(), LI Tian-lai1,2()   

  1. 1. College of Horticulture, Shanxi Agricultural University, Taigu 030801
    2. College of Horticulture, Shenyang Agricultural University, Shenyang 110866
  • Received:2023-04-11 Online:2023-10-26 Published:2023-11-28
  • Contact: ZHANG Yi, LI Tian-lai E-mail:746852776@qq.com;harmony1228@163.com;ltl@syau.edu.cn

Abstract:

The purpose of this study is to analyze the role of tomato transcription factor SlWRKY6 in response to low-phosphorus stress, and to lay a theoretical foundation for studying the molecular mechanism of low-phosphorus tolerance in tomato and exploring tomato germplasm resources of improving low-phosphorus tolerance and phosphorus utilization. Wild-type tomato Ailsa craig was used as the material and its cDNA was used as the template to clone SlWRKY6, and the RNAi-SlWRKY6 and OE-SlWRKY6 transgenic tomato plant lines were constructed by agrobacterium tumefacien-mediated transformation. Tomato plants with three different genotypes of wild type, RNAi-SlWRKY6 and OE-SlWRKY6, were subjected to low phosphorus. On the day 18 of low-phosphorus treatment, the results of phenotype and physiological and biochemical indexes in the leaves and roots were determined. Phenotypic observation showed that OE-SlWRKY6 transgenic tomato plants were of thicker and shorter after low phosphorus treatment while compared with RNAi-SlWRKY6 transgenic tomato plants, they had a higher number of leaves, and were less affected by low-phosphorus stress, and showed stronger low-phosphorus tolerance. The analysis results of physiological and biochemical indexes showed that the organic phosphorus and total phosphorus content in the roots and leaves of transgenic tomato plant OE-SlWRKY6 significantly increased compared with wild type, while the acid phosphatase activity and some organic acid contents in the roots significantly increased. The expressions of phosphorus transporters also significantly reduced. However, the trend of changes in these indicators in the transgenic tomato plant RNAi-SlWRKY6 under low-phosphorus stress was opposite to that in transgenic tomato plant OE-SlWRKY6. After low-phosphorus stress, the relative expressions of LePT1 decreased in the roots of OE-SlWRKY6 plants, which was opposite to that of RNAi-SlWRKY6 plants. The relative expressions of LePT2 in the roots of wild type, RNAi-SlWRKY6 and OE-SlWRKY6 plants showed an overall increasing trend, while the relative expressions of LePT3 showed an overall decreasing trend. According to the above results, SlWRKY6 responded to low-phosphorus stress and its expression was positively correlated with the low-phosphorus tolerance of tomato plants, and might affect the response of phosphorus transporter genes to low phosphorus. The results of this study may provide certain theoretical basis for further revealing the function of tomato WRKY transcription factor family and its response mechanism to low-phosphorus stress.

Key words: tomato, transcription factors, SlWRKY6, low-phosphorus stress, functional analysis, phosphorus content, acid phosphatase