TY  - EJOU
AU  - Qin, Yunduan 
AU  - Su, Kekang 
AU  - Zhao, Meng 
AU  - Xu, Yu 
AU  - Zhang, Yuanyuan 
AU  - Feng, Chunyang 
AU  - Guo, Xinlei 
AU  - Wu, Chunhui 
AU  - Shen, Changwei 
AU  - Yuan, Jingping 

TI  - Construction of a Yeast cDNA Library from Chinese Cabbage and Identification of Upstream Regulators of the Key Tip-Burn Resistance Gene <i>BrWRKY25</i>
T2  - Phyton-International Journal of Experimental Botany

PY  - 
VL  - 
IS  - 
SN  - 1851-5657

AB  - Tip-burn in Chinese cabbage (<i>Brassica rapa</i> L. ssp. <i>pekinensis</i>) is a calcium-deficiency-induced physiological disorder, and BrWRKY25 functions as a negative regulator of tip-burn resistance. To elucidate the regulatory mechanisms underlying <i>BrWRKY25</i>-mediated tip-burn resistance, we constructed a yeast cDNA library from Chinese cabbage subjected to calcium-deficient treatment to identify its key upstream transcription factors. The constructed yeast cDNA library exhibited a titer of 9.5 × 10<sup>6</sup> colony forming unit (CFU)·mL<sup>−</sup><sup>1</sup> and an average insert size exceeding 1000 bp, meeting the quality criteria for downstream applications. Using the 1044-bp promoter of <i>BrWRKY25</i> as bait, we screened several transcription factors, including zinc finger proteins, heat shock proteins, and ion transport proteins. Furthermore, conserved domain analysis of two zinc finger protein transcription factors, BrZFP4 (Bra039750) and BrZFP19 (Bra033588), revealed that BrZFP4 contains a conserved C<sub>2</sub>H<sub>2</sub> zinc finger domain, while BrZFP19 contains two conserved B-box zinc finger domains. Yeast one-hybrid assays and dual-luciferase reporter gene assays demonstrated that both BrZFP4 and BrZFP19 directly bind to the <i>BrWRKY25</i> promoter and activate its transcription. These findings suggest that the BrZFP4/19–<i>BrWRKY25</i> regulatory module plays a pivotal role in tip-burn resistance, offering a theoretical framework for understanding the molecular mechanisms governing <i>BrWRKY25</i>-mediated resistance in Chinese cabbage.
KW  - Chinese cabbage; library construction; promoter; transcription factors

DO  - 10.32604/phyton.2026.085158