WRI1基因在拟南芥幼苗耐热中的功能OA

INTRODUCTION:Heat stress severely impairs plant growth and crop productivity.WRINKLED1(WRI1),an AP2/EREBP-class transcription factor in Arabidopsis thaliana,orchestrates carbon partitioning between glycolysis and fatty acid bio-synthesis,playing pivotal roles in development and stress adaptation.Elucidating its molecular function under high-temperature stress is critical for improving thermotolerance in crops. RATIONALE:While WRI1's metabolic regulatory function has been elucidated,its role in heat response remains unex-plored.To decipher the molecular mechanism of WRI1-mediated thermotolerance,we integrated genetic approaches(wild type,wri1-4,and WRI1-OE(overexpression))with qRT-PCR and phenotyping under controlled heat stress. RESULTS:In this study,histochemical GUS staining of pWRI1::GUS transgenic lines demonstrated constitutive WRI1 expression throughout Arabidopsis seedlings,with significantly enhanced transcription in cotyledons under heat stress(HS)(P＜0.05).Prolonged HS induced gradual transcriptional attenuation,though the transcription levels remained ele-vated than under the optimal temperature(22 ℃).qRT-PCR confirmed thermo-responsive WRI1 upregulation(peak:1 h HS,3-fold induction),followed by threshold-dependent decline,indicating acute early-phase responsiveness.Endoge-nous immunoassays revealed reduced WRI1 protein accumulation under HS,suggesting HS-impaired protein stability or post-translational regulatory mechanisms.Thermotolerance phenotyping of WT,wri1-4,and WRI1-OE lines showed su-perior HS survival rate in WRI1-OE,with acquired thermotolerance exceeding basal thermotolerance across genotypes,confirming WRI1-mediated positive thermoregulation.The survival rate of WRI1-OE seedlings reached approximately 75％-85％,whereas that of wild type and complementary lines was less than 10％.We found that WRI1-OE reduced reactive oxygen species(ROS)accumulation,where direct transcriptional regulation of HSF/HSP genes(e.g.,HSFA2,HSP101)was excluded by qRT-PCR.Nevertheless,differential gene expression across genotypes indicated WRI1's auxiliary role in thermotolerance via ROS scavenging and indirect proteostasis maintenance. CONCLUSION:This study proved WRI1 as a master regulator of thermotolerance,functioning through synergistic acti-vation of chaperone networks(HSFA2-HSPs)and ROS scavenging.The discovery of its cross-pathway coordination mechanism provides novel insights into plant thermal adaptation,and positions WRI1 as a potentially useful target for breeding climate-resilient crops.