近日，51吃瓜网 、果蔬园艺作物种质创新与利用全国重点实验室产祝龙教授团队联合美国 Clemson 大学 Hong Luo 团队和内蒙古农牧业科学院，在 The Plant Journal 在线发表了题为 “LpDREB2A-LpbZIP41/LpbZIP66 module orchestrates heat stress tolerance by modulating ABA biosynthesis and carbonic anhydrase activity in perennial ryegrass” 的研究论文。
多年生黑麦草（Lolium perenne）是世界范围内广泛应用的重要冷季型草坪草和牧草。高温胁迫已成为限制多年生黑麦草生长、草坪质量维持和生产利用的重要因素。高温胁迫相关机制仍有待深入解析。
本研究利用多年生黑麦草多样性群体开展 GWAS 分析，结合转录组数据，鉴定了一个热激显著诱导的 bZIP 转录因子基因LpbZIP41。自然变异分析发现，LpbZIP41位点存在与耐热性显著相关的单倍型。CRISPR-Cas9 敲除株系和过表达株系表型表明LpbZIP41高温的正调控因子。
研究表明，LpbZIP41一方面结合 LpNCED4 启动子并激活其表达，促进 ABA 生物合成，另一方面结合LpβCA2启动子并激活其表达，帮助维持高温下的碳代谢稳定和细胞稳态。LpbZIP66 可与 LpbZIP41 形成异源二聚体，并抑制其对 LpNCED4的激活作用，提示该通路存在负反馈调节机制。进一步结果发现， LpDREB2A能够结合LpbZIP41启动子中的DRE元件并激活其表达，从而增强植物耐热性。
综上，该研究提出了一个多年生黑麦草耐热调控模型：高温诱导LpDREB2A，进而激活LpbZIP41；LpbZIP41通过调控ABA生物合成和碳代谢稳定提升耐热性，而 LpbZIP66 对该过程发挥负调控作用。相关研究揭示了LpDREB2A-LpbZIP41/LpbZIP66 模块调控多年生黑麦草耐热性的分子机制，为多年生黑麦草及冷季型禾草耐热性遗传改良提供了重要候选基因和分子标记资源。
图例：黑麦草中 LpDREB2A–LpbZIP41/LpbZIP66 参与热胁迫响应的调控模型：热胁迫诱导相关基因表达，LpDREB2A 促进 LpbZIP41 转录，LpbZIP41 进一步激活 LpNCED4 和 LpβCA2，而 LpbZIP66 通过与 LpbZIP41 拮抗形成负反馈调控。
英文摘要：Heat stress is a major environmental constraint limiting the productivity of perennial ryegrass (Lolium perenne), a widely cultivated forage and turfgrass. Here, through a genome-wide association study (GWAS) analysis of a diverse perennial ryegrass population, we identified LpbZIP41 as a major heat tolerance quantitative trait locus (QTL) for heat tolerance. Natural variation at this locus comprises three haplotypes showing differential thermotolerance, with evidence of positive selection during breeding. LpbZIP41 localizes to the nucleus and exhibits rapid heat-inducible expression. Functional validation via CRISPR-Cas9-mediated knockout confirmed that LpbZIP41 is essential for heat stress. Overexpression of LpbZIP41 in perennial ryegrass enhanced thermotolerance, as evidenced by improved survival, reduced lipid peroxidation, maintained membrane integrity and global transcriptional reprogramming under heat stress. Mechanistically, we uncovered a transcriptional cascade that LpDREB2A directly activates LpbZIP41 transcription by binding to dehydration-responsive element (DRE) motifs in promoter. LpbZIP41, in turn, regulates LpNCED4, a key abscisic acid (ABA) biosynthesis gene, and LpβCA2, encoding a stress-responsive carbonic anhydrase. Furthermore, LpbZIP66 functions as a negative regulator that antagonizes LpbZIP41 activity via heterodimerization. Collectively, our findings established an LpDREB2A-LpbZIP41/LpbZIP66 regulatory module as a central hub that integrates ABA biosynthesis and metabolic signals to confer heat stress tolerance in a cool-season grass.
论文链接：//doi.org/10.1111/tpj.71059
文图：方正福 编辑：程玉华
审核：产祝龙
