Abstract Elevated CO2 can stimulate plant growth in greenhouses, but the molecular mechanism behind this response is unclear, especially in eggplants. In this study, we evaluated the physiological and photosynthetic response of the eggplant variety ‘Shenyuan 3’ under elevated CO2, and the candidate genes related to this response were identified by transcriptomic analysis. The results showed that elevated CO2 can promote eggplant growth and development in greenhouses; plant height and stem diameter were maximally increased by 28.62% and 5.20%, respectively. Net photosynthetic rate, light saturation point and intercellular CO2 concentration of eggplant leaves increased by 86.11%, 49.94% and 102.06%, respectively, whereas light compensation point, dark breathing rate and stomatal conductance decreased by 35.90%, 27.30% and 26.03%, respectively. A total of 169 differentially expressed genes (DEGs) were screened, of which 99 were up-regulated and 70 were down-regulated. Gene Ontology (GO) function enrichment analysis suggested that these proteins can be classified into 11 molecular functions, including transcription factors, phosphoenolpyruvate carboxylase and oxidoreductase. Pathway analysis indicated that elevated CO2 affects plant growth and development by affecting carbon metabolism, carbon fixation, chlorophyll and porphyrin metabolism. Twelve genes were further detected by qRT-PCR, and 11 genes showed similar dynamics with the transcriptomic data. Bilirubin dehydrogenase Sme2.5_04464.1_g00001 and the malate dehydrogenase gene Sme2.5_03383.1_g00002, which are involved in the chlorophyll porphyrin pathway and carbon metabolism, respectively, were up-regulated. Transcription factors bHLH (Sme2.5_01232.1_g00025) and GATA (Sme2.5_00372.1_g00006) were also up-regulated under elevated CO2 treatment. Further research should focus on cloning these genes and identifying their response mechanism under elevated CO2.

中文翻译：

---

CO2升高条件下茄子光合作用相关候选基因的鉴定

摘要 CO2 升高可以刺激温室中的植物生长，但这种反应背后的分子机制尚不清楚，尤其是茄子。在这项研究中，我们评估了茄子品种“神元 3 号”在 CO2 升高下的生理和光合反应，并通过转录组学分析鉴定了与该反应相关的候选基因。结果表明，升高的CO2可以促进温室茄子的生长发育；株高和茎粗分别增加了28.62%和5.20%。茄子叶片净光合速率、光饱和点和胞间CO2浓度分别增加86.11%、49.94%和102.06%，而光补偿点、暗呼吸率和气孔导度分别降低35.90%、27.30%和26.03% . 共筛选出 169 个差异表达基因 (DEG)，其中 99 个上调，70 个下调。基因本体（GO）功能富集分析表明，这些蛋白质可分为11个分子功能，包括转录因子、磷酸烯醇丙酮酸羧化酶和氧化还原酶。通路分析表明，CO2 升高通过影响碳代谢、固碳、叶绿素和卟啉代谢来影响植物的生长发育。qRT-PCR 进一步检测了 12 个基因，11 个基因显示出与转录组数据相似的动态。分别参与叶绿素卟啉途径和碳代谢的胆红素脱氢酶 Sme2.5_04464.1_g00001 和苹果酸脱氢酶基因 Sme2.5_03383.1_g00002 被上调。转录因子 bHLH (Sme2.5_01232.1_g00025) 和 GATA (Sme2.5_00372.1_g00006) 在 CO2 升高的处理下也上调。进一步的研究应该集中在克隆这些基因并确定它们在二氧化碳升高下的反应机制。