摘要：

为探究外源海藻糖在缓解香稻干旱胁迫中的作用机制,以稻花香2号为材料,以15%聚乙二醇-6000模拟干旱胁迫,设置5,10,15 mmol/L海藻糖喷施处理(T1、T2、T3),以正常供水(CK,清水喷施)和干旱处理(D,清水喷施)为对照,系统分析幼苗生长生理指标时序变化,并结合转录组测序解析其分子调控机制。结果表明:5 mmol/L 海藻糖(T1)处理在胁迫后期(12 d)表现出显著缓解效应,叶片可溶性蛋白和脯氨酸含量分别达5.47,0.132 mg/g,显著高于D处理;抗坏血酸(AsA)含量及超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性在T1处理下均达峰值,其中SOD、CAT活性较D处理显著提高30.10%,91.84%;超氧阴离子(O₂^-)产生速率和丙二醛(MDA)含量则显著低于D处理,降幅分别为55.10%,14.68%。基于形态与生理指标的Z分综合评价显示,T1处理的综合评价值最高(455.18),较D和CK分别提高184.65%,44.02%。转录组分析表明,T1处理共调控1 451个差异表达基因,显著富集于光合作用-天线蛋白、谷胱甘肽代谢、MAPK信号通路等途径,并上调OsFPPS、OsGSTF1、OsTPP1、OsWRKY69等关键基因表达,下调OsPP2C73等负调控因子。综上,外源5 mmol/L海藻糖可通过增强渗透调节与抗氧化能力,并协同调控ABA信号、MAPK信号通路及内源海藻糖代谢相关基因,有效缓解稻花香2号幼苗干旱胁迫,研究结果为香稻抗旱栽培及海藻糖类抗逆剂开发提供了理论依据与分子靶点。

关键词: 香稻, 干旱胁迫, 海藻糖, 生理机制, 转录组分析

Abstract:

To investigate the mechanism of exogenous trehalose in mitigating drought stress in aromatic rice,this study used Daohuaxiang 2 as experimental material and simulated drought stress with 15% polyethylene glycol-6000(PEG-6000).Three trehalose spray treatments were applied at concentrations of 5,10,and 15 mmol/L(T1,T2,T3),with well-watered(CK,sprayed with water)and drought-stressed(D,sprayed with water)conditions as controls.Temporal changes in growth and physiological parameters of seedlings were systematically analyzed and combined with transcriptome sequencing to elucidate the molecular regulatory mechanisms.The results showed that the 5 mmol/L trehalose treatment(T1)exhibited a significant alleviating effect during the late stress stage(12 d),with soluble protein and proline contents in leaves reaching 5.47 and 0.132 mg/g,respectively,significantly higher than those in the D treatment.Under the T₁ treatment,the ascorbic acid(AsA)content and the activities of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),and ascorbate peroxidase(APX)peaked,with SOD and CAT activities significantly increased by 30.10% and 91.84%,respectively,compared with the D treatment.In contrast,the superoxide anion production rate and malondialdehyde(MDA)content were significantly lower in T1 than in D,with reductions of 55.10% and 14.68%,respectively.A Z-score comprehensive evaluation based on morphological and physiological parameters revealed that the T1 treatment had the highest comprehensive evaluation value of 455.18,which was 184.65% and 44.02% higher than that of D and CK,respectively.Transcriptome analysis indicated that the T1 treatment regulated 1 451 differentially expressed genes,which were significantly enriched in pathways such as photosynthesis-antenna proteins,glutathione metabolism,and MAPK signaling pathways.Key genes including OsFPPS,OsGSTF1,OsTPP1,and OsWRKY69 were upregulated,while negative regulators such as OsPP2C73 were downregulated.In conclusion,exogenous application of 5 mmol/L trehalose effectively alleviated drought stress in Daohuaxiang 2 seedlings by enhancing osmotic adjustment and antioxidant capacity,while coordinately regulating ABA signaling,MAPK signaling pathway,and endogenous trehalose metabolism-related genes.These findings provide a theoretical basis and molecular targets for drought-resistant cultivation of aromatic rice and the development of trehalose-based stress resistance agents.

Key words: Aromatic rice, Drought stress, Trehalose, Physiological mechanisms, Transcriptomic analysis

中图分类号: 

• S511稻

• Q786基因的表达