Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Mumbai, 400085, India.
Homi Bhabha National Institute, Mumbai, 400094, India.
Sci Rep. 2021 Feb 4;11(1):3000. doi: 10.1038/s41598-020-80419-6.
Plant bioregulators (PBRs) represent low-cost chemicals for boosting plant defense, especially under stress conditions. In the present study, redox based PBRs such as thiourea (TU; a non-physiological thiol-based ROS scavenger) and hydrogen peroxide (HO; a prevalent biological ROS) were assessed for their ability to mitigate NaCl stress in rice variety IR 64. Despite their contrasting redox chemistry, TU or HO supplementation under NaCl [NaCl + TU (NT) or NaCl + HO (NH)] generated a reducing redox environment in planta, which improved the plant growth compared with those of NaCl alone treatment. This was concomitant with better K retention and upregulated expression of NaCl defense related genes including HAK21, LEA1, TSPO and EN20 in both NT and NH treated seedlings. Under field conditions, foliar applications of TU and HO, at vegetative growth, pre-flowering and grain filling stages, increased growth and yield attributes under both control and NaCl stress conditions. Principal component analysis revealed glutathione reductase dependent reduced ROS accumulation in source (flag leaves) and sucrose synthase mediated sucrose catabolism in sink (developing inflorescence), as the key variables associated with NT and NH mediated effects, respectively. In addition, photosystem-II efficiency, K retention and source-sink relationship were also improved in TU and HO treated plants. Taken together, our study highlights that reducing redox environment acts as a central regulator of plant's tolerance responses to salt stress. In addition, TU and HO are proposed as potential redox-based PBRs for boosting rice productivity under the realistic field conditions.
植物生物调节剂（PBRs）是一种低成本的化学物质，可以增强植物的防御能力，尤其是在胁迫条件下。在本研究中，评估了基于氧化还原的 PBRs，如硫脲（TU；一种非生理硫醇基 ROS 清除剂）和过氧化氢（HO；一种常见的生物 ROS），以评估它们缓解水稻品种 IR 64 中 NaCl 胁迫的能力。尽管它们的氧化还原化学性质相反，但在 NaCl 中添加 TU 或 HO（NaCl+TU（NT）或 NaCl+HO（NH））会在植物体内产生还原氧化还原环境，与单独用 NaCl 处理的植物相比，这会促进植物生长。这与更好的 K 保留以及上调与 NaCl 防御相关的基因表达有关，包括 NT 和 NH 处理的幼苗中的 HAK21、LEA1、TSPO 和 EN20。在田间条件下，在营养生长、开花前和灌浆期对 TU 和 HO 进行叶面喷施，可增加对照和 NaCl 胁迫条件下的生长和产量性状。主成分分析表明，在源（旗叶）中依赖于谷胱甘肽还原酶的还原 ROS 积累和在汇（发育的花序）中蔗糖合酶介导的蔗糖分解代谢是与 NT 和 NH 介导的效应相关的关键变量。此外，TU 和 HO 处理的植物的光合系统 II 效率、K 保留和源-汇关系也得到了改善。总之，我们的研究强调，还原氧化还原环境是植物对盐胁迫耐受反应的中心调节剂。此外，TU 和 HO 被提议作为一种潜在的基于氧化还原的 PBRs，以提高实际田间条件下水稻的生产力。
