Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.
National Agri-Food Biotechnology Institute, Mohali, Punjab, India.
Physiol Plant. 2024 Jan-Feb;176(1):e14209. doi: 10.1111/ppl.14209.
Abiotic stresses such as heat, drought and submergence are major threats to global food security. Despite simultaneous or sequential occurrence of these stresses being recurrent under field conditions, crop response to such stress combinations is poorly understood. Rice is a staple food crop for the majority of human beings. Exploitation of existing genetic diversity in rice for combined and/or sequential stress is a useful approach for developing climate-resilient cultivars. We phenotyped ~400 rice accessions under high temperature, drought, or submergence and their combinations. A cumulative performance index revealed Lomello as the best performer across stress and stress combinations at the seedling stage. Lomello showed a remarkable ability to maintain a higher quantum yield of photosystem (PS) II photochemistry. Moreover, the structural integrity of the photosystems, electron flow through both PSI and PSII and the ability to protect photosystems against photoinhibition were identified as the key traits of Lomello across the stress environments. A higher membrane stability and an increased amount of leaf chlorophyll under stress may be due to an efficient management of reactive oxygen species (ROS) at the cellular level. Further, an efficient electron flow through the photosystems and, thus, a higher photosynthetic rate in Lomello is expected to act as a sink for ROS by reducing the rate of electron transport to the high amount of molecular oxygen present in the chloroplast. However, further studies are needed to identify the molecular mechanism(s) involved in the stability of photosynthetic machinery and stress management in Lomello during stress conditions.
非生物胁迫，如高温、干旱和淹没，是全球粮食安全的主要威胁。尽管这些胁迫在田间条件下同时或顺序发生的情况很常见，但作物对这些胁迫组合的反应还知之甚少。水稻是大多数人类的主食作物。利用水稻现有的遗传多样性来应对复合和/或连续胁迫是开发具有气候适应能力的品种的一种有用方法。我们对约 400 个水稻品种进行了高温、干旱或淹没及其组合处理的表型分析。综合表现指数表明，Lomello 在幼苗期对各种胁迫及其组合的表现最好。Lomello 表现出一种非凡的能力，可以维持更高的光系统 (PS) II 光化学量子产量。此外，还确定了光系统的结构完整性、PSI 和 PSII 中的电子流以及保护光系统免受光抑制的能力是 Lomello 在各种胁迫环境下的关键特征。在胁迫下，较高的膜稳定性和叶片中较多的叶绿素可能是由于细胞水平上对活性氧 (ROS) 的有效管理。此外，Lomello 中通过光系统的有效电子流，从而在光合作用速率较高，预计通过降低电子传递到叶绿体中大量存在的分子氧的速率来充当 ROS 的汇。然而，需要进一步的研究来确定 Lomello 在胁迫条件下应对胁迫和管理光合作用机制的稳定性的分子机制。
