Basit Farwa, Bhat Javaid Akhter, Ulhassan Zaid, Noman Muhammad, Zhao Biying, Zhou Weijun, Kaushik Prashant, Ahmad Ajaz, Ahmad Parvaiz, Guan Yajing
Institute of Crop Science, Zhejiang Key Laboratory of Crop Germplasm, Zhejiang University, Hangzhou 310058, China.
Hainan Research Institute, Zhejiang University, Sanya 572025, China.
Antioxidants (Basel). 2022 Aug 30;11(9):1704. doi: 10.3390/antiox11091704.
Chromium (Cr) is an important environmental constraint effecting crop productivity. Spermine (SPM) is a polyamine compound regulating plant responses to abiotic stresses. However, SPM-mediated tolerance mechanisms against Cr stress are less commonly explored in plants. Thus, current research was conducted to explore the protective mechanisms of SPM (0.01 mM) against Cr (100 µM) toxicity in two rice cultivars, CY927 (sensitive) and YLY689 (tolerant) at the seedling stage. Our results revealed that, alone, Cr exposure significantly reduced seed germination, biomass and photosynthetic related parameters, caused nutrient and hormonal imbalance, desynchronized antioxidant enzymes, and triggered oxidative damage by over-accretion of reactive oxygen species (ROS), malondialdehyde (MDA) and electrolyte leakage in both rice varieties, with greater impairments in CY927 than YLY689. However, seed priming with SPM notably improved or reversed the above-mentioned parameters, especially in YLY689. Besides, SPM stimulated the stress-responsive genes of endogenous phytohormones, especially salicylic acid (SA), as confirmed by the pronounced transcript levels of SA-related genes (OsPR1, OsPR2 and OsNPR1). Our findings specified that SPM enhanced rice tolerance against Cr toxicity via decreasing accumulation of Cr and markers of oxidative damage (HO, O and MDA), improving antioxidant defense enzymes, photosynthetic apparatus, nutrients and phytohormone balance.
铬（Cr）是影响作物生产力的重要环境限制因素。精胺（SPM）是一种调节植物对非生物胁迫反应的多胺化合物。然而，植物中SPM介导的抗铬胁迫耐受机制鲜少被探究。因此，开展了当前这项研究，以探究在幼苗期，0.01 mM的SPM对100 µM铬毒性在两个水稻品种CY927（敏感型）和YLY689（耐受型）中的保护机制。我们的结果显示，单独铬处理显著降低了种子萌发、生物量和光合相关参数，导致营养和激素失衡，抗氧化酶失同步，并通过活性氧（ROS）、丙二醛（MDA）过量积累和电解质渗漏引发氧化损伤，两个水稻品种均受影响，且CY927比YLY689受损更严重。然而，用SPM引发种子显著改善或逆转了上述参数，尤其是在YLY689中。此外，SPM刺激了内源植物激素的胁迫响应基因，尤其是水杨酸（SA），SA相关基因（OsPR1、OsPR2和OsNPR1）的显著转录水平证实了这一点。我们的研究结果表明，SPM通过减少铬的积累以及氧化损伤标志物（HO、O和MDA），改善抗氧化防御酶、光合机构、营养和植物激素平衡，增强了水稻对铬毒性的耐受性。
