Targeting Cd coping mechanisms for stress tolerance in <i>Brassica napus</i> under spiked-substrate system: from physiology to remediation perspective
Creators: name: Menhas, Saiqa
name: Yang, Xijia
name: Hayat, Kashif
name: Niazi, Nabeel Khan
name: Hayat, Sikandar
name: Amna
name: Aftab, Tariq
name: Hui, Nan
name: Wang, Juncai
name: Chen, Xunfeng
name: Zhou, Pei
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Biochemistry
subject: Biotechnology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Ecology
subject: FOS: Biological sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: Plant Biology

description: Cadmium (Cd) is a prevalent, non-essential, carcinogenic, and hazardous heavy metal that reduces plant productivity and capacity of arable land area around the globe. In the present substrate-based pot study, seedlings of <i>Brassica napus</i> 180015 were grown equidistantly in the spiked-substrate medium for 60 days under increasing concentrations of Cd (0, 10, 20, 30, 40, 50 mg kg<sup>−1</sup>). Following harvest, the morpho-physio-biochemical, antioxidative, and Cd-induced tolerance responses were evaluated in <i>B. napus</i> under an increasing Cd stress regime. Additionally, these parameters were also investigated to select the plant's threshold tolerance limit for Cd under the spiked-substrate system. <i>B. napus</i> showed dynamic behavior regarding morpho-physio-biochemical attributes, including agronomic features, biomass, photosynthetic pigments, relative water content under increased Cd toxicity. Cd stress-induced hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) production with high MDA contents and passive EL, followed by the orchestration of both enzymatic (SOD, POD, APX, CAT, and GR) and non-enzymatic antioxidants (flavonoids, TPC, TPA, proline, and total soluble protein) up to a certain limit. In addition, Cd-induced stress upregulated transcriptional levels of antioxidative enzyme <i>SOD</i>, <i>POD</i>, <i>APX</i>, <i>GR,</i> and <i>MT</i> encoded genes in <i>B. napus</i>. The increasing trend of Cd accumulation in different tissues at the highest Cd concentration was as follows: root &gt; leaf &gt; stem. In spiked substrate system, <i>B. napus</i> demonstrated improved metal extractability performance and a high potential for phyto-management of low to moderate Cd contamination, implying that this study could be used for integrative breeding programs and decontaminating heavy metals in real contaminated scenarios. <b>Novelty statement</b> This study provides an insight into Cd-coping mechanisms of oilseed rape involved in alleviating toxicity and simultaneous phyto-management of increasing Cd concentration under spiked substrate system. The current study is the first scientific evidence of using a Cd-spiked soilless substrate medium. The present study will further strengthen our understanding of Cd-instigated positive responses in <i>B. napus</i>. Furthermore, it will provide a useful basis for integrative breeding programs and decontaminating heavy metals in real contaminated scenarios.