Toxic heavy metal and metalloid (THMM) contamination poses a major global challenge, threatening human health and sustainable agriculture. The crucial role of the Cytochrome P450 (CYP) gene family in plant tolerance to THMMs has been recently highlighted, but there is still a lack of comprehensive understanding, especially in relation to metabolites. This study delved into the identification of CYP genes that are linked to the tolerance mechanisms of plants in response to heavy metal stress. The findings highlight the significant metabolic pathways that contribute to this resilience, using rice and Arabidopsis as exemplars. THMM exposure changed CYP gene expression in plants, and THMM antidotes mitigated its downregulation and that of flavonoid biosynthesis genes. CYP genes involved in THMM responses were predominantly enriched in the pathways associated with flavonoid synthesis, indicating functional adaptations to distinct stresses. Notably, anthocyanin (Ant) accumulation, a type of flavonoid, affected the uptake of various heavy metals in Brassica rapa, with flavonoid biosynthesis-associated genes correlating with Cd or As tolerance and Ant content. These findings highlight the critical importance of flavonoid metabolism and the intricate network of biosynthesis genes in bolstering plant resilience against heavy metal stress. This enhanced understanding paves the way for significant advancements in phytoremediation technologies, offering innovative solutions for soil and water decontamination.
Research Authors
Yuanpeng Fang, Zehui Wang, Salah F Abou-Elwafa, Maha Aljabri, Xin Xie
Salt stress is a major environmental factor limiting crop production. High-affinity potassium transporters (HAKs) play a crucial role in environmental adaptation, including salt stress. However, the functional characterization of wheat HAKs in response to salt stress has not yet been reported. In this study, wheat HAK member TaHAK1 was investigated to explore its role in salt stress tolerance. Heterologous expression of TaHAK1 in the R5421 yeast strain revealed that yeast growth expressing TaHAK1 was promoted with increasing K+ concentrations (0.1–100 mM), while potassium supplementation mitigated growth inhibition under 100–200 mM Na+ concentrations. This indicates that TaHAK1 plays a pivotal role in alleviating high Na+ stress. Moreover, TaHAK1-overexpressing transgenic lines in rice significantly increased plant biomass, the content of ascorbic acid and glutathione, and activities of antioxidant enzymes, while markedly reduced malondialdehyde levels. And these rice transgenic lines also maintained higher K+ and lower Na+ contents, suggesting that TaHAK1 could be essential for an optimal Na+/K+ ratio in salt tolerance. Furthermore, transcriptomic analysis revealed that differentially expressed genes related to signal transduction, ion transport, and oxidative stress responses were significantly induced under salt stress. Among these, many genes were involved in the auxin signaling pathway, suggesting it may be a key regulatory mechanism through which TaHAK1 mediates salt tolerance. In conclusion, TaHAK1 alleviates salt stress by modulating reactive oxygen species, maintaining K+/Na+ homeostasis, and up-regulating auxin signaling-related genes. Thus, TaHAK1 holds potential for enhancing salt tolerance in crops and could be utilized in future molecular breeding programs targeting salt stress resilience.
Research Authors
Jin Liu, Xiao-Lan Xu, Bin Wang, Yue Xiao, Meng-Chuan Zhang, Hai-Tao Liu, Ying-Long Chen, Nahaa M Alotaibi, Salah F Abou-Elwafa, Peng-Fei Wang, Tian-Cai Guo, Guo-Zhang Kang, Ge-Zi Li
Comprehensive transcriptome analysis provides molecular insights into the heterosis-associated drought tolerance and reveals ZmbHLH137 that promotes drought tolerance in maize seedlings
Drought, a primary environmental factor, imposes significant constraints on maize’s developmental processes and productivity. Heterosis breeding is one of the most important breeding strategies for reducing drought-induced yield losses. The genetic mechanisms of heterosis for drought tolerance in maize remain unclear to date. This study aims to analyze the expression profiles and potential heterosis-related genes of the ZhengDan618 hybrid (F1) and its parents, Zheng8713 (parental parent) and ZhengC126 (maternal parent), with extreme differences in drought tolerance under well-irrigated (WI) and drought-stressed (DS) conditions by RNA-sequencing. F1 plants exhibited the strongest antioxidant enzyme activity and drought tolerance, followed by the parental parent. Transcriptome analysis revealed 1,259 unique differentially expressed genes (DEGs) in the F1 hybrid after drought stress induction, mainly involved in the “Glutathione metabolism” and “Flavonoid biosynthesis” pathways. There were fewer DEGs between the F1 and the parental parent, with the drought tolerance phenotype mostly attributed to the contribution of the drought-tolerant parent Zheng87. The weighted gene co-expression network analysis combined with non-additive gene mining identified 13 non-additive drought stress-associated genes, among them bHLH137 expression exhibited up-regulated expression in response to drought stress. Under drought stress, ZmbHLH137-overexpressing maize plants revealed the lowest H2O2 and MDA content, followed by the B104 WT plants, whereas the zmbhlh137 knockout mutants exhibited the highest H2O2 and MDA content. Moreover, ZmbHLH137-overexpressing maize plants exhibited the higher glutathione peroxidase, catalase, peroxidase, and superoxide dismutase activities, whereas the zmbhlh137 knockout mutants exhibited the lower oxidase activity. These results indicate that ZmbHLH137 positively regulates drought tolerance in maize at the seedling stage by regulating antioxidant enzyme activity. These findings provide novel insights into heterosis regulation in maize seedlings. The identified genes are important genetic resources and may aid strategies for improving drought tolerance in maize.
Research Authors
Liru Cao, Dongling Zhang, Abbas Muhammad Fahim, Huafeng Liu, Zhe Zhang, Desheng Hu, Feiyu Ye, Chenchen Ma, Salah Fatouh Abou-Elwaf, Nora M Al Aboud, Yinghui Song, Shulei Guo, Qianjin Zhang, Xin Zhang, Xiaomin Lu
The rapid increase in pig production has become a major contributor to environmental issues due to the mismanagement of organic waste. The sustainable and effective transformation of this waste into a fertilization resource has become an urgent topic for environmental protection, and new regulations have been imposed. The present study aimed to investigate the effects of different ratios of swine manure liquid (SML) and chemical fertilizers on soil phosphorus forms and microbial communities through field experiments cultivating spring wheat (cultivar “Jinqiang 10”) in Hebei, China. The results indicated that the application of SML in portions with traditional fertilizer can enhance soil pH and electrical conductivity (EC), as well as available phosphorus, particularly when the proportion of SML is high (SML ≥ 75%). Compared with CK, the available phosphorus content of group C3 increased by 22.3%. SML facilitated the transformation of stable phosphorus to unstable phosphorus, as well as the conversion of organic phosphorus to inorganic phosphorus. Additionally, SML increased the soil content of H2O-P, NaHCO3-Pi, and NaHCO3-Po, and promoted the conversion of NaOH-Po to NaHCO3-Po. Studies on bacterial diversity indicated that different fertilization treatments have no significant impact on the bacterial diversity in the 0–20 cm soil layer, whereas the dominant bacterial and fungal genera were positively correlated with the available phosphorus. The present study may facilitate the combined application of SML and chemical fertilizers for soil improvement and improve phosphorus availability.
Research Authors
Mingjun Pu, Yingyu Zhang, Santanu Mukherjee, Saif F Alharbi, Rupesh Kumar Singh, Salah F Abou-Elwafa, Henrique Trindade, Tao Zhang
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