Cadmium (Cd) stress constitutes a significant issue in agricultural soil, inflicts lethal damages to plants and posing a serious risk to public health as it enters the food chain. This review addresses the cause of Cd toxicity, its numerous forms and absorption mechanism via various transporters and their detrimental impacts on plants. At high level, Cd interacts with cellular molecules leading to overproduction of reactive oxygen species. Under Cd stress, plants naturally synthesize various compatible solutes to enhance the plant's stress tolerance and glycine betaine (GB) is one of such solutes which act as osmoprotectant in plants. The Cd causes oxidative damage to the cells, resulted in changes in morphological attributes, physiological processes etc. and it is indispensable to alleviate Cd toxicity. To mitigate the harmful impacts of Cd, plants adapt self-regulating tolerance mechanism by producing naturally occurring osmolytes and phytochelatins (PCs). Biosynthetic pathway of GB and GB-mediated tolerance mechanism via redox homeostasis, osmotic adjustment, and mechanism of compartmentalization of Cd into the vacuole, the role of genetic engineering in GB biosynthesis in crop plants through which plants can improve their stress tolerance have been discussed. Amalgamation of this strategy must be implemented in the market with synchronization of farmers into cooperatives. This will be beneficial for the improvement in soil, plant and human health alongwith the reduction of Cd toxicity in environment. Further, this strategy must be used by government and non-government agencies, which is the most economical approach to apply at the farmer level.

Rising soil salinity hinders global crop yields by damaging plants, threatening food security. This study assessed glycine betaine (GB) application methods (foliar, seed priming) and salinity levels (0, 60, 120, 180 mM NaCl) on quinoa over two seasons. For ionic homeostasis, seed priming improved K+/Na+ ratio by 10-15 % at low salinity, while foliar was 12-18 % more effective at high salinity. Seed priming remained 10-15 % superior for roots. Foliar enhanced osmolytes by 12-16 % at low salinity, but seed priming had 16-20 % stronger effects at high salinity. Under low salinity, seed priming provided 8-12 % better protection for chlorophyll and photosynthetic efficiency. At high salinity, foliar GB was 10-15 % best for chlorophyll, seed priming 12-16 % more effective for photosynthetic rate, and foliar GB had an 8-10 % edge for Fv/Fm. GB reduced MDA by 8-12 % at low salinity, 12-16 % with seed priming at medium salinity in 2023, and 16-20 % with foliar in 2024. At high salinity, seed priming decreased MDA by 20-25 % in 2023, while foliar showed a 24-28 % reduction. GB moderately enhanced antioxidants by 8-12 % under mild stress, but seed priming and foliar differed 16-20 % in effectiveness under severe stress. For nutrients, seed priming had a 12-16 % advantage for nitrogen at medium salinity in 2023, while foliar excelled with a 16-20 % increase under high stress in 2024. Seed priming was 16-20 % better for phosphorus at high salinity in 2023, but foliar had 20-25 % superior results in 2024. These findings highlight complex plant responses to GB-salinity interactions, with optimal methods varying by trait, stress level, and environmental conditions. (c) 2024 SAAB. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Plant-parasitic nematodes (PPNs) are among the most serious phytopathogens and cause widespread and serious damage in major crops. In this study, using a genome mining method, we identified nonribosomal peptide synthetase (NRPS)-like enzymes in genomes of plant-parasitic nematodes, which are conserved with two consecutive reducing domains at the N-terminus (A-T-R1-R2) and homologous to fungal NRPS-like ATRR. We experimentally investigated the roles of the NRPS-like enzyme (MiATRR) in nematode (Meloidogyne incognita) parasitism. Heterologous expression of Miatrr in Saccharomyces cerevisiae can overcome the growth inhibition caused by high concentrations of glycine betaine. RT-qPCR detection shows that Miatrr is significantly upregulated at the early parasitic life stage (J2s in plants) of M. incognita. Host-derived Miatrr RNA interference (RNAi) in Arabidopsis thaliana can significantly decrease the number of galls and egg masses of M. incognita, as well as retard development and reduce the body size of the nematode. Although exogenous glycine betaine and choline have no obvious impact on the survival of free-living M. incognita J2s (pre-parasitic J2s), they impact the performance of the nematode in planta, especially in Miatrr-RNAi plants. Following application of exogenous glycine betaine and choline in the rhizosphere soil of A. thaliana, the numbers of galls and egg masses were obviously reduced by glycine betaine but increased by choline. Based on the knowledge about the function of fungal NRPS-like ATRR and the roles of glycine betaine in host plants and nematodes, we suggest that MiATRR is involved in nematode-plant interaction by acting as a glycine betaine reductase, converting glycine betaine to choline. This may be a universal strategy in plant-parasitic nematodes utilizing NRPS-like ATRR to promote their parasitism on host plants.