Search

Abiotic stress, including osmotic and salinity stress, significantly affects plant growth and productivity. Copper chaperone for superoxide dismutase (CCS) is essential for copper homeostasis and oxidative stress management. In this study, we investigated the role of the TaCCS1-B gene of bread wheat in enhancing stress tolerance in yeast and transgenic Arabidopsis. Expression of TaCCS1-B increased abiotic stress tolerance in recombinant yeast cells. Phenotypic analysis of Arabidopsis TaCCS1-B expressing lines demonstrated that they exhibited significantly higher germination rates, increased root length and better growth under osmotic and salinity stress than wild type. Additionally, the transgenic lines exhibited higher copper accumulation and enhanced photosynthetic pigments and proline level, coupled with reduced hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) contents. They also showed higher enzymatic antioxidants' activities, indicating reduced oxidative stress in transgenic lines, resulting in reduced flavonoid content. Gene expression analysis indicated modulated expression of stress-responsive genes in the transgenic lines under stress conditions. These findings suggested the role of TaCCS1-B in enhancing stress tolerance by improving copper homeostasis and regulating key stress-responsive genes. This study highlights the potential of TaCCS1-B for the development of better stress resilience crops, which is critical for sustaining agricultural productivity for food security under adverse environmental conditions., (© 2024 Scandinavian Plant Physiology Society.)

Key Message: APX and APX-R gene families were identified and characterized in two important oilseed species of Brassica. Gene expression under abiotic stress conditions, recombinant protein expression, and analysis further divulged their drought, heat, and salt-responsive behavior. Ascorbate peroxidases (APX) are heme-dependent enzymes that rid the cells of H 2 O 2 and regulate diverse biological processes. In the present study, we performed APX gene family characterization in two Brassica sp. (B. juncea and B. rapa) as these are commercially important oilseed crops and affected severely by abiotic stresses. We identified 16 BjuAPX and 9 BraAPX genes and 2 APX-R genes each in B. juncea and B. rapa genomes, respectively. Phylogenetic analysis divided the APX genes into five distinct clades, which exhibited conservation in the gene structure, motif organization, and sub-cellular location within the clade. Structural analysis of APX and APX-R proteins revealed the amino acid substitutions in conserved domains of APX-R proteins. The expression profiling of BjuAPX and BraAPX genes showed that 3 BjuAPX, 7BraAPX, and 2 BraAPX-R genes were drought and heat responsive. Notably, BjuAAPX1a, BjuAPX1d, BjuAAPX6, BraAAPX1a, BraAAPX2, and BraAAPX3b showed high expression levels in RT-qPCR. Cis-regulatory elements in APX and APX-R gene promoters supported the differential behavior of these genes. Further, two stress-responsive genes BjuAPX1d and BraAAPX2 were cloned, characterized, and their roles were validated under heat, drought, salt, and cold stress in bacterial expression system. This study for the first time reports the presence of APX activity in dimeric and LMW form of purified BraAAPX2 protein. The study may help pave way for developing abiotic stress-tolerant Brassica crops., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Mechanosensitive ion channels are pore-forming transmembrane proteins that allow ions to move down their electrochemical gradient in response to mechanical stimuli. They participate in many plant developmental processes including the maintenance of plastid shape, pollen tube growth, etc. Herein, a total of 11, 10, 6, 30, 9, and 8 MSL genes were identified in Aegilops tauschii, Hordeum vulgare, Sorghum bicolor, Triticum aestivum, Triticum urartu, and Zea mays, respectively. These genes were located on various chromosomes of their respective cereal, while MSLs of T. urartu were found on scaffolds. The phylogenetic analysis, subcellular localization, and sequence homology suggested clustering of MSLs into two classes. These genes consisted of cis-regulatory elements related to growth and development, responsive to light, hormone, and stress. Differential expression of various MSL genes in tissue developmental stages and stress conditions revealed their precise role in development and stress responses. Altered expression during CaCl 2 stress suggested their role in Ca 2+ homeostasis and signaling. The co-expression analysis suggested their interactions with other genes involved in growth, defense responses etc. A comparative expression profiling of paralogous genes revealed either retention of function or pseudo-functionalization. The present study unfolded various characteristics of MSLs in cereals, which will facilitate their in-depth functional characterization in future studies.

Background: Plant P-type II Ca 2+ ATPases are formed by two distinct groups of proteins (ACAs and ECAs) that perform pumping of Ca 2+ outside the cytoplasm during homeostasis, and play vital functions during development and stress management. In the present study, we have performed identification and characterisation of P-type II Ca 2+ ATPase gene family in an important crop plant Triticum aestivum., Results: Herein, a total of 33 TaACA and 9 TaECA proteins were identified from the various chromosomes and sub-genomes of Triticum aestivum. Phylogenetic analysis revealed clustering of the homoeologous TaACA and TaECA proteins into 11 and 3 distinct groups that exhibited high sequence homology and comparable structural organization as well. Both TaACA and TaECA group proteins consisted of eight to ten transmembrane regions, and their respective domains and motifs. Prediction of sub-cellular localization was found variable for most of the proteins; moreover, it was consistent with the evolutionarily related proteins from rice and Arabidopsis in certain cases. The occurrence of assorted sets of cis-regulatory elements indicated their diverse functions. The differential expression of various TaACA and TaECA genes during developmental stages suggested their roles in growth and development. The modulated expression during heat, drought, salt and biotic stresses along with the occurrence of various stress specific cis-regulatory elements suggested their association with stress response. Interaction of these genes with numerous development and stress related genes indicated their decisive role in various biological processes and signaling., Conclusion: T. aestivum genome consisted of a maximum of 42 P-type II Ca 2+ ATPase genes, derived from each A, B and D sub-genome. These genes may play diverse functions during plant growth and development. They may also be involved in signalling during abiotic and biotic stresses. The present study provides a comprehensive insight into the role of P-type II Ca 2+ ATPase genes in T. aestivum. However, the specific function of each gene needs to be established, which could be utilized in future crop improvement programs.