Characterization of a novel LmSAP gene promoter from Lobularia maritima: Tissue specificity and environmental stress responsiveness

Abstract

Halophyte Lobularia maritima LmSAP encodes an A20AN1 zinc-finger stress-associated protein which expression is up-regulated by abiotic stresses and heavy metals in transgenic tobacco. To deepen our understanding of LmSAP function, we isolated a 1,147 bp genomic fragment upstream of LmSAP coding sequence designated as PrLmSAP . In silico analyses of PrLmSAP revealed the presence of consensus CAAT and TATA boxes and cis -regulatory elements required for abiotic stress, phytohormones, pathogen, and wound responses, and also for tissue-specific expression. The PrLmSAP sequence was fused to the β-glucuronidase ( gusA ) reporter gene and transferred to rice. Histochemical GUS staining showed a pattern of tissue-specific expression in transgenic rice, with staining observed in roots, coleoptiles, leaves, stems and floral organs but not in seeds or in the root elongation zone. Wounding strongly stimulated GUS accumulation in leaves and stems. Interestingly, we observed a high stimulation of the promoter activity when rice seedlings were exposed to NaCl, PEG, ABA, MeJA, GA, cold, and heavy metals (Al 3+ , Cd 2+ , Cu 2+ and Zn 2+ ). These results suggest that the LmSAP promoter can be a convenient tool for stress-inducible gene expression and is a potential candidate for crop genetic engineering.

Differential Functions of Pepper Stress-Associated Proteins in Response to Abiotic Stresses

“…Stress-associated proteins (SAPs) are a group of zinc-fingertype proteins that are reportedly associated with abiotic stress responses, immunity, and development (Mukhopadhyay et al, 2004;Dixit et al, 2018;Dong et al, 2018;Liu et al, 2019c;Wang et al, 2019;Zhao et al, 2020). Since the discovery of the first SAP gene, the OsiSAP1 (OsSAP1) gene in rice, others have been characterized in various plant species as genome sequencing technology has advanced (Mukhopadhyay et al, 2004;Vij and Tyagi, 2006;Solanke et al, 2009;Giri et al, 2013;Dong et al, 2018;Liu et al, 2019a;Zhang et al, 2019;Ben Saad et al, 2020;Lai et al, 2020;Wang et al, 2021). However, no SAP genes have been isolated from pepper plant.…”

Assessment of Shoot Priming Efficiency to Counteract Complex Metal Stress in Halotolerant Lobularia maritima

“…Usually GSH content depletes, as it is utilized for phytochelatin synthesis [ 77 ]. Metal detoxification in L. maritima is likely to be performed by other compounds, for instance by metal-binding proteins that are abundant in this species [ 27 , 28 , 78 ].…”

“…Genes encoding several stress-associated proteins in L. maritima served as transgenes for stress tolerance improvement in non-tolerant species. The promoter of LmSAP zinc finger was used to enhance tolerance to Al, Cu, Cd, Zn, salinity, and cold in rice [ 27 ], while the thioredoxin-h2 gene encoding plasma membrane protein Trx facilitated tobacco survival under salinity, osmotic and oxidative stress [ 28 ]. There is also an interest in the exploitation of L. maritima as a source of bioactive compounds, food additives, and pharmaceuticals [ 29 ].…”

Evaluation of Halophyte Biopotential as an Unused Natural Resource: The Case of Lobularia maritima

“…Thus, various cis-regulatory motifs of stress-responsive genes from halophytes have been examined in the last two decades [ 77 , 78 , 79 , 80 , 81 ]. The putative promoter region (1147-bp upstream of ATG) of the LmSAP gene ( PrLmSAP ) was also isolated from L. maritima , and its analysis revealed an active and organ-specific promoter induced by environmental stresses and wounding in transgenic rice [ 82 ]. Similar characteristics are exhibited by the promoter of the AlSAP gene, which shows an age-dependent activation, and its response to abiotic stress is induced in a tissue-specific manner [ 83 , 84 ].…”