Salinity is one of the major detrimental abiotic stresses at the forefront of deterring crop productivity globally. Although the exogenous application of phytohormones has formerly proven efficacious to plants, their effect on the moderately stress-tolerant crop “Sorghum bicolor” remains elusive. To investigate this, S. bicolor seeds primed with methyl jasmonate (0; 10 and 15 μM MeJa) were exposed to salt (200 mM NaCl) stress, and their morpho-physiological, biochemical, and molecular attributes were measured. Salt stress significantly decreased shoot length and fresh weight by 50%, whereas dry weight and chlorophyll content were decreased by more than 40%. Furthermore, salt-stress-induced oxidative damage was evident by the formation of brown formazan spots (indicative of H2O2 production) on sorghum leaves and a more than 30% increase in MDA content. However, priming with MeJa improved growth, increased chlorophyll content, and prevented oxidative damage under salt stress. While 15 µM MeJa maintained proline content to the same level as the salt-stressed samples, total soluble sugars were maintained under 10 µM MeJa, indicating a high degree of osmotic adjustment. Shriveling and thinning of the epidermis and xylem tissues due to salt stress was prevented by MeJa, followed by a more than 70% decrease in the Na+/K+ ratio. MeJa also reversed the FTIR spectral shifts observed for salt-stressed plants. Furthermore, salt stress induced the expression of the jasmonic acid biosynthesis genes; linoleate 92-lipoxygenase 3, allene oxide synthase 1, allene oxide cyclase, and 12-oxophytodienoate reductase 1. In MeJa-primed plants, their expression was reduced, except for the 12-oxophytodienoate reductase 1 transcript, which further increased by 67%. These findings suggest that MeJa conferred salt-stress tolerance to S. bicolor through osmoregulation and synthesis of JA-related metabolites.
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Genome-wide identification and multiple abiotic stress transcript profiling of potassium transport gene homologs in Sorghum bicolor
Potassium (K+) is the most abundant cation that plays a crucial role in various cellular processes in plants. Plants have developed an efficient mechanism for the acquisition of K+ when grown in K+ deficient or saline soils. A total of 47 K+ transport gene homologs (27 HAKs, 4 HKTs, 2 KEAs, 9 AKTs, 2 KATs, 2 TPCs, and 1 VDPC) have been identified in Sorghum bicolor. Of 47 homologs, 33 were identified as K+ transporters and the remaining 14 as K+ channels. Chromosome 2 has been found as the hotspot of K+ transporters with 9 genes. Phylogenetic analysis revealed the conservation of sorghum K+ transport genes akin to Oryza sativa. Analysis of regulatory elements indicates the key roles that K+ transport genes play under different biotic and abiotic stress conditions. Digital expression data of different developmental stages disclosed that expressions were higher in milk, flowering, and tillering stages. Expression levels of the genes SbHAK27 and SbKEA2 were higher during milk, SbHAK17, SbHAK11, SbHAK18, and SbHAK7 during flowering, SbHAK18, SbHAK10, and 23 other gene expressions were elevated during tillering inferring the important role that K+ transport genes play during plant growth and development. Differential transcript expression was observed in different tissues like root, stem, and leaf under abiotic stresses such as salt, drought, heat, and cold stresses. Collectively, the in-depth genome-wide analysis and differential transcript profiling of K+ transport genes elucidate their role in ion homeostasis and stress tolerance mechanisms.
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- Award ID(s):
- 2150087
- PAR ID:
- 10395426
- Editor(s):
- Sareen, Sindhu
- Publisher / Repository:
- Frontiers in Plant Science
- Date Published:
- Journal Name:
- Frontiers of plant science
- Volume:
- 13
- ISSN:
- 0016-2167
- Page Range / eLocation ID:
- 965530
- Subject(s) / Keyword(s):
- HAK/KT/KUP, KEA, K+ channels, K+ transporters, Sorghum, Trk/HKT
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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