Molecular Characterisation of Soybean Osmotins and Their Involvement in Drought Stress Response

Abstract

Osmotins are multifunctional proteins belonging to the thaumatin-like family related to plant stress responses. To better understand the functions of soybean osmotins in drought stress response, the current study presents the characterisation of four previously described proteins and a novel putative soybean osmotin (GmOLPa-like). Gene and protein structure as well as gene expression analyses were conducted on different tissues and developmental stages of two soybean cultivars with varying dehydration sensitivities (BR16 and EMB48 are highly and slightly sensitive, respectively). The analysed osmotin sequences share the conserved amino acid signature and 3D structure of the thaumatin-like family. Some differences were observed in the conserved regions of protein sequences and in the electrostatic surface potential. P21-like present the most similar electrostatic potential to osmotins previously characterised as promoters of drought tolerance in Nicotiana tabacum and Solanum nigrum. Gene expression analysis indicated that soybean osmotins were differentially expressed in different organs (leaves and roots), developmental stages (R1 and V3), and cultivars in response to dehydration. In addition, under dehydration conditions, the highest level of gene expression was detected for GmOLPa-like and P21-like osmotins in the leaves and roots, respectively, of the less drought sensitive cultivar. Altogether, the results suggest an involvement of these genes in drought stress tolerance.

Osmotin1 is involved in rice resistance to Schizotetranychus oryzae (Acari: Tetranychidae) infestation

“…Osmotin proteins are members of the pathogenesis‐related PR‐5, 17,26 largely known as multifunctional stress‐responsive and defense proteins whose accumulation is associated with abiotic and biotic stress responses in plants 19,21,27,28 . Therefore, these proteins provide plants with protection against pathogens 17,18,20 and abiotic stressful conditions 21,29–31 . Although Osmotin genes have been genetically engineered aiming disease control and abiotic stress tolerance in different crops, 27,28,31–34 our work is the first to show increased plant resistance to herbivory overexpressing an Osmotin gene.…”

Thaumatin-like Proteins in Legumes: Functions and Potential Applications—A Review

“…Small (S)-type TLPs have molecular masses ranging from 16 to 17 kD and have only 10 cysteines in conserved positions because of a peptide deletion [ 28 ]. All plant TLPs have similar 3D structures within three domains: domain I, containing 11 stranded β-sheets organized as a β-barrel, forming the protein core; domain II, containing an α-helix and a set of disulfide-rich loops; and domain III, containing a β-hairpin and a coil motif, both maintained by a disulfide bond [ 31 ]. There is a cleft structure between domains I and II [ 60 ], and each domain is stabilized by at least one disulfide bridge connected by up to 16 cysteine residues with a conserved spatial distribution throughout the protein [ 61 ].…”

“…GmOLPa-like and P21-like osmotins play important roles in drought tolerance; the former shows higher expression levels in roots, and both are also expressed in nodules. Their highest expression levels can be found in the leaves or roots of the drought-tolerant cultivar [ 31 ]. The TLP1b gene can be induced by wounding the Caesalpinioideae Senna tora [ 73 ].…”

“…Plant TLPs also play diverse roles in abiotic stresses such as drought [ 31 ], freezing [ 32 ], and salinity [ 33 , 34 ]. Computational approaches such as cis-regulatory analysis, promoter analysis, and co-expressed gene analysis have revealed that TLPs play diverse roles in abiotic stresses [ 35 ].…”