The E3 Ligase GmPUB21 Negatively Regulates Drought and Salinity Stress Response in Soybean

Abstract

E3-ubiquitin ligases are known to confer abiotic stress responses in plants. In the present study, GmPUB21, a novel U-box E3-ubiquitin ligase-encoding gene, was isolated from soybean and functionally characterized. The expression of GmPUB21, which possesses E3-ubiquitin ligase activity, was found to be significantly up-regulated by drought, salinity, and ABA treatments. The fusion protein GmPUB21-GFP was localized in the cytoplasm, nucleus, and plasma membrane. Transgenic lines of the Nicotiana benthamiana over-expressing GmPUB21 showed more sensitive to osmotic, salinity stress and ABA in seed germination and inhibited mannitol/NaCl-mediated stomatal closure. Moreover, higher reactive oxygen species accumulation was observed in GmPUB21 overexpressing plants after drought and salinity treatment than in wild-type (WT) plants. Contrarily, silencing of GmPUB21 in soybean plants significantly enhanced the tolerance to drought and salinity stresses. Collectively, our results revealed that GmPUB21 negatively regulates the drought and salinity tolerance by increasing the stomatal density and aperture via the ABA signaling pathway. These findings improved our understanding of the role of GmPUB21 under drought and salinity stresses in soybean.

Divergent Gene Expression Responses to Salinity Stress in 16 Geographically Diverse Spinach Genotypes

“…Spo 11258 and Spo 11709 were downregulated in the leaves of most spinach genotypes under salinity compared to the control (Figure ). Spo 11258 encodes an E3-ubiquitin ligase, which has been shown to negatively regulate drought and salinity responses in soybean by increasing stomata density and aperture through the ABA-signaling pathway . On the other hand Spo 11709 encodes a cysteine-rich receptor-like protein kinase 10 (CRK10).…”

“…Spo11258 encodes an E3-ubiquitin ligase, which has been shown to negatively regulate drought and salinity responses in soybean by increasing stomata density and aperture through the ABA-signaling pathway. 50 On the other hand Spo11709 encodes a cysteine-rich receptor-like protein kinase 10 (CRK10). Although biotic and abiotic stress-responsive pathways were constitutively upregulated in the crk10 mutant in Arabidopsis, 51 direct involvement of CRK10 in salinity tolerance has not been shown.…”

Singlet oxygen makes plant epidermis thicker with less stomata

“…The phenotype of cell wall thickening and stomatal reduction induced by singlet oxygen has important implications for agricultural industry. Declines in stomatal density would enhance plant's tolerance to drought [23][24][25][26][27] , salinity / osmotic stress [25][26][27][28][29] , heat stress 27,30,31 by reducing water transpiration. Genetic manipulation of stomatal density to enhance crop tolerance to environmental stresses is especially important to rice, because that cultivation of rice is particularly water-intensive.…”

Understandings and future challenges in soybean functional genomics and molecular breeding

“…When plants suffer drought stress, reducing water loss through enhancing stomatal closure is the major tolerance strategy, and the abscisic acid (ABA) signaling pathway plays a pivotal role in the process. The circadian rhythm genes LHY and PUB21 (encoding U‐box E3‐ubiquitin ligase) are two negative regulators of drought tolerance involved in regulating stomatal movement and ABA signaling (Wang et al, 2021a; Yang et al, 2022c). With drought treatment, compared to their corresponding wild types, the stomatal apertures of lhy quadruple mutants are narrower and OE‐GmPUB21 transgenic plants are bigger (Wang et al, 2021a; Yang et al, 2022c).…”