Functional identification of the calcineurin B-like protein PavCBL4 in modulating salt tolerance in sweet cherry.

Abiotic stresses, such as high salinity, pose a significant threat to plant growth and development, reducing crop yield and quality. Calcineurin B-like (CBL) proteins serve as crucial calcium sensors in plant responses to diverse environmental stresses. However, the CBL family in sweet cherry has not been identified at the genome-wide level, and the regulatory role of CBL proteins in cherry plants' salt response is unclear. Here, we identified 10 CBL family genes (PavCBLs) from the Prunus avium genome and cloned seven of them. We comprehensively analyzed PavCBL genes for collinearity, phylogenetic relationships, gene structure, and conserved motifs. Expression analysis revealed significant induction of transcription under abiotic stress, with PavCBL4 displaying the most substantial expression change. Additionally, we identified PavCBL4 as a PavSOS2 (Salt Overly Sensitive 2)-interacting protein through Y2H and Split-LUC assays. Subcellular localization analysis indicated that PavCBL4 is present in both the cytoplasm and nucleus. Functional assessment of PavCBL4 in the PavCBL4-overexpressing transgenic 'Gisela 6' plants showed its positive role in enhancing salt tolerance in cherry plants. Measurements of Na+ content and antioxidant enzyme activity under salt stress indicated that PavCBL4 functions positively by inhibiting Na+ accumulation and promoting ROS scavenging in response to salt stress. These findings lay the groundwork for a deeper understanding of the molecular mechanisms underlying PavCBL-mediated salt tolerance in sweet cherry.

[Effects of hydrogen sulfide on mitochondrial function in sweet cherry stigma and ovary under low temperature stress]. / 硫化氢对低温胁迫下甜樱桃柱头和子房线粒体功能的影响.

To investigate the effects of H2S on mitochondrial functions under low temperature stress, we analyzed the effects of 0.05 mmol·L-1 NaHS and 15 µmmol·L-1 HT (hypotaurine and H2S scavenger) on mitochondria antioxidant enzyme activities and mitochondrial permeability transition pore, mitochondrial membrane fluidity, mitochondrial membrane potential, Cyt c/a ratio and H+-ATPase activity in sweet cherry stigma and ovary with sweet cherry variety Zaodaguo under -2 ℃ low temperature stress. The results showed that low temperature stress increased the concentrations of mitochondrial H2O2 and MDA, enhanced the mitochondrial membrane permeability, but decreased the mitochondrial membrane fluidity, membrane potential, Cyt c/a and H+-ATPase acti-vity. Application of NaHS at 0.05 mmol·L-1 could effectively reduce the concentrations of H2O2 and MDA, and keep higher activities of SOD, POD and CAT of mitochondrial for longer time. Furthermore, application of 0.05 mmol·L-1 NaHS could decrease mitochondrial membrane permeability while increase mitochondrial membrane fluidity, membrane potential, Cyt c/a and H+-ATPase activity in stigma and ovary under low temperature stress. The effects of NaHS were completely offset by HT addition. The results suggested that exogenous H2S could alleviate the oxidative damage on stigma and ovary stress through decreasing H2O2 accumulation, regulating mitochondria antioxidant system, increasing H+-ATPase activity, and mitigating mitochondria function under low temperature.

The antioxidative defense system is involved in the premature senescence in transgenic tobacco (Nicotiana tabacum NC89).

BACKGROUND: α-Farnesene is a volatile sesquiterpene synthesized by the plant mevalonate (MVA) pathway through the action of α-farnesene synthase. The α-farnesene synthase 1 (MdAFS1) gene was isolated from apple peel (var. white winter pearmain), and transformed into tobacco (Nicotiana tabacum NC89). The transgenic plants had faster stem elongation during vegetative growth and earlier flowering than wild type (WT). Our studies focused on the transgenic tobacco phenotype. RESULTS: The levels of chlorophyll and soluble protein decreased and a lower seed biomass and reduced net photosynthetic rate (Pn) in transgenic plants. Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) and superoxide radicals (O 2 (·-) ) had higher levels in transgenics compared to controls. Transgenic plants also had enhanced sensitivity to oxidative stress. The transcriptome of 8-week-old plants was studied to detect molecular changes. Differentially expressed unigene analysis showed that ubiquitin-mediated proteolysis, cell growth, and death unigenes were upregulated. Unigenes related to photosynthesis, antioxidant activity, and nitrogen metabolism were downregulated. Combined with the expression analysis of senescence marker genes, these results indicate that senescence started in the leaves of the transgenic plants at the vegetative growth stage. CONCLUSIONS: The antioxidative defense system was compromised and the accumulation of reactive oxygen species (ROS) played an important role in the premature aging of transgenic plants.

The antioxidative defense system is involved in the premature senescence in transgenic tobacco (Nicotiana tabacum NC89)

BACKGROUND: α-Farnesene is a volatile sesquiterpene synthesized by the plant mevalonate (MVA) pathway through the action of α-farnesene synthase. The α-farnesene synthase 1 (MdAFS1) gene was isolated from apple peel (var. white winterpearmain), and transformed into tobacco (Nicotiana tabacum NC89). The transgenic plants had faster stem elongation during vegetative growth and earlier flowering than wild type (WT). Our studies focused on the transgenic tobacco phenotype. RESULTS: The levels of chlorophyll and soluble protein decreased and a lower seed biomass and reduced net photosynthetic rate (Pn) in transgenic plants. Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) and superoxide radicals (O2._) had higher levels in transgenics compared to controls. Transgenic plants also had enhanced sensitivity to oxidative stress. The transcriptome of 8-week-old plants was studied to detect molecular changes. Differentially expressed unigene analysis showed that ubiquitin-mediated proteolysis, cell growth, and death unigenes were upregulated. Unigenes related to photosynthesis, antioxidant activity, and nitrogen metabolism were downregulated. Combined with the expression analysis of senescence marker genes, these results indicate that senescence started in the leaves of the transgenic plants at the vegetative growth stage. CONCLUSIONS: The antioxidative defense system was compromised and the accumulation of reactive oxygen species (ROS) played an important role in the premature aging of transgenic plants.