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Pre-harvest soybean seeds in the field are susceptible to high temperature and humidity (HTH) stress, leading to pre-harvest seed deterioration, which will result in a reduction in grain quality, yield, and seed vigor. To understand the gene expression involved in seed deterioration response under HTH stress, in this study, we conducted an RNA-Seq analysis using two previously screened soybean cultivars with contrasting seed deterioration resistance. HTH stress induced 1081 and 357 differentially expressed genes (DEGs) in the sensitive cultivar Ningzhen No. 1 and resistant cultivar Xiangdou No. 3, respectively. The majority of DEGs in the resistant cultivar were up-regulated, while down-regulated DEGs were predominant in the sensitive cultivar. KEGG pathway analysis revealed that metabolic pathways, biosynthesis of secondary metabolites, and protein processing in endoplasmic reticulum were the predominant pathways in both cultivars during seed deterioration under HTH stress. The genes involved in photosynthesis, carbohydrate metabolism, lipid metabolism, and heat shock proteins pathways might contribute to the different response to seed deterioration under HTH treatment in the two soybean cultivars. Our study extends the knowledge of gene expression in soybean seed under HTH stress and further provides insight into the molecular mechanism of seed deterioration as well as new strategies for breeding soybean with improved seed deterioration resistance. Key words: soybean, high temperature and humidity, RNA-Seq, pre-harvest seed deterioration. Avant la recolte, les graines de soja au champ sont sensibles a un stress cause par une temperature et une humidite elevees (HTH), ce qui peut entrainer une deterioration des grains en pre-recolte, laquelle diminue la qualite des grains, le rendement et la vigueur des graines. Pour comprendre les profils d'expression genique associes a cette deterioration en reponse au stress HTH, les auteurs ont realise une etude RNA-Seq sur deux cultivars prealablement identifies comme presentant une resistance contrastee a cette deterioration. Le stress HTH a permis d'identifier, respectivement, 1081 et 357 genes a expression differentielle (DEG) chez le cultivar sensible Ningzhen No. 1 et le cultivar resistant Xiangdou No. 3. La majorite des DEG chez le cultivar resistant etaient exprimes a la hausse, tandis que les genes moins fortement exprimes etaient predominants chez le cultivar sensible. Une analyse des sentiers KEGG a revele que les 'sentiers metaboliques', la 'biosynthese des metabolites secondaires' et la 'maturation des proteines dans le reticulum endoplasmique' etaient les sentiers predominants touches lors de la deterioration des graines soumis a un stress HTH. Les genes impliques dans la photosynthese, le metabolisme des hydrates de carbone, le metabolisme des lipides et les proteines de choc thermique pourraient contribuer a la reponse differente observee entre les deux cultivars soumis a un traitement de stress HTH. Cette etude accroit les connaissances sur l'expression genique chez les graines de soja en reponse au stress HTH et fournit un eclairage sur le mecanisme moleculaire de la deterioration des graines ainsi que sur de nouvelles strategies pour selectionner des sojas dotes d'une meilleure resistance a la deterioration des graines. [Traduit par la Redaction] Mots-cles : soja, temperature et humidite elevees, RNA-Seq, deterioration des graines en pre-recolte., Introduction Soybean seeds provide major sources of oil and protein globally for human consumption and animal feed (Saha and Sultana 2008). Seed quality is determined by its composition of protein, [...]

Heat stress poses a threat to plants in arid and semiarid regions, leading to soil salinization and plant mortality. Researchers are exploring remedies to alleviate these effects, including using gibberellic acid (GA3) to regulate plant enzymes and antioxidants. Additionally, sodium nitroprusside (SNP) is gaining attention, but its combined effect with GA3 requires further research. To address this gap, we investigated the effects of GA3 and SNP on plants under heat stress conditions. For that, wheat plants were cultivated under 40 °C for 6 h per day (15 days). Sodium nitroprusside (donor of NO and SNP) and gibberellic acid (GA3), respectively, with 100 µM and 5 µg/ml concentrations, were applied as foliar sprays at 10 days after sowing (DAS). Results showed that SNP + GA3 treatment had the highest plant height (4.48% increase), plant fresh weight (29.7%), plant dry weight (87%), photosynthetic rate (39.76%) and stomatal conductance (38.10%), and Rubisco (54.2%) compared to the control. Our findings indicate a significant increase in NO, H2O2, TBARS, SOD, POD, APX, proline, GR, and GB that greatly scavenged reactive oxygen species (ROS) for decreasing the adverse effect of stress. Such findings confirmed the efficacy of the combined treatment of SNP + GA3 under high-temperature stress compared to the solitary application of GA3, SNP, and control. In conclusion, using SNP + GA3 is a better strategy for mitigating heat stress in wheat than individual applications. Further research is recommended to validate the effectiveness of SNP + GA3 in other cereal crops. [ABSTRACT FROM AUTHOR]

Selenium- (Se-) enriched polysaccharide SPMP-2a was extracted and purified from Pleurotus geesteranus. SPMP-2a is a white flocculent polysaccharide and soluble in water, with a molecular weight of 3.32 × 104 Da. Fourier transform infrared spectroscopy spectral analysis indicated that it belongs to an acid Se polysaccharide with α-D-glucopyranoside bond. The effects of Se polysaccharide SPMP-2a in P. geesteranus against hydrogen peroxide- (H2O2-) induced oxidative damage in human keratinocytes (HaCaT) cells were evaluated further. Reduced cell viability and elevated apoptotic rates in H2O2-treated HaCaT cells were proven by MTT and flow cytometry assays. Hoechst 33342 staining revealed chromatin condensations in the nuclei of HaCaT cells. However, with the addition of SPMP-2a, cell viability improved, nuclear condensation declined, and cell apoptotic rates dropped significantly. Ultrastructural observation consistently revealed that treatments with SPMP-2a reduced the number of swollen and vacuolar mitochondria in the H2O2-treated cells compared with the controls. Furthermore, SPMP-2a increased the superoxide dismutase (SOD) and catalase (CAT) activities and reduced reactive oxygen species (ROS) content. Western blot analysis showed that SPMP-2a treatment effectively increased B-cell lymphoma 2 (Bcl-2) protein expression. Therefore, SPMP-2a could improve cellular antioxidant enzyme activities, reduce ROS levels, and increase Bcl-2 protein expression levels, thereby reducing cell apoptosis and protecting HaCaT cells from H2O2-induced oxidative damage. [ABSTRACT FROM AUTHOR]

Selenium- (Se-) enriched polysaccharide SPMP-2a was extracted and purified from Pleurotus geesteranus . SPMP-2a is a white flocculent polysaccharide and soluble in water, with a molecular weight of 3.32 × 10 4  Da. Fourier transform infrared spectroscopy spectral analysis indicated that it belongs to an acid Se polysaccharide with α -D-glucopyranoside bond. The effects of Se polysaccharide SPMP-2a in P. geesteranus against hydrogen peroxide- (H 2 O 2 -) induced oxidative damage in human keratinocytes (HaCaT) cells were evaluated further. Reduced cell viability and elevated apoptotic rates in H 2 O 2 -treated HaCaT cells were proven by MTT and flow cytometry assays. Hoechst 33342 staining revealed chromatin condensations in the nuclei of HaCaT cells. However, with the addition of SPMP-2a, cell viability improved, nuclear condensation declined, and cell apoptotic rates dropped significantly. Ultrastructural observation consistently revealed that treatments with SPMP-2a reduced the number of swollen and vacuolar mitochondria in the H 2 O 2 -treated cells compared with the controls. Furthermore, SPMP-2a increased the superoxide dismutase (SOD) and catalase (CAT) activities and reduced reactive oxygen species (ROS) content. Western blot analysis showed that SPMP-2a treatment effectively increased B-cell lymphoma 2 (Bcl-2) protein expression. Therefore, SPMP-2a could improve cellular antioxidant enzyme activities, reduce ROS levels, and increase Bcl-2 protein expression levels, thereby reducing cell apoptosis and protecting HaCaT cells from H 2 O 2 -induced oxidative damage., Competing Interests: All authors declare that there is no conflict of interests regarding the publication of this paper.