Physiological and proteomic changes of Castanopsis fissa in response to drought stress

Response of Elymus nutans Griseb. seedling physiology and endogenous hormones to drought and salt stress

Elymus nutans Griseb. (E. nutans), a pioneer plant for the restoration of high quality pasture and vegetation, is widely used to establish artificial grasslands and ecologically restore arid and salinized soils. To investigate the effects of drought stress and salt stress on the physiology and endogenous hormones of E. nutans seedlings, this experiment configured the same environmental water potential (0 (CK), - 0.04, - 0.14, - 0.29, - 0.49, - 0.73, and - 1.02 MPa) of PEG-6000 and NaCl stress to investigate the effects of drought stress and salt stress, respectively, on E. nutans seedlings under the same environmental water potential. The results showed that although the physiological indices and endogenous hormones of the E. nutans seedlings responded differently to drought stress and salt stress under the same environmental water potential, the physiological indices of E. nutans shoots and roots were comprehensively evaluated using the genus function method, and the physiological indices of the E. nutans seedlings under the same environmental water potential exhibited better salt tolerance than drought tolerance. The changes in endogenous hormones of the E. nutans seedlings under drought stress were analyzed to find that treatment with gibberellic acid (GA3), gibberellin A7 (GA7), 6-benzyladenine (6-BA), 6-(y,y-dimethylallylaminopurine) (2.IP), trans-zeatin (TZ), kinetin (KT), dihydrozeatin (DHZ), indole acetic acid (IAA), and 2,6-dichloroisonicotininc acid (INA) was more effective than those under drought stress. By analyzing the amplitude of changes in the endogenous hormones in E. nutans seedlings, the amplitude of changes in the contents of GA3, GA7, 6-BA, 2.IP, TZ, KT, DHZ, IAA, isopentenyl adenosine (IPA), indole-3-butyric acid (IBA), naphthalene acetic acid (NAA), and abscisic acid was larger in drought stress compared with salt stress, which could be because the endogenous hormones are important for the drought tolerance of E. nutans itself. The amplitude of the changes in the contents of DHZ, TZR, salicylic acid, and jasmonic acid was larger in salt stress compared with drought stress. Changes in the content of melatonin were larger in salt stress compared with drought stress, which could indicate that endogenous hormones and substances are important for the salt tolerance of E. nutans itself.

Comprehensive Proteomic Analysis of Common Bean (Phaseolus vulgaris L.) Seeds Reveal Shared and Unique Proteins Involved in Terminal Drought Stress Response in Tolerant and Sensitive Genotypes

This study identified proteomic changes in the seeds of two tolerant (SB-DT3 and SB-DT2) and two sensitive (Merlot and Stampede) common bean genotypes in response to terminal drought stress. Differentially expressed proteins (DEPs) were abundant in the susceptible genotype compared to the tolerant line. DEPs associated with starch biosynthesis, protein-chromophore linkage, and photosynthesis were identified in both genotypes, while a few DEPs and enriched biological pathways exhibited genotype-specific differences. The tolerant genotypes uniquely showed DEPs related to sugar metabolism and plant signaling, while the sensitive genotypes displayed more DEPs involved in plant-pathogen interaction, proteasome function, and carbohydrate metabolism. DEPs linked with chaperone and signal transduction were significantly altered between both genotypes. In summary, our proteomic analysis revealed both conserved and genotype-specific DEPs that could be used as targets in selective breeding and developing drought-tolerant common bean genotypes.

Physiological and Proteomic Changes in Camellia semiserrata in Response to Aluminum Stress

Camellia semiserrata is an important woody edible oil tree species in southern China that is characterized by large fruits and seed kernels with high oil contents. Increasing soil acidification due to increased use of fossil fuels, misuse of acidic fertilizers, and irrational farming practices has led to leaching of aluminum (Al) in the form of free Al3+, Al(OH)2+, and Al(OH)2+, which inhibits the growth and development of C. semiserrata in South China. To investigate the mechanism underlying C. semiserrata responses to Al stress, we determined the changes in photosynthetic parameters, antioxidant enzyme activities, and osmoregulatory substance contents of C. semiserrata leaves under different concentrations of Al stress treatments (0, 1, 2, 3, and 4 mmol/L Alcl3) using a combination of physiological and proteomics approaches. In addition, we identified the differentially expressed proteins (DEPs) under 0 (CK or GNR0), 2 mmol/L (GNR2), and 4 mmol/L (GNR4) Al stress using a 4D-label-free technique. With increasing stress concentration, the photosynthetic indexes of C. semiserrata leaves, peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), soluble protein (SP), and soluble sugar (SS) showed an overall trend of increasing and then decreasing, and proline (Pro) and malondialdehyde (MDA) contents tended to continuously increase overall. Compared with the control group, we identified 124 and 192 DEPs in GNR2 and GNR4, respectively, which were mainly involved in metabolic processes such as photosynthesis, flavonoid metabolism, oxidative stress response, energy and carbohydrate metabolism, and signal transduction. At 2 mmol/L Al stress, carbon metabolism, amino sugar and nucleotide sugar metabolism, and flavonoid metabolism-related proteins were significantly changed, and when the stress was increased to 4 mmol/L Al, the cells accumulated reactive oxygen species (ROS) at a rate exceeding the antioxidant system scavenging capacity. To deal with this change, C. semiserrata leaves enhanced their glutathione metabolism, drug metabolism-cytochrome P450, metabolism of xenobiotics by cytochrome P450, and other metabolic processes to counteract peroxidative damage to the cytoplasmic membrane caused by stress. In addition, we found that C. semiserrata resisted aluminum toxicity mainly by synthesizing anthocyanidins under 2 mmol/L stress, whereas proanthocyanidins were alleviated by the generation of proanthocyanidins under 4 mmol/L stress, which may be a special mechanism by which C. semiserrata responds to different concentrations of aluminum stress.