Cytological, Physiological, and Transcriptomic Analyses of the Leaf Color Mutant Yellow Leaf 20 (yl20) in Eggplant (Solanum melongena L.).

Leaf color mutants are ideal materials for studying chlorophyll metabolism, chloroplast development, and photosynthesis in plants. We discovered a novel eggplant (Solanum melongena L.) mutant yl20 (yellow leaf 20) that exhibits yellow leaves. In this study, we compared the leaves of the mutant yl20 and wild type (WT) plants for cytological, physiological, and transcriptomic analyses. The results showed that the mutant yl20 exhibits abnormal chloroplast ultrastructure, reduced chlorophyll and carotenoid contents, and lower photosynthetic efficiency compared to the WT. Transcriptome data indicated 3267 and 478 differentially expressed genes (DEGs) between WT and yl20 lines in the cotyledon and euphylla stages, respectively, where most DEGs were downregulated in the yl20. Gene Ontology (GO) analysis revealed the "plastid-encoded plastid RNA polymerase complex" and the "chloroplast-related" terms were significantly enriched. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis demonstrated that the significantly enriched DEGs were involved in flavone and flavonol biosynthesis, porphyrin and chlorophyll metabolism, etc. We speculated that these DEGs involved in significant terms were closely related to the leaf color development of the mutant yl20. Our results provide a possible explanation for the altered phenotype of leaf color mutants in eggplant and lay a theoretical foundation for plant breeding.

Hyperphosphorylation of tau protein in hippocampus of central insulin-resistant rats is associated with cognitive impairment.

BACKGROUND: Alzheimer's disease (AD) is one of the most common neurodegenerative diseases. Peripheral insulin resistance increases the risk for memory impairment and the development of AD. OBJECTIVE: This study aims to assess changes in cognitive functions and the level of hyperphosphorylated tau proteins in central insulin-resistant rats. METHODS: An in vivo central insulin-resistant (CIR) animal model was generated through intracerebroventricular injection of streptozotocin (STZ) into insulin-resistant (IR) rats that were induced by feeding a high-glucose/-protein/-fat diet. The Morris water maze test was used to assess changes in cognitive functions, pathological changes in the cornu ammonis 1 (CA1) region of the hippocampus were detected by immunohistochemistry, and the phosphorylation levels of tau proteins at specific sites were determined by Western blot analysis. RESULTS: The escape latency time in the Morris water maze test was significantly prolonged; the number of phosphorylated tau proteins in the CA1 region of the hippocampus was significantly increased; and the phosphorylation levels of tau proteins at Ser199, Thr205, Thr212, Thr217 and Ser396 were significantly elevated in the CIR group compared with the IR and control groups. CONCLUSION: This study provides direct evidence that CIR plays an important role in AD pathogenesis by facilitating tau hyperphosphorylation.

Integrating Transcriptomic and Metabolomic Analyses to Explore the Effect of Color Under Fruit Calyx on That of Fruit Apex in Eggplant (Solanum melongena L.).

Fruit color is an important commercial characteristic of eggplant (Solanum melongena L.), which affects both the profits of growers and consumer choice. Two eggplant inbred lines were discovered: "Z," which is a light purple color under the fruit calyx, with purple on the fruit apex; and "L," fruits of which are green under the calyx and at the apex. To determine the molecular mechanisms underlying the effect of fruit peel color under the calyx on that at the fruit apex, we conducted a combined transcriptomic and metabolomic analyses of the Z and L inbred eggplant lines. Transcriptome analysis of peel samples from three fruit regions (under the calyx, the apex, and the middle surface) of each line was conducted by RNA sequencing, and generated a total of 791,512,404 clean reads from 18 samples (three biological replicates). Differentially expressed genes (DEGs; n = 424) were identified in comparisons of peel samples from the three sites of L line fruits. Gene ontology analysis showed that "catalytic activity" was extremely significantly enriched. Further, DEGs (n = 8) were enriched in the Kyoto Encyclopedia of Genes and Genomes pathway "flavonoid biosynthesis." Levels of CHI, LDOX, F3'5'H, and dihydroflavonol reductase were higher in the Z line than the L line. In addition, metabolome analysis showed that, 10 differentially accumulated metabolites were detected between peel samples from the apex of L and Z line fruit. The most significant DAM was delphinidin-3-O-rutinoside (Z line content, 34.89 µg/g vs. L line content 0.01 µg/g). Combined transcriptomic and metabolomic analyses indicated that DFR and F3'5'H were closely related to content of the metabolites, cyanidin and delphinidin, and that some downstream metabolites differed significantly between the L and Z lines. Content levels of delphinidin-3-O-rutinoside, delphinidin-3-O-glucoside, cyanidin-3-O-glucoside, and cyanidin-3-O-rutinoside were markedly down-regulated in the L line. Altogether, increased CHI levels could up-regulate the downstream genes, LDOX, F3'5'H, and DFR, which further lead to increasing the content of delphindin. Thus, the uniform purple color was presented at the apex of fruits in Z plants. These findings not only identify key candidate genes, but will also improve understanding of the genetics and the efficiency of breeding for eggplant fruit color.

Gene characterization and molecular pathway analysis of reverse thermosensitive genic male sterility in eggplant (Solanum melongena L.).

The naturally occurring mutant eggplant line 05ms was identified with reverse thermosensitive genic male sterility (rTGMS), but its temperature-responsive fertility mechanisms remain largely unknown. Here, we studied the flower morphology, anther cellular structure, and genome-wide gene expression of this rTGMS line. Candidate genes for thermosensitive male sterility during the microspore development of 05ms and the temperature-insensitive line S63 under low-temperature (LT) and high-temperature (HT) conditions were identified. Under LT, tapetum cells were vacuolated and had delayed disintegration in 05ms. RNA-seq analysis indicated that DEGs were enriched in the KEGG pathways 'plant hormone signal transduction', 'starch and sucrose metabolism', and 'phenylpropanoid biosynthesis'. We identified two genes, 4CLL1 (Sme2.5_00368.1_g00010.1) and CKI1 (Sme2.5_10056.1_g00002.1), which could potentially regulate eggplant anther development and may be candidate genes for rTGMS. Finally, we propose a working model of anther abortion for rTGMS in eggplant. CKI1 responds to LT stress and causes expression changes in genes related to anther development, such as 4CLL1, and the cellular structure of the tapetum becomes abnormal, causing male sterility. The findings of this study explain the underlying molecular mechanisms of male sterility in eggplant rTGMS lines.

[Studies on the association of angiotensinogen polymorphisms and hypoxia acclimatization].

OBJECTIVE: To research the effects of gene polymorphisms of AGT at G-217A and T174M loci on incidence and the hypoxia acclimation to acute mountain sickness (AMS). METHODS: Step 1:61 Han students origin low landers were exposed in acute hypoxia at 4 800 m altitude-equivalent for 6 hours, and took the supine bicycle exercise for 20 min at quantitative load of 60 r/min, 80 W after entering the cabin for 30 min, then the AMS were evaluated by the Lake Louise acute mountain sickness scoring system (LLS). The physical index of heart rate (HR), ambulatory blood pressure and oxygen saturation (SpO2) were measured during exercise. Step 2:The physical index was measured again in acute hypoxic exposure after 3 weeks increasing hypoxia exercise (At an increasing altitude of 2 500 m, 3 500 m, 4 800 m, time of 2 hours/day, 4 days/week, and in moderate intensity of exercise). PCR-RFLP was used to determine the genotypes and alleles frequencies of AGT at G-217A and T174M loci. RESULTS: In step 1 the hypoxic exposure, for the G-217A locus in AGT, there was no significant difference between GG and GA+AA gene tester. While in step 2 the hypoxic exposure, the SpO2 of GG gene was lower than GA+AA gene obviously (P<0.05). No significant differences of AMS incidence, VE, SpO2, HR and blood pressure were detected in different genotypes and alleles at T174M locusin both hypoxic exposures. CONCLUSIONS: The G-217A may be the genetics sign of hypoxia acclimation. There is no obvious rel-evancy between the T174M polymorphism and the occurrence of AMS/hypoxia acclimation.