查看更多>>摘要：? 2021 Elsevier B.V.The responses of yield, nutritional quality and antioxidant capacity of hydroponic purple-lettuce were investigated in a plant factory to different alternations of temporally overlapped red (R) and blue (B) light under continuous irradiation in which spectral photon flux density distribution changed with various combinations of R and B LEDs on a 24-h cycle. Two constant simultaneous rend and bleu (R-B) light treatments including one normal photoperiod (RB, 16/8 h, 225 μmol·m?2·s?1) and one continuous light (RB’, 24/0 h, 150 μmol·m?2·s?1) as well as three alternating temporally overlapped light treatments (B to R-B and then R, each part lasts the same time) with alternating frequencies of one time (T1), two times (T2) and four times (T4) respectively in 24 h were set up with the same daily light integral (DLI). The lettuce plants were exposed to the irradiation patterns for 14 days. In all treatments, plants received the same quantum number of red or blue light and the same daily light integral (12.96 μmol·m?2). In comparison with normal photoperiod (RB), the results showed that lettuce plants gained greater shoot fresh and dry weight under RB’ and T1 both on the 7 and 14 days after treatment, which depended on leaf area and biomass allocation. Among alternating light treatments, the shoot fresh weight of lettuce decreased with the increase of alternating frequencies. Lettuce plants under alternating temporally overlapped treatments had significantly higher MDA, H2O2 and O2? contents as well as higher SOD and CAT activities than that under RB and RB’. Alternating light treatments also induced phenols accumulation, and particularly lettuce under T2 had significantly higher anthocyanin, flavonoid and total phenol contents than RB. However, prolongation of light period under the same DLI condition might promote nitrate accumulation in lettuce while had no positive effects on starch and soluble sugar contents. Therefore, alternating temporally overlapped red and blue light under continuous irradiation could improve the antioxidant capacity of lettuce to a certain extent, and the responses of lettuce antioxidant system to alternating light exposure might depend on the duration and alternating frequency of two monochromatic light qualities.
查看更多>>摘要：? 2021 Elsevier B.V.Several lines of evidence suggest that glucose (Glc) and abscisic acid (ABA) are important signal molecules involved in plant growth and development. In the study, cucumber (Cucumis sativus ‘Xinchun NO. 4′) was used to understand the roles and relationships of Glc and ABA in adventitious root development. The results show that the effect of Glc and ABA on adventitious rooting in cucumber was dose-dependent, with a maximal biological response at 0.10 mM Glc and 0.05 μM ABA, respectively. However, the promotive roles of Glc in adventitious rooting were suppressed by ABA inhibitor fluridone (FLU), suggesting that endogenous ABA might be involved in Glc-induced adventitious rooting. Glc increased endogenous ABA content and the activity of ABA biosynthesis-related enzyme zeaxanthin epoxidase (ZEP), 9-cis-epoxy-carotenoid dioxigenase (NCED) and aldehyde oxidase (AO) during adventitious rooting. Glc decreased the activity of ABA degradation-related enzyme ABA 8′-hydroxylase (ABA8’-H). Glc significantly up-regulated the expression of ABA biosynthesis-related genes CsNCED1 and CsNCED2 and ABA signal transduction-related genes CsPYR1, CsPYR2, CsPYL8 and CsSRK2E, and significantly down-regulated the expression of ABA degradation-related genes CsCYP707A1 and CsCYP707A2. However, Glc-enhanced ABA content, ABA-related enzyme activity and ABA-related gene expression were reversed by FLU. Therefore, Glc might promote adventitious rooting by enhancing ABA accumulation, in which the activity of ABA biosynthesis enzyme (ZEP, NCED and AO), the expression of ABA biosynthesis-related genes (CsNCED1 and CsNCED2) and ABA signal transduction-related genes (CsPYR1, CsPYR2, CsPYL8 and CsSRK2E) were increased by Glc, and the activity of ABA degradation enzyme ABA8’-H and the expression of ABA degradation-related genes (CsCYP707A1 and CsCYP707A2) were inhibited by Glc.
查看更多>>摘要：? 2021 Elsevier B.V.Drought stress negatively affects the walnut productivity. To ensure the comprehensive benefits of walnut, this study aims to explore the molecular mechanism of drought stress response. Therefore, the downstream target genes of JrWRKY2, a drought tolerance regulator of Juglans regia, are identified by analyses of promoter expression, yeast one-hybrid and co-expression. The results showed that JrWRKY2 could bind to the W-BOX like motifs from the promoters of JrGSTU23 (a tau class glutathione S-transferase) and JrVHAc4 (a c subunit of vacuole H+-ATPase). JrGSTU23 and JrVHAc4 could be up-regulated by drought stress and abscisic acid (ABA). The drought tolerance of transgenic Arabidopsis overexpression of JrGSTU23 or JrVHAc4 were promoted significantly compared to wild type (WT) plants; More importantly, the degree of improvement in drought resistance is enhanced by application of ABA. The transcription levels of the genes from signaling pathways of ABA and mitogen-activated protein kinases (MAPKs) in JrGSTU23 and JrVHAc4 overexpression plants were higher than those in WT with different profiles. These results propose a trifurcate feed-forward pathway involving in JrWRKY2, JrGSTU23, and JrVHAc4 functions on drought stress response that associated with ABA and MAPK signaling pathways, which will offer new insights to reveal plant adaptation mechanism to adverse stimulus.
查看更多>>摘要：? 2021 Elsevier B.V.Molecular markers are important and valuable tools in crop breeding programmes to help in the discovery and manipulation of important genes governing resistance reaction. In potato, several biotic stresses hamper quantity and quality of tuber production. Availability of molecular markers and high throughput screening method provide an excellent opportunity to practice marker assisted selection for potato improvement without waiting for phenotypic screening. In this study, we developed 20 KASP markers related to late blight, PVY and PCN resistance traits to facilitate the screening at earlier stages of potato breeding programmes. Out of these 20 markers, nine KASP assays were validated and associated with the phenotype data on respective traits for reliability in their wider application. The validation was done in a panel of 1447 potato germplasm accessions including varieties from diverse provenience and advanced breeding clones. Among traits, the best association found related to KASP markers for late blight, namely markers snp ST00106, snp ST00020 and snp ST00023. Overall, the allele calls were conclusive for all the nine markers, and the results demonstrate the usefulness of SNP KASP markers in high throughput cost effective marker assisted selection (MAS) for important biotic stress traits in potatoes.
查看更多>>摘要：? 2022The effect of mannose treatment on chlorophyll catabolism and programmed cell death (PCD) in broccoli florets during storage at 20 ℃ has been investigated. The results showed that mannose treatment efficiently restrained chlorophyll degradation in broccoli florets via regulating chlorophyll catabolism genes (BoPPH, BoPAO, BoRCCR, BoSGR1 and BoSGR2). Meanwhile, mannose treatment efficiently suppressed the occurrence of PCD through the mitochondria-dependent pathway in broccoli florets. Less reactive oxygen species content observed in mannose-treated broccoli florets delayed the increase of mitochondrial membrane potential and inhibited unfolding of mitochondria permeability transition pore, which was associated with the inhibition of cytochrome c liberation in mitochondria and the maintenance of high levels of cytochrome c/a and the ratio of Ca2+ content, the activities of cytochrome c oxidase and alternative oxidase . These results suggested that mannose treatment inhibited senescence of broccoli florets through suppressing the chlorophyll degradation and the appearance of PCD.
查看更多>>摘要：? 2021It is generally believed that albino tea cultivars contain high amino acid content, and numerous studies have used them as materials to reveal L-theanine metabolism mechanism. However, few studies on the research of high amino acid green-leaf tea cultivars were reported. Here, high amino acid green-leaf tea cultivars, ‘Baojing Huangjincha1’ (BJ1) and ‘Huangjincha2’ (HJC2) have been discovered. In this study, biochemical ingredients and transcriptomes of high amino acids green-leaf tea cultivars (BJ1, HJC2) and albino tea cultivars, ‘Baiye1’ (BY1) and ‘Huangjinya’ (HJY) were analyzed and compared. Biochemical analyses showed that the contents of chlorophyll and carotenoids in albino tea cultivars (BY1, HJY) were much lower than that in green-leaf tea cultivars (BJ1, HJC2), whereas increases were noted in the ratio of carotenoids to chlorophyll. The content of catechins was lower in HJC2, BY1 and HJY than that in BJ1. The content of L-theanine also showed considerable variability among four tea cultivars. Especially, HJC2 with dark-green leaves contained the highest L-theanine and lowest catechins content. At transcription level, the results revealed expression patterns of genes related to chlorophyll biosynthesis were significantly up-regulated in HJC2. Suppressed expressions of CsCHS in HJC2, CsPAL in BY1, and CsF3′5′H in HJY were responsible for the lower catechins content, respectively. Furthermore, we also found that CsGOGAT and CsGS/TS were key genes leading to differences in the accumulation patterns of L-theanine between HJC2 and BY1. These findings provide basis for further research on regulatory mechanisms of pigments and characteristic secondary metabolites in tea plants.
查看更多>>摘要：? 2022Pomegranate is a tropical and subtropical fruit sensitive to chilling injury during its cold storage, leading to quantitative and qualitative losses, as well as reduced economic value. Recently, melatonin has been considered as an environmentally friendly treatment to maintain the postharvest quality of horticultural products. In this study, the effect of melatonin treatment on chilling tolerance, postharvest quality and antioxidant system of pomegranate fruit was investigated during storage at 4 °C for 120 days. According to the results, pH, titratable acidity and the total soluble solids of the fruit were not influenced by applying melatonin. However, melatonin treatment at 100 μM dramatically improved chilling tolerance in the pomegranate fruit by reducing electrolyte leakage and increasing the total phenol content, as well as the antioxidant potential. Melatonin significantly reduced polyphenol oxidase (PPO) activity and increased the activity of phenyl alanine amylase (PAL), catalase (CAT), ascorbate peroxidase (APX) and superoxide dismutase (SOD) enzymes in the husk and arils of the pomegranate fruit during storage. In addition, melatonin inhibited H2O2 accumulation in the pomegranate fruits. Therefore, our data suggest that melatonin might be useful in improving the postharvest quality and inducing chilling tolerance in pomegranates during the cold storage.
查看更多>>摘要：? 2021 Elsevier B.V.Quality breakdown and decay are the main factors that cause economic losses of fruit and vegetable during storage. Apple fruit (cv. Golden Delicious) were dipped in 1.5 g L?1 trehalose to investigate the changes of quality parameters, activity and gene expression of key enzyme in sucrose and respiratory metabolism. Results showed that trehalose treatment suppressed weight loss and respiratory rate, maintained soluble solid content and flesh firmness in apples. Moreover, trehalose suppressed neutral invertase (NI) and sucrose synthase cleavage (SS-c), cytochrome oxidase (CCO) and succinate dehydrogenase (SDH), glucose phosphate isomerase activities and MdNI, MdSS, MdSDH and MdCCO expressions in apple fruit. Meanwhile, trehalose increased the activities of sucrose phosphate synthase (SPS), sucrose synthase synthesis (SS-s) and glucose 6-phosphate dehydrogenase (G6PDH), and MdSPS, MdG6PDH and MdPFK expressions in apples. These results propose that trehalose treatment maintains storage quality of apples by regulating sucrose and respiratory metabolism during storage.
查看更多>>摘要：? 2021Kiwifruit is a dioecious plant requiring cross pollination. The nectar in kiwifruit flowers is negligible which makes it less attractive to honey bees. Hand pollination is a common practice for effective pollination but this practice is inevitable, laborious and time consuming. Spraying of bee attractants during the periods of anthesis can be helpful in increasing the bee visitation to the flowers and improve yield as well as quality of kiwifruits. Keeping in view the possible beneficial effects of bee attractants, an experiment was carried out during 2018–19 to compare the practice of hand pollination with the application of commercial bee attractant ‘Bee Scent’ (1.25%) and indigenous bee attractants like jaggery solution (10%), sugar solution (10%), honey solution (10%) and sugarcane juice (10%) for their effects on bee activity, fruit set and fruit quality of kiwifruit. The sprays of Bee Scent to the flowers resulted in significant improvement in bee visitation to the flowers, fruit set, yield, proportion of ‘A’ and ‘B’ grade fruits, fruit size & weight, number of seeds, TSS, sugars and ascorbic acid contents. Sugarcane juice was also found equally effective in improving bee activity, fruit set and fruit quality, thus shown the potential to be used as a bee attractant in commercial kiwifruit production system.
查看更多>>摘要：? 2021 Elsevier B.V.Growth-regulating factors (GRFs) as plant-specific transcription factors exert an important role in plant growth and development; however, the function of GRFs has not been reported in apple (Malus domestica). In the present study, we identified 12 MdGRF genes, which located on six chromosomes with different densities. These MdGRFs were phylogenetically classified into four clusters based on the protein sequence similarity, and the intron-exon structure and functional domain of MdGRF genes were similar within each cluster. Interestingly, these MdGRFs were tissue-specific expressed, and several specific MdGRFs were strongly responsive to various hormonal treatments, either positively or negatively. The transgenic apple calli overexpressing MdGRF02 displayed higher fresh weight and the transgenic apple roots exhibited increased root elongation, indicating that MdGRF02 may be related with root growth regulation in apples. This study reports the identification and expression analysis of the MdGRFs and provides some useful information to reveal the potential roles of MdGRFs in apple growth regulation, especially the root growth.
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