Barley and its products are good sources of antioxidants. This experiment was conducted to examine the classification and concentration of phenolic compounds, proanthocyanidins, and anthocyanins in 127 lines of colored barley. Their relationship with 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was also examined. Barley was placed into seven groups using the colorimeter: hulled (black 1, black 2, black 3, and purple) and unhulled (black, blue, and purple). The contents of phenolic compounds and anthocyanins were analyzed by using HPLC. The average content of phenolic compounds in unhulled barley groups (268.6 microg/g) was higher than that in hulled (207.0 microg/g) (P > 0.05). The proanthocyanidins content was determined by modified vanillin assay. The average content of proanthocyanidins was significantly higher in purple and blue barley groups compared with black (P < 0.05). The content of anthocyanins varied from 13.0 to 1037.8 microg/g. Purple and blue barley groups contained higher average contents of anthocyanins than black (P < 0.05). The most common anthocyanin in the purple barley groups was cyanidin 3-glucoside, whereas delphinidin 3-glucoside was the most abundant anthocyanin in the blue and black groups. In colored barley, DPPH radical scavenging activity had high positive correlation to the content of phenolic compounds and proanthocyanidins.

We report high frequencies of embryo production and plant regeneration through isolated microspore culture of hot pepper (Capsicum annuum L.). Microspores cultured in modified NLN medium (NLNS) divided and developed to embryos. Globular and heart-shaped embryos were observed from 3 weeks after the beginning of culture, and many embryos reached the cotyledonary stage after 4 weeks of culture. These cotyledonary embryos developed to plantlets after transfer to solid B5 basal medium. We also optimized conditions for embryo production by varying the pretreatment media, the carbon sources, and culture densities. Heat shock treatment in sucrose-starvation medium was more effective than in B5 medium. Direct comparisons of sucrose and maltose as carbon sources clearly demonstrated the superiority of sucrose compared to maltose, with the highest frequency of embryo production being obtained in 9% (w/v) sucrose. Microspore plating density was critical for efficient embryonic induction and development, with an optimal plating density of 8 x 10(4)-10 x 10(4)/ml. Under our optimized culture conditions, we obtained over 54 embryos, and an average of 5.5 cotyledonary embryos when 10 x 10(4) microspores were grown on an individual plate.

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Potassium is the most abundant cation and a myriad of transporters regulate K+ homeostasis in plant. Potassium plays a role as a major osmolyte to regulate stomatal movements that control water utility of land plants. Here we report the characterization of two inward rectifying shaker-like potassium channels, OsKAT2 and OsKAT3, expressed in guard cell of rice plants. While OsKAT2 showed typical potassium channel activity, like that of Arabidopsis KAT1, OsKAT3 did not despite high sequence similarity between the two channel proteins. Interestingly, the two potassium channels physically interacted with each other and such interaction negatively regulated the OsKAT2 channel activity in CHO cell system. Furthermore, deletion of the C-terminal domain recovered the channel activity of OsKAT3, suggesting that the C-terminal region was regulatory domain that inhibited channel activity. Two homologous channels with antagonistic interaction has not been previously reported and presents new information for potassium channel regulation in plants, especially in stomatal regulation.

This study was conducted to determine the fluctuating levels of isoflavone in soybean (Glycine max L.) seeds of six varieties at different development stages. The average concentration of total isoflavone in the fully matured seed was 669 µg g −1 , whereas those in the seeds of the R5 (beginning), R6 (green full-sized) and R7 (onset of physiological maturity) stages were 145, 296 and 611 µg g −1 , respectively. Sowonkong variety was highest in total isoflavone content of the fully matured and the R7 seed among all the varieties. In all six varieties, total isoflavone levels at the R7 stage were higher than those of R5 and R6 stages. Total isoflavone concentrations rapidly increased as growth stages transitioned from R5 to R7, as indicated by a positive correlation (r = 0.80 * * * ) between the total isoflavone and growth stages. Overall, total isoflavone levels were similar between R7 and the full maturity stages. Of the various isoflavone derivatives, acetylglucoside and aglycon were not significantly correlated with total isoflavone concentrations. However, glucoside (r = 0.97 * * * ), malonylglucoside (r = 0.99 * * * ), TGIN (genistein + genistin + malonylgenistin + acetylgenistin, r = 0.93 * * * ) and TDIN (daidzein + daidzin + malonyldaidzin + acetyldaidzin, r = 0.99 * * * ) were very highly correlated with total isoflavone concentrations. As a result, they constituted most of the total isoflavones in the soybean seeds at R5, R6, R7, and full maturity stages.

Plants adapt to adverse environmental conditions through physiological responses, such as induction of the abscisic acid signaling pathway, stomatal regulation, and root elongation. Altered gene expression is a major molecular response to adverse environmental conditions in plants. Several transcription factors function as master switches to induce the expression of stress-tolerance genes. To find out a master regulator for the cold stress tolerance in rice, we focused on functionally identifying DREB subfamily which plays important roles in cold stress tolerance of plants. Here, we characterized OsDREB1G ( LOC_Os02g45450 ), a functionally unidentified member of the DREB1 subgroup. OsDREB1G is specifically induced under cold stress conditions among several abiotic stresses examined. This gene is dominantly expressed in leaf sheath, blade, node, and root. Transgenic rice overexpressing this gene exhibited strong cold tolerance and growth retardation, like transgenic rice overexpressing other OsDREB1 genes. However, unlike these rice lines, transgenic rice overexpressing OsDREB1G did not exhibit significant increases in drought or salt tolerance. Cold-responsive genes were highly induced in transgenic rice overexpressing DREB1G compared to wild type. In addition, OsDREB1G overexpression directly induced the expression of a reporter gene fused to the promoters of cold-induced genes in rice protoplasts. Therefore, OsDREB1G is a typical CBF/DREB1 transcription factor that specifically functions in the cold stress response. Therefore, OsDREB1G could be useful for developing transgenic rice with enhanced cold-stress tolerance.

Effects of ambient and elevated CO 2 levels (360 and 650 µmol mol −1 respectively), ambient and high (5 • C above ambient) temperatures and their interactions with N application on soybean (Glycine max L.) were studied in 2001. Overall, total isoflavones in whole soybean seeds were highest (1383.0 µg g −1 ) in the elevated CO 2 (AE) treatment without N application and lowest (414.1 µg g −1 ) in the elevated temperature (EA) treatment with N application. Malonylgenistin (449.2 µg g −1 ) and malonyldaidzin (435.9 µg g −1 ) concentrations in the AE treatment without N application were highest among the 12 individual isoflavones, while aglycon and acetyl conjugates showed lower concentrations (below 10 µg g −1 ) than glucoside and malonyl conjugates in all treatments. Overall, N application had no effect on total isoflavone concentration, while both temperature and CO 2 level had a higher effect on increasing isoflavones, including aglycon and acetyl conjugates (P = 0.001). In the biological growth analysis, total dry weight was highest (100.9 g) in the elevated temperature and CO 2 (EE) treatment with N application, while leaf area was more affected by CO 2 than by temperature and increased with N application. There were larger numbers of pods (99) and seeds (176) per plant in the EE treatment with N application, and generally the AE treatment showed a greater increase in 100-seed weight (g per 100 seeds) and in pods and seeds per plant than other treatments. Overall, total dry weight was highly affected (P = 0.001) by three main factors, temperature, CO 2 and N application, but the interactions temperature × N and temperature × CO 2 × N did not affect total dry weight. Also, total dry weight tended to increase with increasing numbers of pods (r 2 = 0.93 * * * ) and seeds (r 2 = 0.93 * * * ) and larger leaf area (r 2 = 0.85 * * * ). In addition, numbers of pods and seeds were significantly affected (P = 0.01-0.001) by temperature, CO 2 and temperature × CO 2 . Generally, elevated CO 2 and temperature did not affect N, P and K concentrations in the seeds but did decrease the concentrations of Ca and Mg, which were increased in the AE treatment. Among the nutrients, Ca and Mg were highly correlated with temperature and CO 2 level. N concentration in the seeds increased with applied N and in particular showed a high increase with elevated temperature and ambient CO 2 (EA treatment). The variation in isoflavones was correlated with temperature (r 2 = −0.70 * * ) and CO 2 (r 2 = 0.67 * * ), while N application was not correlated with isoflavone concentration. Also, Ca (r 2 = −0.85 * * * ) and Mg (r 2 = −0.57 * ) in the seeds were correlated with variation in isoflavones. This indicated that isoflavones were in higher concentrations under conditions of low temperature and increasing CO 2 , which also resulted in low Ca and Mg concentrations in the seeds. The results of this study suggest that the long-term adaptation of the soybean to growth at elevated CO 2 level and high temperature might potentially increase its isofla...

Background The core ABA signaling components functioning in stomatal closure/opening, namely ABA receptors, phosphatases, SnRK2s and SLAC1, are well characterized in Arabidopsis, but their functions in guard cells of rice have not been extensively studied. Results In this study, we confirmed that OsSLAC1 , the rice homolog of AtSLAC1 , is specifically expressed in rice guard cells. Among the rice SAPKs , SAPK10 was specifically expressed in guard cells. In addition, SAPK10 phosphorylated OsSLAC1 in vitro and transgenic rice overexpressing SAPK10 or OsSLAC1 showed significantly less water loss than control. Thus, those might be major positive signaling components to close stomata in rice. We identified that only OsPP2C50 and OsPP2C53 among 9 OsPP2CAs might be related with stomatal closure/opening signaling based on guard cell specific expression and subcellular localization. Transgenic rice overexpressing OsPP2C50 and OsPP2C53 showed significantly higher water loss than control. We also characterized the interaction networks between OsPP2C50 and OsPP2C53, SAPK10 and OsSLAC1 and found two interaction pathways among those signaling components: a hierarchical interaction pathway that consisted of OsPP2C50 and OsPP2C53, SAPK10 and OsSLAC1; and a branched interaction pathway wherein OsPP2C50 and OsPP2C53 interacted directly with OsSLAC1. Conclusion OsPP2C50 and OsPP2C53 is major negative regulators of ABA signaling regarding stomata closing in rice. Those can regulate the OsSLAC1 directly or indirectly thorough SAPK10. Electronic supplementary material The online version of this article (10.1186/s12284-019-0297-7) contains supplementary material, which is available to authorized users.