Ethylene-induced NbMYB4L is involved in resistance against tobacco mosaic virus in Nicotiana benthamiana.

Several MYB transcription factors are known to play important roles in plant resistance to environmental stressors. However, the mechanism governing the involvement of MYBs in regulating tobacco mosaic virus (TMV) resistance in plants is still unclear. In this study, we found that not only is Nicotiana benthamiana MYB4-like involved in defence against TMV, but also that the ethylene pathway participates in MYB4L-mediated resistance. Transcription of NbMYB4L was up-regulated in N. benthamiana infected with TMV. Silencing of NbMYB4L led to intensified TMV replication, whereas overexpression of NbMYB4L induced significant resistance to TMV. Transcription of NbMYB4L was greater in 1-aminocyclopropanecarboxylic acid (ACC, ethylene precursor)-pretreated plants but lower when the ethylene signalling pathway was blocked during TMV infection. Gene expression analysis showed that the transcription of NbMYB4L was largely suppressed in ETHYLENE INSENSITIVE 3-like 1(EIL1)-silenced plants. The results of electrophoretic mobility shift assay and chromatin immunoprecipitation-quantitative PCR (ChIP-qPCR) experiments indicated that NbEIL1 could directly bind to two specific regions of the NbMYB4L promoter. Furthermore, a luciferase assay revealed that NbEIL1 significantly induced the reporter activity of the MYB4L promoter in N. benthamiana. These results point to NbEIL1 functioning as a positive regulator of NbMYB4L transcription in N. benthamiana against TMV. Collectively, our work reveals that EIL1 and MYB4L constitute a coherent feed-forward loop involved in the robust regulation of resistance to TMV in N. benthamiana.

Genome-Wide Identification and Expression Analysis of the ß-Amylase Gene Family in Chenopodium quinoa.

ß-Amylase (BAM) is an important starch hydrolase, playing a role in a variety of plant growth and development processes. In this study, 22 BAM gene family members (GFMs) were identified in quinoa (Chenopodium quinoa), an ancient crop gaining modern consumer acceptance because of its nutritional qualities. The genetic structure, phylogenetic and evolutionary relationships, and expression patterns of CqBAM GFMs in different tissues, were analyzed. Phylogenetic analyses assigned the CqBAMs, AtBAMs, and OsBAMs into four clades. The CqBAM gene family had expanded due to segmental duplication. RNA-seq analysis revealed expression of the duplicated pairs to be similar, with the expression of CqBAM GFM pairs showing a degree of tissue specificity that was confirmed by reverse transcription quantitative PCR (RT-qPCR). Several CqBAM GFMs were also responsive to abiotic stresses in shoots and/or roots. In conclusion, the BAM gene family in quinoa was identified and systematically analyzed using bioinformatics and experimental methods. These results will help to elucidate the evolutionary relationship and biological functions of the BAM gene family in quinoa.

Expressed sequence tags from the halophyte Limonium sinense.

Halophytes can grow under a high salinity condition. Similar to glycophytes, their salt-tolerance possesses a high genetic complexity. There are many morphological and physiological studies on halophytes but very little information is at molecular level why they are salt-tolerant. Limonium sinense is a salt-secreting halophyte and can excretes salts by multi-cellular glands. Here, we report the library construction and sequence analysis of a cDNA library made from leaf tissue of L. sinenes. Among those 1082 expressed sequence tag (EST) obtained, 684 unique genes were identified: 429 showed homology to previously identified genes, 255 matched to uncharacterized genes. Compared with other EST databases, some characteristic features such as abundance genes in related to cytoskeleton and intracellular traffic, membrane transporting were observed, which may be specific to halophytes.

[Anti-tumor effect of ethanol extracts from Thymus quinquecostatus Celak on human leukemia cell line].

OBJECTIVE: To screen the anti-tumor fraction of ethanol extracts from Thymus quinquecostatus Celak and investigate its anti-tumor effect on human leukemia cell line. METHODS: Ethyl acetate, n-butanol and acetone fractions were separated from the ethanol extracts of wild Thymus quinquecostatus Celak. Growth inhibiting effects of these extracts on human leukemia cell lines K562 and HL-60 were determined by live cell counting and cell growth curve analysis. The possible anti-tumor mechanism was studied by morphological analysis with norcantharidin as a positive control. RESULTS: Ethyl acetate fraction could significantly inhibit the proliferations of K562 and HL-60 cells, and the inhibiting effect depended on the concentration of ethyl acetate fraction. Ethyl acetate fraction could induce apoptosis of K562 and HL-60 cells. The n-butanol and acetone fractions had no significant inhibiting effect on K562 and HL-60 cells. CONCLUSION: Ethyl acetate fraction is the major anti-tumor fraction in ethanol extracts from Thymus quinquecostatus Celak.

Association of genetic polymorphism in GH gene with milk production traits in Beijing Holstein cows.

Associations were analysed between polymorphisms of the growth hormone gene (GH-MspI) (localized in intron 3) and milk production traits of Beijing Holstein cows (a total of 543 cows). Polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method was used for identification of various genotypes. Frequencies of genotypes were 0.77, 0.21 and 0.02 for A/A, A/B and B/B, respectively. The frequency of the GH A allele is 0.875. The results of the least squares means show that in all three lactations, the GH A/A cows yielded more milk (P less than 0.01 for lactation I and P less than 0.05 for lactations II and III), whereas A/B cows showed higher milk fat content than A/A individuals (P less than 0.05 for lactations I and II, and P less than 0.01 for lactation III). The A/A cows yielded more fat than A/B individuals (P less than 0.01 only in lactation I). The A/A cows yielded more milk protein than A/B individuals (P less than 0.01 for lactations I, II, and III). The A/A cows produced milk of higher protein content than of A/B individuals (P less than 0.05 only in lactation II).

[Original studies on anti-tumor and immunological effect of extracts from Thymus quinquecostatus Celak in mice].

OBJECTIVE: To study the anti-tumor and immunological effect of extracts from Thymus quinquecostatus Celak on mice transplanted S180 tumor cells. METHODS: Different doses of volatile oil and alcohol extracted substances from Thymus quinquecostatus Celak were given to mice bearing S180 tumor for 9 days. Tumor inhibition rates and coefficients of spleen and thymus were determined. RESULTS: Tumor inhibition rates of the groups with alcohol extracts (40 g crude drug.kg(-1).d(-1) and 20 g crude drug.kg(-1).d(-1)) were 51.5% (P<0.01) and 36.4% (P<0.05) respectively, and those of the groups with volatile oil (40 g crude drug.kg(-1).d(-1) and 20 g crude drug.kg(-1).d(-1))were both 39.4% (P<0.05). CONCLUSION: The extracts from Thymus quinquecostatus Celak have anti-tumor activities. The coefficient of spleen in group with alcohol extracts (40 g crude drug.kg(-1).d(-1))was close to normal value, and its coefficient of thymus was between that of the negative control group and the group with cyclophosphamide (0.02 g.kg(-1).d(-1)). The anti-tumor activity of the alcohol extracts was significantly higher than that of the control group and the tumor inhibition rate was depending on drug concentration. Depending on index of immunity,the extracts from Thymus quinquecostatus Celak may have some influences on immunity.