Transcriptome Dynamics during Spike Differentiation of Wheat Reveal Amazing Changes in Cell Wall Metabolic Regulators.

Coordinated cell proliferation and differentiation result in the complex structure of the inflorescence in wheat. It exhibits unique differentiation patterns and structural changes at different stages, which have attracted the attention of botanists studying the dynamic regulation of its genes. Our research aims to understand the molecular mechanisms underlying the regulation of spike development genes at different growth stages. We conducted RNA-Seq and qRT-PCR evaluations on spikes at three stages. Our findings revealed that genes associated with the cell wall and carbohydrate metabolism showed high expression levels between any two stages throughout the entire process, suggesting their regulatory role in early spike development. Furthermore, through transgenic experiments, we elucidated the role of the cell wall regulator gene in spike development regulation. These research results contribute to identifying essential genes associated with the morphology and development of wheat spike tissue.

Effect of chlorophyll biosynthesis-related genes on the leaf color in Hosta (Hosta plantaginea Aschers) and tobacco (Nicotiana tabacum L.).

BACKGROUND: 'Regal Splendour' (Hosta variety) is famous for its multi-color leaves, which are useful resources for exploring chloroplast development and color changes. The expressions of chlorophyll biosynthesis-related genes (HrHEMA, HrPOR and HrCAO) in Hosta have been demonstrated to be associated with leaf color. Herein, we isolated, sequenced, and analyzed HrHEMA, HrPOR and HrCAO genes. Subcellular localization was also performed to determine the location of the corresponding enzymes. After plasmid construction, virus-induced gene silencing (VIGS) was carried out to reduce the expressions of those genes. In addition, HrHEMA-, HrPOR- and HrCAO-overexpressing tobacco plants were made to verify the genes function. Changes of transgenic tobacco were recorded under 2000 lx, 6000 lx and 10,000 lx light intensity. Additionally, the contents of enzyme 5-aminolevulinic acid (5-ALA), porphobilinogen (PBG), chlorophyll a and b (Chla and Chlb), carotenoid (Cxc), superoxide dismutase (SOD), peroxidase (POD), malondialdehyde (MDA), proline (Pro) and catalase (CAT) under different light intensities were evaluated. RESULTS: The silencing of HrHEMA, HrPOR and HrCAO genes can induce leaf yellowing and chloroplast structure changes in Hosta. Specifically, leaves of Hosta with HrCAO silencing were the most affected, while those with HrPOR silencing were the least affected. Moreover, all three genes in tobacco were highly expressed, whereas no expression was detected in wild-type (WT). However, the sensitivities of the three genes to different light intensities were different. The highest expression level of HrHEMA and HrPOR was detected under 10,000 lx of illumination, while HrCAO showed the highest expression level under 6000 lx. Lastly, the 5-ALA, Chla, Cxc, SOD, POD, MDA, Pro and CAT contents in different transgenic tobaccos changed significantly under different light intensities. CONCLUSION: The overexpression of these three genes in tobacco enhanced photosynthesis by accumulating chlorophyll content, but the influential level varied under different light intensities. Furthermore, HrHEMA-, HrPOR- and HrCAO- overexpressing in tobacco can enhance the antioxidant capacity of plants to cope with stress under higher light intensity. However, under lower light intensity, the antioxidant capacity was declined in HrHEMA-, HrPOR- and HrCAO- overexpressing tobaccos.

Spermine Regulates Water Balance Associated with Ca2+-Dependent Aquaporin (TrTIP2-1, TrTIP2-2 and TrPIP2-7) Expression in Plants under Water Stress.

Spermine (Spm) regulates water balance involved in water channel proteins, aquaporins (AQPs), in plants. An increase in endogenous Spm content via exogenous Spm application significantly improved cell membrane stability, photosynthesis, osmotic adjustment (OA) and water use efficiency (WUE) contributing to enhanced tolerance to water stress in white clover. Spm upregulated TrTIP2-1, TrTIP2-2 and TrPIP2-7 expressions and also increased the abundance of TIP2 and PIP2-7 proteins in white clover under water stress. Spm quickly activated intracellular Ca2+ signaling and Spm-induced TrTIP2-2 and TrPIP2-7 expressions could be blocked by Ca2+ channel blockers and the inhibitor of Ca2+-dependent protein kinase in leaves of white clover. TrSAMS in relation to Spm biosynthesis was first cloned from white clover and the TrSAMS was located in the nucleus. Transgenic Arabidopsis overexpressing the TrSAMS had significantly higher endogenous Spm content and improved cell membrane stability, photosynthesis, OA, WUE and transcript levels of AtSIP1-1, AtSIP1-2, AtTIP2-1, AtTIP2-2, AtPIP1-2, AtPIP2-1 and AtNIP2-1 than wild type in response to water stress. Current findings indicate that Spm regulates water balance via an enhancement in OA, WUE and water transport related to Ca2+-dependent AQP expression in plants under water stress.

Bombyx mori cyclin-dependent kinase inhibitor is involved in regulation of the silkworm cell cycle.

Cyclin-dependent kinase inhibitors (CKIs) are negative regulators of the cell cycle. They can bind to cyclin-dependent kinase (CDK)-cyclin complexes and inhibit CDK activities. We identified a single homologous gene of the CDK interacting protein/kinase inhibitory protein (Cip/Kip) family, BmCKI, in the silkworm, Bombyx mori. The gene transcribes two splice variants: a 654-bp-long BmCKI-L (the longer splice variant) encoding a protein with 217 amino acids and a 579-bp-long BmCKI-S (the shorter splice variant) encoding a protein with 192 amino acids. BmCKI-L and BmCKI-S contain the Cip/Kip family conserved cyclin-binding domain and the CDK-binding domain. They are localized in the nucleus and have an unconventional bipartite nuclear localization signal at amino acid residues 181-210. Overexpression of BmCKI-L or BmCKI-S affected cell cycle progression; the cell cycle was arrested in the first gap phase of cell cycle (G1). RNA interference of BmCKI-L or BmCKI-S led to cells accumulating in the second gap phase and the mitotic phase of cell cycle (G2/M). Both BmCKI-L and BmCKI-S are involved in cell cycle regulation and probably have similar effects. The transgenic silkworm with BmCKI-L overexpression (BmCKI-L-OE), exhibited embryonic lethal, larva developmental retardation and lethal phenotypes. These results suggest that BmCKI-L might regulate the growth and development of silkworm. These findings clarify the function of CKIs and increase our understanding of cell cycle regulation in the silkworm.

In vivo RNA interference of BmNHR96 enhances the resistance of transgenic silkworm to BmNPV.

We previously identified a nuclear hormone receptor gene, BmNHR96, which promotes Bombyx mori nucleopolyhedrovirus (BmNPV) entry into silkworm cells. In an attempt to create an antiviral silkworm strain for better silk production, we used RNAi to downregulate BmNHR96 in silkworm larvae. We screened the resulting BmNHR96-RNAi silkworm strain (NHR) and also explored the antiviral mechanism in vivo. We found that the survival rate of the NHR strain was higher than that of the Dazao strain, when silkworm larvae were infected with BmNPV via oral ODV infection and BV injection. More importantly, the economic characteristics (silk yield) of the transgenic line remained unchanged. These findings reveal that RNAi of BmNHR96 could be an effective way to enhance the tolerance of B. mori to BmNPV infection.

Transgenic RNAi of BmREEPa in silkworms can enhance the resistance of silkworm to Bombyxmori Nucleopolyhedrovirus.

Our previous study has identified a gene, BmREEPa, which affects BmNPV invasion in silkworm cells. In this study, we interfered with BmREEPa in silkworm larvae through transgenic technology and screened BmREEPa-RNAi silkworm strains (RP). We found the mortality in RP was lower than that in Dazao, when silkworm larvae were infected with BmNPV via oral and injection routes. And the expression level of VP39 was lower in RP than in Dazao in the group infected via injection. In the oral infection group, VP39 expression level showed significant reduction at 48 h post-infection. These results revealed that the anti-BmNPV activity was enhanced in RP, and this enhancement probably presents itself during secondary infection via BVs.

[Gene chip analysis of differentially expressed genes in transgenic SlNAC1 Arabidopsis].

Studies have shown that some plant-specific NAC (NAM, ATAF1/2, CUC2) transcription factors may increase plants resistance to stress. We screened the genes differentially expressed in transgenic SlNAC1 Arabidopsis compared to the wild type by cDNA microarry, to provide scientific basis for studying the genes related to abiotic stress responses in transgenic Arabidopsis. There were 3 046 genes differentially expressed more than twice in the total 43 604 genes of transgenic SlNAC1 Arabidopsis. Gene ontology analysis was used on genes differentially expressed more than five-fold. Genes relevant to cellular components occupied 33.05%, genes correlated with molecular function accounted for 33.95% and genes pertinent to biological process constituted a 33.00% portion. The genes differentially expressed more than twice were processed through kyoto encyclopedia of genes and genomes pathways enrichment (KEGG) analysis. The total 2 431 genes were involved in 88 different signaling pathways. The screened genes related to abiotic stress responses provide direction and theoretical support for the following research on the downstream genes regulated by NAC and construction of the regulatory networks.

Establishment of a miR?31 transgenic mouse and its expression in tissues and organs / 中国实验动物学报

Objective To establish a stably overexpressing miR-31 transgenic mouse and detect the expression of miR-31 in the organs and tissues,and to provide qualified tool mice with overexpression of miR-31 in vivo. Methods The miR-31 overexpression vector was constructed by Gateway cloning technology. The vector was injected into fertilized ovum by DNA microinjection technology,then transferred to the pseudopregnant mice and waited for eutocia. Newborn mouse tail DNA was extracted and PCR and agarose gel electrophoresis were performed to identify the positive miR-31 transgenic mice. microRNA was extracted from the organs and tissues of miR-31 transgenic mice and the expression of miR-31 was de-tected by RT-PCR. The expression of Nestin and number of neural stem cells in the nervous system were compared in the positive and WT mice. Results The miR-31 transgenic mice were constructed successfully and bred more than 14 genera-tions in barrier environment. Expression of miR-31 was increased in major organs and tissues. The expression of Nestin and the number of neural stem cells in the positive mice were higher than those in the wild type mice. Conclusions MiR-31 overexpressing transgenic mice are constructed by Gateway cloning technology and the expression of miR-31 is stable in sub-sequent generations. The number of neural stem cells in the nervous system is higher than that in wild-type mice. The miR-31 overexpressing transgenic mice can be a good tool for experimental research of the function of overexpressed miR-31 in vivo and the treatment of nervous system diseases.

Gene chip analysis of differentially expressed genes in transgenic SlNAC1 Arabidopsis / 生物工程学报

Studies have shown that some plant-specific NAC (NAM, ATAF1/2, CUC2) transcription factors may increase plants resistance to stress. We screened the genes differentially expressed in transgenic SlNAC1 Arabidopsis compared to the wild type by cDNA microarry, to provide scientific basis for studying the genes related to abiotic stress responses in transgenic Arabidopsis. There were 3 046 genes differentially expressed more than twice in the total 43 604 genes of transgenic SlNAC1 Arabidopsis. Gene ontology analysis was used on genes differentially expressed more than five-fold. Genes relevant to cellular components occupied 33.05%, genes correlated with molecular function accounted for 33.95% and genes pertinent to biological process constituted a 33.00% portion. The genes differentially expressed more than twice were processed through kyoto encyclopedia of genes and genomes pathways enrichment (KEGG) analysis. The total 2 431 genes were involved in 88 different signaling pathways. The screened genes related to abiotic stress responses provide direction and theoretical support for the following research on the downstream genes regulated by NAC and construction of the regulatory networks.