Transcriptome analysis of Gossypium hirsutum cultivar Zhongzhimian No.2 uncovers the gene regulatory networks involved in defense against Verticillium dahliae.

BACKGROUND: Cotton is globally important crop. Verticillium wilt (VW), caused by Verticillium dahliae, is the most destructive disease in cotton, reducing yield and fiber quality by over 50% of cotton acreage. Breeding resistant cotton cultivars has proven to be an efficient strategy for improving the resistance of cotton to V. dahliae. However, the lack of understanding of the genetic basis of VW resistance may hinder the progress in deploying elite cultivars with proven resistance. RESULTS: We planted the VW-resistant Gossypium hirsutum cultivar Zhongzhimian No.2 (ZZM2) in an artificial greenhouse and disease nursery. ZZM2 cotton was subsequently subjected to transcriptome sequencing after Vd991 inoculation (6, 12, 24, 48, and 72 h post-inoculation). Several differentially expressed genes (DEGs) were identified in response to V. dahliae infection, mainly involved in resistance processes, such as flavonoid and terpenoid quinone biosynthesis, plant hormone signaling, MAPK signaling, phenylpropanoid biosynthesis, and pyruvate metabolism. Compared to the susceptible cultivar Junmian No.1 (J1), oxidoreductase activity and reactive oxygen species (ROS) production were significantly increased in ZZM2. Furthermore, gene silencing of cytochrome c oxidase subunit 1 (COX1), which is involved in the oxidation-reduction process in ZZM2, compromised its resistance to V. dahliae, suggesting that COX1 contributes to VW resistance in ZZM2. CONCLUSIONS: Our data demonstrate that the G. hirsutum cultivar ZZM2 responds to V. dahliae inoculation through resistance-related processes, especially the oxidation-reduction process. This enhances our understanding of the mechanisms regulating the ZZM2 defense against VW.

Transcriptome Analysis of a Cotton Cultivar Provides Insights into the Differentially Expressed Genes Underlying Heightened Resistance to the Devastating Verticillium Wilt.

Cotton is an important economic crop worldwide. Verticillium wilt (VW) caused by Verticillium dahliae (V. dahliae) is a serious disease in cotton, resulting in massive yield losses and decline of fiber quality. Breeding resistant cotton cultivars is an efficient but elaborate method to improve the resistance of cotton against V. dahliae infection. However, the functional mechanism of several excellent VW resistant cotton cultivars is poorly understood at present. In our current study, we carried out RNA-seq to discover the differentially expressed genes (DEGs) in the roots of susceptible cotton Gossypium hirsutum cultivar Junmian 1 (J1) and resistant cotton G.hirsutum cultivar Liaomian 38 (L38) upon Vd991 inoculation at two time points compared with the mock inoculated control plants. The potential function of DEGs uniquely expressed in J1 and L38 was also analyzed by GO enrichment and KEGG pathway associations. Most DEGs were assigned to resistance-related functions. In addition, resistance gene analogues (RGAs) were identified and analyzed for their role in the heightened resistance of the L38 cultivar against the devastating Vd991. In summary, we analyzed the regulatory network of genes in the resistant cotton cultivar L38 during V. dahliae infection, providing a novel and comprehensive insight into VW resistance in cotton.

Effect of microRNA-101 on apoptosis of rabbit condylar cartilage cells by inhibiting target gene SOX9.

OBJECTIVE: To explore the effect of microRNA-101 on apoptosis of condylar cartilage cells and the specific mechanism of molecular biology. METHODS: IL-1 was used to stimulate and establish the model of apoptosis of condylar cartilage cells. The expression change of miR-101 in control group was compared with that in IL-1 stimulation group by qRT-PCR. Overexpression and down-regulation models of miR-101 were established by transfecting Mimics and Inhibitor and verified by qRT-PCR. Flow cytometry was used to detect the effect of miR-101 overexpression and down-regulation on apoptosis. Target gene of miR-101 was analyzed and calculated through bioinformatics. Western blot and Luciferase report assay were used to detect whether SOX9 could become the target gene of miR-101. RESULTS: qRT-PCR results showed that IL-1 stimulation could cause the increase of miR-101 expression. After the transfection of rabbit condylar cartilage cells by Mimics and Inhibitor, qRT-PCR results confirmed the significant effect of miR-101 overexpression and down-regulation. It was confirmed by flow cytometry that overexpression of miR-101 could promote the apoptosis of condylar cartilage cells, and down-regulation of miR-101 could reduce the apoptosis. It was confirmed by Western blot and Luciferase report assay that SOX9 was the target gene of miR-101, and miR-101 inhibited SOX9 expression through complementary pairing with 3'UTR of SOX9 mRNA. CONCLUSIONS: miR-101 can promote the apoptosis of condylar cartilage cells through inhibiting the protein level of target gene SOX9.

[Effects of nitrogen fertilization rate and planting density on cotton boll biomass and nitrogen accumulation in extremely early maturing cotton region of Northeast China].

Taking cotton cultivars Liaomian 19 and NuCoTN 33B as test materials, a field experiment was conducted to study the effects of nitrogen fertilization rate (0, 240 and 480 kg x hm(-2)) and planting density (75000, 97500 and 120000 plants x hm(-2)) on the boll biomass and nitrogen accumulation in the extremely early maturing cotton region of Northeast China. With the growth and development of cotton, the biomass and nitrogen accumulation of cotton boll, cotton seed, and cotton fiber varied in 'S' shape. Both nitrogen fertilization rate and planting density had significant effects on the dynamic characteristics of boll biomass and nitrogen accumulation, and on the fiber yield and quality. In treatment 240 kg x hm(-2) and 97500 plants x hm(-2), the biomass of single boll, cotton seed and cotton fiber was the maximum, the starting time and ending time of the rapid accumulation period of the biomass and nitrogen were earlier but the duration of the accumulation was shorter, the rapid accumulation speed of the biomass was the maximum, and the distribution indices of the biomass and nitrogen were the lowest in boll shell but the highest in cotton seed and cotton fiber.

Cloning and expression analysis of a long type peptidoglycan recognition protein (PGRP-L) from Xenopus tropicalis.

Peptidoglycan recognition proteins (PGRPs) are a family of pattern recognition receptors (PRRs) of the immune system, which bind and hydrolyze bacterial peptidoglycan. Here, a long type PGRP (PGRP-L) was first cloned in the lower vertebrate species Xenopus tropicalis (Xt). The XtPGRP-L possessed a conserved genomic structure with five exons and four introns. The alignment and phylogenetic analysis indicated that XtPGRP-L might be a type of amidase-like PGRP. The 3-D model showed that XtPGRP-L possessed a conserved structure compared with the Drosophila PGRP-Lb. During embryonic development, XtPGRP-L was not expressed until the 72 h tadpole stage. In adult tissues, it was strongly expressed in the liver, lung, intestine, and stomach. Furthermore, after LPS stimulation, the expression of XtPGRP-L was up-regulated significantly in the liver, intestine and spleen, indicating that XtPGRP-L may play an important role in the innate immunity of Xenopus tropicalis.

[Effects of nitrogen fertilization rate and planting density on cotton biomass and nitrogen accumulation in extremely early mature cotton region of Northeast China].

Taking two cotton cultivars Liaomian 19 and NuCOTN 33B with different growth periods as test materials, a field experiment was conducted to study the effects of different nitrogen fertilization rates (0, 240 and 480 kg N x hm(-2)) and different planting densities (75000, 97500 and 120000 plants x hm(-2)) on the cotton biomass, nitrogen accumulation, and accumulative nitrogen utilization in the planting region of extremely early mature cotton in Northeast China. The dynamics of cotton biomass and nitrogen accumulation of the two cultivars with their growth process followed Logistic model. Both nitrogen fertilization rate and planting density had significant effects on the cotton nitrogen accumulation dynamics and the cotton yield and quality. In all treatments, the beginning time of rapid accumulation of nitrogen was about 13 d earlier than that of biomass. In treatment plant density 97500 plants x hm(-2) and nitrogen fertilization rate 240 kg x hm(-2), the eigenvalues of the dynamic accumulation models of nitrogen and biomass for the two cultivars were most harmonious, lint yield was the highest, fiber quality was the best, and accumulative nitrogen utilization efficiency was the highest. In the study region, the earlier beginning time of rapid accumulation of nitrogen and biomass and their higher accumulation rates were benefit to the formation of higher cotton yield.

Cloning of hemoglobin-α1 from half-smooth tongue sole (Cynoglossus semilaevis) and its expression under short-term hypoxia.

This study cloned the hemoglobin α1 from the marine teleost, the half-smooth tongue sole (Cynoglossus semilaevis), and then examined its expression under hypoxia exposure. The full-length of CsHb-α1 (594 bp) cDNA contains an open reading frame encoding 144 amino acids. Sequence analysis shows that the predicted CsHb-α1 amino acids shares high identities with that of other species. Real-time PCR showed that CsHb-α1 was highly expressed in the heart, liver, spleen, kidney and blood. Five to 120 min esposure and long-term (36 h) exposure to hypoxia (1.0 mg/L) significantly increased CsHb-α1 mRNA expression in most tissues compared to those fish held in normoxic conditions (dissolved oxygen (DO): 6.2 mg/L). These results suggested that the up-regulation of Hb-α1 is an important component for adaptation of half-smooth tongue sole to short-term hypoxia.