Autotetraploid rice: challenges and opportunities.

Autotetraploid rice is a type of germplasm developed from the whole genome duplication of diploid rice, leading to large grains, high nutrient content, and resistance. However, its low fertility has reduced yield and hampered commercialization. To address this issue, a new type of high fertility tetraploid rice was developed, which may serve as a useful germplasm for polyploid rice breeding. In this review, we summarize the progress made in understanding the cellular and molecular genetic mechanisms underlying the low fertility of autotetraploid rice and its F1 hybrid, as well as the main types of new tetraploid rice with high fertility. Lastly, the idea of utilizing the multi-generation heterosis of neo-tetraploid rice in the future is proposed as a reference for polyploid rice breeding.

Transcriptomic analysis reveals innate immune mechanisms of an underlying parasite-resistant grouper hybrid (Epinephelus fuscogutatus × Epinephelus lanceolatus).

Hybridization is an artificial breeding strategy for generating potentially desirable offspring. Recently, a novel Hulong grouper hybrid (Epinephelus fuscogutatus × Epinephelus lanceolatus) yielded significant growth superiority over its parent. Improved innate immunity is considered as another desirable feature during hybridization. However, whether this Hulong grouper achieved disease resistance has not yet been revealed. In this study, we first examine the infection intensity of C. irritans in the Hulong grouper, and found that the Hulong grouper is less susceptible to C. irritans primary infection. A higher immobilization titer was found in the infected Hulong grouper at Day 2 when compared with the control grouper. Furthermore, severe hyperplasia was observed in the orange-spotted grouper, but not in the Hulong grouper's skin epidermis. To further understand the innate immune mechanism against C. irritans, we conducted a comparative transcriptome analysis of the Hulong grouper during the infection. There are 6464 differentially expressed genes (DEGs) identified in the skin between the control and infected Hulong grouper. This indicates that the innate immune components, such as the complement system, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, Interleukin 17 (IL-17) signaling pathway, and Toll-like receptor (TLR) signaling pathway were up-regulated during the infection. These results show that the C. irritans infection can induce a remarkable inflammatory response in the Hulong grouper. Moreover, a total of 75 pairs of orthologs with the ratio of nonsynonymous (Ka) to synonymous (Ks) substitutions ＞1, considered rapidly evolving genes (REGs), was identified between the Hulong and orange-spotted grouper. More critically, most REGs were enriched in the immune system, suggesting that rapid evolution of the immune system might occur in the Hulong grouper. These results provide a more comprehensive understanding of the innate immunity mechanism of the hybrid Hulong grouper.

Causal relationship between gut microbiota and puerperal sepsis: a 2-sample Mendelian randomization study.

Background: Some recent observational studies have shown that gut microbiota composition is associated with puerperal sepsis (PS) and no causal effect have been attributed to this. The aim of this study was to determine a causal association between gut microbiota and PS by using a two-sample Mendelian randomization (MR) analysis. Methods: This study performed MR analysis on the publicly accessible genome-wide association study (GWAS) summary level data in order to explore the causal effects between gut microbiota and PS. Gut microbiota GWAS (n = 18,340) were obtained from the MiBioGen study and GWAS-summary-level data for PS were obtained from the UK Biobank (PS, 3,940 cases; controls, 202,267 cases). Identification of single nucleotide polymorphisms associated with each feature were identified based on a significance threshold of p < 1.0 × 10-5. The inverse variance weighted (IVW) parameter was used as the primary method for MR and it was supplemented by other methods. Additionally, a set of sensitivity analytical methods, including the MR-Egger intercept, Mendelian randomized polymorphism residual and outlier, Cochran's Q and the leave-one-out tests were carried out to assess the robustness of our findings. Results: Our study found 3 species of gut microbiota, Lachnospiraceae FCS020, Lachnospiraceae NK4A136, and Ruminococcaceae NK4A214, to be associated with PS. The IVW method indicated an approximately 19% decreased risk of PS per standard deviation increase with Lachnospiraceae FCS020 (OR = 0.81; 95% CI 0.66-1.00, p = 0.047). A similar trend was also found with Lachnospiraceae NK4A136 (OR = 0.80; 95% CI 0.66-0.97, p = 0.024). However, Ruminococcaceae NK4A214 was positively associated with the risk of PS (OR = 1.33, 95% CI: 1.07-1.67, p = 0.011). Conclusion: This two-sample MR study firstly found suggestive evidence of beneficial and detrimental causal associations of gut microbiota on the risk of PS. This may provide valuable insights into the pathogenesis of microbiota-mediated PS and potential strategies for its prevention and treatment.

[Field investigation on ecological effect of windbreak and soil erosion reduction from sandy grasslands].

Through field observation of the variation of vegetational characteristics and sand transported rate in sandy grasslands at different levels of desertification during the spring erosive period, the ecological effects of windbreak and soil erosion reduction from sandy grasslands of the Horqin Sandy Land were studied. The results showed that vegetational coverage varied obviously from 0.3% in the shifting sand land of the severe desertification to 16% in the fixed sand land of the least desertification in mid May. Increases in vegetational coverage led to a corresponding increase in surface roughness length from 0.013 cm in the shifting sand land to 0.111 cm in the fixed sand land, thus resulting in an increase in friction velocity from 0.272 m.s-1 in the shifting sand land to 0.823 m.s-1 in the fixed sand land and a decrease in mean wind speed near the surfaces from 7.0 m.s-1 in the shifting sand land to 3.8 m.s-1 in the fixed sand land. This in turn led to a reduction in the total sand transported rate within the height of 0-20 cm from 88.8 g.(h.cm2)-1 in the shifting sand land to 1.6 g.(h.cm2)-1 in the fixed sand land. When the experimental data were analyzed by regressing the total sand transported rate (Q) against vegetational coverage (VC), a model of predictive regression was developed: Q = 3.93 + 93.66e-0.60VC(R2 = 0.893, p < 0.0001, n = 40).