No abstract

Heterosis or hybrid vigor is extensively used in plant breeding. However, the contribution of metabolites to heterosis is still elusive. Here, we systematically identified the non-volatile and volatile metabolites of two hybrids and their parents in Camellia sinensis. The metabolomics analysis showed prevalent non-additive accumulation in hybrids, among which the non-additive nucleotides, alkaloids, organic acids, and tannins contribute to the positive heterosis of hybrids, including typical inosine, guanosine, adenosine, caffeine, succinic acid, adipic acid, xylonic acid, and gallic acid. The catechins and free amino acids in hybrids showed negative heterosis compared to its maternal cultivar TGY. Furthermore, the significant accumulation of non-additive terpenes combined with the mild heterosis of other types of volatiles contributes to the aroma of tea plant hybrids. The genetics of volatiles from different parents affect the aroma of hybrids processed into oolong tea. The comprehensive heterosis of these non-additive metabolites may play an important role in the formation of desirable breeding traits for hybrids. Our results provide insights into the utilization of heterosis breeding and the regulation of heterosis metabolites in tea plants.

SUMMARY Heterosis is extensively used to improve crop productivity, yet its allelic and chromatin regulation remains unclear. Based on our resolved genomes of the maternal TGY and paternal HD, we analyzed the contribution of allele‐specific expression (ASE) and chromatin accessibility of JGY and HGY, the artificial hybrids of oolong tea with the largest cultivated area in China. The ASE genes (ASEGs) of tea hybrids with maternal‐biased were mainly related to the energy and terpenoid metabolism pathways, whereas the ASEGs with paternal‐biased tend to be enriched in glutathione metabolism, and these parental bias of hybrids may coordinate and lead to the acquisition of heterosis in more biological pathways. ATAC‐seq results showed that hybrids have significantly higher accessible chromatin regions (ACRs) compared with their parents, which may confer broader and stronger transcriptional activity of genes in hybrids. The number of ACRs with significantly increased accessibility in hybrids was much greater than decreased, and the associated alleles were also affected by differential ACRs across different parents, suggesting enhanced positive chromatin regulation and potential genetic effects in hybrids. Core ASEGs of terpene and purine alkaloid metabolism pathways with significant positive heterosis have greater chromatin accessibility in hybrids, and were potentially regulated by several members of the MYB, DOF and TRB families. The binding motif of CsMYB85 in the promoter ACR of the rate‐limiting enzyme CsDXS was verified by DAP‐seq. These results suggest that higher numbers and more accessible ACRs in hybrids contribute to the regulation of ASEGs, thereby affecting the formation of heterotic metabolites.

Aim. e aims of this study were to compare the short-term outcomes of natural orifice specimen extraction surgery (NOSES) and conventional laparoscopic surgery (CLAPS) for colorectal tumours and to evaluate the safety and feasibility of NOSES in colorectal resection. Methods. A literature review was performed on the PubMed, Cochrane Library, and Embase databases up to March 2019. Papers conforming to the inclusion criteria were used for further analysis. e short-term outcomes included intraoperative outcomes and postoperative recovery results. e weighted mean difference (WMD) was calculated for continuous outcomes and odds ratio (OR) for dichotomous results. Study quality was evaluated using the Newcastle-Ottawa Quality Assessment Scale (NOS) or the 6-item Jadad scale. Results. Eight studies comprising 686 patients met the inclusion criteria. Compared with CLAPS, NOSES had more advantages in terms of postoperative complications, postoperative pain, recovery of gastrointestinal function, duration of hospital stay, and cosmetic results. e lymph nodes harvested and intraoperative blood loss in NOSES were comparable with CLAPS; however, a prolonged operative time was observed in NOSES. Conclusions. NOSES was shown to be a safe and viable alternative to CLAPS in colorectal oncology in terms of short-term results. Further long-term and randomized trials are required.

The CA-TAMIS-GP is a new method that is safe and effective in patients with early rectal tumor and appears to have a shorter operation time and less blood loss as compared with ESD.