Comparative population genomics dissects the genetic basis of seven domestication traits in jujube

Jujube(Ziziphus jujuba Mill.)is an important perennial fruit tree with a range of interesting horticultural traits.It was domesticated from wild jujube(Ziziphus acidojujuba),but the genomic variation dynamics and genetic changes underlying its horticultural traits during domestication are poorly understood.Here,we report a comprehensive genome variation map based on the resequencing of 350 accessions,including wild,semi-wild and cultivated jujube plants,at a>15×depth.Using the combination of a genome-wide association study(GWAS)and selective sweep analysis,we identified several candidate genes potentially involved in regulating seven domestication traits in jujube.For fruit shape and kernel shape,we integrated the GWAS approach with transcriptome profiling data,expression analysis and the transgenic validation of a candidate gene to identify a causal gene,ZjFS3,which encodes an ethyleneresponsive transcription factor.Similarly,we identified a candidate gene for bearing-shoot length and the number of leaves per bearing shoot and two candidate genes for the seed-setting rate using GWAS.In the selective sweep analysis,we also discovered several putative genes for the presence of prickles on bearing shoots and the postharvest shelf life of fleshy fruits.This study outlines the genetic basis of jujube domestication and evolution and provides a rich genomic resource for mining other horticulturally important genes in jujube.

The mitochondria-localized protein OsNDB2 negatively regulates grain size and weight in rice

Grain size is a determinant of rice grain yield.In plants,mitochondria supply energy for cellular metabolism via the mitochondrial electron transport chain.Here we report that OsNDB2,which encodes a putative rotenone-insensitive typeⅡNAD(P)H dehydrogenase(ND),negatively regulates grain size and weight in rice.Six ND members representing three major types of rice were identified,and the predicted OsNDB2 protein was localized to mitochondria.Contents of OsNDB2 transcripts were higher in young panicles and leaf blades.OsNDB2 overexpression reduced grain length,grain width,and 1000-grain weight and moderately influenced plant height,while knockout of OsNDB2 increased grain size and 1000-grain weight.Allelic mutations of OsNDB2 were associated with diverse grain appearances.Cellular observations revealed that variations in grain size of transgenic lines were caused by change in cell expansion but not cell proliferation in spikelet hulls.Our study sheds light on OsNDB2 function and provides a new potential breeding approach for increasing rice grain size and weight.

Filamentation initiated by Cas2 and its association with the acquisition process in cells

Cas1-and-Cas2-mediated new spacer acquisition is an essential process for bacterial adaptive immunity.The process is critical for the ecology of the oral microflora and oral health.Although molecular mechanisms for spacer acquisition are known,it has never been established if this process is associated with the morphological changes of bacteria.In this study,we demonstrated a novel Cas2-induced filamentation phenotype in E.coli that was regulated by co-expression of the Cas1 protein.A 30 amino acid motif at the carboxyl terminus of Cas2 is necessary for this function.By imaging analysis,we provided evidence to argue that Cas-induced filamentation is a step coupled with new spacer acquisition during which filaments are characterised by polyploidy with asymmetric cell division.This work may open new opportunities to investigate the adaptive immune response and microbial balance for oral health.

A stable and efficient La-doped MIL-53(Al)/ZnO photocatalyst for sulfamethazine degradation

Photocatalytic technology can solve various environmental pollution problems,especially antibiotic pollution.A novel La-doped MIL-53(Al)/ZnO composite material was successfully synthesized by a combination of hydrothermal method and calcination,showing high photocatalytic degradation percent of sulfamethazine(SMT).The 2 mol%La MIL-53(Al)/ZnO photocatalyst shows the highest degradation efficiency toward SMT(92%)within 120 min,which is 4.1 times higher than pure ZnO(increased from 18%to 92%).In addition,the degradation analysis of SMT by high performance liquid chromatography proves that the products are CO_(2) and H_(2)O.The improved photocatalytic activity is mostly caused by the following factors.(1)Doping La ions can decrease the band gap of ZnO,enhance light response,and effectively enhance the separation rate of photo-generated holes and electrons.(2)MIL-53(Al)can adsorb SMT and promote the separation of electron.This work shows that the synthesized La-doped MIL-53(Al)/ZnO photocatalyst is expected to be used as a green and effective method for treatment of environment water pollution.

Stabilization of switched linear systems under asynchronous switching subject to admissible edge-dependent average dwell time

The problem of stabilizing switched linear systems under asynchronous switching is addressed.The admissible edge-dependent average dwell time method is applied to design a switching signal that comprises slow admissible edge-dependent average dwell time and fast admissible edge-dependent average dwell time.Under this switching signal,the restriction that the maximum delay of asynchronous switching is known in advance is removed.The constructed Lyapunov function is associated with both the system mode and controller mode.The stabilization criteria and the corresponding algorithm are presented to obtain the controller gains and to design the switching signal.Finally,two examples are given to demonstrate the effectiveness of the proposed results.