GABA Enhances Thermotolerance of Seeds Germination by Attenuating the ROS Damage in Arabidopsis

Seeds germination is strictly controlled by environment factor such as high temperature(HT)through altering the balance between gibberellin acid(GA)and abscisic acid(ABA).Gama-aminobutyric acid(GABA)is a small molecule with four-carbon amino acid,which plays a crucial role during plant physiological process associated with pollination,wounding or abiotic stress,but its role in seeds germination under HT remains elusive.In this study we found that HT induced the overaccumulation of ROS,mainly H_(2)O_(2) and O_(2)^(-),to suppress seeds germination,meanwhile,HT also activated the enzyme activity of GAD for the rapid accumulation of GABA,hinting the regulatory function of GABA in con-trolling seeds germination against HT stress.Applying GABA directly attenuated HT-induced ROS accumulation,upregulated GA biosynthesis and downregulated ABA biosynthesis,ultimately enhanced seeds germination.Consistently,genetic analysis using the gad1/2 mutant defective in GABA biosynthesis,or pop2-5 mutant with high endogenous GABA content supported the potential function of GABA in improving seeds germination tolerance to HT through scavenging ROS overaccumulation.Based on these data,we propose that GABA acts as a novel signal to enhance thermotolerance of seeds germination through alleviating the ROS damage to seeds viability.

Carbon Monoxide Signal Breaks Primary Seed Dormancy by Transcriptional Silence of DOG1 in Arabidopsis thaliana

Primary seed dormancy is an adaptive strategy that prevents germination for viable seeds in harsh environment,ensuring seeds germination under favorable condition.Accurately inducing seeds germination in a controllable manner is important for crop production.Thus searching the chemicals that efficiently breaks seed dormancy is valuable.DOG1 protein abundance in the freshly harvested seed is high,and its level is correlated to seed dormancy intensity,thus DOG1 is regarded as the timer to evaluate the seed dormancy degree.In this study,we found the carbon monoxide(CO)donor treatment,the transgenic line with high CO content,showed lower seed dormancy,while scavenging CO,or the mutant with lower CO level,presented strong primary seed dormancy,genetic analysis showed that DOG1 was targeted by CO signal and was prerequisite for CO-dependent seed dormancy release.Furthermore,we found CO signal activated the expression of ERF/AP2 transcriptional factor ERF12,as well as enhanced the binding of ERF12 to the promoter of DOG1,ultimately transcriptional silence of DOG1 expression to break primary seed dormancy.Meanwhile CO signal reduced the histone acetylation level at the chromatin of DOG1 locus to suppress its expression.Together,our results revealed that CO acts as the novel regulator to suppress DOG1 expression and efficiently break primary seed dormancy through activating the negative factor ERF12.

Comparison of gut microbiota in autism spectrum disorders and neurotypical boys in China:A case-control study

Background:Autism spectrum disorders(ASDs)are a set of complex neurobiological disorders.Growing evidence has shown that the microbiota that resides in the gut can modulate brain development via the gut–brain axis.However,direct clinical evidence of the role of the microbiota–gut–brain axis in ASD is relatively limited.Methods:A case-control study of 71 boys with ASD and 18 neurotypical controls was conducted at China-Japan Friendship Hospital.Demographic information and fecal samples were collected,and the gut microbiome was evaluated and compared by 16S ribosomal RNA gene sequencing and metagenomic sequencing.Results:A higher abundance of operational taxonomic units(OTUs)based on fecal bacterial profiling was observed in the ASD group.Significantly different microbiome profiles were observed between the two groups.At the genus level,we observed a decrease in the relative abundance of Escherichia,Shigella,Veillonella,Akkermansia,Provindencia,Dialister,Bifidobacterium,Streptococcus,Ruminococcaceae UCG_002,Megasphaera,Eubacterium_coprostanol,Citrobacter,Ruminiclostridium_5,and Ruminiclostridium_6 in the ASD cohort,while Eisenbergiella,Klebsiella,Faecalibacterium,and Blautia were significantly increased.Ten bacterial strains were selected for clinical discrimination between those with ASD and the neurotypical controls.The highest AUC value of the model was 0.947.Conclusion:Significant differences were observed in the composition of the gut microbiome between boys with ASD and neurotypical controls.These findings contribute to the knowledge of the alteration of the gut microbiome in ASD patients,which opens the possibility for early identification of this disease.