A rice exocyst subunit gene SEC3A is required for anther dehiscence

Anther dehiscence controls optimal interaction between pollen and stigma,thereby determining the successful sexual reproduction.The regulators or mechanisms of this process remain elusive.Here,two CRISPR/Cas9 mutants of a rice exocyst subunit gene SEC3A,sec3a-1 and sec3a-2,showed anther indehiscence at anthesis and male sterility at maturity.Pollen viability and germination in the mutants were partly defective,whereas their female gametes undergone a normal development.Hybrid or self-pollinated seeds could be produced by artificial pollination,suggesting potential use of a weak sec3a mutant as a female line during hybrid breeding.SEC3A is widely expressed in various tissues,including anther walls.Further results showed an excessive IAA accumulation and no endothecium lignification in sec3a-1/2 anthers.Our findings suggest that SEC3A appears to regulate anther dehiscence by modulating auxin signaling,providing insights into regulation of anther dehiscence and function of exocyst in plants.

A polygalacturonase gene OsPG1 modulates water homeostasis in rice

A dynamic plant architecture is the basis of plant adaptation to changing environments.Although many genes regulating leaf rolling have been identified,genes directly associated with water homeostasis are largely unknown.Here,we isolated a rice mutant,dynamic leaf rolling 1(dlr1),characterized by‘leaf unfolding in the morning-leaf rolling at noon-leaf unfolding in the evening’during a sunny day.Water content was decreased in rolled leaves and water sprayed on leaves caused reopening,indicating that in vivo water deficiency induced the leaf rolling.Map-based cloning and expression tests demonstrated that an A1400G single base mutation in Oryza sativa Polygalacturonase 1(OsPG1)/PHOTO-SENSITIVE LEAF ROLLING 1(PSL1)was responsible for the dynamic leaf rolling phenotype in the dlr1 mutant.OsPG1 encodes a polygalacturonase,one of the main enzymes that degrade demethylesterified homogalacturonans in plant cell walls.OsPG1 was constitutively expressed in various tissues and was enriched in stomata.Mutants of the OsPG1 gene exhibited defects in stomatal closure and decreased stomatal density,leading to reduced transpiration and excessive water loss under specific conditions,but had normal root development.Further analysis revealed that mutation of OsPG1 led to reduced pectinase activity in the leaves and increased demethylesterified homogalacturonans in guard cells.Our findings reveal a mechanism by which OsPG1 modulates water homeostasis to control dynamic leaf rolling,providing insights for plants to adapt to environmental variation.

Spatial distribution characteristics of bacterial community structure and gene abundance in sediments of the Bohai Sea

This study investigated differences in the community structure and environmental responses of the bacterial community in sediments of the Bohai Sea.Illumina high-throughput sequencing technology and real-time PCR were used to assay the bacterial 16S rRNA genes in the surface sediments of 13 sampling stations in the Bohai Sea.The results showed that sediments at the majority of the 13 sampling stations were contaminated by heavy metal mercury.The main phyla of bacteria recorded included Proteobacteria(52.92%),Bacteroidetes(11.76%),Planctomycetes(7.39%),Acidobacteria(6.53%)and Chloroflexi(4.97%).The genus with the highest relative abundance was Desulfobulbus(4.99%),which was the dominant genus at most sampling stations,followed by Lutimonas and Halioglobus.The main factors influencing bacterial community structure were total organic carbon,followed by depth and total phosphorus.The content of lead,cadmium,chromium,copper and zinc had a consistent effect on community structure.Arsenic showed a negative correlation with bacterial community structure in most samples,while the impact of mercury on community structure was not significant.The bacterial community in sediment samples from the Bohai Sea was rich in diversity and displayed an increase in diversity from high to low latitudes.The data indicated that the Bohai Sea had abundant microbial resources and was rich in bacteria with the potential to metabolize many types of pollutants.