Soybean(Glycine max)rhizosphere organic phosphorus recycling relies on acid phosphatase activity and specific phosphorusmineralizing-related bacteria in phosphate deficient acidic soils

Bacteria play critical roles in regulating soil phosphorus(P) cycling. The effects of interactions between crops and soil P-availability on bacterial communities and the feedback regulation of soil P cycling by the bacterial community modifications are poorly understood. Here, six soybean(Glycine max) genotypes with differences in P efficiency were cultivated in acidic soils with long-term sufficient or deficient P-fertilizer treatments. The acid phosphatase(AcP) activities, organic-P concentrations and associated bacterial community compositions were determined in bulk and rhizosphere soils. The results showed that both soybean plant P content and the soil AcP activity were negatively correlated with soil organic-P concentration in P-deficient acidic soils. Soil P-availability affected the ɑ-diversity of bacteria in both bulk and rhizosphere soils. However, soybean had a stronger effect on the bacterial community composition, as reflected by the similar biomarker bacteria in the rhizosphere soils in both P-treatments. The relative abundance of biomarker bacteria Proteobacteria was strongly correlated with soil organic-P concentration and AcP activity in low-P treatments. Further high-throughput sequencing of the phoC gene revealed an obvious shift in Proteobacteria groups between bulk soils and rhizosphere soils, which was emphasized by the higher relative abundances of Cupriavidus and Klebsiella, and lower relative abundance of Xanthomonas in rhizosphere soils. Among them, Cupriavidus was the dominant phoC bacterial genus, and it was negatively correlated with the soil organic-P concentration. These findings suggest that soybean growth relies on organic-P mineralization in P-deficient acidic soils, which might be partially achieved by recruiting specific phoCharboring bacteria, such as Cupriavidus.

Miniaturized structured illumination microscopy with diffractive optics

Structured illumination microscopy(SIM)is an advanced microscope system that provides superresolution capability with excellent imaging speed,which has become a practical tool for live-cell imaging.However,the bulky size is blocking the application of SIM in wider study fields and scenarios.Here,we developed a miniaturized SIM(Mini SIM)system that provided periodic illumination using a diffractive optical element(DOE)for the first time.This optimized phase-only DOE generated the two-dimensional sinusoidal illumination by optical Fourier transform with an illuminating objective lens,which substantially simplified and miniaturized the illumination system.We built up a Mini SIM prototype and demonstrated lateral superresolution imaging of fluorescence beads and A549 cell slides.The proposed Mini SIM greatly simplifies the experimental setup and may lead to important applications in bio-imaging.